We also found that the beneficial effects of breastfeeding
were strongest at 8 weeks after birth, and that the
association was weaker at 8 months and onwards. This
finding is in line with the findings of the only other longitudinal
research in this area [37] which significant effects
at 6 weeks but not at 12 weeks postpartum. Our results are
nevertheless important, because of the established relationship
between depression, even in the very early postpartum
period, and maternal-infant bonding [38].
Estimates for the smaller group of mothers who had
shown signs of depression during pregnancy were less
precise, but differed from the estimates for non-depressed
women in two important ways. The protective effects of
breastfeeding as planned were smaller for women who had
been depressed during pregnancy; but exclusive breastfeeding
for 4 weeks appeared to exercise a protective effect
for this group, which it did not do for the women who had
not been depressed in pregnancy