Psychological well-being in early pregnancy and pregnancy outcomes: A cohort study

OBJECTIVE: Mental health status during pregnancy may matter for both maternal and infant outcomes. We aimed to evaluate the association between psychological well-being during early pregnancy and pregnancy outcomes: preeclampsia, preterm birth, and fetal growth deviations. METHODS: The study sample comprised 36,835 women from the Copenhagen Pregnancy Cohort with complete data on psychological well-being during early pregnancy, who gave birth to live-born singletons from October 2012 to December 2022. The exposure of interest was low psychological well-being, defined as a score of ≤ 50 on the World Health Organization-5 Well-Being Index (WHO-5 index). The outcomes were preeclampsia, preterm birth, and fetal growth deviations -defined as small for gestational age (SGA) and large for gestational age (LGA) - identified using Danish national registries. Multivariable logistic regression analyses were conducted to estimate associations, while adjusting for relevant a priori selected covariates. RESULTS: We found that women with low psychological well-being measured on the WHO-5 index had a statistically significantly lower risk of preeclampsia compared to those with higher psychological well-being (adjusted odds ratio 0.81, 95% CI: 0.69-0.95, p = 0.009). No significant associations were found for preterm birth or fetal growth deviations (SGA and LGA). CONCLUSIONS: Low psychological well-being measured by the WHO-5 index was associated with a lower risk of preeclampsia, while no associations were found for preterm birth or fetal growth deviations. This finding highlights the complex interplay between maternal mental health and pregnancy outcomes. Future studies are needed to evaluate whether this finding replicates and clarify their clinical implications.