Increased levels of the hormone, oxytocin, lowers blood pressure in mothers who breast-feed their infants, say researchers. Scientists at the University of North Carolina at Chapel Hill report the findings help explain why breastfeeding mom's report feeling more relaxed after nursing.
Oxytocin is a hormone primarily known for its role in the release of breast milk. But it also appears to lower blood pressure through effects on blood vessels, and helps turn off the body's stress response system, explained lead researcher Dr. Kathleen C. Light. Higher blood levels of oxytocin may also boost mood and decrease sensitivity to pain, she said. "For breastfeeding moms, the message is enjoy these times of closeness when you nurse you baby, and notice the warm relaxed feeling it gives you. This may be the sign do you are benefiting from oxytocin."
About 50% of breastfeeding moms observed had high levels of oxytocin, compared with only 8% of moms who bottle-fed their babies And, participants who had the greatest rise in oxytocin levels showed blood pressure readings an average of 10mm Hg lower I hour following feeding, 6 - 9 mm Hg lower during sleep and 4 - 5 mm Hg lower during the day.
In addition, breast-feeding had a calming effect on the volunteers. Dr. Light, explained that, "High oxytocin responding mothers also seemed to have less angry or hostile feelings and more positive mood and interpersonal interactions, based on questionnaires." The new findings "are another reason to breastfeed,' she added.
Smith TE, Johns JM, Chung SH, Adamain W, Hofheimer JA, Light KC Oxytocin relationships to blood pressure in breast- and bottle-feeding mothers of infants American Psychosomatic Society March 20, 1999