I apologize if this has already been posted. I got it from an Internet
clipping service.

Bonny Nothern, IBCLC

APS MEETING: Breast-Feeding Hormone Lowers Nursing Moms' Blood Pressure



CHAPEL HILL, NC -- March 17, 1999 -- A new study at the University of North
Carolina at Chapel Hill links increased levels of the hormone oxytocin to
lower blood pressure among mothers who nurse their babies.
The findings help explain why many breast-feeding mothers report feeling
mellow and relaxed after nursing.
"Oxytocin is most commonly known for its role in the letdown of milk during
breast-feeding, but also has effects on brain areas involved in emotion and
stress responses," said Dr. Kathleen Light, the study's senior investigator
and professor of psychiatry at the UNC-CH School of Medicine.
The results -- reported for the first time today at the American
Psychosomatic Society annual meeting in Vancouver, B.C. -- demonstrated that
mothers with higher oxytocin levels in the blood had lower blood pressure
before and after discussing recent life problems.
The UNC-CH study involved 26 mothers of infants; 14 breast-fed their babies
and 12 bottle-fed them. Blood pressure and blood levels of oxytocin were
measured before, during and after the stressful speech experience.
"A high oxytocin response appeared to help the mother limit the duration of
the stress response," Light explained. "She showed a normal response during
the stressful task, but less evidence of stress anticipating the event or
recovering after it. Through their questionnaires, high oxytocin-responding
mothers also seemed to have less hostile feelings and more positive mood and
interpersonal interactions."
The lower blood pressure seen in the laboratory part of the study continued
when the mothers had 24-hour monitoring at home. Blood pressure levels of
high oxytocin reactors were 10 points lower than that of other women for one
hour after feeding and six to nine points lower during sleep. They were also
about four to five points lower during daytime ambulatory monitoring, Light
said. The study suggests that mothers who nurse their infants are much more
likely to be high oxytocin reactors than bottle-feeders, 50 percent versus
eight percent.
"Parenting is such a stressful time, especially in the beginning," said Tara
Smith, presenting study author and student assistant. "Biologists may know
much more about the causes of increases in stress. But it is very exciting
to find out more about what causes decreases in stress."

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