(HealthDay News) — Young women who breastfeed may have a reduced risk for early subclinical atherosclerosis during midlife, compared with those who bottle feed their babies, according to research published in Obstetrics & Gynecology.
The findings are based on 846 U.S. women who, in the 1980s, enrolled in a long-term study of cardiovascular (CV) health. They were between the ages of 18 and 30 at the time. All of the women underwent ultrasound scans of the carotid artery 20 years after entering the study.
The researchers found that, on average, women who had breastfed their babies for 1 month, or not at all, had higher common carotid intima-media thickness, whereas those who had breastfed for 10 months or longer had lower common carotid intima-media thickness.
Mean differences in carotid intima-media thickness between those who breastfed for 10 months or longer vs. 0 to less than 1 month ranged from –0.062 mm for unadjusted models (P for trend<.001) to –0.029 mm for models adjusted for prepregnancy BMI and cardiometabolic risk factors, parity, smoking and sociodemographics (P for trend=.010).
The association between lactation and carotid intima-media thickness was modestly attenuated to –0.027 mm and –0.023 mm after stepwise addition of potential mediators, including BMI, systolic blood pressure at 20-year follow-up (P for trend=.019 and .054).
“Pregnancy is an incredibly stressful physiologic process,” lead researcher Erica Gunderson, PhD, MPH, of Kaiser Permanente Northern California’s division of research in Oakland, told HealthDay. “It puts greater demands on the cardiovascular and metabolic systems.”
Breastfeeding, she said, may help “reset” those systems after pregnancy.