Self-rated health before pregnancy and adverse birth outcomes in Sweden: A population-based register study.

BACKGROUND Poor self-rated health (SRH) at time of childbirth has been associated with adverse birth outcomes. However, it is not known whether prepregnancy SRH contributes to these outcomes or whether SRH is a proxy for some other factors. Therefore, the purpose of this study was to explore the associations between poor SRH before pregnancy and adverse birth outcomes. In addition, maternal characteristics associated with SRH before pregnancy were explored. METHODS A population-based register study encompassing 261 731 deliveries in Sweden between January 2013 and July 2017 was conducted. The associations between poor SRH before pregnancy, rated at first antenatal visit, and the adverse birth outcomes of stillbirth, small for gestational age (SGA), and preterm birth were investigated with logistic regression analyses and presented as crude (OR) and adjusted odds ratios (aOR) with 95% confidence intervals (CI). RESULTS Poor SRH before pregnancy was largely characterized by a history of psychiatric care and was associated with stillbirth (OR 1.37, 95% CI 1.04-1.79), SGA birth (OR 1.29, 95% CI 1.19-1.39), and preterm birth (OR 1.41, 95% CI 1.32-1.50). Adjusting for established risk factors for adverse birth outcomes, poor SRH remained associated with SGA birth (aOR 1.16, 95% CI 1.07-1.26) and preterm birth (aOR 1.25, 95% CI 1.17-1.33), but not with stillbirth (aOR 1.08, 95% CI 0.81-1.43). CONCLUSIONS SRH assessments could be used in early pregnancy to identify women in need of more extensive follow-up, as SRH appears to capture something beyond currently known risk factors for adverse birth outcomes.