The Influence of reproductive hormones on asthma

Abstract

Abstract Changes in reproductive hormones have important influences on asthma in women. In early childhood, asthma is less common in girls (the female to male ratio is about 1: 2), but by menarche, the gender ratio is equal. Perimenstrual exacerbation(s) of asthma occurs in about 40% of women. Asthma symptoms and exacerbation(s) may increase perimenstrually with considerable reduction in expiratory airflow or change in non-specific airways hypereactivity. Oral contraceptives may attenuate these changes, especially in those women who experience more severe exacerbations with menstruation compared to those not receiving oral contraceptives. This appears to be related to suppression of the luteal phase rise in reproductive hormones caused by oral contraceptives. Case reports demonstrating a reduction in the frequency and severity of asthma exacerbation(s) during treatment with continuous gonadotropin releasing hormone antagonist analogues may also provide a clue to the mechanism(s) of perimenstrually exacerbated asthma. Leukotrienes are implicated in the pathogenesis of perimenstrually associated asthma and agents which block the effects of leukotrienes may be useful in the treatment of perimenstrually associated asthma. Further support for a relationship between reproductive hormones and asthma is derived from studies of asthma in pregnancy. Changes in asthma severity ranging from improvement to deterioration to no change may occur. Women generally experience a similar pattern from one pregnancy to the next, whatever the change. At menopause, the epidemiology of asthma changes again. The age-adjusted risk of asthma is lower in post-menopausal women who have never received hormone replacement therapy compared to pre-menopausal women or to post-menopausal women who have used hormone replacement therapy. The risk of asthma is greatest in women with the longest duration of hormone replacement therapy and those currently using conjugated estrogens. Previous exposure to an oral contraceptive agent(s) is independently associated with a small increased risk of asthma. These data suggest that female reproductive hormones play a significant role in the pathophysiology of asthma in women. The findings may have significant implications in the management of asthma in women.