Pregnancy outcomes in preterm multiple gestations: Results from a prospective study in India and Pakistan (PURPOSe)

Objective: To evaluate perinatal outcomes in preterm multiple compared with singleton pregnancies in India and Pakistan. Design: Prospective, observational study. Settings: Study hospitals in India and Pakistan. Population: We evaluated 3897 preterm pregnancies. These mothers gave birth to 3615 (92.8%) singleton infants, 267 (6.8%) sets of twins, 14 (0.4%) sets of triplets and one set of quadruplets. Main outcome measures: Neonatal mortality, stillbirth, cause of death. Results: Of the singleton infants, 691 (19.1%) were stillborn and 2924 (80.9%) live born. Of the 534 infants from twin pregnancies, 41 (7.7%) were stillborn and 493 (92.3%) were live born. Of the 267 sets of twins, in 14 cases (5.2%) both were stillborn, in 13 cases (4.8%) one was stillborn and one live born, and in 240 cases (90.0%) both were live born. In both preterm twins and preterm singletons, the three most common causes of death were intrauterine hypoxia, infections acquired prior to birth and infections acquired at or after birth. The preterm twins appeared less likely to have died from intrauterine hypoxia but more likely to have died from infections acquired at or after birth. Respiratory distress syndrome (RDS) was less likely considered by the panel to be the primary cause of death in either the twins (9.6%) or singletons (9.7%). Congenital anomalies were also not often judged to be the cause of death in either the preterm twins 2 (2.4%) or singletons 27 (5.3%). Conclusion: In the PURPOSe study, neonatal mortality rates in preterm twins compared with singletons when evaluated by sex, GA, birthweight and SGA, were generally similar to rates of preterm singleton neonatal mortality in those groups. Thus, the higher rate of mortality in live-born twin infants is related to the fact that these infants were more likely to be born earlier rather than to any inherent characteristics of the babies themselves.