(695) Factors associated with perinatal mortality in twin pregnancies

Twin pregnancies have an increased risk of multiple adverse outcomes which includes a higher risk of perinatal mortality compared to singleton pregnancies. This study aimed to study perinatal mortality in twins compared to singletons and investigate the characteristics associated with this.

Study Design:

The perinatal mortality database includes 3668 perinatal deaths (stillbirth n=2459 (67%) and early neonatal deaths n=1209 (33%) with a birthweight ≥500g or gestational age at delivery ≥24 weeks) occurring in any of 19 maternity hospitals within the Republic of Ireland, from 2011-2019.  Data were collected by the National Perinatal Epidemiology Centre for their annual perinatal mortality clinical audit. The maternal characteristics, antenatal care factors including location of care, and cause of death for all cases of perinatal mortality were analysed.  Pearson chi-squared tests studied the difference between mortality in twins and singletons.

Results:

A higher proportion of twins were born in tertiary units (70% v 55.7%, p= < .001) and there was a significantly higher proportion of maternal antenatal care transferred from another unit in the case of twin pregnancies (17.8% v 8% singletons, p= < .001). Twins had a higher proportion of planned caesarean sections (30.1% v 12.4%, p= < .001). The actual reported number of caesarean births for this cohort was 45.6% v 21.4% singletons. A higher proportion of twins were born extremely pre-term < =27 weeks (55.1% v 31.1%) while a higher proportion of singletons were born between 28-36 weeks (37.2% v 35%multiples) and >36 weeks (31.7% v 9.9% multiples). The main cause of death in twins was spontaneous premature labour (18% v 3.2% of singletons). Twin pregnancies had higher rates of death due to chorioamnionitis (10.8% v 5.0%) but a lower proportion of chromosomal disorders (7.8% v 16.1%).

Conclusion: This study highlights the differences observed in the characteristics of perinatal mortality between twins and singletons. It is essential to ensure twin pregnancies are managed in appropriate healthcare services to further optimise care and improve neonatal outcomes.