A recent study in the Medical Journal of Australia found that not only were Indigenous mothers-to-be more prone to being overweight or obese during their pregnancy, they were also at higher risk for gestational diabetes mellitus (GDM), and hypertensive disorders of pregnancy (HDP).

Lead author Aaron P. Thrift, PhD, with the QIMR Berghofer Medical Research Institute in Brisbane said he and fellow researcher Leonie K. Calloway sought to assess whether the effect of pre-pregnancy overweight or obesity on maternal complications and perinatal outcomes is modified by Indigenous status.

“As obesity rates at all ages are higher among Indigenous Australians, obesity-related health disparities between Indigenous and non-Indigenous Australians are a public health concern,” the authors wrote. “We aimed to estimate the prevalence of maternal overweight or obesity among Indigenous and non-Indigenous women separately, and to examine whether the effect of overweight or obesity on maternal complications and perinatal outcomes is modified by Indigenous status.”

Thrift and Calloway used a population-based study that looked at aggregate data on pregnancies from more than 13,000 Indigenous women and more than 240,000 non-Indigenous women. They looked at DGM, HDP and delivery statistics among the data.

The results showed than in 57 percent of Indigenous pregnancies and 49 percent of non-Indigenous pregnancies, the mother was either overweight, obese or severely obese.
“Prevalences of GDM, preterm birth and low birthweight were higher in Indigenous than non-Indigenous pregnancies,” the authors wrote.

Almost half of all single births in Queensland between 2007 and 2011 were born to overweight or obese women, the highest rates observed in Indigenous women. Of these births, 5 and 6 percent of the pregnancies involved HDP and GDM respectively.

“Compared with pregnancies in normal-weight non-Indigenous women, the prevalence of HDP or GDM was more than fourfold higher in pregnancies in severely obese non-Indigenous women,” the researchers concluded.  “40 percent of cases of HDP and GDM in non-Indigenous pregnancies may be attributed to overweight or obesity.”

The authors noted that there may be a possible genetic difference between Indigenous and non-Indigenous women that might explain different rates of the pregnancy conditions and that this is an important area for further study.