A recent study from Denmark showed that obese women had twice the risk of stillbirth or infant death within 1 month as normal-weight women. Among all women, regardless of weight, a stillbirth or newborn death is not common. Among obese women, however, the rate was found to be <12 per 1000 births and the rate of infant deaths to be ~7 per 1000 births. Among normal-weight women, the rate was 4 stillbirths per 1000 births and <3 newborn deaths per 1000 births. Overweight women had rates comparable to those of normal-weight women.
The study included more than 24,000 women in Denmark. It was not the first study to link obesity with a greater likelihood of stillbirth and newborn deaths. Previous studies have linked these risks to a greater likelihood of diabetes or high blood pressure that may occur in overweight pregnant women. When women with those conditions were excluded, the rates were still the same. The researchers were unable to determine a cause for the increased mortality rates, but obesity is known to affect the hormonal system and the metabolism of blood fats. Furthermore, "high cholesterol may affect certain substances in the body that control blood clotting and blood vessel dilation, and thereby impair the blood flow to the placenta."
Ms. Farley is a freelance medical writer based in Wakefield, RI.