Weight Rises for Pregnant Women and Newborns

Study Shows BMI Is Increasing for Pregnant Women and Their Babies

From the WebMD Archives

May 3, 2010 -- More babies are being born with more body fat at the same time that body mass index (BMI) -- a measurement calculated from height and weight measurements -- has increased among pregnant women, according to research presented at a national pediatrics conference.

There are few studies on newborn body fat composition and how this measurement influences the risk of childhood obesity, a condition that is prevalent in the U.S. Researchers question whether the path to obesity may begin as early as in the womb.

A research team from Children's Mercy Hospitals and Clinics in Kansas City, Mo., analyzed data from 1990 to 2005 and looked at more than 74,000 births. They found that the ponderal index, a measurement of newborn body fat composition, correlated with the mother's BMI and also increased over the study period. Babies with a higher ponderal index tend to have more body fat.

The findings were presented at the Pediatric Academic Societies annual meeting in Vancouver, British Columbia.

Mom's Weight Affects Baby's Weight

Study researcher Felix Okah, MD, MS, professor of pediatrics and director of the Neonatal-Perinatal Medicine Fellowship Program at Children's Mercy Hospitals and Clinics, and colleagues looked at the mothers' prenatal care, their BMI, and overall weight gain.

They found that while mothers from all racial and ethnic groups gained weight over the 15-year study period, there were some racial and ethnic differences between the groups:

  • The average maternal BMI was 24 for whites; 24.9 for African-Americans; and 25.4 for Hispanics.
  • Among these groups of mothers, weight gain increased 47%, 51%, and 54%, respectively.
  • Hispanic newborns were more likely to have had a higher ponderal index than other infants.

Excess weight and obesity are risk factors for several chronic diseases, including diabetes and heart disease. Extra pounds can also increase the risk for pregnancy complications, including gestational diabetes.

A woman's pre-pregnancy BMI influences fetal growth and newborn body weight. Not surprisingly, mothers with higher BMIs are more likely to give birth to larger babies.

For adults, a BMI between 25 and 29 is considered overweight; a BMI of 30 or higher is considered obese, according to national guidelines. Currently in the U.S., nearly two-thirds of all adults age 20 and older are either overweight or obese. Among children who are overweight in the U.S.:

  • 11% are ages 2 to 5
  • 15% are ages 6 to 11
  • 18% are ages 12 to 19


Doctors and public health authorities say that curbing childhood obesity is key to reducing the risk of health problems later in life.

"Health care providers need to pay closer attention to the body mass index of women before they get pregnant, and equal attention to how much weight they gain during the pregnancy," said Okah. "Adult diseases like obesity may have their foundation during the fetal period, so efforts to safeguard the health of the fetus could translate to future adult health for these newborns."

WebMD Health News Reviewed by Laura J. Martin, MD on May 03, 2010



News release, Children's Mercy Hospitals and Clinics.

Pediatric Academic Societies Annual Meeting, Vancouver, May 1-4, 2010.

Chu, S. Diabetes Care, April 6, 2007.

CDC web site: "About BMI for Adults," "Obesity and Overweight."

© 2010 WebMD, LLC. All rights reserved.


Subscribe to the Pregnancy & Child Development Newsletter.

Get essential updates about your growing baby and what to expect each week.

Sign Up