Twins Should Be Delivered at 37 Weeks to Minimize Deaths

A new study concludes that in order to minimize perinatal deaths, twin pregnancies delivery should be considered at 37 weeks’ gestation, and delivery of identical twins should be considered at 36 weeks.

Researchers at the University of Adelaide (UA; Australia), Queen Mary, University of London (QMUL; United Kingdom), and other institutions participating in the Global Obstetrics Network (GONet) collaboration analyzed the results of 32 studies published within the past 10 years of women with uncomplicated twin pregnancies reporting stillbirth and neonatal mortality rates at various gestational ages after 34 weeks. Overall, the studies included 35,171 twin pregnancies, 29,685 of them dichorionic and 5,486 monochorionic.

The results revealed that in dichorionic twin pregnancies beyond 34 weeks, the prospective weekly risk of stillbirths from expectant management and the risk of neonatal death from delivery were balanced at 37 weeks’ gestation; delay in delivery by one week led to an additional 8.8 perinatal deaths per 1,000 pregnancies. In monochorionic pregnancies beyond 34 weeks, there was a trend towards an increase in stillbirths, with an additional 2.5 per 1,000 perinatal deaths beyond week 36.

The rates of neonatal morbidity showed consistent reduction with increasing gestational age in both monochorionic and dichorionic pregnancies, with admission to the neonatal intensive care unit (nICU) being the commonest neonatal complication. The authors speculated that the actual risk of stillbirth near term might even be higher than reported estimates, but is not realized due to the global policy of planned delivery in twin pregnancies. The study was published on September 6, 2016, in BMJ.

“In women with dichorionic twin pregnancies, delivery should be considered at 37 weeks' gestation to prevent the significant increase in stillbirths associated with expectant management, compared with the risk of neonatal deaths associated with early delivery,” concluded senior author professor of maternal and perinatal health Shakila Thangaratinam, MD, PhD, of QMUL. “In monochorionic twin pregnancies, there is no clear evidence to support routine delivery before 36 weeks' gestation.”

Twin pregnancies are high risk, with a thirteen-fold increase in rates of stillbirth in monochorionic and a fivefold increase in dichorionic twins, when compared to singleton pregnancies. Uncomplicated twin pregnancies are often delivered early in an attempt to prevent late stillbirth, but delivery before term is associated with neonatal prematurity complications. The recent global drive to prevent stillbirth has highlighted multiple pregnancy as a major risk factor in high-income countries, with calls to prioritize evaluation of timing of delivery and outcomes in twin pregnancies.

Related Links:
University of Adelaide
Queen Mary, University of London