Continuous Glucose Monitoring During Breastfeeding in Women with Recent Gestational Diabetes Mellitus

This study monitored blood glucose profiles in normotolerant breastfeeding women, with and without previous gestational diabetes, in real life in order to identify normal blood glucose fluctuations during breastfeeding. Two groups were studied: (1) 18 women with recent gestational diabetes mellitus but normotolerant postpartum (pGDM-N group) and (2) 15 women normotolerant both during pregnancy and postpartum (pN-N group). All participants underwent continuous glucose monitoring during which they recorded their main daily activities and three standardized events: "suckling," "meal," and "meal and suckling." Other than these three events, these women were essentially on an "ad lib" diet. Data were expressed as median and SD values. Student's t test and Fisher's test were used to compare mean, variances, and percentages. Differences were significant with P<0.05. Clustering analysis was used to determine the normal range of glucose values. The two groups were matched for age, follow-up duration, and monitoring measurements but not for body mass index. Blood glucose levels and variances were higher in the pGDM-N group, particularly during daytime and the three standardized events, and were not related to body mass index. Suckling had no direct effect on glucose profile during both the non-fed and the fed state. Blood glucose levels that best represent the normal breastfeeding population were between 50 and 126 mg/dL (from 2.8 to 7.0 mmol/L). Three months after delivery, normotolerant women with recent gestational diabetes had higher daily blood glucose levels than women who were always normotolerant, with no direct effect of suckling. The blood glucose profiles of healthy subjects could be representative of the normal range of the population during breastfeeding.