The role of depressive symptoms in the pathway of demographic and psychosocial risks to preterm birth and small for gestational age

Objective: depressive symptoms during pregnancy are associated with preterm birth (PTB) and small for gestational age (SGA). Depressive symptoms and PTB and SGA, however, share similar demographic and psychosocial risk factors. Therefore, we investigated whether depressive symptomatology is an independent risk factor, or a mediator in the pathway of demographic and psychosocial risks to PTB and SGA. Design: multicentre follow-up study. Participants and setting: pregnant women (n=1013) from midwifery practices, secondary hospitals and a tertiary hospital in three urban areas in the Netherlands. Measurements: initial risk factors and depressive symptoms were assessed with the Mind2Care instrument, including Edinburgh Depression Scale (EDS) during early pregnancy. Pregnancy outcomes were extracted from medical records. A formal mediation analysis was conducted to investigate the role of depressive symptoms in the pathway to PTB and SGA. Findings: a univariate association between depressive symptoms and PTB (OR:1.04; 95% CI:1.00-1.08) was observed. After adjusting for the risk factors educational level and smoking in the mediation analysis, this association disappeared. One educational aspect remained associated: low education OR: 1.06; 95%-CI:1.02-1.10. Key conclusions: depressive symptomatology appeared no mediator in the pathway of demographic and psychosocial risks to PTB or SGA. The presumed association between depressive symptoms and PTB seems spurious and may be explained by demographic and psychosocial risk factors.