Birthweight and early pregnancy body mass index may risk pregnancy complications

Women who were born with a low birthweight are at increased risk of pregnancy complications, according to a new Obesity study. The findings suggest that women who were born small may have been affected by unfavourable intrauterine conditions, and the physiological demands of pregnancy may act as a "second hit" leading to pregnancy complications.

In the study of 5,336 women, those who reported a birthweight under 2500g had a 1.7 times higher risk of developing preeclampsia during pregnancy compared with those who had a birthweight of 3000-3499g. Women who reported a birthweight of 3500- 3999g or a birthweight of 4000g or higher had a 40 percent reduced risk of preeclampsia compared with the control group. Also, women who reported a low birthweight were at increased risk of developing gestational hypertension and gestational diabetes compared with women who had a normal birthweight.

Risks were especially high for women who had a low birthweight but subsequently became overweight or obese.

"Further studies assessing the influence of modifiable factors including diet and exercise on the relationship between low birthweight and pregnancy complications may yield important results on whether modifiable lifestyle factors could reduce the risk of pregnancy complications among those born small," said lead author Dr. Prabha Andraweera, of The University of Adelaide, in Australia.