Managing Diabetes in Pregnancy: What You Need to Know
If you’re pregnant and have diabetes-whether it was there before pregnancy or developed during it-you’re probably wondering what medications are safe. The short answer: insulin is still the gold standard. But it’s not the only option. Oral medications like metformin are used too, though with important limits. The goal isn’t just to keep your blood sugar in range-it’s to protect your baby from complications like excessive birth weight, early delivery, or low blood sugar after birth.
Here’s what actually works, what’s risky, and what you should avoid. No fluff. Just what the latest guidelines from the Endocrine Society, ACOG, and Joslin Diabetes Center say as of 2025.
Why Blood Sugar Control Matters So Much
High blood sugar during pregnancy doesn’t just affect you. It crosses the placenta. Your baby’s pancreas responds by making more insulin, turning extra glucose into fat. That’s why babies of mothers with uncontrolled diabetes are more likely to be large for gestational age (LGA), face breathing problems at birth, or end up in the NICU.
The targets are strict-and for good reason:
- Fasting blood sugar: under 95 mg/dL (5.3 mmol/L)
- 1 hour after meals: under 140 mg/dL (7.8 mmol/L)
- 2 hours after meals: under 120 mg/dL (6.7 mmol/L)
These aren’t suggestions. They’re based on data from thousands of pregnancies. Hitting them cuts the risk of complications by nearly half. That’s why treatment starts early-even before you’re pregnant, if possible.
Insulin: The Go-To Choice, No Surprises
Insulin is the most studied and safest medication for diabetes in pregnancy. It doesn’t cross the placenta, so it doesn’t reach your baby. That’s why doctors start here, whether you have type 1, type 2, or gestational diabetes that won’t respond to diet and exercise.
Not all insulins are the same. Here’s what’s recommended:
- Rapid-acting analogs (lispro, aspart): Best for meals. They work fast, clear quickly, and lower the risk of low blood sugar compared to older regular insulin.
- Long-acting analogs (detemir, glargine): Used for background control. Detemir has solid data in pregnancy. Glargine is considered safe based on multiple studies involving over 700 women.
- Avoid: Glulisine and degludec. There’s not enough safety data yet. Don’t risk it.
Many women switch from pills to insulin once pregnant. That’s normal. Your body changes fast-your insulin needs can double or triple by the third trimester. That’s not a sign you’re failing. It’s biology.
Metformin: The Controversial Oral Option
Metformin is the only oral medication with enough data to be used in pregnancy. It’s cheaper, easier to take than injections, and studies show it lowers the risk of having a very large baby, preeclampsia, and neonatal hypoglycemia compared to insulin.
But here’s the catch:
- It crosses the placenta. Your baby is exposed to it.
- About half of women on metformin still need insulin later in pregnancy because metformin alone isn’t enough.
- Some studies suggest possible long-term effects on the baby’s metabolism, though no clear harm has been proven yet.
The Endocrine Society says metformin can be used for gestational diabetes-but not as an add-on to insulin in type 2 diabetes. Why? Because adding it increases the risk of having a small baby, and the benefits don’t outweigh that risk.
Joslin Diabetes Center takes a harder line: they say metformin shouldn’t be used beyond the first trimester. Other centers use it longer. This is where you need to talk to your doctor. There’s no universal rule.
What You Should Avoid Completely
Some diabetes drugs are off-limits during pregnancy. Period.
- GLP-1 receptor agonists (like semaglutide, liraglutide): These are linked to birth defects in animal studies. The Endocrine Society recommends stopping them before conception-not when you find out you’re pregnant.
- SGLT2 inhibitors (like empagliflozin, dapagliflozin): These cause fetal malformations in animals and have zero human safety data in pregnancy. Don’t use them.
- DPP-4 inhibitors (like sitagliptin) and alpha-glucosidase inhibitors (like acarbose): Too little data. Avoid unless in a rare, monitored research setting.
If you’re on any of these and planning pregnancy, talk to your doctor now. Switching to insulin before conception is safer than trying to manage it once you’re pregnant.
Preconception Planning: The Most Important Step
Waiting until you’re pregnant to fix your diabetes is risky. The first 8 weeks of pregnancy are when your baby’s organs form-and that’s often before you even know you’re pregnant.
Here’s what you need to do ahead of time:
- Get your HbA1c below 6.5%. If it’s above 10%, delay pregnancy. Use birth control until your numbers are stable.
- Stop unsafe medications. Switch to insulin or metformin (if appropriate) before trying to conceive.
- Start taking 81-100 mg of aspirin daily from week 12. This reduces your risk of preeclampsia, which is much higher if you have diabetes.
- See an endocrinologist and high-risk OB together. Team care saves lives.
Women who plan ahead have dramatically better outcomes. It’s not about being perfect-it’s about being prepared.
During Labor and Delivery: What to Expect
Even if your diabetes is well-controlled, labor is a stress test. Your body’s hormones can spike your blood sugar fast.
Hospital teams will monitor your glucose every hour. You’ll likely get IV insulin if needed. You won’t be left to manage it alone. Insulin pumps can usually continue during labor, but your team will adjust settings.
After birth, your insulin needs drop fast-sometimes by 50% in the first 24 hours. Watch for low blood sugar. If you’re breastfeeding, you’ll need to eat more often and check your sugar more closely.
After Delivery: What Happens to Your Medications?
Good news: most women with gestational diabetes stop all medications after delivery. Your blood sugar usually returns to normal.
If you had type 2 diabetes before pregnancy, you’ll likely need to restart your pre-pregnancy meds-or switch back to insulin if you stopped it. Metformin is safe while breastfeeding. Insulin is safe too-it doesn’t pass into breast milk.
Don’t assume you’re "cured" after birth. Women with gestational diabetes have a 50% chance of developing type 2 diabetes within 10 years. Get tested 6-12 weeks after delivery, then every 1-3 years.
What’s Still Unknown
Science hasn’t answered everything. We don’t know yet if metformin exposure in the womb affects a child’s weight or risk of diabetes later in life. We don’t know if newer insulins like degludec are truly safe. We don’t have enough data on continuous glucose monitors (CGMs) for type 2 diabetes in pregnancy.
That’s why guidelines stay cautious. Insulin remains the default because we know it works. Everything else comes with questions.
Bottom Line: What to Do Now
If you’re pregnant and on diabetes meds:
- Stick to insulin unless your doctor says otherwise.
- Metformin? Maybe-but only if you’re on it before pregnancy and your doctor agrees.
- Stop GLP-1 agonists, SGLT2 inhibitors, and DPP-4 inhibitors now.
- Check your blood sugar daily. Use a meter or CGM if recommended.
- See your endocrinologist and OB together, every 2-4 weeks.
If you’re planning pregnancy:
- Get your HbA1c below 6.5%.
- Switch to safe meds before conceiving.
- Start low-dose aspirin at 12 weeks.
- Don’t wait until you’re pregnant to fix this.
Diabetes in pregnancy is manageable. It’s not easy-but with the right plan, most women have healthy babies. The key is acting early, staying informed, and trusting your care team.
Is metformin safe during pregnancy?
Metformin is used during pregnancy for gestational diabetes and sometimes for type 2 diabetes, but it’s not first-line. It crosses the placenta, and about half of women need insulin anyway. Some guidelines allow it throughout pregnancy; others recommend stopping after the first trimester. It’s not recommended as an add-on to insulin in type 2 diabetes because it may increase the risk of having a small baby.
Can I take insulin while breastfeeding?
Yes. Insulin does not pass into breast milk. It’s safe for both you and your baby. Your insulin needs will drop after delivery, so monitor your blood sugar closely and adjust doses with your doctor’s help.
What diabetes medications should I avoid before and during pregnancy?
Avoid GLP-1 receptor agonists (like Ozempic, Wegovy), SGLT2 inhibitors (like Jardiance, Farxiga), DPP-4 inhibitors (like Januvia), and alpha-glucosidase inhibitors (like Precose). These have little or no safety data in pregnancy and may pose risks to the fetus. Stop them before conception, not after you find out you’re pregnant.
Do I need to switch from pills to insulin when pregnant?
Most women with type 2 diabetes or gestational diabetes who were on oral meds will need to switch to insulin during pregnancy. That’s because insulin doesn’t cross the placenta and offers more precise control. Metformin is an exception in some cases, but even then, many women end up needing insulin later.
How often should I check my blood sugar during pregnancy?
Check your blood sugar at least four times a day: fasting, and 1-2 hours after each meal. Some providers recommend 7-point checks (before and after each meal, plus bedtime and 3 a.m.) if your numbers are unstable. Continuous glucose monitors (CGMs) are helpful, especially for type 1 diabetes, but aren’t yet standard for type 2.
Can I use an insulin pump during pregnancy?
Yes. Insulin pumps are safe and effective during pregnancy. Many women find them easier to manage than multiple daily injections, especially as insulin needs change rapidly. Your pump settings will need frequent adjustments, so work closely with your diabetes care team.
What’s the best way to prepare for pregnancy if I have diabetes?
Start at least 3-6 months before trying to conceive. Get your HbA1c below 6.5%, stop unsafe medications, start low-dose aspirin, and see both an endocrinologist and high-risk OB. Use birth control if your HbA1c is above 10%. Planning ahead cuts your baby’s risk of complications by up to 70%.
Comments
Josh Gonzales
Just want to say the insulin dosing info here is spot on. My wife went from 40 units/day pre-pregnancy to 140 by 36 weeks. No drama, no guilt - just biology. Switched from metformin at 8 weeks and never looked back. CGM was a game changer for us.
Valérie Siébert
OMG YES. I was on metformin for PCOS and got preggo and my doc was like 'yep bye' and put me on insulin. Felt like a failure at first but then I saw my baby's ultrasound and was like... oh. this was the right call. insulin is a gift not a punishment 💪
katia dagenais
Let me just say this - if you're even *thinking* about using semaglutide while pregnant, you're not just being reckless, you're playing Russian roulette with a fetus. I work in OB-GYN. I've seen the outcomes. The baby doesn't care if you're 'trying to lose weight' - your pancreas isn't a dating app. Stop pretending this is about 'personal choice.' It's about neurodevelopment, placental transfer, and the fact that your body is now a life-support system for another human. If you need to lose weight, do it before you get pregnant. Or don't get pregnant. But don't risk a child's entire metabolic future because you want to keep taking Ozempic 'for the vibes.'
I'm not mad. I'm just disappointed. And honestly? The fact that this even needs saying is a symptom of a culture that treats pregnancy like a lifestyle upgrade instead of a physiological revolution.
Metformin? Fine. Insulin? Perfect. GLP-1s? Absolutely not. End of story. If your doctor is okay with it, find a new one. And if you're reading this and you're on it right now - stop. Call your provider. Today. Not tomorrow. Today.
And yes, I know some of you will say 'but my doctor said it's fine.' I also know that in 2020, a doctor told a woman it was okay to keep smoking while pregnant because 'it helps with anxiety.' We don't need more of that. We need science. And science says: don't cross the placenta with a drug that causes neural tube defects in mice. Not even once.
Don't be the person who says 'I didn't know.' You know now.
Jack Riley
Insulin is the gold standard? Sure. But let's not pretend it's not a nightmare. I've been on it since week 6. Five injections a day. Finger pricks so often my thumbs are calloused. My partner says I scream at the glucometer. I do. Because it's not just a number - it's a verdict. And insulin doesn't fix your anxiety. It just gives you a new way to feel guilty.
Metformin? I took it for 14 weeks. Felt like a ghost. Nausea, diarrhea, and still had to go on insulin anyway. So what was the point? To save me from needles? I got the needles and the nausea. Classic.
And don't get me started on the 'preconception planning' section. Like I had the luxury of waiting 6 months to get my HbA1c down. I was 32, single, working two jobs, and got pregnant by accident. Now I'm being lectured like I'm some kind of medical failure for not having a plan. Newsflash: not everyone has a 401(k) and a fertility specialist on speed dial.
So yeah. Insulin works. But don't act like it's some noble sacrifice. It's exhausting. It's expensive. And it's not the only way to have a healthy baby - it's just the one we're told to choose because it's 'safe.' Meanwhile, the women who can't afford it, or who can't inject themselves because of trauma, or who are undocumented - they're just supposed to... what? Guess?
Science is great. But real life? It's messy. And if your advice doesn't acknowledge that, it's just another form of privilege wrapped in a white coat.
Jacqueline Aslet
It is of paramount importance to underscore the clinical imperative of adhering strictly to the evidence-based guidelines delineated by the Endocrine Society, ACOG, and the Joslin Diabetes Center. The pharmacokinetic profiles of GLP-1 receptor agonists and SGLT2 inhibitors, particularly their transplacental permeability and potential teratogenic effects, render them categorically contraindicated during gestation. The notion that 'personal preference' or 'convenience' should supersede fetal safety is not only medically indefensible, but ethically untenable.
Furthermore, the assertion that metformin may be employed beyond the first trimester is, in the context of current literature, a misinterpretation of the available data. The Joslin Center's position, which advocates for discontinuation after the first trimester, is supported by longitudinal cohort studies demonstrating increased incidence of intrauterine growth restriction when exposure persists beyond 12 weeks. To recommend otherwise is to engage in clinical negligence disguised as innovation.
It is also worth noting that the continued reliance on insulin as the primary modality is not an artifact of conservatism, but a reflection of over 100 years of cumulative, peer-reviewed, randomized controlled trials. To dismiss insulin as 'archaic' or 'inconvenient' is to misunderstand the very nature of medical progress: it is not about novelty, but about demonstrable, reproducible safety.
Finally, the notion that 'planning ahead' is a privilege reserved for the affluent is a red herring. The standard of care does not change based on socioeconomic status. It is incumbent upon the medical system to provide access - not to lower the standard to accommodate it.
Caroline Marchetta
Oh sweet mercy. Another article that makes you feel like a criminal if you ever thought about taking a pill. Let me guess - the author has never had to choose between paying rent and buying insulin. Or had to explain to their 3-year-old why Mommy cries when she pricks her finger. Again.
Metformin? It’s 'controversial.' But so is being poor. So is being a single mom. So is having a job that doesn't give you paid leave to see an endocrinologist every two weeks.
And don't even get me started on 'preconception planning.' Like I was sitting around with a calendar and a spreadsheet, waiting for the perfect HbA1c to pop up like a pop-up ad. Meanwhile, I got pregnant because I was tired of being alone. Not because I was trying to be a 'perfect mother.'
So yeah. Insulin is 'safe.' But so is silence. So is shame. So is being told you're doing it wrong while you're literally trying to keep yourself alive.
Maybe next time, instead of listing all the things we shouldn't do - tell us where to get free insulin. Or how to find a doctor who won't judge us for being on welfare. Or how to stop feeling like our bodies are betraying our babies.
Because here's the truth: we don't need more guidelines. We need more compassion.
Kimberley Chronicle
This is such a clear, well-structured guide - thank you for compiling this. I'm an endocrine nurse and I've shared this with three patients this week. The part about insulin needs tripling in the third trimester? So many women panic thinking they're 'failing' - but it's just physiology. I love how you normalize that.
Also, the note about low-dose aspirin starting at 12 weeks? I wish more OBs knew that. We had a patient last month who developed preeclampsia at 28 weeks - turns out she never got the recommendation. A simple 81mg tablet could've changed everything.
And yes - metformin is a tool, not a trap. Used right, it helps. Used wrong, it doesn't. The key is individualized care. No one-size-fits-all here.
Patricia McElhinney
As a board-certified endocrinologist with 22 years of experience, I must correct several inaccuracies in this article. First, glargine is NOT 'considered safe based on multiple studies involving over 700 women' - it's FDA-approved for pregnancy. Second, detemir has less data than glargine, and its use is off-label in the US. Third, the claim that 'metformin increases risk of small baby' as an add-on is misleading - the 2023 meta-analysis in AJOG showed no significant difference in SGA rates when used with insulin vs insulin alone. You're cherry-picking outdated data.
Also, the statement that 'degludec has no safety data' is false. The DEG-PILOT trial published in Diabetologia in 2024 included 156 pregnant women with type 1 diabetes and showed no adverse fetal outcomes. This article is dangerously outdated. Please update your references before giving medical advice.
And for the love of God - stop saying 'don't risk it' with glulisine. That's not evidence. That's fearmongering. We're talking about a molecule that's identical to human insulin with a slightly altered structure. The placenta doesn't care.
Dolapo Eniola
Y’all in the West be acting like pregnancy is some high-tech lab experiment. In Nigeria, we got women taking metformin, glibenclamide, even herbal mixtures - and their babies are fine. You think insulin is the only way? Nah. You think your glucose meter is God? Nah. We don’t have that luxury. We have faith, food, and family. And guess what? Our babies thrive too.
Stop acting like your way is the only way. I’ve seen babies born in mud huts with no insulin, no CGM, no endocrinologist - and they’re running around at age 5. You’re not saving lives. You’re selling fear.
And you say 'stop GLP-1s before pregnancy' - bro, I know women who got pregnant while on Ozempic and their kids are perfectly healthy. Science? Maybe. But real life? It’s not your algorithm.
Stop lecturing. Start listening.
Rachel Villegas
Thank you for this. I had gestational diabetes and was terrified. This was the only article that didn’t make me feel like a failure. I switched to insulin at 20 weeks and honestly? It gave me back control. I didn’t feel like I was failing my baby anymore.
Also - the part about breastfeeding and insulin? Huge relief. I was worried I’d have to pump and dump. So glad to know it’s safe.
giselle kate
Metformin is a gateway drug to fetal metabolic syndrome. If you're not on insulin, you're not serious about protecting your child. This isn't a debate - it's a moral obligation. Stop normalizing risk. Stop pretending convenience matters more than biology. Your baby doesn't care if you hate needles. Your baby just wants to survive.
Josh Gonzales
Just read Patricia’s comment. She’s right about degludec. I checked the DEG-PILOT trial last week - 156 women, no adverse events. We’re starting to use it in our clinic for type 1s who need ultra-long coverage. The guidelines are lagging behind the data. Good catch.