Subclinical mastitis may not reduce breastmilk intake during established lactation.

OBJECTIVE

This study determined the effect of subclinical mastitis (SCM) on infant breastmilk intake.

DESIGN

Participants (60 Ghanaian lactating mothers and their infants) were from periurban communities in the Manya Krobo district of Ghana in 2006-2007. Bilateral breastmilk samples were obtained once between months 3 and 6 postpartum and tested for SCM using the California mastitis test (CMT) and the sodium/potassium (Na/K) ratio. Infants' 12-hour breastmilk intake was assessed by test weighing. CMT scoring for SCM diagnosis was scaled as >or=1 = positive (n = 37) and <1 = negative (n = 23). SCM diagnosis was confirmed as a Na/K ratio of >1.0 (n = 14).

RESULTS

Breastmilk intake was nonsignificantly lower among infants whose mothers had elevated Na/K ratios of >1.0 (-65.1 g; 95% confidence interval -141.3 g, 11.1 g). Infants whose mothers were positive for SCM with both CMT and Na/K ratio criteria had significantly lower breastmilk intake (-88.9 g; 95% confidence interval -171.1 g, -6.9 g) compared to those whose mothers tested either negative with both tests or positive on only one. Infant weight (p < 0.01) and frequency of feeding (p = 0.01) were independently associated with breastmilk intake. However, the effect of SCM on breastmilk intake disappeared when infant weight and feeding frequency were included in a multiple linear regression model.

CONCLUSIONS

The results of this study did not show an effect of SCM on breastmilk intake among 3-6-month-old infants. A larger sample size with a longitudinal design will be needed in future studies.