Causes of stillbirths in diabetic and gestational diabetes pregnancies at a NSW tertiary referral hospital

Background: Diabetes in pregnancy may result in stillbirth or neonatal death.

Aim: This audit examined stillbirths of mothers with pre-existing diabetes in pregnancy (DIP) and gestational diabetes (GDM) to determine maternal and diabetic characteristics implicated in these deaths.

Materials and methods: A retrospective cohort study was conducted to identify stillbirths occurring in diabetic pregnancies at Westmead Hospital during 2006-2017. Medical records were reviewed to obtain data relating to maternal factors, diabetes history, glycaemic control and cause of death.

Results: There were 37 women (seven with type 1 diabetes [T1DM], 11 with type 2 diabetes [T2DM] and 19 with GDM) who had 38 stillbirths. The leading cause of stillbirth was lethal congenital malformations in nine cases, followed by placental and umbilical abnormalities in six, intra-uterine growth restriction (IUGR) in six, and obstetric factors in four cases. Malformations were predominantly cardiovascular (n = 7), musculoskeletal (n = 5) and gastrointestinal (n = 4). There was no difference in the proportion of stillbirths related to malformations between the DIP and GDM groups (P = 0.22). In the pre-conception period or first trimester, all T1DM subjects and all but two T2DM subjects had HbA1c >7% or there was no measurement. HbA1c was >7% in 6/7 T1DM subjects and 7/11 T2DM subjects at some stage during the pregnancy.

Conclusion: Stillbirth remains a problem in diabetic pregnancy in the 21st century. Lethal malformations, placental abnormalities and IUGR were the leading causes of stillbirth related to diabetes. Pre-conception counselling and planning to achieve better glycaemic control in pregnancy needs to be improved.