Medication
Metformin Pregnancy: Diabetes, PCOS and NHS Checks
Published 2026-07-08 | By SafeMama Editorial Team | Editorial policy
Short answer
Metformin may be continued or used in pregnancy for type 2 diabetes, gestational diabetes, insulin resistance or PCOS when your clinician recommends it. Do not stop or start it without a pregnancy diabetes plan.
Use only with your diabetes or pregnancy clinician
What is the safest way to think about this?
MotherToBaby says metformin use in pregnancy is not expected to increase the chance of birth defects, while poorly controlled diabetes can increase pregnancy risks. NHS says metformin can be taken during pregnancy, alone or with insulin. ADA patient guidance says insulin is the preferred medicine for blood glucose management during pregnancy, so medication changes should be clinician-led. LactMed and NHS describe low breast milk transfer, with extra caution for newborn, premature or medically fragile infants.
Checking a different medicine? The Pregnancy Medication Safety Hub collects all 154 SafeMama medicine guides, including the active-ingredient and dose questions worth raising with a pharmacist.
What is generally okay?
- Ask the clinician managing your diabetes, PCOS, fertility or pregnancy care whether to continue metformin after a positive test.
- Follow your glucose monitoring, nutrition, activity, insulin and prenatal follow-up plan if you have diabetes or gestational diabetes.
- Report vomiting, dehydration, kidney disease, severe weakness, unusual breathing, or side effects promptly because metformin plans can change when you are unwell.
What should you avoid or double-check?
- Avoid stopping diabetes medicine because you are pregnant unless your clinician gives you a replacement plan.
- Avoid using metformin for weight loss during pregnancy.
- Avoid replacing metformin, insulin, glucose monitoring, nutrition care or prescribed treatment with berberine, glucose supplements, PCOS blends or diet-only advice from the internet.
How SafeMama helps
SafeMama can flag metformin, Glucophage, Glumetza, Fortamet, extended-release labels, diabetes medicines, PCOS products, berberine, GLP-1 medicines and weight-loss terms so users know what to review with their pregnancy team.
Open the SafeMama app, scan the barcode or search the ingredient, then use the result as a starting point for a conversation with your healthcare provider.
Sources
Frequently asked questions
What does MotherToBaby say about metformin in pregnancy?
MotherToBaby says metformin use during pregnancy is not expected to increase the chance of birth defects, and it also stresses that poorly controlled diabetes can increase pregnancy risks. Use the fact sheet as a prompt for a care-team discussion, not as a self-treatment plan.
Can I stop metformin because I am pregnant?
Call your clinician first. Abruptly stopping diabetes or PCOS-related treatment can leave blood sugar or the reason for treatment unmanaged.
Can metformin treat gestational diabetes?
Some clinicians use metformin in selected gestational diabetes cases, while others use nutrition changes, insulin or other plans. Follow your own glucose targets and treatment plan.
Is metformin the same as insulin in pregnancy?
No. ADA patient guidance says insulin is the preferred medication for managing blood glucose during pregnancy. If your clinician wants to switch from metformin to insulin or use both, ask how to monitor glucose and handle low blood sugar.
Can metformin be used for PCOS in pregnancy?
PCOS-related metformin decisions are individualized. Ask whether the medicine is still needed after pregnancy is confirmed and whether your plan changes by trimester.
Is metformin okay while breastfeeding?
NHS and LactMed describe low metformin transfer into breast milk. Ask your clinician or pharmacist for infant-specific advice, especially with a newborn, premature infant, kidney problems, poor feeding, unusual sleepiness or other health concerns.
Can berberine replace metformin during pregnancy?
No. Do not replace prescribed diabetes or PCOS medicine with berberine or a supplement stack. NCCIH says pregnant and breastfeeding people should not use berberine.
What if I have vomiting, dehydration or kidney disease while taking metformin?
Contact your clinician promptly. Illness, dehydration and kidney problems can change whether metformin is appropriate and whether you need extra glucose or ketone guidance.
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