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Prepregnancy BMI, gestational weight gain influence C-reactive protein levels in breast milk

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November 30, 2017

Women with a high prepregnancy BMI or those who gain excessive weight during pregnancy are more likely to have higher levels of the inflammatory marker C-reactive protein in breast milk, possibly raising obesity risk in offspring, according to findings in Obesity.

“Obesity is considered a condition of low-grade systemic inflammation; therefore, maternal weight status before, during and after pregnancy could affect the concentrations of CRP and IL-6 found in breast milk,” Kara M. Whitaker, PhD, MPH, of the division of epidemiology and community health at the University of Minnesota in Minneapolis, and colleagues wrote in the study background. “This may have important implications for the infant’s health, as elevated levels of serum CRP and IL-6 are associated with cardiovascular disease, type 2 diabetes and metabolic syndrome.”

Whitaker and colleagues analyzed data from 134 exclusively breast-feeding mother-infant dyads taking part in the Mothers and Infants Linked for Health (MILK) study, who provided breast milk samples. Prepregnancy BMI and gestational weight gain were assessed through medical records; postpartum weight loss and breast milk concentrations of C-reactive protein (CRP) and interleukin-6 were measured at the 1- and 3-month study visits. Researchers used linear regression analysis to examine the associations of maternal weight status with repeated measures of breast milk CRP and Il-6 at 1 and 3 months, after adjustments for maternal age, parity, mode of delivery, gestational age at delivery and lifestyle factors.

For each 1 standard deviation increment in BMI, log-transformed breast milk CRP protein was greater by 0.43 U and 0.49 U (P < .001 for all) in crude and adjusted analyses, respectively.

Excessive gestational weight gain was also positively associated with breast milk CRP levels (beta = 0.68; P < .001), with the association persisting after adjustment for education and gestational age at birth (beta = 0.67; P < .01) and prepregnancy BMI (beta = 0.51; P = .01).

Researchers did not observe an association between gestational weight gain, postpartum weight loss at 1 and 3 months and breast milk CRP.

Researchers observed no associations between maternal BMI or weight gain and levels of Il-6 in breast milk.

“CRP has antimicrobial properties and clear bacterial infections,” the researchers wrote. “If breast milk CRP survives digestion, it could alter the diversity and relative abundance of different intestinal microbiota in early development. Our finding that CRP is elevated in the milk of women with obesity and excessive [gestational weight gain] suggests the need for mechanistic research to delineate the links between maternal nutrition, the wise variety of milk immune factor concentrations and infant outcomes.” – by Regina Schaffer

Disclosures: The authors report no relevant financial disclosures.