Associations between reproductive factors and the prevalence of depression: findings from the National Health and Nutrition Examination Survey (NHANES) 2005-2018.

Background: This study aims to explore the relationship between female reproductive factors (age at first birth (AFB), age at last birth (ALB), gravidity, and number of live birth (NLB)) and prevalence of depression among the US women.

Methods: The relationship between AFB, ALB, gravidity, and NLB with the prevalence of depression was explored using publicly available data from the National Health and Nutrition Examination Survey 2005-2018. This cross-sectional study included female participants aged 20 years and older, with reproductive factors and depressive symptoms reported by the participants. Depression was evaluated using the Patient Health Questionnaire-9, with a score of ≥ 10 representing major depression disorder. Weighted multivariable logistic regression and restricted cubic splines (RCS) were utilized to explore the association of AFB, ALB, gravidity and NLB with depression.

Results: In this study of 11,488 US women, 1,332 (11.6%) women had depression. Compared to the reference group of women with AFB under 18 years, the fully adjusted ORs and 95% CIs for depression were 0.83 (95% CI: 0.68-0.99), 0.75 (95% CI: 0.60-0.95), and 0.69 (95% CI: 0.51-0.93) for women with AFB of 21-23, 24-26, and 27-29 years, respectively. Furthermore, women with five or more pregnancies had a significantly higher prevalence of depression compared to those with two or fewer pregnancies (OR = 1.20, 95% CI: 1.01-1.42). RCS models demonstrated linear associations of ALB, gravidity and NLB with the prevalence of depression. Additionally, the RCS analysis revealed a roughly L-shaped relationship between AFB and prevalence of depression.

Conclusions: Women with later AFB are associated with a decreased prevalence of depression, while multiple pregnancies are associated with an increased prevalence of depression. These findings suggest that reproductive factors should be considered when screening for and developing preventive strategies for depression.