Background: Other than premenstrual dysphoria, few studies have examined the extent to which basic characteristics of the menstrual cycle and the occurrence of other reproductive landmarks impact on the risk of major depression.
Methods: From a population-based sample of 4161 premenopausal women 36-45 years of age, we identified 332 women who met DSM criteria for past or current major depression and a sample of 644 women with no such history. In person interviews included a detailed assessment of menstrual cycle characteristics from age at menarche through study enrollment as well as other reproductive landmarks.
Results: Risk of depression increased significantly with decreasing age at menarche (P<0.001). The risk of depression was also higher in women with heavier menstrual flow and cycle irregularity during the first 5 years of menstruation. Women with a history of multiple abortions were 2-3-times more likely to develop major depression (95% CI 1.6-4.1). Increasing months of breastfeeding was associated with a decreased risk of depression after adjustment for education, marital status, and number of livebirths (P-value, test of trend=0.012). This association was largely confined to depression during the postpartum period.
Limitations: Menstrual and pregnancy history exposures were self-reported and retrospectively assessed. However, women with and without a HISTORY of depression were subject to similar recall requirements that likely resulted in an underestimate of most risk estimates.
Conclusions: Clinicians involved in routine obstetrical and gynecological care of women need to recognize that menstrual and pregnancy history events may serve as potential markers for subsequent psychiatric sequelae.