Tobacco, alcohol and cannabis use during pregnancy: clustering of risks

Background: Antenatal substance use poses significant risks to the unborn child. We examined use of tobacco, alcohol and cannabis among pregnant Aboriginal and Torres Strait Islander women; and compared characteristics of women by the number of substances reported. Methods: A cross-sectional survey with 257 pregnant Indigenous women attending antenatal services in two states of Australia. Women self-reported tobacco, alcohol and cannabis use (current use, ever use, changes during pregnancy); age of initiation of each substance; demographic and obstetric characteristics. Results: Nearly half the women (120; 47% (95%CI:40%, 53%) reported no current substance use; 119 reported current tobacco (46%; 95%CI:40%, 53%), 53 (21%; 95%CI:16%, 26%) current alcohol and 38 (15%; 95%CI:11%, 20%) current cannabis use. Among 148 women smoking tobacco at the beginning of pregnancy, 29 (20%; 95%CI:14%, 27%) reported quitting; with 80 of 133 (60%; 95%CI:51%, 69%) women quitting alcohol and 25 of 63 (40%; 95%CI:28%, 53%) women quitting cannabis. Among 137 women reporting current substance use, 77 (56%; 95%CI:47%, 65%) reported one and 60 (44%; 95%CI:35%, 53%) reported two or three. Women using any one substance were significantly more likely to also use others. Factors independently associated with current use of multiple substances were years of schooling and age of initiating tobacco. Conclusions: While many women discontinue substance use when becoming pregnant, there is clustering of risk among a small group of disadvantaged women. Programmes should address risks holistically within the social realities of women's lives rather than focusing on individual tobacco smoking. Preventing uptake of substance use is critical.