The association between the number of pregnancies and depressive symptoms: A population-based study

Depression is a psychosomatic disorder that affects reproductive health. The number of pregnancies is an important indicator of reproductive health. Multiple pregnancies and births may aggravate the risk of depression in females. However, the evidence of the connection between the number of pregnancies and depression is unclear. We aimed to investigate the relationship between the number of pregnancies and depressive symptoms. We used the National Health and Nutrition Examination Survey (NHANES) data with a total of 17,216 women from 2005 to 2020. The number of pregnancies obtained from the self-report questionnaire. Depressive symptoms were measured by the nine-item patient health questionnaire (PHQ-9). Multivariate logistic regression models were used to examine the risk factors of depression. The restricted cubic spline (RCS) was applied to explore the nonlinear relationship. In addition, subgroup analysis was used to support the accuracy of our findings. We found that the number of pregnancies is positively associated with the prevalence of depression. According to the multivariable logistic regression model, pregnant women were 1.52-fold higher than the normal group to experience depression in the fully-adjusted model. No interaction between number of pregnancies and covariates in subgroups. This study was cross-sectional, which limits its ability to draw conclusions about the causal relationship between the number of pregnancies and depression. In the United States, the number of pregnancies was positively associated with the prevalence of depression. It is critical to register the number of pregnancies for monitoring depressive symptoms.