Is Insulin safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Insulin. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
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 ] A review of 10 years of reports to the European adverse drug reaction database EudraVigilance found 3 unspecified serious adverse reactions reported in breastfed infants associated with insulin glargine. Further details of the cases were not reported.[ 37 ]
Effects on milk supply
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.[ 19 , 38 ] 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.[ 13 ] 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.[ 27 ] A small, controlled trial of women with gestational diabetes compared those treated with insulin to women treated with diet and exercise. Those treated with insulin had a lower rate of exclusive breastfeeding than those treated with diet and exercise (57% vs 81%).[ 28 ]
Levels in milk
Maternal Levels. Insulin is normally present in breastmilk.[ 29 , 30 ] In one study, insulin levels in milk were 60 milliunits/L (range 6.5 to 306 milliunits/L) in 42 mothers without diabetes who had fullterm infants between 3 and 30 days postpartum.[ 2 ] Insulin levels averaged 59 milliunits/L on day 3 postpartum and 40 milliunits/L on day 7 postpartum in 24 mothers without diabetes who had fullterm infants. Mothers of preterm infants had nonsignificant changes in milk insulin levels.[ 31 ] In a study of 7 diabetic nursing mothers and 10 nondiabetic nursing mothers, blood glucose was elevated to about 300 mg/dL using a continuous intravenous glucose infusion. Regular pork insulin was then given intravenously to lower the blood glucose. Glucose and insulin were measured in the breastmilk of all the mothers. The milk glucose of women with diabetes approximately tripled during the experiment, but milk glucose remained low in the nondiabetic women. Milk insulin was elevated in the diabetic women, with the peak milk insulin level occurring between 30 to 50 minutes after the intravenous injection. Nine of the 10 nondiabetic women had detectable insulin levels in breastmilk which ranged from 5.1 to 13 milli-IU/mL.[ 32 ] Insulin was measured in donor milk from 34 nondiabetic women who were between 1 month and 1 year postpartum. The average insulin concentration was 163 picomoles/L. After pasteurization using the Holder method (62.5 degrees C for 30 min), the average concentration was 88 picomoles/L.[ 33 ] A small study measured breastmilk insulin concentrations in control mothers (n = 5; 1 to 6 months postpartum), mothers with type 1 diabetes mellitus (n = 4; 2 to 5 months postpartum) and type 2 diabetes (n = 5; 5 to 6 months postpartum). No differences were found in the insulin content among the 3 groups and little circadian variation was found. Mothers with type 1 diabetes were well controlled on insulin aspart and insulin glargine. No endogenous insulin was found in the
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.