Fetal trauma in term pregnancy
Descrição do Produto
Research
www. AJOG.org
OBSTETRICS
Fetal trauma in term pregnancy Thomas F. Baskett, MB; Victoria M. Allen, MD, MSc; Colleen M. O’Connell, PhD; Alexander C. Allen, MDCM OBJECTIVE: The objective of the study was to determine the incidence and type of fetal trauma in term pregnancy in relation to method of delivery, maternal age, parity, and birthweight. STUDY DESIGN: From the Nova Scotia Atlee Perinatal Database, fetal trauma was evaluated in all term (37 weeks or longer) singleton fetuses without major anomaly in vertex presentation over a 14-year period (1988-2001).
risks [RRs], 9.59; 95% confidence interval [CI], 1.34-68.47, and RR, 11.25; 95% CI, 5.05-25.09, respectively). Cesarean delivery was protective for major and minor fetal trauma, compared with vaginal delivery (adjusted RRs, 0.21; 95% CI, 0.12-0.40, and RR, 0.46; 95% CI, 0.39-0.54, respectively).
RESULTS: The overall risk of fetal trauma was low (2.0%); that of ma-
CONCLUSION: The risk of significant fetal trauma in term pregnancy is very low and most likely to be associated with labor and with assisted vaginal delivery.
jor fetal trauma was 0.16%. Major and minor fetal trauma was significantly increased with labor, compared with no labor (adjusted relative
Key words: fetal trauma, method of delivery
Cite this article as: Baskett TF, Allen VM, O’Connell CM, et al. Fetal trauma in term pregnancy. Am J Obstet Gynecol 2007;197:499.e1-499.e7.
F
etal trauma at delivery is a rare but significant perinatal complication. Maternal and fetal factors, such as preexisting diabetes,1 breech presentation,2 and birthweight,1,3-5 have been associated with fetal trauma, and shoulder dystocia, which is most likely to occur at term, is known to be a significant risk
From the Department of Obstetrics and Gynaecology (Drs Baskett, V. Allen, and A. Allen), the Perinatal Epidemiology Research Unit (Drs O’Connell and A. Allen), and the Department of Pediatrics (Dr A. Allen), Dalhousie University, Halifax, NS, Canada. The results of this study were presented in part at the 58th Annual Clinical Meeting of the Society of Obstetricians and Gynaecologists of Canada, Winnipeg, Manitoba, Canada, Jun. 20-24, 2002, and at the 19th Annual Meeting of the Society for Pediatric and Perinatal Epidemiologic Research, Seattle, Washington, Jun. 20-21, 2006. Received Sep. 25, 2006; revised Dec. 22, 2006; accepted Mar. 14, 2007. This work was supported in part by a Canadian Institutes of Health Research New Investigator Award (to V.A.) and a Dalhousie University Clinical Research Scholar Award (to V.A.). Reprints not available from the authors. 0002-9378/$32.00 © 2007 Mosby, Inc. All rights reserved. doi: 10.1016/j.ajog.2007.03.065
factor for trauma such as brachial plexus palsy.6-9 Operative vaginal delivery may be associated with other fetal trauma such as fractures or intracranial hemorrhage.1,3,4,10-13 Although the maternal and perinatal risk factors for trauma with shoulder dystocia and breech presentation associated with vaginal delivery, as well as long-term outcomes, are well documented,3,5,9,12,14-18 the occurrence of fetal trauma associated with other methods of delivery, separate from other serious neonatal morbidity is less clear.19-21 An evaluation of fetal trauma outcomes and an estimation of the magnitude of the excess risk of fetal trauma associated with method of delivery may influence clinical decision making with obstetrical interventions such as operative delivery. In this study, we assessed the effect of method of delivery on the incidence of major and minor fetal trauma using data from a large provincial database for infants born at gestational age 37 weeks or longer.
M ATERIALS AND M ETHODS The Nova Scotia Atlee Perinatal Database is a population-based clinical database containing comprehensive coded information on pregnancy outcomes and was used to evaluate the relationship
between fetal trauma and type of labor and method and mode of delivery. Maternal and newborn data, including demographic variables, procedures, maternal and newborn diagnoses, and morbidity and mortality information, are available for every pregnancy and birth (500 g or more) occurring in Nova Scotia hospitals and to Nova Scotia residents since 1988. There are approximately 10,000 live births in Nova Scotia,22 which has a homogeneous, predominantly white population of approximately 1 million,23 each year. Maternal data included in this study consisted of information from pregnancies to Nova Scotia residents between 1988 and 2001. Pregnancies were included if there was a live born singleton of 37 weeks or longer. Pregnancies were excluded if there was a major fetal anomaly or if there was nonvertex presentation. Identification of fetal trauma was by clinical diagnosis and confirmed radiographically, where appropriate. Trauma included in these analyses were intracranial hemorrhage (defined as tentorial tear, spinal cord hemorrhage, subgaleal hemorrhage, or other intracranial hemorrhage); cephalhematoma; brachial plexus injury; facial palsy; skull fractures (depressed or linear); and other fractures (clavicle, ribs, hu-
NOVEMBER 2007 American Journal of Obstetrics & Gynecology
499.e1
Research
Obstetrics
merus, or femur). Fetal trauma was considered major trauma if 1 or more of the following were present: depressed skull fracture, intracranial hemorrhage, or brachial plexus palsy. Minor trauma was considered if 1 or more of the following were present: linear skull fracture, other fractures, facial palsy, or cephalhematoma. Type of labor was defined as present or absent, mode of delivery was defined as vaginal or cesarean, and method of delivery was defined as spontaneous vaginal, assisted vaginal (vacuum, forceps), failed assisted vaginal (vacuum, forceps), and cesarean delivery (with and without labor). The failed assisted vaginal delivery group was classified by the first attempted obstetrical intervention, regardless of other obstetrical interventions required for delivery. To evaluate the unique relationship of each potential confounding variable on the outcome of fetal trauma, binary logistic regressions were run. This procedure was run separately for minor trauma only and for major trauma with and without minor trauma. The variables entered in the regression models reflected both maternal and fetal measures. Maternal variables included age at delivery of 35 years or older (yes/no), nulliparity (yes/no), and type of delivery (6 categories included forceps, vacuum, failed forceps, failed vacuum, and cesarean delivery with and without labor). During the time period of the study, the vacuum soft cup was used. The fetal measure included in the models was birthweight in the categories of less than 4000 g, from 4000 g to 4499 g, and 4500 g and more. For the yes/no variables, the referent groups were the subjects in the “no” categories. For birthweight, the category of less than 4000 g was the referent group. For type of labor, no labor was the referent group; for mode of delivery, vaginal delivery was the referent group; for method of delivery, spontaneous unassisted delivery was the referent group; for type of assisted vaginal delivery, vacuum-assisted delivery was the referent group; for type of failed assisted vaginal delivery, failed vacuum-assisted delivery was the referent group; and for cesarean delivery 499.e2
www.AJOG.org
TABLE 1
Total fetal trauma among deliveries in Nova Scotia, 1988-2001 n Major trauma*
187
Rate per 1000 1.6
.....................................................................................................................................................................................................................................
Depressed skull fracture
4
0.03
Intracranial hemorrhage
18
0.2
..................................................................................................................................................................................................................................... .....................................................................................................................................................................................................................................
Brachial plexus palsy
165
1.4
2198
18.4
.............................................................................................................................................................................................................................................. †
Minor trauma
.....................................................................................................................................................................................................................................
Linear skull fracture
7
0.06
.....................................................................................................................................................................................................................................
Other fractures
235
2.0
.....................................................................................................................................................................................................................................
Facial palsy
79
0.7
1877
15.7
.....................................................................................................................................................................................................................................
Cephalhematoma
..............................................................................................................................................................................................................................................
No trauma
117,097
—
..............................................................................................................................................................................................................................................
* One major trauma with or without minor trauma. †
One or more minor traumas with or without major trauma.
alone, cesarean without labor was the referent group. Categorical variables were compared using 2 analysis and Fisher exact test where appropriate. Logistic regression analyses accounted for the effect of maternal age, parity, birthweight, and year of birth on the risk of trauma with type of labor or delivery. The odds ratios obtained from logistic regression models were interpreted as relative risks because outcomes considered were rare (rate less than 10%). Statistical analyses were performed using the SAS programming package for Windows (version 8.0, SAS Institute, Cary, NC) and EpiInfo (Centers for Disease Control and Prevention, Atlanta, GA). Ethical approval was obtained from the Reproductive Care Program of Nova Scotia and the Research Ethics Board at the IWK Health Centre in Halifax, Nova Scotia.
R ESULTS The potential study population in Nova Scotia for the 14-year period (19882001) was 153,209. Twenty-two percent of the population was excluded based on the inclusion criteria of singleton (1%), term (7%), no major anomalies (3%), no fetal deaths (0.1%), and in vertex presentation (11%) to give the actual study population of 119,432. The total number of major trauma, minor trauma, and no trauma, occurring alone or in combina-
American Journal of Obstetrics & Gynecology NOVEMBER 2007
tion with other major or minor trauma, is summarized in Table 1. The overall risk of any fetal trauma was low (2.0%), and major fetal trauma occurred in 1.6 per 1000 deliveries. Brachial plexus palsy contributed the most (1.4 per 1000) to the rate of major fetal trauma; depressed skull fracture contributed the least (0.03 per 1000). Cephalhematoma contributed the most (15.7 per 1000) to the rate of minor fetal trauma and linear skull fracture contributed the least (0.06 per 1000). No infant had more than 1 major trauma. Of those infants with a major trauma (n ⫽ 187), 27 (14%) also had 1 minor trauma, and 1 (0.5%) also had 2 minor traumas. No infant had more than 2 minor traumas. Of the 2127 newborns with 1 minor trauma only, 1847 (87%) had cephalhematoma. Of those with 2 minor traumas only (n ⫽ 21), cephalhematoma was 1 of the 2 minor traumas in all cases. The rates of operative deliveries changed significantly from 1988 to 2001 in this population. The use of vacuumassisted vaginal delivery increased from 0.3% to 4.8% (P ⬍ .001), whereas forceps-assisted vaginal delivery decreased from 13.5% to 4.5% (P ⬍ .001). The rates of both cesarean delivery in labor and cesarean without labor increased (10.8% vs 12.8%; P ⬍ .001, and 7.5% vs 10.2%; P ⬍ .001, respectively). The rates
Obstetrics
www.AJOG.org
TABLE 2
Rates of major, minor, and no fetal trauma in newborns by method of delivery, Nova Scotia, 1988-2001 Method of delivery Spontaneous
n 88,324
Major trauma, n (%)
Minor trauma, n (%)
106 (0.12)
1150 (1.30)
No trauma, n (%) 87,068 (98.58)
..............................................................................................................................................................................................................................................
Assisted vaginal
.....................................................................................................................................................................................................................................
Vacuum
3175
12 (0.38)
214 (6.74)
2949 (92.88)
Forceps
10,478
54 (0.52)
556 (5.31)
9868 (94.18)
.....................................................................................................................................................................................................................................
..............................................................................................................................................................................................................................................
Failed assisted vaginal
.....................................................................................................................................................................................................................................
Vacuum
609
5 (0.82)
59 (9.69)
545 (89.49)
Forceps
714
5 (0.70)
35 (4.90)
674 (94.40)
Cesarean in labor
10,731
4 (0.04)
128 (1.19)
10,599 (98.77)
Cesarean no labor
5401
1 (0.02)
6 (0.11)
5394 (99.87)
119,432
187 (0.16)
2148 (1.80)
117,097 (98.04)
.....................................................................................................................................................................................................................................
.............................................................................................................................................................................................................................................. .............................................................................................................................................................................................................................................. ..............................................................................................................................................................................................................................................
Total
of spontaneous vaginal delivery remained unchanged (70.8% vs 66.4%; P ⫽ .22). Table 2 summarizes the rates of categories of trauma in newborns associated with different methods of delivery. In the category of major trauma (including all major trauma regardless of the presence of minor trauma), the highest trauma rates were associated with assisted vaginal delivery (vacuum 0.4%, forceps 0.5%) and failed assisted vaginal delivery (failed vacuum 0.8%, failed forceps 0.7%). These relationships were also demonstrated in the category of minor trauma only, in which assisted vaginal delivery (vacuum 6.7%, forceps 5.3%) and failed assisted vaginal delivery (failed vacuum 9.7%, failed forceps 4.9%) were associated with the highest rates of trauma. Cesarean delivery of any type had the lowest rates of major trauma (in labor 0.04%, no labor 0.02%) and minor trauma (in labor 1.2%, no labor 0.11%). Tables 3 and 4 summarize the crude and adjusted risks in newborns associated with different types of labor and delivery for major and minor trauma. Regardless of mode of delivery, all labor was associated with a 9-fold increased risk of major trauma (95% confidence interval [CI], 1.34-68.47) and an 11-fold increased risk of minor trauma (95% CI, 5.05-25.09), compared with no labor,
after adjusting for maternal age (P ⫽ .10), parity (P ⫽ .01), birthweight (P ⬍ .001), and year of birth (P ⫽ .03). Regardless of type of labor, cesarean delivery was associated with a 79% reduction in risk for major trauma (95% CI, 0.120.40) and a 54% reduction in risk of minor trauma (95% CI, 0.39-0.54), compared with vaginal delivery, after adjusting for maternal age (P ⫽ .07), parity (P ⬍ .001), birthweight (P ⬍ .001), and year of birth (P ⫽ .02). Regardless of type of labor, major trauma was significantly associated with failed vacuum (relative risk [RR] 4.86; 95% CI, 1.92-12.31) followed, in decreasing magnitude, by forceps delivery (RR, 4.20; 95% CI, 2.91-6.06), failed forceps delivery (RR, 3.80; 95% CI, 1.499.71), and vacuum delivery (RR, 2.71; 95% CI, 1.47-5.02), compared with the spontaneously delivered referent group with adjusted analyses. Cesarean delivery, with and without labor (and without preceding attempted forceps or vacuum), was associated with a lower risk of major fetal trauma (RR, 0.18; 95% CI, 0.07-0.49 and RR, 0.12; 95% CI, 0.020.85, respectively), compared with spontaneous vaginal delivery. The regression analysis comparing spontaneous vaginal delivery with other methods of delivery accounted for maternal age (P ⫽ .15), parity (P ⫽ .59), birthweight (P ⬍ .001), and year of birth (P ⫽ .003). Determina-
Research
tion of the risk for minor trauma produced results with a similar magnitude of effect to those described for the risk of major trauma, adjusting for maternal age (P ⫽ .046), parity (P ⬍ .001), birthweight (P ⬍ .001), and year of birth (P ⬍ .001). There was a similar reduction in risk of major (88%) and minor (89%) trauma with cesarean delivery without labor, compared with spontaneous vaginal delivery. A 30% reduction in risk of minor trauma was seen with cesarean delivery in labor, compared with spontaneous vaginal delivery, whereas an 82% reduction in risk of major trauma was observed. Among assisted vaginal deliveries only, forceps and failed forceps deliveries were not associated with a decreased risk of major fetal trauma (RR, 1.13; 95% CI, 0.60-2.10, and RR, 0.83; 95% CI, 0.203.35, respectively) but were associated with a decreased risk of minor trauma (RR, 0.53; 95% CI, 0.45-0.64, and RR, 0.35; 95% CI, 0.20-0.60, respectively), compared with vacuum and failed vacuum assisted deliveries. For major trauma, assisted vaginal delivery analyses included significant contribution from birthweight (P ⬍ .001), whereas failed assisted vaginal delivery analyses had no significant contributions from confounding variables. For minor trauma, assisted and failed assisted vaginal delivery analyses included significant contribution from parity (P ⫽ .003) and year of birth (P ⬍ .001) and from maternal age (P ⫽ .04) and year of birth (P ⫽ .02), respectively. Among cesarean deliveries only, cesarean in labor was not associated with an increase in risk of major trauma (RR, 3.72; 95% CI, 0.39-35.91) but was associated with an increased risk of minor trauma (RR, 7.55; 95% CI, 3.19-17.89), compared with cesarean delivery without labor. Maternal age, parity, birthweight, and year of birth did not contribute significantly to the regression analysis among cesarean deliveries only for major trauma, whereas for minor trauma, only nulliparity (P ⬍ .001) and year of birth (P ⬍ .001) were significant contributors.
NOVEMBER 2007 American Journal of Obstetrics & Gynecology
499.e3
Research
Obstetrics
www.AJOG.org
TABLE 3
Crude and adjusted risks for major fetal trauma in newborns categorized by type of labor and type of delivery, Nova Scotia, 1988-2001 Frequency n (%)
Crude RR
95% CI
Adjusted RR*
95% CI
Labor
.......................................................................................................................................................................................................................................................................................................................................................................
Type of labor
.............................................................................................................................................................................................................................................................................................................................................................. †
No labor
1/5401 (0.02)
—
—
—
—
8.81
1.23-62.86
9.59
1.34-68.47
..............................................................................................................................................................................................................................................................................................................................................................
Labor
186/114,031 (0.16)
................................................................................................................................................................................................................................................................................................................................................................................
Delivery
.......................................................................................................................................................................................................................................................................................................................................................................
Mode of delivery
.............................................................................................................................................................................................................................................................................................................................................................. †
Vaginal
176/102,538 (0.17)
—
—
—
—
0.38
0.21-0.70
0.21
0.12-0.40
..............................................................................................................................................................................................................................................................................................................................................................
Cesarean
11/16,894 (0.07)
.......................................................................................................................................................................................................................................................................................................................................................................
Method of delivery
.............................................................................................................................................................................................................................................................................................................................................................. †
Spontaneous vaginal
106/88,324 (0.12)
—
—
—
—
..............................................................................................................................................................................................................................................................................................................................................................
Assisted vaginal
.....................................................................................................................................................................................................................................................................................................................................................
Vacuum
12/3175 (0.38)
3.15
1.74-5.71
2.71
1.47-5.02
Forceps
54/10,478 (0.51)
4.29
3.10-5.96
4.20
2.91-6.06
..................................................................................................................................................................................................................................................................................................................................................... ..............................................................................................................................................................................................................................................................................................................................................................
Failed assisted vaginal
.....................................................................................................................................................................................................................................................................................................................................................
Vacuum
5/609 (0.82)
6.84
2.80-16.72
4.86
1.92-12.31
.....................................................................................................................................................................................................................................................................................................................................................
Forceps
5/714 (0.70)
5.84
2.39-14.27
3.80
1.49-9.71
4/10,731 (0.04)
0.31
0.11-0.84
0.18
0.07-0.49
1/5401 (0.02)
0.15
0.02-1.11
0.12
0.02-0.85
..............................................................................................................................................................................................................................................................................................................................................................
Cesarean in labor
..............................................................................................................................................................................................................................................................................................................................................................
Cesarean without labor
................................................................................................................................................................................................................................................................................................................................................................................
Type of assisted delivery
....................................................................................................................................................................................................................................................................................................................................................................... †
Vacuum
12/3175 (0.38)
Forceps
54/10,478 (0.51)
—
—
—
—
1.36
0.73-2.55
1.13
0.60-2.10
....................................................................................................................................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................................................................................................................................................
Type of failed assisted delivery
....................................................................................................................................................................................................................................................................................................................................................................... †
Vacuum
5/609 (0.82)
—
—
—
—
Forceps
5/714 (0.70)
0.85
0.25-2.93
0.83
0.20-3.35
....................................................................................................................................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................................................................................................................................................
Type of cesarean delivery
....................................................................................................................................................................................................................................................................................................................................................................... †
Without labor
1/5401 (0.02)
—
—
—
—
4.70
0.60-36.70
3.72
0.39-35.91
.......................................................................................................................................................................................................................................................................................................................................................................
In labor
10/11,493 (0.09)
................................................................................................................................................................................................................................................................................................................................................................................
* Adjusted for maternal age, nulliparity, birthweight, and year of birth where significant. †
Referent group.
C OMMENT Most studies of fetal trauma have focused primarily on trauma resulting from vaginal delivery with shoulder dystocia.5,8,9,12,16-18,24 Previous work by these authors evaluating shoulder dystocia in the Nova Scotia population6 demonstrated that shoulder dystocia is not a reliably predictable event in labor. The majority of cases of shoulder dystocia in that study occurred in the absence of increasing birthweight and operative vaginal delivery. Few studies have considered trauma risks by comparing method of 499.e4
delivery, and these studies may be limited in generalizability because some have considered hospital-based rates, combined major and minor trauma rates, trauma in combination with other serious neonatal morbidities, or vaginal delivery only. Our population-based study evaluated specific major and minor fetal trauma in singleton pregnancies in cephalic presentation at term, by type of labor, and type of delivery to clarify the magnitude of the effect of delivery on rates of trauma. In this study, rates of major and minor fetal trauma were significantly increased
American Journal of Obstetrics & Gynecology NOVEMBER 2007
with labor vs no labor and were significantly decreased with cesarean delivery vs vaginal delivery. Minor fetal trauma only was significantly increased with cesarean delivery in labor vs cesarean delivery without labor. The lower rates of fetal trauma occurred with spontaneous vaginal delivery, cesarean delivery without labor, and cesarean delivery in labor, whereas the highest trauma rate was seen with failed vacuum-assisted vaginal delivery. Although not recorded in the present study, cesarean delivery may be made more difficult if impaction of the
Obstetrics
www.AJOG.org
Research
TABLE 4
Crude and adjusted risks for minor fetal trauma in newborns categorized by type of labor and type of delivery, Nova Scotia, 1988-2001 Frequency, n (%)
Crude RR
95% CI
Adjusted RR*
95% CI
Labor
.......................................................................................................................................................................................................................................................................................................................................................................
Type of labor
.............................................................................................................................................................................................................................................................................................................................................................. †
No labor
6/5401 (0.11)
—
—
—
—
16.91
7.59-37.66
11.25
5.05-25.09
..............................................................................................................................................................................................................................................................................................................................................................
Labor
2142/114,031 (1.88)
................................................................................................................................................................................................................................................................................................................................................................................
Delivery
.......................................................................................................................................................................................................................................................................................................................................................................
Mode of delivery
.............................................................................................................................................................................................................................................................................................................................................................. †
Vaginal
1974/102,362 (1.93)
—
—
—
—
..............................................................................................................................................................................................................................................................................................................................................................
Cesarean
174/16,883 (1.03)
0.53
0.46-0.62
0.46
0.39-0.54
.......................................................................................................................................................................................................................................................................................................................................................................
Method of delivery
.............................................................................................................................................................................................................................................................................................................................................................. †
Spontaneous vaginal
1150/88,324 (1.30)
—
—
—
—
..............................................................................................................................................................................................................................................................................................................................................................
Assisted vaginal
.....................................................................................................................................................................................................................................................................................................................................................
Vacuum
214/3175 (6.74)
5.18
4.49-5.96
5.49
4.69-6.43
Forceps
556/10,478 (5.31)
4.08
3.69-4.50
2.95
2.64-3.29
..................................................................................................................................................................................................................................................................................................................................................... ..............................................................................................................................................................................................................................................................................................................................................................
Failed assisted vaginal
.....................................................................................................................................................................................................................................................................................................................................................
Vacuum
59/609 (9.69)
7.44
5.80-9.55
7.87
5.93-10.44
.....................................................................................................................................................................................................................................................................................................................................................
Forceps
35/174 (4.90)
3.76
2.71-5.23
2.71
1.91-.85
128/10,731 (1.19)
0.92
0.76-1.10
0.70
0.58-0.85
6/5401 (0.11)
0.09
0.04-0.19
0.11
0.05-0.24
..............................................................................................................................................................................................................................................................................................................................................................
Cesarean in labor
..............................................................................................................................................................................................................................................................................................................................................................
Cesarean without labor
.......................................................................................................................................................................................................................................................................................................................................................................
Type of assisted delivery
.............................................................................................................................................................................................................................................................................................................................................................. †
Vacuum
214/3175 (6.74)
Forceps
556/10,478 (5.31)
—
—
—
—
..............................................................................................................................................................................................................................................................................................................................................................
0.79
0.68 to 0.92
0.53
0.45 to 0.64
.......................................................................................................................................................................................................................................................................................................................................................................
Type of failed assisted delivery
.............................................................................................................................................................................................................................................................................................................................................................. †
Vacuum
59/609 (9.69)
Forceps
35/714 (4.90)
—
—
—
—
..............................................................................................................................................................................................................................................................................................................................................................
0.51
0.34 to 0.76
0.35
0.20 to 0.60
.......................................................................................................................................................................................................................................................................................................................................................................
Type of cesarean delivery
.............................................................................................................................................................................................................................................................................................................................................................. †
Without labor
6/5401 (0.11)
—
—
—
13.17
5.84 to 29.71
—
..............................................................................................................................................................................................................................................................................................................................................................
In labor
168/11,483 (1.46)
7.55
3.19 to 17.89
................................................................................................................................................................................................................................................................................................................................................................................
* Adjusted for maternal age, nulliparity, birthweight, and year of birth where significant. †
Referent group.
fetal head occurs with all failed assisted delivery. High birthweight is generally accepted as a significant risk factor for fetal injury, and, therefore, our adjusted analyses included birthweight categories. Gestational age at delivery was not considered separately in the regression analyses because it is highly correlated with infant birthweight and because this study population was limited to those pregnancies delivered at term. In a previous population-based study with a low-risk cohort limited only to cesarean delivery in labor,25 the rate of
composite neonatal trauma (consisting of brachial plexus palsy, facial palsy, fractures, and intracranial hemorrhage) was less than 1%. In the present study, rates of overall (2.0%) and major (0.16%) fetal trauma were low and may in part be attributed to the presence of in-house consultant obstetricians and anesthesiologists in our tertiary center at which approximately 50% of all provincial births occur. The rate of overall birth injury determined from a US national cohort was 2.9 per 1000 births for vaginal deliveries only.11
Other population-based studies evaluating major and minor infant trauma by method of delivery have demonstrated similar rates to our study.26,27 Although minor fetal trauma was found in our study, to be 1.8%, these generally have no long-term sequelae,13 particularly cephalhematoma, which accounted for 85% of all cases of minor trauma in our series. By far the majority of studies addressing fetal trauma have focused on risks of brachial plexus injury with shoulder dystocia associated with operative vaginal delivery at term. Indeed, in
NOVEMBER 2007 American Journal of Obstetrics & Gynecology
499.e5
Research
Obstetrics
our study, brachial plexus injury accounted for 89% of major trauma. North American population-based studies suggest a rate of obstetrical brachial plexus palsy of 1.9 to 4.6 per 1000 births.26-28 Our study demonstrated that for spontaneous vaginal delivery, the overall total fetal trauma rate was 1.42%, with a risk of major fetal trauma of 0.12% and a risk of minor trauma of 1.3%. This finding is consistent with other studies, which have demonstrated that trauma may occur with spontaneous vaginal delivery in the absence of inappropriate force13,24,29,30 or at cesarean delivery.31,32 A study from California evaluating major and minor trauma in infants born to nulliparous women at term showed that the rate of intracranial hemorrhage was higher among infants delivered by vacuum and forceps, compared with spontaneous delivery; however, the study also demonstrated an increased risk of trauma with cesarean delivery in labor.27 Consistent with our study results, a Quebec study showed higher rates of major and minor trauma when vacuum or forceps-assisted vaginal delivery was compared with spontaneous delivery and comparable rates of either trauma when vacuum was compared with forceps, with the exception of minor trauma (represented by cephalhematoma, which showed a 2-fold increase, and brachial plexus palsy injury, which showed an 80% reduction).26 A study using 2 large cohorts in the United States concluded that, although composite birth injury rates with forceps were reduced by 31%, compared with vacuum, the rates of specific trauma such as intracranial hemorrhage and retinal hemorrhage were comparable between forceps and vacuum as well as between forceps and the sequential use of vacuum and forceps.11 A metaanalysis10 has demonstrated that vacuum extraction was twice as likely to be associated with cephalhematoma and retinal hemorrhage as forceps-assisted vaginal delivery, whereas scalp and face injuries were comparable between the 2 methods. In a hospital-based study designed to evaluate neonatal trauma by method of delivery, there was a 63% reduction in serious 499.e6
www.AJOG.org trauma with cesarean delivery, compared with vaginal delivery.19 Neonatal trauma was significantly increased when cesarean delivery was performed after instrumental delivery, compared with immediate cesarean delivery, but not increased, compared with successful instrumental vaginal delivery,19 consistent with the findings in our study. Other authors have found that cesarean delivery was not protective for injuries such as fetal hemorrhage, lacerations, or brachial plexus palsy.20,32,33 For macrosomic infants, Gregory et al4 determined that birth trauma rates were comparable for those delivered by cesarean without labor and those delivered by vaginal delivery, although long bone injury was reduced in cesarean delivery without labor (RR, 0.4; 95% CI, 0.2-0.9). The decrease in rate of forceps-assisted vaginal delivery seen in Nova Scotia between 1988 and 2002 was consistent with the pattern of decreased operative vaginal delivery seen across Canada34 and elsewhere.11,35 During the years of our study, disposable soft-cup vacuum extractors were used with a manual vacuum pump. These soft cups are known to have a higher failure rate to deliver than the metal or the hard plastic cups.36,37 Soft cups have also been shown to have less scalp trauma and comparable rates of cephalhematoma and severe intracranial hemorrhage.37 Since 2002, the Kiwi Omnicup vacuum delivery system (Clinical Innovations, Murray, UT), shown to be as safe as conventional softcup vacuums,38,39 has been used in our center as an option for operative vaginal delivery. This change in practice may improve the vacuum-assisted vaginal delivery rate and may alter the risks associated with vacuum and failed vacuum-assisted vaginal delivery. Although year of birth was a significant contributor to the regression in the majority of the analyses (75%), the point estimate for this variable in the regression analyses was consistently close to unity (0.9-1.1). Whereas longer-term outcomes and mortality associated with shoulder dystocia and fetal trauma have been evaluated and rates appear low,12,14,24 this study was not able to evaluate the effect of trauma on later disability or mortality.
American Journal of Obstetrics & Gynecology NOVEMBER 2007
In addition, this study did not attempt to address the risk of maternal trauma associated with different methods of delivery, although this outcome has been evaluated in similar25,40,41 and other3,10,37 populations. A limitation of our study includes the inability to evaluate the degree of difficulty of forceps or vacuum extraction or elevation of the fetal head at cesarean delivery or the number of pulls (this information is not captured in the database). The experience of the providers is consistent because all operative deliveries in Nova Scotia are attended by a consultant obstetrician. This study also did not attempt to address the medicolegal implications or outcomes associated with a diagnosis of fetal trauma. Whereas retrospective studies in general are limited by the reliability of data, information in the Nova Scotia Atlee Perinatal Database is known to be of high quality. Data checks and edits are routinely made at the time of data collection by qualified health records personnel, and validation42,43 and reabstraction studies confirm the quality of the data in the database. This population-based study determined a low overall rate of fetal trauma. Major trauma was most likely to be associated with labor and assisted vaginal delivery. Cesarean delivery with and without labor was associated with a significant reduction in risk of both minor and major fetal trauma. Information based on delivery allowed an evaluation of fetal trauma outcomes and an estimation of the magnitude of the excess risk of fetal trauma associated with method of delivery, which may be an important influence on clinical decision making with obstetrical interventions such as timing and method of operative delivery. f ACKNOWLEDGMENTS The authors are grateful to the Reproductive Care Program of Nova Scotia for data access.
REFERENCES 1. Bar J, Dvir A, Hod M, Orvieto R, Merlob M, Neri A. Brachial plexus injury and obstetrical risk factors. Int J Gynecol Obstet 2001;73:21-5. 2. Hannah ME, Hannah WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR. Planned caesarean section versus planned vaginal birth for breech
Obstetrics
www.AJOG.org presentation at term: a randomised multicentre trial. Lancet 2000;356:1375-83. 3. Gudmundsson S, Henningsson AC, Lindqvist P. Correlation of birth injury with maternal height and weight. BJOG 2005;112:764-7. 4. Gregory KD, Henry OA, Ramicome E, Chan LS, Platt LD. Maternal and infant complications in high and normal birth weight infants by method of delivery. Obstet Gynecol 1998; 92:507-13. 5. Gherman RB, Ouzounian JG, Satin AJ, Goodwin TM, Phelan JP. A comparison of shoulder dystocia-associated transient and permanent brachial plexus palsies. Obstet Gynecol 2003;102:544-8. 6. Baskett TF, Allen AC. Perinatal implications of shoulder dystocia. Obstet Gynecol 1995; 86:14-7. 7. Poggi SH, Stallings SP, Ghidini A, Spong CY, Deering SH, Allen RH. Intrapartum risk factors for permanent brachial plexus injury. Am J Obstet Gynecol 2003;189:725-9. 8. Christoffersson M, Kannisto P, Rydhstroem H, Stale H, Walles B. Shoulder dystocia and brachial plexus injury: a case-control study. Acta Obstet Gynecol Scand 2003;82:147-51. 9. Mollberg M, Hagberg H, Bager B, Lilja H, Ladfors L. Risk factors for obstetric brachial plexus palsy among neonates delivered by vacuum extraction. Obstet Gynecol 2005;106:913-8. 10. Johanson RB, Menon V. Vacuum extraction versus forceps for assisted vaginal delivery. Cochrane Database Syst Rev 1999, Issue 2. Art No CD000224. 11. Demissie K, Rhoads GG, Smulian JC, et al. Operative vaginal delivery and neonatal and infant adverse outcomes: population based retrospective analysis. BMJ 2004;329:24-9. 12. Lipscomb KR, Gregory K, Shaw K. The outcome of macrosomic infants weighing at least 4500 grams: Los Angeles County and University of Southern California experience. Obstet Gynecol 1995;85:558-64. 13. Whitby EH, Griffiths PD, Rutter S, et al. Frequency and natural history of subdural haemorrhages in babies and relation to obstetric factors. Lancet 2004;363:846-51. 14. Whyte H, Hannah ME, Saigal S, et al. Outcomes of children at 2 years after planned caesarean birth versus planned vaginal birth for breech presentation at term: the International Randomized Term Breech Trial. Am J Obstet Gynecol 2004;191:864-71. 15. Youssef R, Ramalingam U, Macleod M, Murphy DJ. Cohort study of maternal and neonatal morbidity in relation to use of episiotomy at instrumental vaginal delivery. BJOG 2005;112:94-5. 16. Mollberg M, Hagberg H, Bager B, Lilja H, Ladfors L. High birth weight and shoulder
dystocia: the strongest risk factors for obstetric brachial plexus palsy in a Swedish population-based study. Acta Obstet Gynecol Scand 2004;84:654-9. 17. Mazouni C, Porcu G, Bretelle F, Loundou A, Heckenroth H, Gamerre M. Risk factors for forceps delivery in nulliparous patients. Acta Obstet Gynecol Scand 2006;85:298-301. 18. Smit-Wu M-N, Moonen-Delarue DMWG, Benders MJNL, Brussel W, Zondervan H, Brus F. Onset of vacuum-related complaints in neonates. Eur J Pediatr 2006;165:374-9. 19. Murphy DJ, Liebling RE, Verity L, Swingler R, Patel R. Early maternal and neonatal morbidity associated with operative delivery in the second stage of labor: a cohort study. Lancet 2001;358:1203-7. 20. Gould JB, Danielsen B, Korst LM, et al. Cesarean delivery rates and neonatal morbidity in a low-risk population. Obstet Gynecol 2004;104: 11-9. 21. Caughey AB, Musci TJ. Complications of term pregnancies beyond 37 weeks of gestation. Obstet Gynecol 2004;103:57-62. 22. Allen AC, Attenborough R, Dodds L, Luther ER, Pole J. Perinatal care in Nova Scotia 19881995. Report from the Nova Scotia Atlee Perinatal Database. Halifax (Canada): The Reproductive Care Program of Nova Scotia; 1996. 23. Statistics Canada, 2001. Census Nation Tables. Available at: http://www40.statcan.ca/ 101/cst01/demo26d.htm Accessed Sept. 8, 2006. 24. O’Mahony F, Settatree R, Platt C, Johanson R. Review of singleton fetal and neonatal deaths associated with cranial trauma and cephalic delivery during a national intrapartum-related confidential enquiry. BJOG 2005;112:619-26. 25. Allen VM, O’Connell CM, Baskett TF. Maternal and perinatal morbidity of caesarean delivery at full cervical dilatation compared with caesarean delivery in the first stage of labor. BJOG. 2005;112:986-90. 26. Wen SW, Liu S, Kramer MS, et al. Comparison of maternal and infant outcomes between vacuum extraction and forceps delivery. Am J Epidemiol 2001;153:103-7. 27. Towner D, Castro MA, Eby-Wilkens E, Gilbert WM. Effect of mode of delivery in nulliparous women on neonatal intracranial injury. N Engl J Med 1999;341:1709-14. 28. Pondaag W, Malessy MJA. Natural history of obstetric brachial plexus palsy: a systematic review. Dev Med Child Neurol 2004;46:138-44. 29. Heise RH, Srivatsa PJ, Karsell PR. Spontaneous intrauterine linear skull fracture: a rare complication of spontaneous vaginal delivery. Obstet Gynecol 1996;87:851-4.
Research
30. Allen RH, Gurewitsch ED. Temporary ErbDuchenne palsy without shoulder dystocia or traction to the fetal head. Obstet Gynecol 2005;105;1210-2. 31. Hager RM, Daltveit AK, Hofoss D, et al. Complications of cesarean deliveries: rates and risk factors. Am J Obstet Gynecol 2004;190: 428-34. 32. Alfonso I, Papazian O, Shuhaiber H, Yaylali I, Grossman JA. Intrauterine shoulder weakness and obstetric brachial plexus palsy. Pediatr Neurol 2004;31:225-7. 33. Smith JF, Hernandez C, Wax JR. Fetal laceration injury at caesarean delivery. Obstet Gynecol 1997;90:344-6. 34. Health Canada. Canadian Perinatal Health Report, 2003. Ottawa (Canada): Minister of Public Works and Government Services Canada; 2003. 35. Kozak LJ, Weeks JA. U.S. trends in obstetric procedures, 1990-2000. Birth 2002;29: 157-61. 36. O’Grady JP, Pope CS, Patel SS. Vacuum extraction in modern obstetric practice: a review and critique. Curr Opin Obstet Gynecol 2000;12:475-80. 37. Johanson RB, Menon V. Soft versus rigid vacuum extractor cups for assisted delivery. Cochrane Database Syst Rev 1999, Issue 2. Art No CD000446. 38. Vacca A. Vacuum-assisted delivery: an analysis of traction force and maternal and neonatal outcomes. Aust N Z J Obstet Gynaecol 2006;46:124-7. 39. Groom KM, Jones BA, Miller N, PatersonBrown S. A prospective randomized controlled trial of the Kiwi Omnicup versus conventional ventouse cups for vacuum-assisted vaginal delivery. BJOG 2006;113:183-9. 40. Allen VM, O’Connell CM, Liston RM, Baskett TF. Maternal morbidity associated with cesarean delivery without labor compared with spontaneous onset of labor at term. Obstet Gynecol 2003;102:477-82. 41. Allen VM, O’Connell CM, Baskett TF. Maternal morbidity associated with cesarean delivery without labor compared with induction of labor at term. Obstet Gynecol 2006;108: 286-94. 42. Fair M, Cyr M, Allen AC, Wen SW, Guyon G, MacDonald RC. An assessment of the validity of a computer system probabilistic record linkage of birth and infant death records in Canada. Chronic Dis Can 2000;21:8-13. 43. Fair M, Cyr M, Allen AC, Wen SW, Guyon G, MacDonald RC. Validation study for a record linkage of births and infant deaths in Canada. Catalogue No. 84F0013XIE. Ottawa (Canada): Statistics Canada; 1999.
NOVEMBER 2007 American Journal of Obstetrics & Gynecology
499.e7
Lihat lebih banyak...
Comentários
