(Medical Xpress) -- While the benefits of breastfeeding for the baby are well established and some studies have shown that mothers who breastfeed have lower risks of diabetes, high cholesterol and heart disease, a new study published in the American Journal of Epidemiology shows that breastfeeding may also have another benefit for the mother.
Experts recommend that new mothers breastfeed their babies exclusively for the first six months and then continue until age one as a supplement to solid food. Breastfeeding has been shown to help babies fight against diarrhea and ear infections.
This new study, led by Dr. Alison M. Stuebe from the University of North Carolina, was designed to look for a possible connection between breastfeeding and the development of high blood pressure in mothers.
Researchers looked at 56,000 U.S. women that were a part of the Nurses Health Study II. Each participant had given birth to at least one child. They discovered that 8,900 women developed high blood pressure, but women who had not breastfed their child were 22 percent more likely to develop high blood pressure than those mothers that had breastfed for at least six months.
While these results do not prove a direct connection between breastfeeding and a reduced risk for developing high blood pressure, there is evidence in animal research that the hormone oxytocin, which plays a role in breastfeeding, has a lasting effect on blood pressure.
Because of this possible connection and the other proven health benefits for both mother and baby connected to breastfeeding, researchers recommend that breastfeeding be encouraged and made easier. They recommend that lactation counseling be more readily available and not dependent on insurance coverage.
Current laws require employers with more than 50 workers provide 12 weeks of un-paid maternity leave. Stuebe recommends that paid maternity leave and required break times at work to allow for breast pumping may encourage and allow more mothers to breastfeed.
Explore further: Warning to breastfeeding mothers
More information: Duration of Lactation and Incidence of Maternal Hypertension: A Longitudinal Cohort Study, Am. J. Epidemiol. (2011) doi: 10.1093/aje/kwr227
Never or curtailed lactation has been associated with an increased risk for incident hypertension, but the effect of exclusive breastfeeding is unknown. The authors conducted an observational cohort study of 55,636 parous women in the US Nurses Health Study II. From 1991 to 2005, participants reported 8,861 cases of incident hypertension during 660,880 person-years of follow-up. Never or curtailed lactation was associated with an increased risk of incident hypertension. Compared with women who breastfed their first child for ≥12 months, women who did not breastfeed were more likely to develop hypertension (hazard ratio (HR) = 1.27, 95% confidence interval (CI): 1.18, 1.36), adjusting for family history and lifestyle covariates. Women who never breastfed were more likely to develop hypertension than women who exclusively breastfed their first child for ≥6 months (HR = 1.29, 95% CI: 1.20, 1.40). The authors found similar results for women who had never breastfed compared with those who had breastfed each child for an average of ≥12 months (HR = 1.22, 95% CI: 1.13, 1.32). In conclusion, never or curtailed lactation was associated with an increased risk of incident maternal hypertension, compared with the recommended ≥6 months of exclusive or ≥12 months of total lactation per child, in a large cohort of parous women.