If you're facing preterm labor or preterm birth risk, your healthcare provider may recommend corticosteroid injections—most commonly betamethasone. These are given as a single course (typically two injections, 24 hours apart) to help your baby's lungs mature in case delivery happens early.
The injections work by reducing inflammation and speeding up fetal lung development, which dramatically improves outcomes for premature babies. It's one of the most evidence-based, beneficial treatments in pregnancy medicine.
But here's the thing: if you have gestational diabetes, these steroid injections will almost certainly spike your blood sugar. And that's worth understanding ahead of time.
Corticosteroids raise glucose levels. This is a well-documented side effect, and it happens because steroids increase insulin resistance—your cells don't respond to insulin as effectively, so glucose stays higher in your bloodstream.
In people with diabetes mellitus (including gestational diabetes), this effect is more pronounced. Your body is already working harder to manage blood sugar, and steroids make that job even tougher.
What happens:
Blood sugar typically rises within hours of the injection
The elevation can be significant (20–100+ mg/dL above your baseline, depending on your sensitivity)
Hyperglycemia (elevated blood sugar) is one of the most common side effects
This is the question every mama with gestational diabetes wants answered, and here's the honest answer: it varies, but usually 24–72 hours is the peak impact.
Timeline:
First 6–12 hours: Blood sugar starts climbing
24–48 hours: Peak elevation (this is when you'll see the biggest spikes)
48–72 hours: Gradual decline as your body metabolizes the steroids
By day 5–7: Usually back to baseline (though some people take longer)
The duration depends on:
Your individual insulin sensitivity
Your baseline blood sugar control
Whether you're on insulin therapy already
Your diet and activity level during this time
Julija notes: This is temporary. Your blood sugar will come back down. It's not a sign that your GD is worse or that you're "failing"—it's a predictable, documented response to medication.
If you have continuous glucose monitoring (CGM like Dexcom), you'll see the rise in real time—which can be anxiety-inducing, but also really helpful for understanding what's happening.
If you're using fingerstick testing, test more frequently during this window:
Test before the injection
Test 2–4 hours after
Test before meals and after meals
Test at bedtime and fasting
What your healthcare provider is watching for:
Hyperglycemia that requires temporary insulin adjustments
Diabetic ketoacidosis (very rare, but a risk in extreme cases—your healthcare provider will monitor for this)
How your body responds so they can adjust your treatment plan if needed
Your family physician or diabetes care team may temporarily increase your insulin dose or adjust your diet during this period. This is normal and expected.
You can't prevent the blood sugar rise, but you can support your body:
Nutrition:
Stick to balanced meals (carb + protein + fat + fiber)
Avoid "naked carbs" or high-sugar foods
Smaller, more frequent meals can help keep spikes smaller
Stay hydrated (dehydration can push glucose levels higher)
Need meal and snack ideas? Browse our GD Toolkit for ideas.
Movement:
Gentle walks after meals can help blunt spikes
Don't overdo it, but light activity helps
Monitoring:
Test more often so you're not guessing
Share data with your healthcare provider
Don't panic if numbers are higher—it's temporary
Medication:
If you're already on insulin therapy, your dose may be adjusted temporarily
If you're diet-controlled, you might need temporary insulin (this is okay and temporary)
Follow your provider's guidance on any dosage changes
Yes. The clear benefit for your baby far outweighs the temporary blood sugar disruption.
Beneficial effects of antenatal corticosteroids:
Reduces risk of respiratory distress syndrome (RDS) by 34–44% (Source)
Lowers risk of intraventricular hemorrhage (IVH/brain bleeding) by ~46% (Source)
Reduces neonatal mortality (Source)
Improves outcomes for infants born prematurely (Source)
The minor side effects (like elevated blood sugar) are temporary and manageable. Your healthcare provider wouldn't recommend them if the risks outweighed the benefits.
Most people experience hyperglycemia (elevated blood sugar) as the main side effect. But watch for:
Extreme hyperglycemia (blood sugar >300 mg/dL consistently): Contact your healthcare provider
Symptoms of diabetic ketoacidosis (nausea, vomiting, difficulty breathing, fruity-smelling breath): Seek emergency care immediately
Severe injection site reactions (redness, swelling, warmth): Tell your provider
Symptoms of preterm labor (contractions, bleeding, fluid leakage): Seek emergency care
These complications are rare, but your healthcare provider will monitor you closely.
If you have a medical history of:
Asthma: Steroids may actually help (they reduce inflammation)
Inflammatory bowel disease: Discuss with your provider about timing
Arthritis or other inflammatory conditions: Steroids may provide temporary relief
Adrenal gland issues: Your provider will monitor more closely
Always share your full medical history with your healthcare provider before receiving steroid injections.
Steroid injections with gestational diabetes can happen together, and it's manageable. Yes, your blood sugar will likely spike—that's expected and temporary. No, it doesn't mean you're doing anything wrong. Your body is responding exactly as it should to medication that's protecting your baby.
How long do steroid shots affect blood sugar? Usually 24–72 hours of noticeable elevation, with a gradual return to baseline by day 5–7.
What you can do:
Monitor more frequently
Eat balanced meals
Stay hydrated
Follow your healthcare provider's guidance on medication adjustments
Remember: this is temporary
You're doing the hard work to keep you and your baby safe. That's what matters. 🫶
1. How do steroid injections affect blood sugar in gestational diabetes?
Steroid injections (corticosteroids like betamethasone) increase insulin resistance, so glucose stays higher in your bloodstream. Blood sugar often rises within hours, peaks around 24–48 hours, and then gradually improves over several days.
2. How long do steroid shots affect blood sugar?
For many people, the strongest impact is 24–72 hours. Some return close to baseline by day 5–7, but it can vary based on insulin sensitivity, diet, activity, and whether you’re on insulin therapy.
3. Do I need insulin if I have gestational diabetes and get steroid injections?
Some people need temporary insulin or a short-term dose increase. This is common and expected—your healthcare provider will guide you based on your readings.
4. Are steroid injections safe if I have gestational diabetes?
In situations like preterm labor risk, the potential benefits for baby’s lung maturity can be significant. Your healthcare provider will weigh risks and benefits and monitor your glucose closely.
5. What should I do to manage blood sugar during steroid injections?
Monitor more frequently, keep meals balanced (carb + protein + fat + fiber), stay hydrated, add gentle movement after meals if you can, and follow your provider’s plan for insulin adjustments.
Disclaimer: This post is not medical advice. Please talk to your healthcare provider about your specific situation and follow their treatment plan.
Get a Free 20-Day Shopping List
Join 12K+ moms in the HIgedi community sharing real meals, blood sugar results, and judgment-free support.
