Obesity ups risk of preterm birth

Women who are overweight or obese are more likely to have pre-term delivery, according to a new  study.

Those with the highest Body Mass Index (BMI) also had the highest statistical risk of giving pre-term birth - and especially extremely pre-term birth.

"For the individual woman who is overweight or obese, the risk of an extremely pre-term delivery is still small. However, these finding are important from a population perspective. Pre-term infants and, above all, extremely pre-term infants account for a substantial fraction of infant mortality and morbidity in high income countries," said the Dr. who led the study.

Compared to women of normal weight, overweight women had a 25 percent increased risk of extremely pre-term delivery. Women with mild obesity had a 60 percent increased risk of giving birth extremely pre-term  For women with severe obesity (BMI 35-39.9) or extreme obesity (BMI 40 or more) the corresponding risk was doubled and tripled, respectively.

Risks of very and moderately pre term deliveries also increased with BMI.

Overweight and obesity also increase the risk of maternal pregnancy complications, including pre-eclampsia  gestational diabetes, and Caesarean delivery, said the Dr.

Infection and inflammation are considered main risk factors for spontaneous extremely pre-term delivery with a spontaneous onset, and maternal obesity is associated with increased production of inflammatory proteins. The researchers hypothesize that the increased inflammatory state in obese women may make them more susceptible to infections, which may increase their risk of spontaneous extremely pre-term delivery.