Women are being encouraged to ensure their body mass index (BMI) is within a healthy range before pregnancy to ensure the best outcomes for their babies.

A new study by University of Queensland researchers has shown that BMI prior to conception could have a significant impact on pregnancy complications including gestational diabetes and hypertension.

UQ School of Public Health PhD candidate Danielle Schoenaker said the research shows a close link between BMI, diet and pregnancy complications.

“Women with gestational diabetes or hypertensive disorders of pregnancy are not only at increased risk during pregnancy, but after pregnancy both mothers and their children face an increased risk of type II diabetes and cardiovascular disease,” Ms Schoenaker said.

The researchers examined data from more than 3000 women from the Australian Longitudinal Study on Women’s Health (ALSWH).

“We previously found that a Mediterranean diet – one high in vegetables, olive oil and moderate protein before pregnancy was associated with a lower risk of developing complications.

“Young women with low consumption of vegetables, legumes, fruit, nuts, fish, and wholegrain cereal and pasta before pregnancy had a 35 per cent higher risk of gestational diabetes and a 41 per cent greater risk of developing gestational hypertension or pre-eclampsia.

“We have now demonstrated that much of the effect of a Mediterranean diet on risk of complications is explained by its impact on BMI.

“Encouraging young women to consume a Mediterranean diet could help in maintaining a healthy BMI before pregnancy, thereby reducing the risks for themselves and their children.”

ALSWH Director Professor Gita Mishra said a large proportion of women of child-bearing age do not have a healthy BMI.

“According to the latest National Health Survey, between 33 per cent and 58 per cent of Australian women aged 18-45 years were classified as overweight or obese,” Professor Mishra said.

The research has been published in the American Journal of Clinical Nutrition.