Childhood abuse and unplanned pregnancies: a cross-sectional study of women in the Norwegian Mother and Child Cohort Study

Objective To study if childhood emotional, physical and sexual abuse are determinants for having an unplanned pregnancy, if the categories of abuse interact, and if a potential bias due to the selection of the participants (collider stratification bias) could explain the effect of childhood abuse. Design A cross-sectional study. Setting The study is based on the Norwegian Mother and Child Cohort Study (MoBa) and uses data from the Medical Birth Registry of Norway. Sample Women participating in the MoBa for the first time, >= 18 years of age who responded to questions regarding childhood abuse and pregnancy planning (n = 76 197). Methods Data were collected using questionnaires. We conducted analyses using modified Poisson regressions and the relative excess risks due to interaction (RERI). Sensitivity analyses were performed. Main outcome measure An unplanned pregnancy (yes/no). Results Exposure to childhood emotional (adjusted relative risk (RR) 1.14, 95% CI 1.10-1.19), physical (adjusted RR 1.11, 95% CI 1.04-1.18) and sexual (adjusted RR 1.20, 95% CI 1.14-1.27) abuse increased the risk of having an unplanned pregnancy. The effects could not be explained by the collider stratification bias. The different combinations of categories of abuse did not show any interaction effects. Conclusions Childhood emotional, physical and sexual abuses separately increase the risk of having an unplanned pregnancy. The results indicate that victims of childhood abuse are in greater need of support to achieve their reproductive goals. Tweetable abstract Childhood abuse increases the risk of having an unplanned pregnancy. #reproductivehealth #epitwitter.