Tool 46/54·Charts & Guides
Normal targets, gestational diabetes thresholds, and OGTT reference values — all in one place.
Medical Disclaimer
This chart is for educational purposes only and does not constitute medical advice. Blood sugar targets during pregnancy are individualized. Always follow the specific targets set by your obstetrician, midwife, or endocrinologist. Do not adjust medication or diet without professional guidance.
Display Units
To convert: mg/dL ÷ 18 = mmol/L | mmol/L × 18 = mg/dL
Source: American Diabetes Association (ADA) Standards of Care in Diabetes 2024.
Measured first thing in the morning before eating or drinking anything.
GDM threshold: ≥ 95 mg/dLMeasured exactly 60 minutes from the first bite of a meal.
GDM threshold: ≥ 140 mg/dLMeasured exactly 120 minutes from the first bite of a meal.
GDM threshold: ≥ 120 mg/dLInsulin resistance changes throughout pregnancy — here is what to expect.
For Mother
For Baby
The Oral Glucose Tolerance Test (OGTT) is the gold standard for diagnosing gestational diabetes. Two protocols are used — choose the tab that matches your provider's approach.
Two-step (US): A 50 g glucose challenge first; if positive, a 100 g 3-hour OGTT confirms diagnosis. Two or more abnormal values = GDM. One-step (WHO/IADPSG): A single 75 g 2-hour OGTT; one abnormal value is sufficient for diagnosis.
| Test / Draw | Dose | Normal (mg/dL) | Timing |
|---|---|---|---|
1-Hour Glucose Challenge (GCT) No fasting required. A positive screen does not diagnose GDM — it triggers further testing. | 50 g glucose | < 130–140 | 24–28 weeks (screening) |
3-Hour OGTT — Fasting Requires overnight fasting. Blood drawn before the drink. | 100 g glucose | < 95 | After positive GCT |
3-Hour OGTT — 1 hour Blood drawn 60 minutes after the glucose drink. | 100 g glucose | < 180 | After positive GCT |
3-Hour OGTT — 2 hours Blood drawn 120 minutes after the glucose drink. | 100 g glucose | < 155 | After positive GCT |
3-Hour OGTT — 3 hours Blood drawn 180 minutes after the glucose drink. | 100 g glucose | < 140 | After positive GCT |
2-Hour OGTT — Fasting WHO / IADPSG one-step protocol. Requires overnight fasting. | 75 g glucose | < 92 | 24–28 weeks (one-step method) |
2-Hour OGTT — 1 hour Blood drawn 60 minutes after the 75 g glucose drink. | 75 g glucose | < 180 | 24–28 weeks (one-step method) |
2-Hour OGTT — 2 hours Blood drawn 120 minutes after the 75 g glucose drink. | 75 g glucose | < 153 | 24–28 weeks (one-step method) |
Sources: American Diabetes Association (ADA) 2024; ACOG Practice Bulletin No. 190; WHO/IADPSG criteria.
The good news: When gestational diabetes is well-managed through diet, regular blood sugar monitoring, and medication when needed, most mothers and babies have healthy outcomes. Early diagnosis and consistent care dramatically reduce all of the risks above.
During pregnancy, the placenta produces hormones that help the baby grow — but these same hormones block insulin from working normally in the mother's cells. This is called insulin resistance, and it is a natural part of pregnancy that ensures the baby receives enough glucose. For most women the pancreas compensates by making more insulin. When it cannot keep up, blood sugar rises above normal and gestational diabetes (GDM) develops.
GDM affects roughly 2–10% of pregnancies in the United States, making it one of the most common pregnancy complications. Risk factors include obesity, a family history of type 2 diabetes, age over 35, previous GDM, and polycystic ovary syndrome (PCOS). However, GDM can develop in women with no risk factors at all, which is why universal screening at weeks 24–28 is recommended for all pregnant women.
Why Pregnancy Targets Are Lower Than Normal Adult Targets
Non-pregnant adults aim for a fasting glucose below 100 mg/dL (5.6 mmol/L). During pregnancy the target tightens to < 95 mg/dL (5.3 mmol/L). This is because even slightly elevated glucose is transported across the placenta to the baby, stimulating the baby's own insulin production and driving excess growth. The pregnancy-specific targets exist to protect the fetus, not just the mother.
For most women with GDM, blood sugar normalizes within days to weeks after delivery. However, GDM is a strong signal of underlying susceptibility to type 2 diabetes. The Caloria app can help you track your diet long-term — studies show that losing 5–7% of body weight and staying active reduces the risk of developing type 2 diabetes by over 50% in women who had GDM.
The ADA recommends a postpartum 75 g 2-hour OGTT at 4–12 weeks after delivery, and then diabetes screening every 1–3 years for life. Children born to mothers with GDM should also be monitored for obesity and glucose abnormalities as they grow.
01
A normal fasting blood glucose level during pregnancy is below 95 mg/dL (5.3 mmol/L), according to the American Diabetes Association. This is lower than the standard non-pregnant fasting target of < 100 mg/dL because the placenta's hormones increase insulin resistance, and tighter control protects the baby. Always confirm your personal target with your OB or midwife.
02
Using the standard two-step US protocol with a 100 g 3-hour OGTT, gestational diabetes is diagnosed when two or more values meet or exceed these thresholds: fasting ≥ 95, 1-hour ≥ 180, 2-hour ≥ 155, or 3-hour ≥ 140 mg/dL. Using the one-step WHO/IADPSG protocol (75 g 2-hour OGTT), just one abnormal value is enough: fasting ≥ 92, 1-hour ≥ 180, or 2-hour ≥ 153 mg/dL.
03
For gestational diabetes managed by diet alone, most providers recommend checking 4 times a day: once fasting in the morning, and once 1–2 hours after each main meal. If you are on insulin or medication, your provider may recommend additional checks. Record every reading to share with your care team at each visit.
04
Yes, if left unmanaged, high blood sugar crosses the placenta and causes the baby's pancreas to over-produce insulin, leading to excessive growth (macrosomia). This raises the risk of birth injuries, cesarean delivery, neonatal hypoglycemia, and jaundice. With good blood sugar control through diet, exercise, and medication when needed, most babies are born healthy.
05
In most cases, blood sugar returns to normal within a few weeks after delivery. However, women who had GDM have a 40–60% lifetime risk of developing type 2 diabetes. The American Diabetes Association recommends a 2-hour 75 g OGTT at 4–12 weeks postpartum, and then diabetes screening every 1–3 years thereafter.
06
Avoid or strictly limit foods that spike blood sugar quickly: sugary drinks (juice, soda, sports drinks), white bread, white rice, refined pasta, candy, desserts, and large fruit servings. Instead, focus on non-starchy vegetables, lean protein, healthy fats, and modest portions of high-fibre complex carbohydrates paired with protein or fat to blunt glucose spikes. A registered dietitian can create a personalized meal plan.
Medical Disclaimer: The information on this page is for general educational purposes and does not replace professional medical advice, diagnosis, or treatment. Blood sugar targets during pregnancy are individualized and may differ from the values shown here based on your health history and your provider's clinical judgment. Always consult a qualified healthcare professional — including your obstetrician, certified nurse-midwife, or endocrinologist — for personalized guidance. In a medical emergency, call 911 or your local emergency number immediately.