Introduction: The lactational amenorrhea method (LAM) of postpartum contraception is more effective than typical use of condoms or birth control pills. However, LAM may be underutilized due to incomplete perinatal counseling. Methods: We compared perceptions of the effectiveness of postpartum contraceptives including LAM among U.S.-born nulliparous pregnant women recruited using social media for a trial (NCT04601987). We used descriptive statistics to summarize data. Results: Of 760 individuals screened, 627 were invited to participate, and 451 (72%) were enrolled. Most (81%) had a college degree; 79% intended to breastfeed for at least 1 month. Only 8% believed exclusive breastfeeding reduces the chance of pregnancy "a lot" within 6 months of delivery and 2% indicated that exclusive breastfeeding is typically more effective than birth control pills or condoms. Compared with those planning to use other postpartum contraceptives, the 17% of respondents who planned to use LAM were more likely to know that breastfeeding delays return of menses (84% versus 44%, p ≤ 0.0001) and provides protection from pregnancy until menses return (54% versus 22%, p ≤ 0.0001). Although 25% of those planning to use LAM believed exclusive breastfeeding reduces pregnancy risk by "a lot," only 5% thought LAM is more effective than birth control pills and only 9% thought that it is more effective than condoms. Conclusions/Implications: First-time U.S. mothers are often unaware of breastfeeding's effects on menses and fertility. Clinicians providing counseling about postpartum contraceptive options should include more information on LAM.
Keywords: breastfeeding; contraception; human milk; lactational amenorrhea; postpartum.