Years of education mediate the association between adverse childhood experiences and unintended pregnancy: A population-based study in Japan.

Background: Adverse childhood experiences (ACEs) have been associated with unintended pregnancies, including mistimed pregnancies (MP) and unwanted pregnancies (UWP). However, it remains unknown which cluster of ACEs (i.e., child maltreatment/household dysfunction and deprivation/threat) are associated with MP/UWP and whether years of education mediate these associations.
Objective: To investigate the association of the clusters of ACEs with MP and UWP, while also examining the mediating effect of education years.
Participants and Setting: A retrospective cohort study among 7652 postpartum women in Chiba, Japan.
Methods: MP/UWP was defined by emotional responses to confirming pregnancy. Multinomial logistic regression analyses with multiple imputed datasets estimated the relative risk ratio (RRR) of MP/UWP by cumulative scores and each cluster of ACEs. Causal mediation analysis assessed the indirect effects of years of education.
Results: Women with 4 or more ACEs were at a 2.4 times higher risk of MP (95 % confidence interval (CI): 1.6-3.8) and a 5.0 times higher risk of UWP (95 % CI: 3.1-8.2). Among ACE clusters, having 3 or more household dysfunction showed the strongest association with MP (RRR: 1.91, 95 % CI: 1.23-2.95), and having 3 or more deprivation showed the strongest association with UWP (RRR: 3.69, 95 % CI: 2.00-6.83). Education years mediated 16 % and 11 % of the association between total ACEs and MP/UWP, respectively, with a similar trend observed in each cluster.
Conclusions: Not only ACEs score but also each cluster of ACEs was associated with MP and UWP. The mediating effects of years of education were modest.
Competing Interests: Declaration of competing interest None.
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