Australian and New Zealand Journal of Obstetrics and Gynaecology 2003; 43: 232– 235
Case Series
Blackwell Publishing Ltd.
Interstitial ectopic pregnancy
Interstitial ectopic pregnancy: A contemporary case series Lisa VERITY,1 Joanne LUDLOW1 and Jan E. DICKINSON1,2 1
Department of Obstetrics and Gynaecology, King Edward Memorial Hospital for Women, Subiaco and 2Department of Obstetrics and Gynaecology, University of Western Australia, Perth, Western Australia, Australia
Introduction Throughout the world, rates of ectopic pregnancy are increasing.1 Interstitial pregnancies comprise 2–4% of all ectopic pregnancies.2 The terms interstitial and cornual pregnancy are used interchangeably in published medical reports.3 However, other authors suggest they are separate entities.4 A cornual ectopic pregnancy is that located in one horn of a bicornuate or sub septate uterus. An interstitial pregnancy is one that develops in the interstitial part of the fallopian tube.4 There are also references in published reports to angular pregnancies.5 These are differentiated from interstitial ectopic pregnancies according to whether they are located medial or lateral to the uterotubal junction, respectively.6 A series of six consecutive interstitial ectopic pregnancies managed at our institution over a 3-year period forms the basis of the present study. For the purpose of the present report we will use the term interstitial ectopic pregnancy to describe an ectopic gestation located lateral to the uterotubal junction. The aim of the present case series is to describe the clinical presentation, diagnostic methods and management strategies employed to optimise the clinical outcome in this uncommon form of ectopic pregnancy.
Case 1 A 36-year-old nulliparous woman presented at 6 weeks amenorrhoea, with a 4-day history of heavy vaginal bleeding and abdominal discomfort. Physical examination was unremarkable. A transvaginal ultrasound scan revealed an empty uterus with a 4.5 × 4.7 × 4.2 cm left adnexal mass. No free intraperitoneal fluid was present. Quantitative beta human chorionic gonadotropin (βHCG) was 5780 IU/L. At laparoscopy a left interstitial ectopic pregnancy was seen. The pregnancy mass was directly injected under laparoscopic vision with 50 mg of methotrexate. Two further intramuscular doses of 50 mg methotrexate were given on days 2 and 4 post-laparoscopy. Serum βHCG remained detectable for 65 days following the first methotrexate injection. By 232
6 months post diagnosis the pelvic ultrasound appearance was normal, with resolution of the interstitial mass.
Case 2 A 45-year-old nulliparous woman presented 6 weeks following embryo transfer with a 4-day history of vaginal bleeding and right iliac fossa pain. Three years previously she had undergone a partial left salpingectomy for a tubal ectopic pregnancy. Transvaginal ultrasound revealed a well-defined mass (2 × 2 cm) with a 6-mm central echo-free area in the right isthmus with blood flow in the surrounding tissue, suggestive of a right interstitial pregnancy. There was no free intraperitoneal fluid. The quantitative βHCG was 5578 IU/L. At laparoscopy a right interstitial pregnancy was confirmed, and the mass was directly injected with 50 mg of methotrexate. Bleeding at the injection site was encountered and haemostasis achieved by bipolar diathermy. Serial βHCG level monitoring demonstrated a progressive fall such that the hormone was undetectable 31 days post-surgery.
Case 3 A 22-year old nulliparous woman presented with 6 weeks of amenorrhoea and a 3-week history of intermittent pelvic pain. A laparoscopic right salpingectomy had been carried out 6 months earlier for an ampullary tubal ectopic pregnancy. On examination, left iliac fossa and adnexal tenderness were present. Transvaginal ultrasound scan revealed an eccentrically located 4-week size gestation sac in the left interstitium and no free intraperitoneal fluid (Fig. 1). Quantitative βHCG was 1060 IU/L. Laparoscopy was not undertaken as ultrasound appearances were definitive and there was no evidence of rupture. Intramuscular methotrexate
Correspondence: Dr Lisa Verity, King Edward Memorial Hospital, 374 Bagot Road, Subiaco, Western Australia 6008, Australia. Email:
[email protected] Received 2 September 2002; accepted 20 January 2003.
Interstitial ectopic pregnancy
Figure 1 Transvaginal scan, transverse plane, showing a gestation sac with surrounding vascularity in the left interstitium.
(75 mg) was administered, but subsequent βHCG levels rose to 1890 IU/L on day 4 necessitating a second dose. Outpatient monitoring of the βHCG levels demonstrated a fall to undetectable levels by day 49 post-methotrexate injection.
Case 4 A 20-year-old woman in her first pregnancy presented at 8 weeks amenorrhoea with a 7-day history of suprapubic pain and 1 day of vaginal bleeding. Examination revealed mild right iliac fossa and adnexal tenderness. Quantitative βHCG was 5560 IU/L. Transvaginal ultrasound scan showed an area of increased vascularity (3 × 3 cm) in the right interstitium, suggestive of a right interstitial pregnancy. Two doses of 50 mg intramuscular methotrexate were administered 48 h apart. Serial ultrasound examinations demonstrated persistent vascularity in the right interstitial area for 5 weeks following treatment, normalising by 10 weeks. The βHCG levels declined steadily and were undetectable by day 60 following methotrexate.
Case 5 A 24-year-old multiparous woman presented with a history of painless vaginal bleeding 8 weeks following her last period. A left interstitial pregnancy had been excised 3 years previously. There was mild discomfort on abdominal palpation. A transvaginal ultrasound scan demonstrated an eccentrically placed gestation sac (3.5 × 3 cm) in the left cornu containing a fetal pole of 13 mm without cardiac pulsation. Doppler studies demonstrated marked vascularity around the gestation sac. There was no free intraperitoneal fluid. The serum quantitative βHCG was 3510 IU/L. Systemic methotrexate was administered in two doses of 95 mg (regimen of 1 mg / kg). Serial quantitative βHCG monitoring demonstrated a steady decline in level and were almost negative by day 30 following treatment, after which the patient failed to attend her outpatient appointments.
Case 6 A 38-year-old woman in her first pregnancy presented at approximately 6 weeks’ gestation with vaginal bleeding. Serum βHCG was 7900 IU/L. Transvaginal ultrasound
revealed a right-sided eccentrically located gestation sac with a fetal pole and cardiac activity. There was a suboptimal rise in the βHCG levels (8280 IU/L in the first 48 h, 9070 IU/L in the next 48 h). Repeat ultrasound in 6 days was highly suggestive of a right interstitial pregnancy (mean sac diameter 15 mm). There was no free fluid in the pelvis. A single intramuscular dose of 80 mg of methotrexate (dose 1 mg /kg) was administered as an outpatient. Right abdominal discomfort after the methotrexate occurred. Serum βHCG levels steadily declined and was undetectable by day 46 postmethotrexate. The transvaginal ultrasound appearances normalised within 2 months of treatment.
Discussion Due to their unique location, the traditional management of interstitial pregnancies was laparotomy, with either cornual resection or hysterectomy.6 More recently, conservative therapeutic measures have been advocated in published reports.5,7,8 Our experience would concur with the apparent safety of non-surgical management techniques for nonruptured small (in the present series less than 4 cm dimension with βHCG levels
