Oral contraceptives significantly change body composition in female athletes with oligomenorrhea or amenorrhea but have little immediate effect on physical performance, according to a study.

Dr. Anette Rickenlund of Karolinska University Hospital in Stockholm, Sweden, and her colleagues proposed that even small changes in body composition would affect athletic performance and competitive ability. Others have assessed effects of hormonal changes from oral contraceptives (OCs) only in nonathletic women.

The study included 26 endurance athletes--13 with regular menstruation, 8 with amenorrhea, 5 with oligomenorrhea, and 12 sedentary, normally menstruating controls (J. Clin. Endocrinol. Metab. 89[9]:4364-70, 2004).

Participants were aged 16-35 years, had a body mass index between 18 and 24, and were nulliparous, healthy nonsmokers. Treatment was a low-dose, monophasic, combined OC containing 30 [micro]g ethinyl estradiol and 150 [micro]g levonorgestrel.

The regularly menstruating athletes had almost no body composition changes, and control women had none. Athletes with menstrual abnormalities had significant increases in weight (2.4 kg), total fat mass (3%), and bone mineral density (0.02 g/c[m.sup.2]) after 10 months. There were no changes in lean body mass. There was an association with decreased androgen levels, but "the precise mechanisms responsible for the increases in weight and body fat during OC treatment remain to be elucidated," the researchers wrote.

COPYRIGHT 2004 International Medical News Group
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