Summary

Diabetes is known to adversely affect women and their babies during pregnancy, labour and delivery. This differs by maternal diabetes status and has not been described at the national level before. This report explores these differences in Australian mothers and their babies.

Key points

Diabetes in pregnancy is common, affecting about 1 in 20 pregnancies

  • Pre-existing diabetes in pregnancy affected less than 1% of pregnancies, and gestational diabetes mellitus (GDM) affected about 5% in 2005–07.
  • Among Aboriginal and Torres Strait Islander mothers, pre-existing diabetes affecting pregnancy was 3 to 4 times as common, and GDM twice as common, as in non-Indigenous mothers. The rate of Type 2 diabetes in Indigenous mothers was 10 times as high.
  • Mothers born in high-diabetes-risk regions, such as Polynesia, Asia and the Middle East, were slightly more likely to have Type 2 diabetes, and 3 times as likely to have GDM, as mothers born in Australia.

Mothers with pre-existing diabetes, and their babies, were at highest risk of adverse effects…

  • Mothers with pre-existing diabetes were more likely to have pre-term birth, pre-term induced labour, caesarean section, hypertension and longer stay in hospital than mothers with GDM or without diabetes in pregnancy.
  • Babies of mothers with pre-existing diabetes had higher rates of stillbirth, pre-term birth, high birthweight, low Apgar score, high-level resuscitation, admission to special care nursery/neonatal intensive care unit, and longer stay in hospital than babies of mothers with GDM or without diabetes in pregnancy.

…and there were differences depending on the type of pre-existing diabetes

  • Mothers with Type 1 diabetes had higher rates of caesarean section, hypertension and pre-term birth than mothers with Type 2 diabetes.
  • Babies of mothers with Type 2 diabetes were more likely to be stillborn than babies of mothers with Type 1 diabetes.

Mothers with GDM, and their babies, were also at higher risk of adverse outcomes

  • Mothers with GDM were at highest risk of induced labour and were more likely to have a pre-term birth, caesarean section, hypertension and longer hospital stay than mothers without diabetes in pregnancy.
  • Babies of mothers with GDM had higher rates of all adverse effects studied, with the exception of stillbirth, and high and low birthweight, than babies of mothers without diabetes.

The occurrence of adverse effects differed between population groups

  • Aboriginal and Torres Strait Islander mothers and their babies were more likely to have most adverse effects of pregnancy, labour and delivery studied than non-Indigenous mothers and their babies.
  • Mothers born in high-diabetes-risk regions, such as Polynesia, Asia and the Middle East, were less likely to have most adverse effects of pregnancy, labour and delivery than Australian-born mothers. Babies of mothers from high-diabetes-risk regions had similar or lower rates of these adverse effects compared with babies of Australian-born mothers.