Hormonal contraceptives and onset of asthma in reproductive-age women: Population-based cohort study

Bright I. Nwaru* (Corresponding Author), Rebecca Pillinger, Holly Tibble, Syed A. Shah, Dermot Ryan, Hilary Critchley, David Price, Catherine M. Hawrylowicz, Colin R. Simpson, Ireneous N. Soyiri, Francis Appiagyei, Aziz Sheikh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Despite well-described sex differences in asthma incidence, there remains uncertainty about the role of female sex hormones in the development of asthma.

We sought to investigate whether hormonal contraceptive use, its subtypes, and duration of use were associated with new-onset asthma in reproductive-age women.

Using the Optimum Patient Care Research Database, a UK national primary care database, we constructed an open cohort of 16- to 45-year-old women (N = 564,896) followed for up to 17 years (ie, January 1, 2000, to December 31, 2016). We fitted multilevel Cox regression models to analyze the data.

At baseline, 26% of women were using any hormonal contraceptives. During follow-up (3,597,146 person-years), 25,288 women developed asthma, an incidence rate of 7.0 (95% CI, 6.9-7.1) per 1000 person-years. Compared with nonuse, previous use of any hormonal contraceptives (hazard ratio [HR], 0.70; 95% CI, 0.68-0.72), combined (HR, 0.70; 95% CI, 0.68-0.72), and progestogen-only therapy (HR, 0.70; 95% CI, 0.67-0.74) was associated with reduced risk of new-onset asthma. For current use, the estimates were as follows: any (HR, 0.63; 95% CI, 0.61-0.65), combined (HR, 0.65; 95% CI, 0.62-0.67), and progestogen-only therapy (HR, 0.59; 95% CI, 0.56-0.62). Longer duration of use (1-2 years: HR, 0.83; 95% CI, 0.81-0.86; 3-4 years: HR, 0.64; 95% CI, 0.61-0.67; 5+ years: HR, 0.46; 95% CI, 0.44-0.49) was associated with a lower risk of asthma onset than nonuse.

Hormonal contraceptive use was associated with reduced risk of new-onset asthma in women of reproductive age. Mechanistic investigations to uncover the biological processes for these observations are required. Clinical trials investigating the safety and effectiveness of hormonal contraceptives for primary prevention of asthma will be helpful to confirm these results.
Original languageEnglish
Pages (from-to)438-446
Number of pages9
JournalJournal of Allergy and Clinical Immunology
Issue number2
Early online date15 Apr 2020
Publication statusPublished - Aug 2020


  • Asthma
  • cohort study
  • females
  • hormonal contraception
  • incidence
  • estrogen
  • progesterone
  • sex hormones


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