Preconception contraceptive use and miscarriage: prospective cohort study.

To evaluate the association between preconception contraceptive use and miscarriage. Prospective cohort study. Residents of the United States of America or Canada, recruited from 2013 until the end of 2022. 13 460 female identified participants aged 21-45 years who were planning a pregnancy were included, of whom 8899 conceived. Participants reported data for contraceptive history, early pregnancy, miscarriage, and potential confounders during preconception and pregnancy. Miscarriage, defined as pregnancy loss before 20 weeks of gestation. Preconception use of combined and progestin-only oral contraceptives, hormonal intrauterine devices, copper intrauterine devices, rings, implants, or natural methods was not associated with miscarriage compared with use of barrier methods. Participants who most recently used patch (incidence rate ratios 1.34 (95% confidence interval 0.81 to 2.21)) or injectable contraceptives (1.44 (0.99 to 2.12)) had higher rates of miscarriage compared with recent users of barrier methods, although results were imprecise due to the small numbers of participants who used patch and injectable contraceptives. Use of most contraceptives before conception was not appreciably associated with miscarriage rate. Individuals who used patch and injectable contraceptives had higher rates of miscarriage relative to users of barrier methods, although these results were imprecise and residual confounding was possible.

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Déclaration de conflit d'intérêts

Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institute of Health. LAW is a consultant for AbbVie, inc. and the Gates Foundation, and receives in-kind donations from Swiss Precision Diagnostics (Clearblue home pregnancy tests) and Kindara.com (fertility tracking apps). The authors report no other relationships or activities that could appear to have influenced the submitted work.