Hormonal predictors of postnatal depression at 6 months in breastfeeding women

Postnatal depression occurs in 10-15% of postpartum women. Studies have shown associations with endogenous hormone levels (oestrogen, progesterone, cortisol and thyroxin) and with autoimmune thyroid dysfunction. Breastfeeding has not been shown to increase the risk of developing postpartum depression. A prospective study involving 54 breastfeeding mothers of mixed parity and similar socio-economic status and education used bivariate analysis to look for associations between hormone levels and postnatal depression. Total oestradiol, total progesterone, prolactin and thyrotropin (TSH) levels were determined at four time points (ante- and postnatally) from finger-prick blood spots by fluoro-immunoassay. EPDS and life event check lists were completed at 6 months postpartum. Ten women were screened positive for sub-clinical depression (score≥10). Bivariate analysis showed that antenatal prolactin and postpartum progesterone levels were significantly associated with postnatal depression at 6 months (p=0.03). Only the result for progesterone persisted in a multiple logistic regression, which controlled for life events. Women with lower progesterone levels in the immediate postnatal period were more likely to be depressed at 6 months.