Optimal age at first birth for lower anxiety risk: findings from the NHANES 2007–2012

Objective: Anxiety disorders are more prevalent among women, but the relationship between reproductive factors and anxiety risk remains inadequately explored. Therefore, this study evaluated the associations of reproductive factors—namely, age at first birth (AFB), age at last birth (ALB), number of live births (NLB), and number of pregnancies—with anxiety risk among women to provide evidence for the development of targeted interventions and improvement of mental health outcomes. Methods: Using data from 4,761 female participants in the National Health and Nutrition Examination Survey (NHANES 2007–2012), we conducted multivariable-adjusted logistic regression to assess associations of AFB, ALB, NLB, and number of pregnancies with anxiety. Anxiety symptoms were assessed using the Health-Related Quality Of Life questionnaire. To explore potential effect modification, further analyses stratified by age, hysterectomy status, female hormone use, and race were performed. Results: A significant inverse linear dose-response relationship was observed between AFB and anxiety ( P for trend < 0.001). Specifically, women with an AFB between 21 and 32 years exhibited reduced odds of anxiety compared with those with an AFB <18 years. Multiparous women (≥5 vs ≤2 pregnancies) had a higher anxiety risk after adjustment for age and race (OR = 1.397, P = 0.003). Stratified analyses revealed significant age-dependent associations between an older ALB and anxiety risk ( P for interaction = 0.036). Notably, an older ALB was associated with increased anxiety risk among women aged 45 years or older compared with women aged <18 years. Conclusion: These findings highlight the potential importance of AFB, particularly 21–32 years, in relation to anxiety symptoms, indicating that reproductive timing is associated with anxiety risk.