Covid-19 vaccination and menstrual cycle length in the Apple Women’s Health Study

  1. Elizabeth A. Gibson
  2. Huichu Li
  3. Victoria Fruh
  4. Malaika Gabra
  5. Gowtham Asokan
  6. Anne Marie Z. Jukic
  7. Donna D. Baird
  8. Christine L. Curry
  9. Tyler Fischer-Colbrie
  10. Jukka-Pekka Onnela
  11. Michelle A. Williams
  12. Russ Hauser
  13. Brent A. Coull
  14. Shruthi Mahalingaiah

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Abstract

COVID-19 vaccination may be associated with change in menstrual cycle length following vaccination. We estimated covariate-adjusted differences in mean cycle length (MCL), measured in days, between pre-vaccination cycles, vaccination cycles, and post-vaccination cycles within vaccinated participants who met eligibility criteria in the Apple Women’s Health Study, a longitudinal mobile-application-based cohort of people in the U.S. with manually logged menstrual cycles. A total of 9652 participants (8486 vaccinated; 1166 unvaccinated) contributed 128,094 cycles (median = 10 cycles per participant; inter-quartile range: 4–22). Fifty-five percent of vaccinated participants received Pfizer-BioNTech’s mRNA vaccine, 37% received Moderna’s mRNA vaccine, and 8% received the Johnson & Johnson/Janssen (J&J) vaccine. COVID-19 vaccination was associated with a small increase in MCL for cycles in which participants received the first dose (0.50 days, 95% CI: 0.22, 0.78) and cycles in which participants received the second dose (0.39 days, 95% CI: 0.11, 0.67) of mRNA vaccines compared with pre-vaccination cycles. Cycles in which the single dose of J&J was administered were, on average, 1.26 days longer (95% CI: 0.45, 2.07) than pre-vaccination cycles. Post-vaccination cycles returned to average pre-vaccination length. Estimated follicular phase vaccination was associated with increased MCL in cycles in which participants received the first dose (0.97 days, 95% CI: 0.53, 1.42) or the second dose (1.43 days, 95% CI: 1.06, 1.80) of mRNA vaccines or the J&J dose (2.27 days, 95% CI: 1.04, 3.50), compared with pre-vaccination cycles. Menstrual cycle change following COVID-19 vaccination appears small and temporary and should not discourage individuals from becoming vaccinated.

Article activity feed

  1. Version published to 10.1038/s41746-022-00711-9
  2. Rapid Reviews Infectious Diseases

    Thomas P Bouchard

    Review 3: "Covid-19 Vaccination and Menstrual Cycle Length in the Apple Women’s Health Study"

    Reviewers found this study to be potentially informative to reliable, with one reviewer suggesting clearer justifications of the analytic methods.

  4. Rapid Reviews Infectious Diseases

    Jacqueline Maybin

    Review 2: "Covid-19 Vaccination and Menstrual Cycle Length in the Apple Women’s Health Study"

    Reviewers found this study to be potentially informative to reliable, with one reviewer suggesting clearer justifications of the analytic methods.

  5. Rapid Reviews Infectious Diseases

    Blair Darney

    Review 1: "Covid-19 Vaccination and Menstrual Cycle Length in the Apple Women’s Health Study"

    Reviewers found this study to be potentially informative to reliable, with one reviewer suggesting clearer justifications of the analytic methods.

  7. Version published to 10.1101/2022.07.07.22277371v1 on medRxiv