The association between threatened miscarriage in early pregnancy and depression or anxiety in offspring in late adolescence

Background: Adolescent mental health is a known determinant of health across the lifespan underscoring the importance of identifying determining factors. Threatened miscarriage is a common pregnancy complication, yet its influence on child mental health outcomes is unclear. Here we examined the association between pregnancies complicated by threatened miscarriage and the risk of offspring depression or anxiety in late adolescence using the representative longitudinal UK Millennium Cohort Study. Methods: Maternal reported data on threatened miscarriage and potential confounders were collected at 9-months postpartum. Data on depression and anxiety were collected as one variable when children were aged 17 years using self-reported doctor diagnosis. Multivariable logistic regression adjusted for several maternal and sociodemographic factors. We examined separate interaction effects for threatened miscarriage and hypertensive disorders of pregnancy, small for gestational age (SGA) and preterm birth. Results: N = 9521 mother-child dyads were included in the analyses, with n = 574 (6 %) women experiencing a threatened miscarriage, and 978 (10.3 %) children reported depression or anxiety diagnosis. Adjusted results suggested that threatened miscarriage was associated with a 34 % increase in the odds of depression or anxiety (OR: 1.34, 95 % CI 1.03, 1.73). An interaction effect was observed for threatened miscarriage and SGA (OR: 2.09, 95 % CI: 1.01, 4.36) and threatened miscarriage and preterm birth (OR:2.23, 95 % CI: 1.26, 3.95). Conclusion: Threatened miscarriage was associated with an increased odds of depression or anxiety in offspring by age 17 years, albeit residual and unmeasured confounding cannot be ruled out. Future research should examine the potential biological mechanisms mediating this association.