Perinatal outcome of monochorionic diamniotic twin pregnancies complicated with isolated amniotic fluid volume abnormality of one twin less than 26 weeks of gestation.

Abstract

To evaluate the incidence of twin-twin transfusion syndrome (TTTS) and the perinatal outcome at 28 days of age in monochorionic diamniotic (MCDA) pregnancies complicated with isolated polyhydramnios (I-Poly) and isolated oligohydramnios (I-Oligo) diagnosed < 26 weeks of gestation. This was a retrospective study of women with MCDA pregnancies diagnosed with I-Poly or I-Oligo before 26 weeks of gestation over a period of six years. The incidence of subsequent TTTS and neonatal outcome in terms of intact survival (IS) at 28 days of age were evaluated. Intact survival was defined as being alive without any neurological complications at 28 days of age. There were 30 cases of I-Poly and 53 of I-Oligo that were eligible as per the inclusion criteria. Subsequent TTTS were complicated in six (20.0%) of the I-Poly and 26 (49.0%) of the I-Oligo cases. Among subjects with I-Poly, 17 had spontaneously normalized amniotic fluid volume. Prolonged oligohydramnios until intrauterine death, delivery or the onset of emerging TTTS was noted in 16 cases of I-Oligo. Both the twins exhibited IS in 26 (86.7%) cases of I-Poly and 31 (58.4%) cases of I-Oligo. One-fifth of I-Poly and half of I-Oligo MCDA twins at < 26 weeks of gestation potentially develop TTTS. I-Oligo in particular should be regarded as a high-risk condition as neonatal IS is less than 60%.