REPLY

We thank Stadterman et al¹ for their interest in our paper, and we would like to provide a few points of clarification. Although there is inconclusive evidence of harm regarding the sole use of marijuana during pregnancy and adverse birth and neonatal outcomes, in utero exposure to marijuana may lead to later learning and developmental impairments.² Existing research, including our findings, suggests that concurrent use of other substances known to be teratogenic (ie, alcohol, tobacco) is common among marijuana users.

Guidelines from the American College of Obstetricians and Gynecologists³ recommend universal screening for all maternal substance use, irrespective of whether a substance is legal. Universal screening could be performed by maternal self-report during clinical encounters using validated screening tools as part of a woman's general health history.

The American College of Obstetricians and Gynecologists guidelines acknowledge the complex legal issues regarding universal screening and that punitive measures resulting from substance use screening are not “applied evenly across sex, race, and socioeconomic status.” However, the guidelines state that “in fulfillment of the therapeutic obligation, physicians must make a substantial effort” to “... practice universal screening questions, brief intervention, and referral to treatment in order to provide benefit and do no harm ...” and “protect confidentiality and the integrity of the physician-patient relationship wherever possible within the requirements of legal obligations, and communicate honestly and directly with patients about what information can and cannot be protected.”³ Thus, effective screening, as well as appropriate provider training and resources for patient education and care, is needed to support pregnant women who may want assistance with cessation.

Finally, we would like to clarify that women were asked in the National Surveys on Drug Use and Health whether they used marijuana in the past month and in the past year. They were then analytically coded as past month users and past 2–12 month users. We described the timing of pregnancy and past 2–12 month use as a limitation of this data source. However, because pregnant women were on average in their second trimester, past-month use is likely reflective of use during pregnancy. Our point estimate of 3.9% is within the range of use during pregnancy reported by individual states (2.6% Hawaii and 7.1% in Alaska).^4,5 In the context of legalization, monitoring use of marijuana in pregnancy, as well as unintended consequences, is needed.