Purpose: To determine the influence of breastfeeding on the results of a postpartum oral glucose tolerance test in women recently diagnosed with gestational diabetes mellitus.
Methods: The data were obtained from the electronic medical records of the Endocrinopathy Sector during pregnancy, HCMED laboratory system ofHospital das Clínicas of São Paulo , and by telephone. According to the inclusion criteria adopted, 132 patients were eligible for the study. For statistical analysis, the patients were divided into two groups according to whether or not they breastfed. The results were analyzed by the Student t-test and by the Mann-Whitney, Chi-square and Fisher's exact tests, depending on the variable analyzed, with the level of significance set at p<0.05.
Results: Of the 132 patients included in the study, 114 breastfed and 18 did not. Most of the patients in both groups were overweight or obese. The breastfeeding group had a lower pre-pregnancy Body Mass Index than the non-breastfeeding group (p=0.006). Insulin was introduced earlier in the group that did not breastfeed (23.21±4.33 versus 28.84±6.17; p=0.04). The group that did not breastfeed had a higher mean postpartum fasting glucose value in the oral glucose tolerance test than the group that breastfed (91.3±8.7 versus 86.5±9.3; p=0.01). Breastfeeding acted as a protective factor against the development of glucose intolerance in the postpartum oral glucose tolerance test (OR=0.27; 95%CI 0.09-0.8). By logistic regression, breastfeeding was shown to be an independent protective factor.
Conclusion: There was a statistically significant relationship between breastfeeding and a decreased risk of developing glucose intolerance. Breastfeeding should be encouraged because it is an effective, low cost intervention easily accessible to all patients during the postpartum period.