Obese Women more Likely to Give Birth Prematurely

Maternal obesity and unnecessary weight gain during pregnancy can increase the risk of premature birth, a new study says.

Researchers from Karolinska Institutet in Sweden reached the conclusion after closely examining the cases of more than 1.5 million births between 1992 and 2010 in Sweden.

Babies born before 37 weeks of gestational age are considered to be premature. Preterm birth is the leading cause of newborn deaths and the second leading cause of death of children aged below 5 in the world. In the country, more than half a million babies are born prematurely. A preterm birth can bring in many health problems for the child, including intellectual disabilities, cerebral palsy, breathing or respiratory problems, feeding or digestive problems and vision or hearing loss.

For the study, Dr. Sven Cnattingius and colleagues collected information about the women, their pregnancy and birth outcomes from the nationwide Swedish Medical Birth Register. Using the data on participants' first prenatal visit, researchers estimated their BMI. (BMI is a number calculated from a person's weight and height, to measure body fat.)

When the researchers compared the maternal BMI with the gestational age of babies, the total 1,599,551 births included in the study had cases of extremely preterm (between 22 and 27 weeks - 3,082), very preterm (between 28 and 31 weeks - 6,893) and moderately preterm (between 32 and 36 weeks - 67,059) births.

Researchers who published their study in the June 12 issue of Journal of the American Medical Association (JAMA) found that risks of premature birth were shooting up with an increase in maternal BMI.

"This just reinforces the fact that the complications of obesity and additional weight gain are deleterious to both mother and fetus," Dr. Raul Artal, a professor and chairman of the department of obstetrics, gynecology and women's health at the Saint Louis University School of Medicine, told Health Day. Artal was not involved in the study.

"The concept that we propagated for years that pregnancy is not a good time for weight loss and physical activity is wrong," he added.

A body mass index (BMI) of 19 to 25 is considered to be the ideal weight for conceiving. A healthy body and optimum weight during pregnancy is crucial for having a smooth pregnancy and delivering a healthy child. However, one-third of women of childbearing age and one in five pregnant women in the United States are obese.

Previous studies have shown that maternal obesity during pregnancy increases the risks of giving birth to babies with iron deficiency, contributing to cardiovascular risks in the child, passing risks of obesity to grandchildren and escalating the risks of giving birth via C-section.