By Caleb Radford / 15th of November, 2016

Originally posted on The LEAD SA


WOMEN who conceive in winter are more likely to develop diabetes and increase the likelihood of harmful risks for both child and mother.

A study led by researchers at the University of Adelaide in South Australia investigated more than 60,000 births in the state over a five-year period and confirmed a seasonal variation in gestational diabetes.

It also found that these women were at high risk of developing Type 2 Diabetes within the five years after delivery as well as cardiovascular disease.

Lead Researcher Claire Roberts from the University’s Robinson Research Institute said although the causes of gestational diabetes were still being understood, it could be attributed to vitamin D deficiency.

“It is important to note that the research supports the notion that diabetes is on the rise and it brings with it long-term consequences for women and their children,” she said.

“There have been a number of studies in different countries that have shown that women with low vitamin D are more likely to develop gestational diabetes.

“Obviously in winter we have lower exposure to ultraviolet light so the work we are doing is looking at investigating vitamin D as being a seasonal factor and how that contributes to pregnancy complications.”

Professor Roberts said the data showed a strong correlation between vitamin D and elevated BMI as well.

She said the average BMI of pregnant women was at an all-time high and more than 50 per cent of women entering pregnancy were overweight.

“This issue is really important and women need to look after themselves better than they do now with better diets, and maybe losing weight before conception, to give themselves the best possible chance,” she said.

Gestational diabetes mellitus is a serious pregnancy complication characterised by inadequate blood sugar control in pregnancy.

Complications of gestational diabetes include excessive birth weight, pre-term birth, low blood sugar (which, in extreme cases, can lead to seizures in the baby), and developing type 2 diabetes later in life.

The study found that:

  • Women who conceived in winter were more likely to develop gestational diabetes during their pregnancy, with 6.6% of pregnancies from winter conceptions affected
  • Women who conceived in summer were less likely to develop gestational diabetes, with 5.4% of summer conceptions affected.
  • In the five years from 2007-2011, the incidence of pregnancies affected by gestational diabetes increased, with 4.9% of pregnancies affected in 2007, increasing to 7.2% in 2011.

“Our study is the first of its kind to find strong evidence of a relationship between gestational diabetes and the season in which a child is conceived,” lead author and University of Groningen professor Petra Verburg said.

“Not only should our results be confirmed in other populations, future research should also investigate other factors that vary with season.”

According to the World Health Organisation, the number of people with diabetes in 2014 was 422 million, up from 108 million in 1980. In 2012, an estimated 1.5 million deaths were directly caused by diabetes and another 2.2 million deaths were attributable to high blood glucose.

The study titled Seasonality of gestational diabetes mellitus: a South Australian population study was published in the journal BMJ Diabetes Research & Care.

It was a collaboration between the University of Adelaide, the University of Groningen in the Netherlands and the Pregnancy Outcome Unit of SA Health.

South Australia’s capital Adelaide has three long-standing public universities, Flinders UniversityUniversity of South Australia and the University of Adelaide, each of which are consistently rated highly in the international higher education rankings.

Key contacts

Claire Roberts Deputy Director Robinson Research Institute
61 8 8313 3118