Introduction: Pre-gestational diabetes confers an increased risk of antenatal complications and adverse pregnancy outcome.
Design: Retrospective cohort study of women with pre-gestational diabetes attending for pregnancy care at the Royal Women’s Hospital (RWH), Melbourne, Australia’s largest quaternary level maternity centre.
Method: Women with pre-gestational diabetes, including type I (T1DM) and type II diabetes (T2DM), attending for antenatal care at RWH between January 2010 and December 2020, were identified from the hospital database. Maternal demographic data, antenatal complications such as hypertensive disease in pregnancy or pre-eclampsia, mode of delivery, birthweight and labour complications were collected.
Results: Our study cohort comprised of 792 women; 48% had T1DM (n=382) and 52% had T2DM (n=410). This corresponds to a steady number of 72 pregnant patients seen each year through our multi-disciplinary obstetric endocrine service. Women with T1DM were younger (mean age 30 vs 33 years) and more commonly nulliparous (49% vs 36%) than their T2DM counterparts. The rate of obesity (BMI>35) was significantly higher in the T2DM group (33% vs 8%). The rate of hypertensive complications in pregnancy was similar between the groups, with 1 in 5 women developing either pregnancy induced hypertension or pre-eclampsia. Women with T1DM delivered at a mean gestational age of 36 weeks (range 21-39) with 38% giving birth prior to 37 weeks. The mean birthweight was 3403g (range 390-5860g) and 8% of infants weighed over 4500g. Overall 69% of women with T1DM gave birth by Caesarean section. Women with T2DM gave birth later (mean GA 36.4 weeks) with a lower rate of macrosomia (mean BW 3041g; 3% weighing more than 4500g). More women in the T2DM group achieved a vaginal birth (41% vs 31%). Women with T1DM had a higher rate of shoulder dystocia (1.8% vs 1.16%) and admission to the neonatal unit for postnatal management of their newborn (53% vs 34%) than women with T2DM. The perinatal mortality rate was similarly high in both groups including 18 stillbirths and 7 neonatal deaths in the entire cohort of 792 women with pre-gestational diabetes (PNMR 31.6 per 1000 births).
Conclusion: These contemporary data provide useful information on pregnancy outcomes in women with pre-gestational diabetes, which can be utilised for counselling in the antenatal setting.