Study: Birth Control Pills Not a Factor in Adolescent Weight Gain

Birth control pills do not contribute to weight gain in adolescents and young women, according to researchers at the Penn State Milton S. Hershey Medical Center.

The new, long-term study, reported in Obstetrics and Gynecology, found that oral contraceptives used during adolescence are not linked to weight gain or increased body fat.

"Until now, most of the major studies on the effects of oral contraceptive use have looked at women aged 20 and over," said Tom Lloyd, PhD, professor of health evaluation sciences and principle investigator on the study. "This study provides new information about the effects of oral contraceptive use on adolescents and young women."

"Oral contraceptives prevent pregnancy the same way in teenage women as they do in adult women," said Dr. Richard Legro, associate professor of obstetrics and gynecology and co-author of the study. "However, we know very little about how a teenager's metabolism may be affected by oral contraceptive use.

"Because young women's bodies change so much during adolescence, we felt it was important to understand whether using oral contraceptives during these developmental years causes metabolic and physiologic changes," Legro said.

The study involved 66 females, 39 of whom used oral contraceptives for a minimum of six months, were still users at age 21, and had used oral contraceptives for an average of 28 months. The 27 members of the control group had never used oral contraceptives.

Researchers took blood samples from the young women once a year. From ages 12.5 to 21, they took body composition measurements. The young women filled out questionnaires with information about their physical activity so researchers could adjust results for both body mass index and level of activity.

"Although perceived weight gain is a common complaint among women who use oral contraceptives, previous studies have shown that this is not the case with adult women and this study provides evidence that body composition of young women using oral contraceptives also is not affected," said Legro. "Based on this new information, we suggest that potential users be counseled by their health care providers accordingly."

Other sources: Penn State Milton S. Hershey Medical Center