973 The risk of perinatal mortality by week of expectant management in pregnancies complicated by diabetes

Abstract

The optimal timing of delivery of pregnancies complicated by diabetes is unknown. The risk of neonatal morbidity and mortality decreases with advancing gestation, which is countered by an increased risk of stillbirth. The objective of this study was to compare the risk of stillbirth and infant death per week of expectant management versus delivery in pregnancies complicated by pregestational (PGD) and gestational diabetes (GDM). A population based retrospective cohort study of non-anomalous singleton pregnancies complicated by either PGD or GDM was performed using national linked birth and death certificate data from 2014-2016. The incidences of stillbirth and neonatal death were determined for each week of pregnancy from 34 to 40 completed weeks’ gestation. A composite perinatal mortality risk with each week of expectant management was calculated by adding the risk of still birth in a given week to the neonatal death risk of delivery in the following week. The relative risk (RR) and 95% confidence interval (CI) of perinatal mortality with expectant management versus delivery was calculated comparing the composite perinatal mortality with the neonatal death risk of delivery in the same week. A total of 989,477 pregnancies were included (PGD: 12.6%, GDM: 87.4%). For both PGD and GDM pregnancies, the risk of stillbirth increased while the risk of infant death decreased with advancing gestation; Table 1. In PGD pregnancies, the risk of neonatal mortality was significantly lower at 37 weeks’ gestation compared to the composite perinatal mortality, favoring delivery over expectant management (RR: 0.52; CI: 0.38-0.71). For GDM pregnancies, this risk was significantly reduced with immediate delivery at 38 weeks’ gestation (RR: 0.48; CI: 0.40-0.59); Figure 1. There does not appear to be a benefit for iatrogenic preterm delivery in either PGD or GDM pregnancies, with results favoring delivery at 37 and 38 weeks’ gestation respectively. This data does not consider glycemic control and delivery timing should be individualized.View Large Image Figure ViewerDownload Hi-res image Download (PPT)