Causal associations of mood swings with preterm birth: a Mendelian randomization analysis

Mood swings are associated with an elevated risk of preterm birth. However, the causal relationships between them still remain unclear. We performed a two-sample Mendelian randomization (MR) analysis to clarify the association between mood swings and preterm birth. To investigate the proportion mediated by recognized risk factors, we applied two-step MR mediation analyses. Three regression methods were used in MR analyses and using inverse-variance weighted (IVW) as main method. The MR analysis included 373,733 individuals with data on mood swings and 204,913 participants with data on preterm birth. The results demonstrated significant causal effects of mood swings on preterm birth (OR = 1.761, 95% confidence interval (CI): 1.151, 2.692). Further mediation analysis indicated hypertension (7.283%, 95% CI: 0.387–15.394%) and high cholesterol (5.012%, 95% CI: 1.302–8.613%) may mediate the causal pathways from mood swings to preterm. Mood swings have a notable causal impact on preterm birth, partly mediated by hypertension and high cholesterol.