Infant Growth Faltering Linked to Subclinical Mastitis, Maternal Fecal-Oral Contamination and Breastfeeding Practices.

Infant growth faltering occurs in breastfed infants < 6 months of age. The possibility that maternal health status contributes to this growth faltering is underexplored. We investigated whether 1) subclinical mastitis (SCM), an asymptomatic inflammation of the breast, 2) maternal intestinal nematode and protozoan infections, indicators of fecal-oral contamination or 3) poor breastfeeding practices increased the odds of stunting (LAZ < -2SD), underweight (WAZ < -2SD) or low head circumference (HCAZ < -2SD) in breastfed infants in rural indigenous communities in Guatemala. Mother-infant dyads (n = 105) were subdivided into those with and without SCM (milk Na:K ratio > 0.6). Maternal and infant anthropometry were measured at the time of breast milk collection. Maternal stool samples were examined for the presence of intestinal nematodes and protozoa. Questionnaires were used to characterize breastfeeding practices (exclusivity, frequency) and support, hygiene (latrine use, household faucet) and infant diarrhea. SCM occurred in 14% of women and was associated with increased odds of infant stunting (OR=4.3; CI 1.1, 15.8), underweight (OR=9.2; CI 1.8, 48.0) and low head circumference (OR=15.9; CI 2.6, 96.9). Maternal pathogenic protozoa and nematodes were uncommon (<4%), but non-pathogenic protozoa were common (e.g. Entamoeba coli (39%)). Entamoeba coli increased the likelihood (OR=3.3; CI 1.02, 10.6) of low head circumference whereas higher breastfeeding frequency lowered its odds (OR=0.74, CI 0.56-0.97). Prevention of SCM may improve early infant growth, but public health measures that increase breastfeeding frequency and reduce fecal-oral contamination may be required to minimize low head circumference.