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Metformin Pregnancy and Breastfeeding Warnings

Metformin is also known as: Fortamet, Glucophage, Glucophage XR, Glumetza, Riomet

Medically reviewed on Jun 21, 2018

Metformin Pregnancy Warnings

Animal studies do not indicate harmful effects with respect to pregnancy, embryo or fetal development, birth or postnatal development. Current evidence suggests metformin has a good safety profile in women with no increased long-term effects in offspring up to 18 months; however, much of the evidence is from observational studies, small and/or nonrandomized studies, and therefore data must be interpreted cautiously. Many experts continue to recommend insulin as the drug of choice for type 1, type 2, and gestational diabetes (if diet therapy alone is unsuccessful in controlling blood sugars), especially if insulin is available for use. High maternal glucose levels during pregnancy are associated with maternal and fetal adverse effects. The long-term effects of metformin exposure in utero are unknown. There are no adequate and well-controlled studies in pregnant women.

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 B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

This drug should be used during pregnancy only if clearly needed.

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

Comments: During pregnancy, maternal glucose levels should be well controlled to avoid both maternal and fetal adverse effects.

See references

Metformin Breastfeeding Warnings

AU: Use is contraindicated.
US and UK: 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: There is limited data available on the effects in the nursing infant.

Drug levels are expected to be 0.5% of their mother's weight-adjusted dosage and are expected to be relatively constant, therefore timing of breastfeeding with drug administration is expected to be of little benefit. In one large study, no adverse effects were observed in breastfed infants. Low detectable serum levels were found in some breastfed infants. This drug should be used with caution while nursing a newborn or premature infant, especially among those with renal impairment.

See references

References for pregnancy information

  1. "Product Information. Glucophage (metformin)." Bristol-Myers Squibb, Princeton, NJ.
  2. "Product Information. Riomet (metFORMIN)." Ranbaxy Pharmaceuticals, Jacksonville, FL.
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  4. "Product Information. Fortamet (metFORMIN)." Physicians Total Care, Tulsa, OK.
  5. "Product Information. Glumetza (metFORMIN)." Biovail Pharmaceuticals Canada, Mississauga, IA.
  6. Cerner Multum, Inc. "Australian Product Information." O 0
  7. Lindsay RS, Loeken MR "Metformin use in pregnancy: promises and uncertainties " Diabetologia 60 (2017): 1612-9

References for breastfeeding information

  1. "Product Information. Glucophage (metformin)." Bristol-Myers Squibb, Princeton, NJ.
  2. "Product Information. Fortamet (metFORMIN)." Physicians Total Care, Tulsa, OK.
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  5. "Product Information. Glumetza (metFORMIN)." Biovail Pharmaceuticals Canada, Mississauga, IA.
  6. "Product Information. Riomet (metFORMIN)." Ranbaxy Pharmaceuticals, Jacksonville, FL.
  7. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT." ([cited 2013 -]):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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