Twin pregnancy and perinatal outcomes: Data from 'Birth in Brazil Study'

Twin pregnancies account for 0.5-2.0% of all gestations worldwide. They have a negative impact on perinatal health indicators, mainly owing to the increased risk for preterm birth. However, population-based data from low/middle income countries are limited. The current paper aims to understand the health risks of twins, compared to singletons, amongst late preterms and early terms.

Data is from "Birth in Brazil", a national inquiry into childbirth care conducted in 2011/2012 in 266 maternity hospitals. We included women with a live birth or a stillborn, and excluded births of triplets or more, totalling 23,746 singletons and 554 twins. We used multiple logistic regressions and adjusted for potential confounders.

Twins accounted for 1.2% of gestations and 2.3% of newborns. They had higher prevalence of low birth weight and intrauterine growth restriction, when compared to singletons, in all gestational age groups, except in the very premature ones (<34 weeks). Amongst late preterm's, twins had higher odds of jaundice (OR 2.7, 95% CI 1.8-4.2) and antibiotic use (OR 1.8, 95% CI 1.1-3.2). Amongst early-terms, twins had higher odds of oxygen therapy (OR 2.7, 95% CI 1.3-5.9), admission to neonatal intensive care unit (OR 3.1, 95% CI 1.5-6.5), transient tachypnoea (OR 3.7, 95% CI 1.5-9.2), jaundice (OR 2.8, 95% CI 1.3-5.9) and antibiotic use (OR 2.2, 95% CI 1.14.9). In relation to birth order, the second-born infant had an elevated likelihood of jaundice, antibiotic use and oxygen therapy, than the first-born infant.

Although strongly mediated by gestational age, an independent risk remains for twins for most neonatal morbidities, when compared to singletons. These disadvantages seem to be more prominent in early-term newborns than in the late preterm ones.