Introduction: Tobacco and alcohol use in pregnancy are modifiable yet frequent risk factors of poor perinatal outcomes. We examined whether characteristics associated with substance use in pregnancy vary between native and migrant women, who often differ in terms of socio-demographic characteristics.
Methods: Data come from a nationally representative sample of children born in France in 2011 (ELFE study, n = 18,014). Maternal substance use in pregnancy (tobacco: >= 1 cigarette/day, alcohol: >= 1 time, binge drinking: >= 3 units of alcohol on one occasion) was assessed using survey methodology by a) trained interviewers and b) self-reports. Migration status was determined based on country of birth (native-born vs. migrant). The sample included 2330 migrant women, predominantly from North Africa (35.4% - primarily Algeria and Morocco), Sub-Saharan Africa (27.3% - primarily Senegal, Ivory Coast, the Congo and Cameroun), Europe (20.2% - primarily Portugal and Germany) and Asia (10.2% - primarily Turkey). Characteristics potentially associated with substance use included socio-demographics (maternal age, number of children, relationship status, educational attainment, employment status), health (psychological difficulties, incomplete prenatal care) and partner's characteristics (migration status, employment).
Results: Compared to the native-born, migrant women had lower levels of tobacco smoking (8.8 vs. 21.9%) and alcohol use (23.4 vs. 40.7%), but not binge drinking (2.9 vs. 3.3%). Unfavorable socioeconomic circumstances were associated with tobacco smoking in native-born women only. Single parenthood was associated with alcohol use only in migrant women. In migrant women, co-occurring use of another substance and psychological difficulties were more strongly associated with use of tobacco, alcohol or binge drinking than in native-born women.
Conclusions: Migrant women have less favorable socioeconomic characteristics than native women but are generally less likely to use tobacco and alcohol in pregnancy. However those who experience single-parenthood need special attention, as they are disproportionately likely to use psychoactive substances which put them and their children at risk of poor health outcomes.

Highlights:
In France, migrant pregnant women have low levels of tobacco and alcohol use but similar levels of binge drinking.
Tobacco use and binge drinking follow a socioeconomic gradient in native women, not in migrants.
Migrant women who are single-parents or experience psychological difficulties have high levels of substance use in pregnancy.
In migrant women, tobacco and alcohol use in pregnant are more likely to co-occur than in native women.
Health professionals should systematically inquire about tobacco and alcohol use throughout pregnancy to improve detection of women with addictive behaviors.