Oral Contraceptive Use Does Not Affect Bone Mass

Peak hip bone mineral density is achieved in late adolescence, usually by age 16. In this study, participants had their total body and hip bone density measured with using a DXA scanner. Bone density and bone mass was measured to see if there was any change caused by OCP use.

The study involved 62 white females who were studied from ages 12 to 20. There were 28 young women who used birth control pills for at least 6 months and were still using at age 20, with the average duration of use of 22 months; and 34 non-users. They are part of the Penn State Young Women's Health Study, which is a prospective epidemiological study that began in 1990 and believed to be the largest study of its kind.

Tom Lloyd, professor of health evaluation sciences and obstetrics and gynecology, said, "There was no difference in bone density between the two groups. This is good news because hormones in OCPs might, in theory, affect bone density, and peak bone mass is important in preventing osteoporosis later in life."

He notes that while there has been extensive research with older women on the use of OCPs and bone density, no previous studies have been conducted with teenaged women.

"We know that young women in particular are also very concerned about undesirable body changes," says Lloyd. "The average woman gains 40 to 50 percent of her skeletal mass – approximately 1,000 grams of bone mass during adolescence."

Lloyd, also director, Penn State Young Women's Health Study; Denise Taylor, clinical research coordinator; Hung Mo Lin, biostatistician and assistant professor of health evaluation sciences; Amy Matthews, biostatistical analyst; Douglas Eggil, associate professor of radiology; and Richard Legro, M.D., associate professor of obstetrics and gynecology, all Penn State College of Medicine, published their findings in "Oral Contraceptive Use by Teenage Women Does Not Affect Peak Bone Mass: A Longitudinal Study," is published in the October issue of the journal Fertility and Sterility.

Their work was sponsored by the National Institutes of Health through its support of the General Clinical Research Center at Penn State Milton S. Hershey Medical Center.