Perinatal transitions in tobacco product use and postpartum relapse in Japan: a nationwide web-based study

Background Japan leads the global market for heated tobacco products (HTPs); however, whether prepregnancy tobacco product type influences cessation during pregnancy and postpartum relapse remains unknown. We examined tobacco use patterns from before pregnancy to postpartum and assessed whether prepregnancy product type affects cessation during pregnancy or relapse postpartum. Methods This cross-sectional analysis used pooled data from the 2021–2022 Japan COVID-19 and Society Internet Survey (JACSIS), assessing postpartum women at least 3 months after delivery (median 10.3 months postpartum). Of the 5985 participants, 532 (8.9%) used cigarettes and/or HTPs before pregnancy, categorised as cigarette only, HTPs only or dual use. Transitions across prepregnancy, pregnancy and postpartum were assessed, and multivariable logistic regression examined factors associated with failure to quit during pregnancy and with postpartum relapse. Results Among the 532 women who used cigarettes and/or HTPs before pregnancy, 437 (82.1%) quit during pregnancy. At postpartum follow-up, 315 women (59.2%) reported no tobacco use, 83 (15.6%) reported cigarette-only use, 111 (20.9%) reported HTP-only use and 23 (4.3%) engaged in dual use; 144 of 437 (33.0%) women who ceased use during pregnancy relapsed postpartum. Prepregnancy product type was not significantly associated with failure to quit during pregnancy. However, among those who quit during pregnancy, prepregnancy HTP-only use was associated with higher odds of postpartum relapse than cigarette-only use (adjusted OR: 2.00; 95% CI 1.17 to 3.44). Conclusions Most women stopped tobacco use during pregnancy yet one-third relapsed postpartum. Prepregnancy HTP-only use was associated with postpartum relapse, underscoring the need for targeted perinatal prevention.