The purpose of the study was to examine demographic, immune, endocrine, stress and
health characteristics of depressed mothers, measured between 4 and 6 weeks
postpartum, and compare them to non-depressed mothers. The top decile (N ¼ 25) of
Profile of Mood States depression scores was used to categorize mothers as depressed and
these data were then compared to means of the remaining mothers (N ¼ 175) in a study of
stress and immunity during the postpartum. Depressed mothers were younger, had smaller
birth weight infants, and their babies experienced more illness symptoms at 4–6 weeks
postpartum. Depressed mothers were less likely to be breastfeeding and had lower serum
prolactin levels. Depressed mothers were more likely to smoke, to have daytime
sleepiness, and more symptoms of infection than non-depressed mothers. Depressed
mothers also had higher perceived stress, postpartum stress, and negative life event
reports.
There was evidence suggesting that depressed mothers had a downregulated hypothalamic–
pituitary–adrenocortical (HPA) axis, in that salivary cortisol was lower in depressed
mothers. Depressed mothers also had lower serum levels of Interferon-gamma (IFN-g) and
a lower IFN-g/Interleukin-10 (IL-10) ratio in both sera and in whole blood stimulated
cultures, suggesting a depressed Th1/Th2 ratio in depressed mothers. The data supports
the possibility that postpartum depression may be associated with a dysregulated HPA axis
and possible depressed cellular immunity.