Immunohistochemistry / Comparative Study / Apoptosis / Pregnancy / Humans / Placenta / Female / Cell Death / Pregnancy Loss / Amniotic Fluid / Human reproduction / Adult / Western blot / Protein Expression / Gestational Age / Fas Ligand / DNA fragmentation / Placenta / Female / Cell Death / Pregnancy Loss / Amniotic Fluid / Human reproduction / Adult / Western blot / Protein Expression / Gestational Age / Fas Ligand / DNA fragmentation