Subclinical mastitis, defined as raised milk sodium/potassium (Na/K) in the absence of clinical symptoms, is associated with poor infant weight gain and increased risk of mother-to-child HIV transmission. Similarly to clinical mastitis, subclinical mastitis appears to have multiple causes, one being poor lactation practice. We investigated whether a single session of lactation counselling around the time of delivery could decrease subclinical mastitis among women in rural Bangladesh. The counselling messages included the importance of giving colostrum, exclusive breastfeeding, feeding on demand and how to achieve good positioning and attachment. Women who had delivered prior to our instituting the counselling intervention (mean 1 month) constituted the uncounselled group. At 1 month postpartum, sodium and potassium were measured in spot milk samples from each breast by flame photometry and interleukin-8 (IL8) by ELISA. Geometric mean Na/K ratios and the proportion of milk samples with raised Na/K ratio were significantly (p < 0.05) lower in the counselled group [mean 0.42, 95% confidence interval (CI) 0.39-0.45, n = 116 samples; 10% Na/K ratio > 0.6] than in the non-counselled group [mean 0.49, 95% CI 0.45-0.53, n = 127; 25% Na/K ratio > 0.6]. Milk IL8 concentration did not differ between groups. The results show that among Bangladeshi women a simple lactation counselling intervention could improve lactation practice in ways likely to improve infant health.
