Objective: To calculate an updated prospective risk of fetal death in monochorionic-biamniotic (MCBA) twins.
Study design: We evaluated 520 MCBA twin pregnancies that had intensive prenatal surveillance and delivered in a single Portuguese referral center. The prospective risk of fetal death was calculated as the total number of deaths at the beginning of the gestational period divided by the number of continuing pregnancies at or beyond that period. Data were compared to the 2006 previous report.
Results: Nearly 80% of the neonates weighed <2500 g, including 13.5% who weighed <1500 g. Half were born at <36 weeks, including 13.8% who were born at <32 weeks. The data indicate an increased IUFD rate over time - 16 fetal deaths per pregnancy (3.1%) and 22 IUFDs per fetus (2.1%). The rate of IUFD after 32-33 weeks, however, was halved (1/187 pregnancies and 1/365 fetuses, 0.5 and 0.3%, respectively).
Conclusion: Intensive prenatal surveillance might decrease the unexpected fetal death rates after 33 week's gestation and our data do not support elective preterm birth for uncomplicated MCBA twins.