Maternal pregnancy and birth complications by plurality: the Massachusetts outcomes study of assisted reproductive technologies

To compare pregnancy and birth complications by plurality on a population basis. Longitudinal cohort study, linking cycles from the SART CORS, hospital discharge, and vital records from 2004-2010 in Massachusetts. The study included three groups based on plurality at birth: singletons, twins, and triplet+ (triplets and quadruplets). The risks of six adverse outcomes were modeled using logistic regression, adjusted for parental ages, race/ethnicity, education, payor status, maternal pre-existing conditions (diabetes and chronic hypertension), and fertility status (ART, subfertile, and fertile), and reported as adjusted odds ratios (AORs) and 95% confidence intervals. The study population included 470,258 pregnancies: 459,623 singletons, 10,352 twins, and 283 triplet+. Women with multiple pregnancies were significantly older (29.5 ± 6.1 for singletons vs 32.3 ± 5.8 yrs for twins and 33.6 ± 4.6 yrs for triplet+), more likely to be college-educated (42.0% for singletons vs 56.9% for twins, 65.0% for triplets+), and have private insurance (58.3% for singletons vs 74.0% for twins, 82.0% for triplets+). Mean birthweight and length of gestation was 3,359g ± 552 and 39.0 ± 1.8 weeks for singletons, 2,408g ± 613 and 35.6 ± 3.0 weeks for twins, and 1,700g ± 567 and 32.2 ± 3.5 weeks for triplets+. The risks of adverse outcomes by plurality are shown below. These contemporary estimates indicate that women with multiple pregnancies are at substantially higher risk for perinatal complications, even after adjustment for fertility status and other important covariates.Tabled 1SingletonsTwinsTriplets+%AOR, 95% CI%AOR, 95% CI%AOR, 95% CIGestational Diabetes5.71.00, Reference9.21.44, 1.33-1.5516.32.58, 1.86-3.58Pregnancy Hypertension8.71.00, Reference22.72.91, 2.75-3.0732.74.70, 3.63-6.09Prenatal Hospitalizations4.01.00, Reference16.24.65, 4.44-4.8831.811.09, 9.52-12.93Prenatal Bleeding0.71.00, Reference1.71.36, 1.15-1.613.92.68, 1.45-4.97Placental Complications1.81.00, Reference3.81.36, 1.22-1.535.01.49, 0.87-2.57Primary Cesarean Delivery18.41.00, Reference57.64.83, 4.63-5.0479.412.50, 9.34-16.77 Open table in a new tab