Breastfeeding and the basal insulin requirement in type 1 diabetic women.

OBJECTIVE: To evaluate whether breastfeeding in women with type 1 diabetes mellitus is associated with a decreased insulin requirement. METHODS: In this prospective study conducted between September 2006 and August 2008, type 1 diabetic pregnant women were recruited before the third trimester of pregnancy. Eligible women had no evidence of diabetes-related complications and were treated with continuous subcutaneous insulin infusion pump therapy. During pregnancy and in the first 8 weeks of the postpartum period, participants performed daily fingerstick blood glucose monitoring with at least 12 measurements per day; insulin dosages were adjusted to maintain normoglycemia. Participant characteristics, diabetic parameters, and neonatal growth were compared between women who breastfed exclusively and women who did not breastfeed. RESULTS: Of 18 women, 12 breastfed and 6 did not. Compared with nonbreastfeeding mothers, breastfeeding mothers showed a decreased need for total daily basal insulin (0.21 +/- 0.05 units/kg per day vs 0.33 +/- 0.02 units/kg per day). The mean value of total daily basal insulin was significantly lower in the breastfeeding group than in the non-breastfeeding group. The mean number of hyperglycemic episodes in the first 2 weeks post partum and during the third to eighth weeks was not different between the groups. However, the mean number of hypoglycemic episodes in the first 2 weeks post partum in the breastfeeding group was significantly higher than in the nonbreastfeeding group (11.9 +/- 2.6 episodes vs 5.5 +/- 1.6 episodes, P<.001). No differences were observed between the groups in neonatal birth weight or infant weight after 8 weeks of age. CONCLUSIONS: Decreased need in total daily basal insulin is caused by increased glucose use during lactation. We recommend that the starting total daily basal insulin dosage for type 1 diabetic women who breastfeed be calculated as 0.21 units times the weight in kg per day. This regimen results in normoglycemia and minimizes the risk of severe hypoglycemia associated with lactation.

Using meal-based self-monitoring of blood glucose as a tool to improve outcomes in pregnancy complicated by diabetes.

OBJECTIVE: To review the importance of controlling blood glucose levels and the role of self-monitoring of blood glucose (SMBG) in the management of pregnancy complicated by diabetes. METHODS: This report describes the relationship between hyperglycemia and maternal and neonatal complications, reviews the utility of meal-based SMBG in modifying food choices and adjusting insulin doses, and proposes an algorithm to achieve normoglycemia in pregnancies complicated by diabetes. RESULTS: The risk of diabetes-related complications in pregnancy is more strongly associated with 1-hour postprandial plasma glucose concentrations than with fasting plasma glucose levels. SMBG strategies that incorporate postprandial glucose testing provide better glycemic control and greater reductions in risk of complications than does preprandial glucose testing alone. Although the optimal timing and frequency of SMBG remain controversial, available clinical evidence supports testing 4 times per day (before breakfast and 1 hour after each meal) in women with gestational diabetes managed by medical nutrition therapy only and 6 times per day (before and 1 hour after each meal) in pregnant women treated with insulin. CONCLUSION: Meal-based SMBG is a valuable tool for improving outcomes in pregnancy complicated by diabetes. The lessons learned in this setting should have relevance to the general population of patients with diabetes, in whom microvascular and macrovascular complications are the outcomes of importance.