Placental implantation on the amniotic sheet: effect on pregnancy outcome.

PURPOSE: To assess pregnancy outcome in patients with amniotic sheets and to determine whether outcome is affected by placental implantation on the amniotic sheet. MATERIALS AND METHODS: Sonograms obtained during the 2nd and 3rd trimesters were reviewed in 157 patients with amniotic sheets to confirm the presence of an amniotic sheet and to determine the relationship of the placenta to the amniotic sheet. The cesarean section rate, gestational age at birth, birth weight, birth weight percentile, and Apgar score 1 minute after birth were recorded in patients in whom the postnatal follow-up data were available. Data were compared with overall data obtained at the authors' institution during the same period. RESULTS: The placenta appeared implanted on the amniotic sheet in 41 (26.1%) of the 157 patients. In the 120 patients with amniotic sheets and follow-up data, the cesarean section rate was 32.5% compared with 21.5% overall. The mean gestational age at birth was slightly lower than that overall (38.2 vs 39.0 weeks, P < .001), but the birth weight percentile was similar (48.6% vs 50.0%, P = .58). No statistically significant differences were found in postnatal follow-up data between pregnancies with placental implantation on and in those without implantation on the amniotic sheet. CONCLUSION: Pregnancy outcome is similar in patients with and in those without placental implantation on the amniotic sheet.