disorders occurred in 39% of modafinil users and 4.5% of methylphenidate users, and use of other psychoanalytics in the modafinil-and methylphenidate-exposed groups was reported to be 41% and 30%, respectively (Table ).There were 6 major congenital malformations in the modafinil-exposed group (no patient with multiple sclerosis received teriflunomide, a suspected teratogen), 43 in the methylphenidate-exposed group, and 32 466 in the unexposed pregnancies group, for absolute risks of 12% for modafinil, 4.5% for methylphenidate, and 3.9% for unexposed. The adjusted ORs were 3.4 (95% CI, 1.2-9.7) comparing modafinil and methylphenidate and 2.7 (95% CI, 1.1-6.9) comparing modafinil with unexposed (Figure).Discussion | In this nationwide study, first-trimester in utero exposure to modafinil compared with methylphenidate or no medication was significantly associated with an increased risk of congenital malformations.In 2 case series totaling 274 patients with narcolepsy, no malformations among 13 modafinil-exposed pregnancies were reported. 4,5 Narcolepsy itself does not appear to increase the risk of congenital malformations. 6 There are several limitations. First, the potential for residual confounding exists. For example, baseline differences in psychiatric medications were adjusted for, but adjusting for psychiatric diagnoses was not feasible. Although methylphenidate was used as an active comparator to address confounding by indication, methylphenidate is indicated for ADHD as well as narcolepsy. Second, prescription redemptions were a proxy for actual use. Third, the small numbers of exposed women and events reflect the rarity of the exposure and decrease the precision of the point estimates. Fourth, specific malformations were not identifiable.Although further research is needed, women contemplating pregnancy should currently avoid or discontinue modafinil.