Morphologic and histopathologic characteristics of placentas from twin pregnancies spontaneously conceived and from reduced and nonreduced assisted reproductive technologies

OBJECTIVE: To prospectively evaluate morphologic and histopathologic charac teristics of placentas from twin pregnancies obtained by assisted reproduct ive technologies (ART) and non-ART and to evaluate the influence of previou s fetal reduction on placental features. STUDY DESIGN: Fifty-five placentas from consecutive deliveries of ART-obtai ned and 50 placentas from consecutive deliveries of non-ART-conceived twin pregnancies were investigated by one pathologist, who was blinded to specim en origins. The patients' demographic and clinical data were also recorded. RESULTS: The mean maternal and gestational ages were similar in both groups . ART-obtained pregnancies were associated with an increased incidence of p regnancy complications and lower mean birth weight. Placentas from ART-obta ined pregnancies were mostly of the dichorionic type and were thinner, weig hed less and had more infarctions as compared to non-ART-conceived pregnanc ies. Placental characteristics of reduced ART-obtained twin pregnancies wer e comparable to those of nonreduced ones. The second twin's placenta in all groups weighed less and had a higher incidence of anomalous umbilical cord insertion. CONCLUSION: Placentas from ART-obtained twin pregnancies appear to have mor e pathologic features as compared to those of non-ART-conceived ones. Fetal reduction does not significantly affect the remaining placentas.