Losing weight after first pregnancy can improve outcomes for the second pregnancy

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Being overweight while pregnant can increase several health risks. But after you have your baby, it’s not too late to try to lose the pounds if you want to have another.

A recent study found that obese women who lost weight between their pregnancies were less likely to have an oversized baby.

Losing weight between pregnancies did not increase obese women’s risk of having an underweight baby unless they lost a great deal of weight.

Overweight moms thinking of becoming pregnant may want to discuss with their doctor what the healthiest weight is for them.

The study, led by Arun P. Jain, MD, of the Department of Obstetrics, Gynecology and Women’s Health at Saint Louis University School of Medicine in Missouri, looked at how women’s weight changes between pregnancies affected their second pregnancy.

The researchers analyzed the medical records of 10,444 obese women in Missouri who had their first two children between 1998 and 2005.

The researchers looked at the body mass index (BMI) of the women just before both their first and second pregnancies. BMI is a ratio of a person’s height to weight that is used to determine whether they have a healthy weight.

The researchers then looked at whether the women’s babies were born at an appropriate weight or whether they were large or small for the week of pregnancy when they were born.

The results showed that women who lost enough weight to have a BMI two or more points lower on their second pregnancy were almost half as likely to have a baby that was oversized for the week of pregnancy when it was born.

Women who gained weight – at least two BMI points – between pregnancies had a 37 percent higher risk for delivering a baby that was oversized.

Gaining or losing weight between pregnancies did not appear to change the risk for delivering underweight babies unless the women lost so much weight that their BMI dropped more than eight points.

In general, however, the more weight women lost, the less likely they were to have a baby who was larger than average.

The more weight women gained between their pregnancies, the more likely it was that they would have an oversized baby during their second pregnancy.

The researchers concluded the period of time between pregnancies may be an ideal time for obese women to attempt to lose weight.

“Mild-to-moderate inter-pregnancy weight loss in obese women reduced the risk of subsequent birth of large-for-gestational-age infants without increasing the risk of small-for-gestational-age infants,” the researchers wrote.

Large-for-gestational-age means a baby is larger than he or she should be at birth. Small-for-gestational-age means being born underweight.

Ronald de la Peña, MD, an OB/GYN at Los Robles Hospital in Thousand Oaks, California, and a dailyRx expert, said he works with his patients at the start of each pregnancy to develop a nutrition, activity/exercise and weight gain plan.

“Obese patients, those women with a body mass index at 30 or greater, are advised to have sensible 1,800-2,200 calorie diets, increased physical activity – 5 hours of walking per week – and a goal weight gain of 0 to 12 pounds,” he said. Body mass index is a ratio of a person’s height to weight and is used to determine if they are a healthy weight.

After his patients give birth, Dr. de la Peña said he works with moms to map out a strategy for weight management.

“Many patients are breast feeding and bonding with their baby and will not start on a weight loss regimen until two to three months after delivery,” Dr. de la Peña said. “Obese patients are advised to continue an active lifestyle with exercise as they are able, and are encouraged to strive for the best BMI.”

He said when patients return for their visit six months after their child’s birth, many are ready to embrace a fitness and weight loss plan that helps them prepare for another pregnancy at a lower weight.

“The discussion about a woman’s weight is a sensitive issue, but we use a caring attitude and direct approach to find a plan that works for her,” Dr. de la Peña said.

His suggestions for women planning another pregnancy are to try to avoid becoming or staying obese because of the increased complications. If a woman is obese at the start of a pregnancy, she should discuss a diet, fitness and weight management plan with her doctor.

“After pregnancy, don’t delay more than three to six months to meet with your doctor to stay focused on weight management,” Dr. de la Peña recommended.

The study was published in the June issue of the American Journal of Obstetrics and Gynecology. The research did not use external funding, and the authors declare no conflicts of interest.


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