A growing mountain of evidence demonstrates that breast-feeding
benefits babies, both psychologically and physically. Turns out it's good
for moms, too.
Breast-feeding, researchers say, may actually reduce the level of
stress hormones that flood a woman's body in response to difficult
Scientists at the National Institute of Mental Health convinced a
group of new mothers--some breast-feeders, some not--to spend 20
less-than-idyllic minutes on a treadmill that became progressively
steeper and faster. It's the same challenging "stress test" doctors use
to assess cardiovascular health.
During the test, levels of stress hormones like cortisol and ACTH
increased in all the women. But in lactating moms, hormone levels rose
only a third to half as much as in moms who relied on bottles, Margaret
Altemus, M.D., and colleagues report in the Journal of Clinical
Endocrinology and Metabolism (Vol. 80, No. 9)
Researchers haven't yet sorted out the chemical cascade through
which lactation alters stress response. But figuring out the process "may
lead us to new treatments for anxiety disorders not just in lactating
women, but for everyone," contends Altemus, chief of the institute's
adult OCD research unit.
As for why a woman's body would mute the stress response during
breast-feeding, Altemus and colleagues offer three theories (more than
one of which could be correct). One possibility is to keep a nursing
mom's immune system healthy and happy; stress can wreak havoc on the
Or it might be an energy conservation strategy. Both stress and
milk production tax the body's resources; cutting back on the stress
response may help ensure new mothers have enough nutrients left to
produce nourishing milk.
Finally, the connection between breast-feeding and stress reduction
could serve as a sort of, well, sanity-preserver. The care and feeding of
an infant can seem overwhelming in the best of circumstances. If a new
mother's stress system were to kick in full-throttle every time the baby
cries or spits up, motherhood might seem even more psychologically
challenging than it already is.