Reproductive studies in rats and rabbits at doses up to 500 times the human dose have not revealed evidence of harm, while rat pups exposed to 6250 times the maximum recommended human dose have shown shortening of the long bones (humerus and femur) during the period of lactation, not during organogenesis. Abnormal blood glucose levels during pregnancy are associated with a higher incidence of congenital abnormalities. Neonates born to mothers receiving a sulfonylurea at the time of delivery have experienced prolonged severe hypoglycemia, especially with use of agents that have prolonged half-lives. Sulfonylureas may not be suitable for the treatment of diabetes during pregnancy as significant metabolic changes occurring during this time make control of blood sugar difficult. There are no adequate and well-controlled studies in pregnant women.

In the US, this drug has been used in women with gestational diabetes. A retrospective cohort study looking at employer-based insurance claims suggests newborns born to mothers receiving glyburide were more likely to experience adverse reactions than those born to mothers receiving insulin. Of the 110,879 women identified with gestational diabetes mellitus, 4982 women were treated with glyburide and 4191 received insulin. Newborns of mothers treated with glyburide were at an increased risk for neonatal intensive care unit admission, respiratory distress, hypoglycemia, birth injury, and large for gestational age. They were not at increased risk for obstetric trauma, preterm birth, or jaundice; the risk of cesarean delivery was 3% lower. Additional studies are needed to fully assess the risks of this drug during pregnancy.

AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

AU and UK: Use is contraindicated
US: Use during pregnancy only if the benefit justifies the risk to the fetus.

AU TGA pregnancy category: C
US FDA pregnancy category: C

Comments:
-Insulin is recommended during pregnancy to maintain blood glucose levels as normal as possible.
-If this drug is used during pregnancy, it should be discontinued at least 2 weeks before the expected delivery date.

See references

A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes

Comments: If diet alone is inadequate for controlling blood glucose, insulin therapy should be considered.

There is limited data which suggests negligible levels of this drug are present in breast milk. A study in 8 women receiving a single-dose shortly after delivery estimates the maximum dose a fully breastfed infant would receive with 5 and 10 mg doses at less than 1.5% and less than 0.7% of the maternal weight-adjusted dose, respectively. Due to the limited data available and the potential for hypoglycemia in the nursing infant, the manufacturer suggests women who are not able to manage their blood sugar on diet alone consider insulin therapy while breastfeeding.

See references