Association between aneuploidy screening analytes and adverse outcomes in twin gestations

Objectives To evaluate associations between serum analytes used for genetic screening and obstetric complications among twin pregnancies. Methods This cohort included twins delivered at a tertiary care hospital from 2009 to 2017. Abnormal levels of pregnancy associated plasma protein (PAPP-A), first and second trimester human chorionic gonadotropin (hCG), alpha fetoprotein (AFP), estriol, and inhibin, reported as multiples of the median (MoM), were defined as <5 %ile or >95 %ile for our cohort. Associations between abnormal analytes and preterm delivery, small for gestational age, and pregnancy-associated hypertension were calculated using Fisher’s exact test. Results A total of 357 dichorionic/diamniotic and 123 monochorionic/diamniotic twins were included. Among dichorionic/diamniotic twins, elevated AFP (>3.70 MoM) was associated with increased preterm delivery <34 weeks (44.4 vs. 16.5 %, p=0.007), while elevated inhibin (>4.95 MoM) was associated with increased preterm delivery<37 weeks (94.1 vs. 58.8 %, p=0.004). For monochorionic/diamniotic twins, elevated inhibin (>6.34 MoM) was associated increased preterm delivery <34 weeks (66.7 vs. 24.8 %, p=0.04) and hypertension (66.7 vs. 21.4 %, p=0.03). Conclusions Selected abnormal analyte levels were associated with increased rates of adverse outcomes in twin pregnancies, which differed by chorionicity. Our findings assist providers in interpreting abnormal analyte levels in twin pregnancies and may help to identify those at increased risk for adverse outcomes.