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Insulin Pregnancy and Breastfeeding Warnings

Insulin Pregnancy Warnings

Insulin crosses the human placenta in small amounts. In one study, in which 28 cord-serum samples from pregnant women who were receiving animal insulin were evaluated, animal insulin constituted 27% of the total insulin measured from cord serum.

The rate of congenital malformations appears to be associated with the severity of maternal diabetes rather than the use of insulin, a naturally-occurring hormone. The question of whether exogenous insulin itself or insulin-induced hypoglycemia causes the significantly elevated incidence of congenital malformations in infants of diabetic mothers has been evaluated. A significantly higher percentage of major malformations has been associated with elevated hemoglobin A1C levels, suggesting that hyperglycemia, or poor control of diabetes, and not insulin, is the causal factor.

Diabetes portends risk during pregnancy. In a nationwide, four-year retrospective review of 491 insulin-dependent diabetic pregnancies in Sweden, the rates of pregnancy-induced hypertension or preeclampsia, premature delivery, Cesarean section, large-for-age offspring, and perinatal mortality in the diabetic group were more than four times higher than normal. Insufficient maternal insulin secretion or action may result in increased insulin secretion by the fetus, increased fetal growth and fat deposition, and neonatal hypoglycemia. Maternal diabetes mellitus may be complicated by fetal macrosomia, relatively large-for-age offspring, and predisposes the offspring to diabetes. Gestational age appears to be a determinant of neonatal morbidity. Many experts recommend delivery at 38 weeks, if possible.

There is an impaired counterregulatory response to hypoglycemia in pregnant diabetic women. Relative to nonpregnant diabetic women or normal controls, this group demonstrates suppressed basal growth hormone during late pregnancy and blunted or decreased glucagon levels during hypoglycemia. Fortunately, the fetus appears to be protected from maternal hypoglycemia. Neither fetal death nor congenital malformations have been associated with insulin-induced hypoglycemic reactions.

Insulin use may significantly increase in pregnant women with diabetes mellitus type I during pregnancy. In one study, the average increase was 52 units per day, and was significantly related to maternal weight gain between 20 and 29 weeks and maternal weight at presentation, and was inversely related to the duration of diabetes. A small number of pregnant patients required less insulin.

Insulin has been assigned to pregnancy category B. It is the drug of choice for the treatment of diabetes during pregnancy. Data from human pregnancy have revealed an increased incidence of teratogenicity associated with diabetes mellitus; the association with the use of insulin is probably coincidental. Because of the strong association between diabetes or hyperglycemia and perinatal morbidity and multiple congenital malformations, most experts recommend strict control of maternal plasma glucose with the use of insulin during pregnancy. Insulin should only be given during pregnancy when need has been clearly established.

See references

Insulin Breastfeeding Warnings

Limited data reveal that the milk of women with insulin dependent diabetes mellitus (IDDM) has significantly lower lactose and higher total nitrogen relative to nondiabetic women. The infants of women with IDDM in this study had significantly less milk intake. The data indicate delayed lactogenesis for women with IDDM. The differences in milk composition of women with IDDM do not preclude them from breast-feeding.

Insulin is not excreted into human milk.

See references

References for pregnancy information

  1. Burt RL, Davidson IW. Insulin half-life and utilization in normal pregnancy. J Obstet Gynaecol. 1974;43:161-70.
  2. Stangenberg M, Persson B, Stange L, Carlstrom K. Insulin-induced hypoglycemia in pregnant diabetics. Acta Obstet Gynecol Scand. 1983;62:249-52.
  3. Steel JM, West CP. Intrauterine death during continuous subcutaneous infusion of insulin. Br Med J. 1985;290:1787.
  4. Menon RK, Cohen RM, Sperling MA, et al. Transplacental passage of insulin in pregnant women with insulin-dependent diabetes mellitus. N Engl J Med. 1990;323:309-15.
  5. Crombach G, Siebolds M, Mies R. Insulin use in pregnancy. Clinical pharmacokinetic considerations. Clin Pharmacokinet. 1993;24:89-100.
  6. Soler NG, Walsh CH, Malins JM. Congenital malformations in infants of diabetic mothers. Q J Med. 1976;45:303-13.
  7. Dignan PS. Teratogenic risk and counseling in diabetes. Clin Obstet Gynecol. 1981;24:149-59.
  8. Kjos SL, Henry OA, Montoro M, Buchanan TA, Mestman JH. Insulin-requiring diabetes in pregnancy: a randomized trial of active induction of labor and expectant management. Am J Obstet Gynecol. 1993;169:611-5.
  9. Hanson U, Persson B. Outcome of pregnancies complicated by type 1 insulin-dependent diabetes in Sweden: acute pregnancy complications and morbidity. Am J Perinatol. 1993;10:330-3.
  10. Hunter DJ, Burrows RF, Mohide PT, Whyte RK. Influence of maternal insulin-dependent diabetes mellitus on neonatal morbidity. Can Med Assoc J. 1993;149:47-52.
  11. Thompson DM, Dansereau J, Creed M, Ridell L. Tight glucose control results in normal perinatal outcome in 150 patients with gestational diabetes. Obstet Gynecol. 1994;83:362-6.
  12. Steel JM, Johnstone FD, Hume R, Mao JH. Insulin requirements during pregnancy in women with type I diabetes. Obstet Gynecol. 1994;83:250-8.
  13. Kitzmiller JL. Sweet success with diabetes. The development of insulin therapy and glycemic control for pregnancy. Diabetes Care. 1993;16 Suppl 3:107-21.
  14. Breschi MC, Seghieri G, Bartolomei G, Gironi A, Baldi S, Ferrannini E. Relation of birthweight to maternal plasma glucose and insulin concentrations during normal pregnancy. Diabetologia. 1993;36:1315-21.
  15. Knopp RH, Van Allen MI, McNeely M, Walden CE, Plovie B, Shiota K, Brown Z. Effect of insulin-dependent diabetes on plasma lipoproteins in diabetic pregnancy. J Reprod Med. 1993;38:703-10.
  16. Miller E, Hare JW, Cloherty JP, et al. Elevated maternal hemoglobin A in early pregnancy and major congenital anomalies in infants of diabetic mothers. N Engl J Med. 1981;304:1331-4.
  17. Adam PA, Teramo K, Raiha N, Gitlin D, Schwartz R. Human fetal insulin metabolism early in gestation. Diabetes. 1969;18:409-16.
  18. Gabbe SG, Mestman JH, Freeman RK, et al. Management and outcome of pregnancy in diabetes mellitus, Classes B to R. Am J Obstet Gynecol. 1977;129:723-32.
  19. Garner P. Type i diabetes mellitus and pregnancy. Lancet. 1995;346:157-61.
  20. Briggs GG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. Baltimore, MD: Williams & Wilkins. 1998.

References for breastfeeding information

  1. Neubauer SH, Ferris AM, Chase CG, Fanelli J, Thompson CA, Lammi-Keefe CJ, Clark RM, Jensen RG, Bendel RB, Green KW. Delayed lactogenesis in women with insulin-dependent diabetes mellitus. Am J Clin Nutr. 1993;58:54-60.
  2. Neville MC, Sawicki VS, Hay WW Jr. Effects of fasting concentrations on milk secretion in women. J Endocrinol. 1993;139:165-73.
  3. Briggs GG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. Baltimore, MD: Williams & Wilkins. 1998.

Further information

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