Yland JJ, Bresnick KA, Hatch EE, et al. Pregravid contraceptive use and fecundability: prospective cohort study. BMJ. 2020;371:m3966.
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Most US women aged 15 to 49 currently use contraception, with long-acting reversible contraception (LARC)—IUDs and the contraceptive implant—increasing in popularity over the last decade.1 Oral contraceptive pills, male condoms, and LARC are the most common reversible methods used.1 While the efficacy and safety of contraception have been established, few studies have examined the effect of recent contraceptive use on fertility.
Fecundability is the probability of pregnancy during a single menstrual cycle for a couple engaging in regular intercourse and not using contraception.2 Small studies have found short-term reductions in fecundability after discontinuing combined oral contraceptives and larger reductions after stopping injectable contraceptives, with no long-term differences among methods.3,4
Data are limited regarding the effects of other forms of contraception on fecundability, particularly LARC methods. A recent study was designed to evaluate the association between the last contraceptive method used and subsequent fecundability.2
Details of the study
Yland and colleagues pooled data from 3 prospective cohort studies of 17,954 women planning pregnancies in Denmark, Canada, and the United States. Participants reported the contraceptive method used most recently before trying to conceive. They completed questionnaires every 2 months for 12 months or until they reported a pregnancy. Women were excluded if they tried to conceive for more than 6 menstrual cycles at study entry.
The authors calculated the fecundability ratio—the average probability of conception per cycle for a specific contraceptive method compared with a reference method—using proportional probability models adjusted for potential confounders. They also calculated pregnancy attempt time using participant-reported menstrual cycle length and date of last menstrual period during follow-up questionnaires.
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