Estrogen replacement therapy and nocturnal periodic limb movements: A randomized controlled trial

Objective: To evaluate the effect of estrogen replacement therapy on noctur nal periodic limb movements in a randomized, double-masked, placebo-control led, crossover trial. Methods: Seventy-one healthy postmenopausal women volunteered in answer to a newspaper announcement; 62 women completed the follow-up. Frequency of no cturnal body movements was measured with the static-charge-sensitive bed an d all-night polysomnographic recordings. Serum estradiol (E2) and FSH conce ntrations were also measured at baseline and after each treatment period. T he power of the study setup was 94%. Results: Nearly half the women presented with episodes of periodic limb mov ements (30 of 62 women, or 48%, during placebo and 27, or 44%, during estro gen therapy). In 17 (27%) during placebo and 19 (31%) during estrogen thera py, frequency of periodic limb movements exceeded index level 5 per hour wh ile subjects were in bed. Incidence or intensity of movements, movement dur ations, and movement intervals did not change with estrogen therapy. The ar ousal index was similar during the two treatments (medians = 1.7 for placeb o and 1.3 for estrogen, P = .758). Variations in serum E2 concentration, ag e, and body mass index did not explain variations in movement activity. Conclusion: Estrogen replacement therapy in doses used to control climacter ic symptoms does not alter the incidence or intensity of nocturnal periodic limb movements. (C) 2001 by The American College of Obstetricians and Gyne cologists.