Worldwide, about 2.65 million stillbirths occurred in 2008. And in that same year, an estimated 3.6 million infants died in their first month of life.

There are many factors that could contribute to these numbers. One of which was recently identified by researchers at the Imperial College London, Oslo University, and Loma Linda University. These scientists found that a pregnant woman's BMI - or body mass index- in the early stages of pregnancy was linked to her baby's risk of death before or shortly after birth.

For the study, published in the Journal of the American Medical Association, researchers evaluated 38 studies from all over the world - but primarily in Europe and North America. They analyzed the prenatal BMI and fetal and infant death of the women and babies enrolled and concluded that “moderate to strong increases in the relative risk of fetal death, stillbirth, neonatal death, perinatal death and infant death were found with increasing maternal BMI.”

They found even a small increase in an obese pregnant woman's weight was linked to an increased risk of fetal death, stillbirth and infant death.

Severely obese women - or those with a BMI of at least 40 - had a two- to three-fold increase in risk in stillbirth or infant death, when compared to women whose BMI measured closer to 20. Even women with a BMI around 25 (which is considered overweight and not obese) had an increased risk for complications.

The study's authors were quick to stress that the overall risk for stillbirth and infant death is still relatively small. But they are concerned about the link between the mother's prenatal BMI and the risk for complications.

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Infant death tied to mom's prenatal BMI
Researchers find that even small increases in prenatal weight were linked to increases in risk for stillbirth and infant death.