Infant twin mortality and hospitalisations after the perinatal period – a prospective cohort study from Guinea-Bissau

Objective: To examine mortality and hospitalisations among infant twins and singletons after the perinatal period in Guinea-Bissau. Methods: The study was conducted from September 2009 to November 2012 by the Bandim Health Project (BHP). Newborn twins and unmatched singleton controls were included at the National Hospital Simão Mendes in the capital Bissau. Children were examined clinically at enrolment. Maternal, pregnancy and obstetric information was collected and HIV testing offered at birth. Follow-up occurred at home at 2, 6 and 12 months and through linkage with the paediatric admission register at the National Hospital. Results: About 495 twins and 333 singletons were alive on day 7 after birth. In total, 36 twins and 12 singletons died during follow-up, the post-perinatal infant mortality rate being 91/1000 person-years for twins and 42/1000 for singletons (HR = 2.11, 95% CI: 1.09–4.07). In a multivariable analysis among twins only, birth weight <2000 g [3.32, (1.36–8.07)], death of the cotwin perinatally [2.54, (1.16–5.57)] and severe maternal illness during pregnancy [2.35, (1.00–5.51)] were significant risk factors for twin death. In the subgroup with available HIV status, maternal HIV infection was strongly associated with twin mortality [3.16, (1.24–8.05)]. Death occurred at home for 60% of twins and 67% of singletons. During follow-up, 90 first-time hospital admissions were registered, with similar rates observed for twins (139/1000) and singletons (143/1000) [0.97, (0.61–1.52)]. Conclusion: The post-perinatal infant mortality rate of twins was double that of singletons. No excess in twin hospitalisations was observed, possibly implying obstacles to hospital admission for twins in case of severe illness.