Objective: To estimate alcohol, tobacco, and recreational drug use during pregnancy among nulliparous women.
Methods: In a cohort of nulliparous women followed through pregnancy from the first-trimester nuMoM2b (Nulliparous Outcomes in Pregnancy: Monitoring Mothers to be) study, self-reported use of alcohol, tobacco, and drugs was chronicled longitudinally at four study visits in this secondary analysis. Rates of use before pregnancy, in each trimester (visit 1, visit 2, visit 3, approximating each trimester), and at the time of delivery (visit 4) were recorded. The amount of alcohol, tobacco, and drug exposure were recorded using validated measures, and trends across pregnancy were analyzed.
Results: Of the 10,038 study participants, 10,028 had information regarding alcohol, tobacco, and drug use at visit 1, 9,412 at visit 2, 9,217 at visit 3, and 7,167 at visit 4. The rates of drinking alcohol, which had been 64.6% in the 3 months before pregnancy, were lower in pregnancy (3.9% at visit 1, 5.6% at visit 2, 7.0% at visit 3, and 6.1% at visit 4, P<.001 for all). Rates later in pregnancy were all greater than in the first trimester (P<.01). The rate of smoking in the 3 months before pregnancy, which was 17.8%, also declined at visit 1 (5.9%), and continued to decline through pregnancy (5.3% at visit 2, 4.7% at visit 3, and 3.9% at visit 4, with all rates lower than that of visit 1 [P<.01]). Although recreational drug use was relatively common in the months before pregnancy (33.8%), it also declined during pregnancy (1.1% at visit 2, 0.7% at visit 3, 0.4% at visit 4).
Conclusions: In this geographically and ethnically diverse cohort of nulliparous women, rates of self-reported alcohol, smoking, and recreational drug use were all significantly lower during than before pregnancy. Nonetheless, rates of alcohol use rose as pregnancy progressed, highlighting the need for continued counseling throughout all trimesters of pregnancy.
Clinical trial registration: ClinicalTrials.gov, NCT01322529.