Perinatal deaths in twin and singleton infants in Ireland: A comparison of characteristics and causes

Twin pregnancies are associated with significantly higher perinatal mortality (PM) rates compared to singletons, primarily due to complications like fetal growth restriction, preterm birth, and congenital anomalies. This study aimed to compare the characteristics associated with PM in twin pregnancies and compare maternal and obstetric factors and cause of death among twins and singletons in the Republic of Ireland.

Data spanning 2011 to 2022 from the National Perinatal Epidemiology Centre's annual perinatal mortality clinical audit included 4494 perinatal deaths. Maternal characteristics, antenatal care factors and cause of death were analysed with relative risk calculated using national Hospital In-Patient Enquiry data. Pearson's chi-squared tests studied the difference between mortality in twins and singletons.

Twins accounted for 10.4% of all perinatal deaths, despite representing only 3.6% of total births. The PM rate for twins was 17.3 per 1000 births, 3.1 times higher than for singletons. Early neonatal deaths (ENNDs) were more frequent in twins (54.2%), while stillbirths predominated among singletons (68.6%). Younger maternal age and lower BMI were associated with higher PM risks in twins. A considerable proportion of twin deaths with major congenital anomalies or birth before 28 weeks gestation occurred in non-tertiary hospitals, suggesting limitations in referral pathways to centres with appropriate neonatal expertise.

Twin pregnancies pose a higher risk of perinatal mortality, particularly among younger mothers and preterm births. The findings highlight the need for updated guidelines that prioritise early risk assessment, targeted interventions, and improved referral systems.