Is Insulin Safe in Breastfeeding

I am a breastfeeding mother and i want to know if it is safe to use Insulin? Is Insulin safe for nursing mother and child? Does Insulin extracts into breast milk? Does Insulin has any long term or short term side effects on infants? Can Insulin influence milk supply or can Insulin decrease milk supply in lactating mothers?

Insulin is a component present in breast milk that helps to lower the risk for Diabetes Mellitus Type I among breastfed infants. A small quantity of insulin is absorbed orally which is a factor that promotes maturation of the intestine, induces glucose tolerance and prevents development of Diabetes type 1. Insulin requirements decrease about 25% after birth in diabetic mothers who breastfeed their babies. Those mothers are in need of higher self-control of disease, and, higher caloric intake is required (500 to 800 kcal/day). Attachment and nursing should be started as soon as possible since second stage of Lactogenesis may be delayed in diabetic mothers. Diabetic mothers who breastfeed would attain a better metabolic control of the disease while breastfeeding.

Mothers with diabetes using insulin may nurse their infants.[1] Exogenous insulin is excreted into breastmilk, including newer biosynthetic insulins (e.g., aspart, glargine glulisine, lispro). Insulin is a normal component of breastmilk and may decrease the risk of type 1 diabetes in breastfed infants.[2][3][4] Pasteurization of milk by the Holder method reduces the concentration of insulin by about half.[5] Insulin requirements are reduced postpartum in women with type 1 diabetes.[1][6] In one study, insulin requirements were lower than prepregnancy dosage only during the first week postpartum: 54% of prepregnancy dosage on day 2 and 73% on day 3 postpartum. On day 7 postpartum, insulin dosage returned to prepregnancy requirements.[7] Another study found that dosage requirements did not return to normal for up to 6 weeks in some mothers.[8] A third study found that at 4 months postpartum, patients with type 1 diabetes who exclusively breastfed had an average of 13% lower (range -52% to +40%) insulin requirement than their prepregnancy requirement.[9] A retrospective case-control study found a 34% decrease in postpartum insulin requirement compare to preconception values. There was a nonsignificant trend towards lower requirements in exclusively breastfeeding mothers compared to partial or full formula feeding.[6] Breastfeeding appears to improve glucose postpartum glucose tolerance in mothers with gestational diabetes mellitus[10][11] and in normal women.[12] A small, well-controlled study of women with type 1 diabetes mellitus using continuous subcutaneous insulin found that the average basal insulin requirement in women with type 1 diabetes who breastfed was 0.21 units/kg daily and the total insulin requirement was 0.56 units/kg daily. In similar women who did not breastfeed, the basal insulin requirement was 0.33 units/kg daily and the total insulin requirement was 0.75 units/kg daily. The 36% lower basal insulin requirement was thought to be caused by glucose use for milk production.[13] Lactation onset occurs later in patients with type 1 diabetes than in women without diabetes, with a greater delay in mothers with poor glucose control.[7][14] Mothers with type 1 diabetes also discontinue nursing at a higher rate during the first week postpartum.[15][16][17] Women with any form of diabetes during pregnancy had more problems with low milk supply than women without diabetes.[18] Once established, lactation persists as long in mothers with diabetes as in mothers without diabetes.[14][19] However, as in women without diabetes, smoking has a strong negative impact on lactation among mothers with type 1 diabetes.[9][20] Other factors that have been identified as causes of shorter duration of breastfeeding among type 1 diabetic patients are more frequent caesarean sections and earlier delivery.[21] Among patients with gestational diabetes, those treated with insulin have a delayed onset of lactogenesis II compared to those not treated with insulin.[22]

Relevant published information was not found as of the revision date. Insulin in breastmilk is thought to be necessary for intestinal maturation of the infant and may help decrease the risk of contracting type 1 diabetes in breastfed infants.[2][3]

Proper insulin levels are necessary for lactation. Good glycemic control enhances maternal serum and milk prolactin concentrations and decreases the delay in the establishment of lactation that can occur in mothers with type 1 diabetes.[14][29] One-hundred two of 107 consecutive mothers with type 1 diabetes mellitus who delivered were followed at a Danish hospital. Mothers were given prenatal information on breastfeeding and were offered postnatal counseling by a nurse on the benefits of breastfeeding. All infants were admitted to the neonatal intensive care unit at about 2 hours of age for the following 24 hours. When possible, mothers either breastfed or pumped milk for their infants during this time. Mothers were contacted at 5 days and 4 months postpartum to determine their breastfeeding status. The rates of initiation of exclusive and nonexclusive breastfeeding and exclusive formula feeding and the rates at 4 months postpartum were no different from those of the Danish population.[9] Eight hundred eighty-three women with gestational diabetes were interviewed at 6 to 9 weeks postpartum. Those who had been treated with insulin more frequently reported having a delayed onset of lactogenesis II (>72 hours) postpartum than those not treated with insulin, independent of other maternal risk factors. The odds ratio of having delayed lactogenesis II was 3.1 among insulin-treated mothers compared to mothers with gestational diabetes who did not receive insulin.[22]