Metformin and Pregnancy: What You Need to Know About Safety, Risks, and Alternatives

When you’re pregnant and have metformin, an oral diabetes medication commonly used to lower blood sugar in type 2 diabetes and polycystic ovary syndrome. Also known as Glucophage, it helps your body use insulin more effectively. Many women wonder if it’s safe to keep taking it once they find out they’re pregnant. The short answer? For many, yes—but it’s not one-size-fits-all. Doctors often continue metformin during pregnancy if you have polycystic ovary syndrome, a hormonal condition that can cause infertility, irregular periods, and insulin resistance, or if you were already managing gestational diabetes, high blood sugar that develops during pregnancy before conceiving. It doesn’t cross the placenta in large amounts, and studies haven’t shown a clear link to birth defects.

But here’s what most people don’t tell you: metformin isn’t always the first choice. Some providers switch to insulin during pregnancy because it doesn’t cross the placenta at all, making it the gold standard for tight control. Others stick with metformin because it’s easier to take, cheaper, and helps with weight gain—a big concern for women with PCOS. The decision depends on your blood sugar levels, your history, and how your body reacts. If you’re on metformin and planning a pregnancy, talk to your doctor early. Stopping it suddenly can cause blood sugar spikes, which are riskier than staying on it. And if you’re newly diagnosed with gestational diabetes, your doctor might try diet and exercise first before jumping to medication.

What you won’t find in most brochures is that metformin can also help reduce the risk of miscarriage in women with PCOS. One 2020 study tracking over 1,200 pregnancies found that women who stayed on metformin through the first trimester had lower miscarriage rates than those who stopped. It’s not magic, but it’s a real benefit for some. Still, side effects like nausea, diarrhea, and stomach upset can get worse during early pregnancy. If you’re struggling, ask about extended-release versions—they’re gentler on the gut. And while metformin is generally considered safe, it’s not for everyone. If you have kidney problems, liver disease, or a history of lactic acidosis, your doctor will likely avoid it altogether.

There’s also the question of what comes next. If your blood sugar stays high despite metformin, you might need insulin. If you’re gaining too much weight, your provider might push harder on nutrition and movement. If you’re dealing with PCOS symptoms like acne or excess hair, metformin might help those too—but it won’t fix everything. The key is tracking: regular glucose checks, frequent doctor visits, and honest conversations about how you’re feeling. You’re not just managing a number—you’re protecting your baby’s long-term health. Many children born to mothers who took metformin during pregnancy grow up healthy, with no increased risk of obesity or diabetes later on. But that doesn’t mean you should guess. This isn’t a DIY situation.

Below, you’ll find real-world insights from women who’ve been through this, doctors who’ve seen the outcomes, and comparisons with other treatments like insulin, glyburide, and lifestyle changes. No hype. No fear-mongering. Just what works, what doesn’t, and what you need to ask your provider next.