Alcohol and drug use and attainment of pregnancy preferences in the southwestern United States: A longitudinal cohort study.

Abstract

Aims: Addressing design and measurement limitations of prior studies, we examined whether individuals who use alcohol or drugs are less likely to attain their pregnancy preferences over one year.

Design: Longitudinal cohort study.

Setting: Five southwestern US states.

Participants: 2015 individuals ages 15-34 years, capable of pregnancy and non-pregnant at enrollment from 23 primary and reproductive healthcare facilities (2019-2022).

Measurements: Data were collected over 13.5 months. Past-month alcohol, cannabis and other drug use were self-reported at baseline; prospective pregnancy preferences (prior to pregnancy) were reported quarterly using the Desire to Avoid Pregnancy (DAP) scale (range 0-4, 4 representing higher desire to avoid pregnancy); and incident pregnancy was reported every 6 weeks. We used adjusted mixed effects linear regression models to assess associations between baseline substance use and quarterly DAP scores and Cox proportional hazard models to investigate differential attainment of pregnancy preferences by substance use.

Findings: At baseline, 40% (795/1968) of participants reported drinking heavily, 16% (308/1968) reported cannabis use and 3% (53/1968) reported other drug use. Heavy (vs. moderate, low or no) drinking and daily cannabis (vs. no use) were associated with higher desire to avoid pregnancy [coefficient = 0.06, 95% confidence interval (95% CI) = 0.01-0.12], P = 0.02; coefficient = 0.14, 95% CI = 0.07-0.22, P < 0.001], but DAP scores did not differ by other drug use (coefficient = 0.13, 95% CI = -0.07 to 0.33, P = 0.21). 282 participants reported incident pregnancies; of these, 46% (130/282), 29% (81/282) and 25% (71/282) were among participants with low, mid-range and high DAP scores. Among those with high DAP scores, heavy drinking was positively associated with pregnancy [adjusted hazard ratio (aHR) = 1.51, 95% CI = 1.12-2.04, P < 0.01]. Among those with low DAP scores, less than daily versus no cannabis use was associated with pregnancy (aHR = 1.64, 95% CI = 1.13-2.38, P = <0.01). Among those with mid-range DAP scores, heavy drinking was inversely associated with pregnancy (aHR 0.62, 95% CI = 0.42-0.90, P = 0.01). Other drug use was not associated with pregnancy regardless of DAP score.

Conclusions: Heavy drinking, but not cannabis use or other drug use, appears to be associated with elevated pregnancy risk among those who most desire to avoid pregnancy.