Aug. 26, 2004 -- As the Olympic athletes compete for the gold in Greece, new research shows female athletes on oral contraceptives are not jeopardizing their performance.
Women in high-endurance sports are more prone to menstrual problems such as light or no periods (amenorrhea). To combat this, oral contraceptives are often prescribed to competitive athletes as a way to regulate their menstrual cycles.
But oral contraceptives can cause weight gain, so researchers looked at whether they can negatively affect a female athlete's performance.
Anette Rickenlund, MD, and researchers at the Karolinska Institute in Sweden compared 26 endurance athletes (half with normal periods, half with irregular periods) with a dozen average women with normal periods.
All of the women received 10 months of a low-dose oral contraceptive containing both estrogen and progestin. Hormonal function, heart rate, bone mineral density, weight, body fat, endurance capacity, and strength were determined before and after 10 months of treatment.
The athletes with abnormal periods who took oral contraceptives increased their weight and body fat. But there was no change in the amount of muscle. The findings are published in the September issue of the Journal of Clinical Endocrinology and Metabolism.
An increase in body fat could negatively affect athletic performance. However, endurance athletes have little body fat to begin with, and the added body fat had little impact on strength, endurance, and athletic performance on the women in this small study. The researchers say more study is needed to make a definite conclusion.
The researchers also found an increase in bone mineral density among all women who took oral contraceptives.