High Estrogen/Progestin Levels May Reduce Asthma Severity, Say Pittsburgh Researchers

"We found that women's lung function and asthma symptoms improve when estrogen and progesterone levels are raised, both naturally during certain times in the menstrual cycle and with the administration of oral contraceptives or hormone replacement therapy," said Catherine L. Haggerty, Ph.D., M.P.H., GSPH post-doctoral fellow and senior author of the report. "These studies suggest that estrogen and progesterone play a role in strengthening respiratory muscle and in increasing relaxation of bronchial smooth muscle, thereby reducing the contractile response. The two hormones also have been shown to exhibit anti-inflammatory properties."

Dr. Haggerty and her colleagues reviewed scientific data generated between 1966 and 2001 and discovered that asthmatic patients experienced increased asthma episodes, increased hospitalizations for asthma and decreased pulmonary function during the premenstrual and menstrual phase, when hormonal levels are low. Conversely, some women experience improved pulmonary function and a decrease in asthma exacerbation while taking oral contraceptives and hormone replacement therapy.

"Estrogen and progesterone are highly elevated during pregnancy, reaching their greatest concentrations during the final trimester. In some women, improvements in asthma symptoms from preconception to pregnancy parallel these changes in hormonal levels, with the lowest rate of symptoms occurring during the last four weeks," Dr. Haggerty said.

According to the authors, certain subgroups of women may be more susceptible to hormone cycles. Testosterone, estrogen and progesterone may each independently affect pulmonary function to varying degrees.

"A further understanding of the role of hormones in asthma may better predict exacerbations and direct therapeutic strategies. Such an understanding may help to improve the quality of life in women who suffer from this often-debilitating disease," said Dr. Haggerty.