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 characteristics of placentas from twin pregnancies obtained by assisted reproductive technologies (ART) and non-ART and to evaluate the influence of previous fetal reduction on placental features. STUDY DESIGN: Fifty-five placentas from consecutive deliveries of ART-obtained and 50 placentas from consecutive deliveries of non-ART-conceived twin pregnancies were investigated by one pathologist, who was blinded to specimen 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 pregnancy complications and lower mean birth weight. Placentas from ART-obtained pregnancies were mostly of the dichorionic type and were thinner, weighed less and had more infarctions as compared to non-ART-conceived pregnancies. Placental characteristics of reduced ART-obtained twin pregnancies were 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 more pathologic features as compared to those of non-ART-conceived ones. Fetal reduction does not significantly affect the remaining placentas.