More C-Sections for Overweight Moms

Obese pregnant women and women gaining excess weight may be more at risk for birth interventions

(RxWiki News) Women are supposed to gain weight during a healthy pregnancy. But weighing too much at the start or gaining too much weight during pregnancy may increase certain risks.

A recent study looked at the birth delivery methods among women based on their weight before pregnancy. The study also looked at these methods according to how much weight women gained during pregnancy.

The researchers found that obese pregnant women were more likely to have a cesarean section or a vaginal delivery with vacuum extraction.

In addition, women who gained more than 35 pounds were more likely to have a C-section or need forceps or a vacuum extraction during a vaginal birth.

"Ask your OB or midwife about appropriate pregnancy weight gain."

The study, led by Nils-Halvdan Morken, of the Department of Public Health and Primary Health Care, University of Bergen in Norway, aimed to find out whether women's weight gain during pregnancy was related to their method of giving birth.

A cesarean section (C-section) is a procedure in which the baby is surgically removed through an incision rather than arriving through the vaginal birth canal. Forceps are instruments used to pull the baby out of the birth canal when the woman is unable to push the baby out, which can happen if the baby is too large to get through the birth canal naturally.

A vaginal birth with a vacuum extraction occurs when the doctor attaches a cup to the head of the baby and uses a vacuum pump that help get the baby out of the birth canal.

The study included 50,416 Norwegian women who were pregnant with a single child. None of the women had a breech baby (head not facing downward), pre-eclampsia, chronic hypertension, diabetes, gestational diabetes or placenta previa (where the placenta is blocking part or all of the opening to the cervix).

The researchers categorized the women according to their pre-pregnancy weight based on their body mass index (BMI). BMI is a ratio of a person's height to weight in metric measurements. It is used to determine whether someone is a healthy weight, underweight or overweight.

Then the researchers compared the women's BMI to their method of delivery to see if there was a link. They looked at whether the women had a vaginal delivery, a vaginal delivery with forceps or vacuum extraction or a C-section.

The researchers found that women who were overweight or obese were more likely to have a C-section than women of healthy weight.

Women with a pre-pregnancy BMI of more than 40 were 3.4 times more likely than women of a healthy BMI to have a C-section. A BMI over 40 is considered morbidly obese, or severely obese.

Women with a BMI of more than 40 before they became pregnant were also about 50 percent more likely to have a vacuum extraction than other women.

Women who gained more than 35 pounds during their pregnancy were slightly more likely than women who gained less than this amount to have a C-section or a vaginal delivery with forceps or vacuum extraction.

These women were 20 percent more likely to have a vaginal delivery with forceps or a vacuum extraction and 30 percent more likely to have a C-section.

Women who were obese when they became pregnant tended to gain less weight during pregnancy than non-obese women, but obese women's children tended to be larger.

The study was published March 5 in the journal Acta Obstetricia et Gynecologica Scandinavica. The research was funded by the Norwegian Ministry of Health and the Ministry of Education and Research, the US National Institutes of Health, the Norwegian Research Council and the Schering Plough Research Foundation. The authors declared no conflicts of interest.

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Review Date: 
March 6, 2013