When is the glucose test done in pregnancy?

The glucose screening test is routinely done between weeks 24 and 28 of pregnancy. If you have risk factors such as a previous gestational diabetes diagnosis or a high BMI, your provider may test earlier in pregnancy as well.

What are normal blood sugar levels during pregnancy?

Commonly used home-monitoring targets in pregnancy are: fasting 95 mg/dL (5.3 mmol/L) or below, 140 mg/dL (7.8 mmol/L) or below one hour after meals, and 120 mg/dL (6.7 mmol/L) or below two hours after meals. Your provider's personal targets for you always take priority.

Do I need to fast for the 1-hour glucose test?

No — the 1-hour screening (glucose challenge test) does not require fasting. The confirmatory 3-hour glucose tolerance test does require fasting for about 8 hours beforehand. Follow the instructions your clinic gives you.

Does gestational diabetes go away after birth?

For most mothers, blood sugar returns to normal within weeks of delivery. Gestational diabetes does increase your lifetime risk of type 2 diabetes, so a follow-up glucose test 6-12 weeks postpartum and periodic screening afterwards are recommended.

The Glucose Test in Pregnancy: What to Expect, Normal Levels & How to Prepare

Janeen Team · Updated July 2026 · 7 min read

Somewhere between week 24 and 28, almost every pregnant woman drinks the famous orange (or lemon-lime) glucose drink. If your glucose test is coming up — or your result came back high — here's exactly what happens, what the numbers mean, and why a gestational diabetes diagnosis is far more manageable than it sounds.

Why is everyone tested?

Pregnancy hormones from the placenta naturally make your body more resistant to insulin — that's by design, to keep more sugar available for your baby. In about 1 in 10 pregnancies, the body can't fully compensate, and blood sugar rises. This is gestational diabetes, and it usually has no symptoms at all — which is exactly why screening is universal rather than symptom-based. Not sure which week you're in? Calculate your due date and current week here.

The 1-hour screening test (glucose challenge)

No fasting needed. Eat normally beforehand unless your clinic says otherwise.
You drink a 50 g glucose solution — finish it within about 5 minutes.
Blood is drawn exactly one hour later.
Most clinics use a cutoff around 130-140 mg/dL. Below it: you're done. Above it: you'll be booked for the confirmatory test — a high screening result alone does not diagnose you. Many women pass the second test.

The 3-hour tolerance test (the one that decides)

Fast for about 8 hours (water is fine — stay hydrated).
Fasting blood draw, then a 100 g drink, then draws at 1, 2 and 3 hours.
Two or more values above the reference thresholds → gestational diabetes diagnosis.
Bring a snack for the moment the last draw is done, something to watch or read, and don't plan to drive yourself if you tend to feel faint when fasting.

💡 Some countries (and many clinics for high-risk moms) skip the screening and use a single fasting 75 g / 2-hour test instead — the process is similar, one value above threshold is enough there. Your clinic's protocol is the right one for you.

Normal blood sugar levels in pregnancy

If you're asked to monitor at home, these are the commonly used targets (per ACOG and the American Diabetes Association):

Timing	Common target
Fasting (first thing in the morning)	≤ 95 mg/dL (5.3 mmol/L)
1 hour after a meal	≤ 140 mg/dL (7.8 mmol/L)
2 hours after a meal	≤ 120 mg/dL (6.7 mmol/L)

Important: these are general reference ranges. The targets your own provider sets for you always win.

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Diagnosed? Here's what actually changes

First: this is not your fault — placental hormones, not sugar cravings, drive gestational diabetes. For most women the plan is surprisingly simple:

Eat smaller meals every ~3 hours instead of three big ones — spreading carbohydrates prevents spikes.
Never eat carbs alone: pair them with protein or healthy fat (toast + eggs, fruit + nuts, rice + chicken).
Walk 10-15 minutes after meals — the simplest, most effective natural tool against post-meal spikes.
Keep breakfast lower-carb: morning hormones make blood sugar hardest to control early in the day.
Skip juices and sweetened drinks — even "natural" ones are the fastest route to a spike.
Sleep enough — poor sleep genuinely raises blood sugar.

If diet and movement aren't enough, medication or insulin simply means your placenta's hormones are strong — not that you failed. Controlled blood sugar is the only goal, and with it, the overwhelming majority of gestational diabetes pregnancies end with a healthy mom and a healthy baby.

⚠️ Call your provider promptly if

Your readings exceed targets 3+ times in a week despite following the plan
Fasting readings stay above ~110 mg/dL daily
You have low-sugar symptoms (shakiness, sweating, dizziness) — especially on medication
Your baby's movements decrease noticeably

FAQ

Can I refuse the glucose drink?

Talk to your provider — some clinics offer alternatives (jelly beans protocols, home monitoring for a period). Skipping screening entirely means undetected gestational diabetes stays untreated, which carries real risks for you and your baby.

Will gestational diabetes go away after birth?

Usually yes, within weeks. It does mark a higher lifetime risk of type 2 diabetes, so get the 6-12 week postpartum glucose test and yearly screening after — and know that breastfeeding and a healthy weight measurably lower the risk.

Does gestational diabetes mean a C-section?

No — well-controlled gestational diabetes is compatible with normal vaginal delivery in most cases. Your provider will discuss options near term based on your baby's estimated size and your readings.

I felt sick and couldn't finish the drink — now what?

It happens, especially if you're still dealing with morning sickness. Tell the clinic — they'll reschedule or offer an alternative protocol.

Bottom line

The glucose test is a routine, universal check at weeks 24-28 — not a judgment of how you've eaten. If you pass, one thing off the list. If you're diagnosed, you'll join millions of mothers who managed it with smaller meals, post-meal walks, regular readings, and a care team watching closely 💛

⚕️ Educational content — not a substitute for medical advice. Reference numbers are general; your provider's targets take priority. Sources: ACOG, American Diabetes Association, WHO.