Pregnancy and Pregnancy Outcomes in a National Population Cohort of Patients Treated for Substance Use Disorders.

Objectives: The objectives of this study were to i) provide population-level prevalence rates of pregnancy, birth, elective termination, and miscarriage among females treated for SUDs and their demographic counterparts and ii) examine associations between SUD treatment and pregnancy and elective terminations.

Methods: Data were analyzed from a prospective registry-linkage study of all females (15-45 years) recorded as treated for SUDs in the Norwegian Patient Registry over a 2-year period (n = 6470) and a non-treated frequency-matched cohort of females from the general population (n = 6286). Pregnancy and pregnancy outcomes over a 4-year follow-up were retrieved from the Norwegian Patient Registry. Multivariable logistic regression models tested for associations of SUD treatment with pregnancy and with elective termination among pregnant females.

Results: Annual pregnancy and elective termination rates per 1000 females were significantly higher for the SUD cohort than the non-treated cohort (94.2 vs 71.3 for pregnancy, P < 0.001; 54.7 vs 17.8 for elective termination, P < 0.001), the annual birth rate was lower for the SUD cohort (25.3 vs 41.8, P < 0.001), and the rate of miscarriage did not differ across cohorts. Multivariable analysis showed that SUD treatment was associated with a significant increase in the odds of pregnancy (adjusted Odds Ratio 1.34, Confidence Interval [1.18-1.54]) and the odds of an elective termination, conditional on pregnancy (aOR 2.55, Confidence Interval [1.97-3.29]).

Conclusions: Females treated for SUDs had substantially higher odds of pregnancy and elective terminations than the non-treated cohort. To improve their reproductive health, targeted interventions such as free long-acting contraception and integration of family planning guidance into substance use treatment should be considered.