Study Links Progesterone-Only Contraceptive Pill to Increased Asthma Attacks in Women

A comprehensive study involving approximately 260,000 women has identified a link between the use of progesterone-only contraceptive pills and a higher incidence of asthma attacks in certain women. Published in ERJ Open Research, the research reveals that women under 35 who take this form of contraception, particularly those using fewer asthma medications or diagnosed with eosinophilic asthma—a type characterized by high levels of blood eosinophils—are more prone to experiencing asthma exacerbations.

The study differentiated between women using combined estrogen and progesterone contraceptive pills and those on progesterone-only pills, finding no increased risk associated with the former. However, women on the progesterone-only pill showed a significant rise in asthma attacks, especially among younger women, those with less intensive asthma treatment, and specific asthma subtypes.

Led by Dr. Chloe Bloom from Imperial College London, the research utilized the UK's Clinical Practice Research Datalink to analyze data from women aged 18 to 50 diagnosed with asthma between 2004 and 2020. The findings indicated that women under 35 on the progesterone-only pill had a 39% higher risk of asthma attacks. Similarly, women with eosinophilic asthma and those using fewer asthma medications faced elevated risks of around 20-24%.

The researchers emphasized that this is the first large-scale, detailed study to investigate the effects of progesterone on asthma over time. They suggest that sex hormones, particularly progesterone, might influence asthma severity and could partly explain why women tend to suffer more severe asthma than men. Studying medication use in women provides clearer insights into hormonal impacts, avoiding the complications of measuring hormonal levels at different life stages.

Dr. Bloom highlighted the importance of understanding these risks for women of reproductive age who often use contraceptives. She advocates for healthcare providers to consider these findings when advising on contraception options for women with asthma. The study also calls for further research into how progesterone, hormone replacement therapy, and pregnancy influence asthma outcomes.

Professor Apostolos Bossios, an expert in respiratory diseases not involved in the study, remarked on the importance of this research, emphasizing the need for more studies to fully understand the underlying reasons for gender disparities in asthma severity. He advised women with asthma, especially those on the combined contraceptive pill, to consult their healthcare providers about their contraception choices and to adhere strictly to their prescribed asthma treatments to maintain good control.

The ongoing research aims to deepen our understanding of hormonal influences on respiratory health, potentially guiding better personalized treatment strategies for women with asthma.

Source: https://medicalxpress.com/news/2025-05-asthma-common-women-progesterone-pill.html