Lab result explainedMetabolic panelLast updated November 11, 2026

1-hour glucose test (glucose challenge test): normal range, what failing means and how to prepare

Glucose challenge test (GCT) · Prenatal screening at 24–28 weeks (50 g oral glucose, plasma glucose drawn 1 hour later) · reported in mg/dL (plasma glucose; some reports give mmol/L: divide mg/dL by 18)

The glucose challenge test (GCT), usually called the 1-hour glucose test, is the screening test for gestational diabetes that most pregnant people in the US take between 24 and 28 weeks. You drink a flavored solution containing 50 grams of glucose, often called glucola, and exactly one hour later a blood sample is drawn. No fasting is needed. A result under the clinic's cut-off, which is 130, 135 or 140 mg/dL depending on the practice, is a pass. A result at or above the cut-off is not a diagnosis; it means you go on to the longer 3-hour glucose tolerance test, which is the test that actually decides.

Roughly 15 to 25 percent of people screen positive on the 1-hour test, and most of them pass the 3-hour test: overall only about 6 to 9 percent of US pregnancies end up with a diagnosis of gestational diabetes, so about one in three to one in four people who fail the screen have it. A 1-hour value of 200 mg/dL or more is the exception; many practices treat that as diagnostic on its own and skip straight to management. Gestational diabetes is worth finding because treating it with diet, monitoring and when needed medication cuts the rate of serious newborn complications and large babies by half or more.

The 1-hour test is a screen, so it is set up to catch nearly everyone who has the condition at the cost of flagging many who do not. Where it sits relative to the cut-off, what you ate beforehand, whether you were ill or on steroids, and your own risk factors all shape what a borderline result means. If you have a BMI of 30 or more, had gestational diabetes before, have polycystic ovary syndrome or a strong family history of type 2 diabetes, you may be tested earlier in pregnancy as well, and some practices use a single-step 75 g 2-hour test instead of the two-step approach.

GCT at a glance

  • What it is: a screening test for gestational diabetes; 50 g of oral glucose followed by a plasma glucose measurement one hour later, done at 24–28 weeks (earlier if you have risk factors). No fasting required.
  • Pass: under 140 mg/dL at most US practices; some use 135 or 130 mg/dL. The lower the cut-off, the more people are sent for the 3-hour test but the fewer cases are missed.
  • Positive screen: 140–199 mg/dL (or above the clinic's lower cut-off). This is not a diagnosis; it means a fasting 3-hour, 100 g oral glucose tolerance test is needed.
  • 200 mg/dL or higher: many clinicians diagnose gestational diabetes without further testing, or confirm with a fasting glucose.
  • Of people who fail the 1-hour test, only about a quarter to a third have gestational diabetes on the 3-hour test.
  • Next step after a positive screen: schedule the 3-hour test within about a week, eat your normal diet (at least 150 g of carbohydrate a day) beforehand, and fast 8–14 hours overnight before it.

Have your whole report? Paste it into the free Lab Explainer

Every marker explained in plain language, in context with the others, with questions to bring to your appointment. No account needed.

What GCT measures

In pregnancy the placenta makes hormones, chiefly human placental lactogen, progesterone, cortisol and growth hormone, that deliberately make the mother's tissues less sensitive to insulin so that more glucose stays in the blood for the fetus. Insulin resistance rises steadily from mid-pregnancy and peaks in the third trimester. A healthy pancreas compensates by roughly doubling or tripling insulin output; gestational diabetes is what happens when it cannot keep up. The 1-hour test gives the pancreas a standard load of 50 g of glucose and measures how far blood glucose has climbed an hour later, which is close to the usual peak. The higher the value, the more likely the insulin response is inadequate.

The test was designed as a screen, not a diagnosis. At the 140 mg/dL threshold it detects about 80 to 85 percent of gestational diabetes while sending about 15 percent of all pregnant people for the 3-hour test; at 130 mg/dL it detects over 90 percent but sends 20 to 25 percent for further testing. The American College of Obstetricians and Gynecologists accepts any of 130, 135 or 140, which is why the pass mark differs between practices and why a 134 can be a pass at one clinic and a fail at another. The sample should be venous plasma run in a laboratory; finger-stick meters are not accurate enough for this decision.

Timing is 24 to 28 weeks because insulin resistance is high enough by then to reveal the problem while leaving two to three months to treat it. People with risk factors (BMI of 30 or more, prior gestational diabetes, a previous baby over 9 pounds, polycystic ovary syndrome, a first-degree relative with diabetes, prior prediabetes, or being from a higher-risk ethnic group) are often tested at the first prenatal visit as well, usually with an A1C or fasting glucose to look for undiagnosed type 2 diabetes, and then again at 24 to 28 weeks if the early test was normal. Some practices skip the two-step approach entirely and use a single fasting 75 g 2-hour test with lower thresholds (92, 180 and 153 mg/dL), which diagnoses about twice as many people.

Normal range for GCT

Reference ranges vary between labs and by age, sex and pregnancy. Use the range printed on your own report.

GroupTypical range (mg/dL (plasma glucose; some reports give mmol/L: divide mg/dL by 18))Notes
Negative screen (pass), common thresholdBelow 140 mg/dL (7.8 mmol/L)Used by most US practices. Detects about 80–85 percent of gestational diabetes.
Negative screen, stricter thresholdsBelow 135 or below 130 mg/dLUsed by some practices and recommended where the population risk is higher; catches more cases, flags more people for the 3-hour test.
Borderline band130–139 mg/dLA pass or a fail depending on the clinic's cut-off. Worth asking which threshold your practice uses.
Positive screen140–199 mg/dL (or above the clinic's cut-off)Not a diagnosis. About 70–75 percent of people in this band pass the 3-hour test.
Very high screen200 mg/dL (11.1 mmol/L) or higherMany clinicians diagnose gestational diabetes without a 3-hour test, or confirm with a fasting glucose, because the 3-hour test is likely to be positive and may cause marked hyperglycemia.
Early pregnancy (first trimester) testing for pre-existing diabetesFasting 126 mg/dL or more, A1C 6.5 percent or more, or random 200 or moreThese values at the first visit mean overt (pre-existing) diabetes, not gestational diabetes, and are managed differently.
One-step alternative: 75 g 2-hour test (IADPSG)Fasting 92, 1-hour 180, 2-hour 153 mg/dLOne value at or above any threshold is diagnostic. Used instead of the 1-hour screen by some practices.
After delivery (4–12 weeks postpartum)75 g 2-hour test: under 140 normal, 140–199 prediabetes, 200 or more diabetesRecommended for everyone who had gestational diabetes, then every 1–3 years for life.

High 1-hour glucose (failed glucose challenge test)

A result at or above your practice's cut-off means your blood glucose rose further than expected after the 50 g drink and you need the diagnostic 3-hour test. It does not mean you have gestational diabetes, and it does not mean you did anything wrong: insulin resistance in pregnancy is driven by placental hormones, and the people most likely to be flagged are those with a family history of type 2 diabetes, a higher BMI, polycystic ovary syndrome, age over 35 or a prior large baby. A value in the 140s is passed on the 3-hour test by about three in four people; the likelihood of a diagnosis rises steadily with the number, and at 180 to 199 mg/dL roughly half will have gestational diabetes.

A 1-hour value of 200 mg/dL or more is treated differently because the chance of a positive 3-hour test is very high and the 100 g load could push glucose uncomfortably high. Many clinicians diagnose gestational diabetes at this point, or confirm it with a single fasting glucose, and begin glucose monitoring and nutrition counseling right away. If the test was done early in pregnancy, a very high result raises the possibility of undiagnosed type 2 diabetes, which is checked with an A1C.

A few things can push a result over the line without reflecting your true insulin response. Eating a large or sugary meal in the hour or two before the drink, a course of steroids (betamethasone for fetal lung maturity raises glucose for about five days; prednisone and inhaled high-dose steroids to a lesser extent), an acute illness, several days of unusually low carbohydrate intake beforehand, and a blood draw taken much earlier than the one-hour mark all raise the number. These are reasons to mention the circumstances, not reasons to skip the 3-hour test.

Common causes

  1. Gestational diabetes

    The pancreas cannot produce enough extra insulin to overcome pregnancy-related insulin resistance. Diagnosed in about 6–9 percent of US pregnancies by the two-step method and 15–18 percent by the one-step method; the rate rises with age and BMI.

  2. Undiagnosed pre-existing type 2 diabetes or prediabetes

    About 1–2 percent of pregnancies involve diabetes that predates conception. A first-trimester A1C of 6.5 percent or more or fasting glucose of 126 or more identifies it; it carries higher risks of birth defects and needs tighter early control.

  3. Higher BMI and excess gestational weight gain

    Each 1 kg/m² of pre-pregnancy BMI raises gestational diabetes risk by about 8 percent; a BMI of 30 or more roughly triples it compared with a BMI under 25, through greater baseline insulin resistance.

  4. Polycystic ovary syndrome and family history

    PCOS roughly doubles to triples the risk because of underlying insulin resistance; a first-degree relative with type 2 diabetes raises it about 2 to 3 fold.

  5. Previous gestational diabetes or a previous large baby

    Gestational diabetes recurs in about 40–50 percent of subsequent pregnancies, and a previous baby weighing over 9 pounds (4,000 g) suggests unrecognized hyperglycemia in that pregnancy.

  6. Steroid medication

    Betamethasone or dexamethasone given for threatened preterm birth raises maternal glucose for up to 5 days; prednisone, high-dose inhaled steroids and some injections do the same. Screening is usually delayed at least a week after a steroid course.

  7. A large meal or sugary drink shortly before the test

    Although fasting is not required, glucose from a recent meal adds to the glucose load; most clinics advise eating normally but avoiding a big carbohydrate-heavy meal or sweet drink in the hour or two before.

  8. Carbohydrate restriction in the days before the test

    Several days of low carbohydrate intake reduces the insulin response to a sudden glucose load ('starvation diabetes'), which is why diagnostic protocols require at least 150 g of carbohydrate a day for 3 days before an oral glucose test.

  9. Acute illness, poor sleep and inactivity

    Infection, pain and stress hormones raise glucose transiently; bed rest and short sleep reduce insulin sensitivity by 20–30 percent within days.

  10. Twin or higher-order pregnancy

    A larger placental mass produces more insulin-resistance hormones, raising gestational diabetes rates to about 1.5 times those of single pregnancies.

Symptoms that can go with it

  • Usually none; gestational diabetes is almost always silent, which is why everyone is screened
  • Increased thirst and urination beyond what is usual in pregnancy, when glucose is very high
  • Unusual fatigue
  • Recurrent yeast infections or urinary tract infections
  • A baby measuring large for dates, or excess amniotic fluid (polyhydramnios), on ultrasound
  • Glucose in the urine on a routine prenatal dipstick (common in normal pregnancy too, so not diagnostic)

Low 1-hour glucose

There is no official lower limit on the glucose challenge test, and a low number (many people ask about results in the 70s or 80s) is a pass. It usually means you are insulin sensitive, that the drink emptied slowly from your stomach, or that you had not eaten for many hours before the test. Several observational studies have found that values below about 85 to 90 mg/dL are associated with a modestly higher chance of a smaller-than-average baby, roughly 1.3 to 1.6 times the usual rate, but this is a statistical association in large groups and is not used to make decisions for an individual pregnancy; if your baby is growing normally on ultrasound, no action follows.

What people more often notice is how they feel. The 50 g drink causes a brisk insulin release, and in some people glucose then dips below where it started at 90 to 120 minutes, producing shakiness, sweating, nausea or lightheadedness just as the blood is drawn or on the way home. This reactive dip is uncomfortable but not harmful, and it is not the same as a diagnosis of hypoglycemia. Eating a snack with protein and complex carbohydrate right after the draw prevents most of it. Vomiting the drink within the hour invalidates the test and it is rescheduled.

Common causes

  1. Normal insulin sensitivity

    Lean, physically active people and those with no family history of diabetes clear a 50 g load quickly; values of 70–100 mg/dL at one hour are common and entirely normal.

  2. Prolonged fasting before the test

    Arriving after 10–12 hours without food lowers the starting glucose and can blunt the peak; it also makes nausea and lightheadedness after the drink more likely. A normal breakfast an hour or two before is fine for the 1-hour test.

  3. Reactive dip after the glucose load

    A strong first-phase insulin response can overshoot, dropping glucose into the 60s or 70s around 90–150 minutes with sweating and shakiness; it resolves with food and does not indicate disease.

  4. Slow gastric emptying or vomiting

    Nausea of pregnancy, iron tablets or a full stomach slow absorption; vomiting part of the drink means less than 50 g was absorbed and the test must be repeated.

  5. Delayed processing of the blood sample

    Red cells keep consuming glucose in the tube at about 5–7 mg/dL per hour at room temperature unless a fluoride (gray-top) tube is used and the sample is processed promptly; a delayed sample reads falsely low.

  6. Walking around during the hour

    Muscle activity takes up glucose; protocols ask you to sit quietly because exercise can lower the result by 10–20 mg/dL.

Symptoms that can go with it

  • None in most cases; a low result is a normal result
  • Shakiness, sweating, pounding heart or lightheadedness 1–2 hours after the drink
  • Nausea or queasiness, which is the most common side effect of the drink itself
  • Hunger and fatigue later in the day
  • A baby measuring small for dates on ultrasound, which is investigated on its own merits rather than attributed to the test result

Read it alongside

  • 3-hour 100 g oral glucose tolerance test — the diagnostic test after a positive screen; two or more values at or above 95 (fasting), 180 (1 h), 155 (2 h) and 140 mg/dL (3 h) confirm gestational diabetes by Carpenter-Coustan criteria.
  • A1C — at the first prenatal visit, 6.5 percent or more identifies pre-existing diabetes; it is not used to diagnose gestational diabetes because pregnancy lowers A1C by about 0.5 percent.
  • Fasting glucose — 126 mg/dL or more at any point in pregnancy means overt diabetes; 92–125 on the one-step test means gestational diabetes.
  • Urine glucose and ketones — glucose in the urine is common in normal pregnancy (the kidney threshold falls) and does not diagnose anything; ketones suggest you are not eating enough carbohydrate.
  • Blood pressure and urine protein — gestational diabetes roughly doubles the risk of preeclampsia, so both are watched more closely after a diagnosis.
  • Fetal growth ultrasound — estimated fetal weight and abdominal circumference above the 90th percentile, or excess amniotic fluid, are the practical consequences being prevented.
  • Postpartum 75 g 2-hour glucose tolerance test — at 4–12 weeks after delivery; up to half of people with gestational diabetes develop type 2 diabetes within 10 years, so this and follow-up every 1–3 years matter.

What usually happens next

  1. If you passed, no further glucose testing is planned unless symptoms, glucose in the urine or a large baby on ultrasound prompt a repeat later in pregnancy.
  2. If you screened positive below 200 mg/dL, book the 3-hour test within about a week; eat your usual diet with at least 150 g of carbohydrate a day for 3 days before, then fast for 8–14 hours overnight (water is allowed), bring a snack for afterward and plan to sit for the full 3 hours.
  3. If your result was 200 mg/dL or more, ask whether your practice diagnoses gestational diabetes on this value alone or confirms with a fasting glucose; either way, expect a referral for nutrition counseling and a glucose meter within days.
  4. Tell your clinician if you had a steroid injection, an infection, a very large meal just before the test or several days of very low carbohydrate intake, because any of these can justify repeating the screen rather than proceeding straight to the 3-hour test.
  5. Ask which threshold (130, 135 or 140 mg/dL) your practice uses, so you understand why a borderline result was treated as it was.
  6. If you are diagnosed, the standard plan is checking fasting and 1- or 2-hour post-meal glucose four times a day, a meal plan from a dietitian, regular walking, and insulin or sometimes metformin if targets (fasting under 95, 1-hour under 140, 2-hour under 120 mg/dL) are not met; growth ultrasounds and discussion of delivery timing follow.

Diet, lifestyle and natural levers with evidence

What can move GCT once the cause is known. Nothing here replaces finding the cause.

Eating normally, not restricting carbohydrate, before the test

Moderate evidence

Cutting carbohydrate for days before a glucose test raises, not lowers, the result, because the pancreas and muscles adapt to low intake and respond sluggishly to a sudden load; this is why every oral glucose test protocol specifies at least 150 g of carbohydrate a day for 3 days beforehand. For the 1-hour screen, the practical advice is a normal breakfast or lunch 1 to 2 hours before, no sweet drinks or large dessert in that window, no smoking, and sitting quietly during the hour. Trying to 'game' the test risks missing a condition whose treatment halves serious newborn complications.

Regular physical activity through pregnancy

Strong evidence

A meta-analysis of 106 randomized trials in more than 11,000 pregnant women found that structured exercise (at least about 140 minutes a week of moderate activity such as brisk walking, swimming or stationary cycling, started in the first or early second trimester) reduced the odds of gestational diabetes by 38 percent, along with a 39 percent reduction in gestational hypertension. After a diagnosis, a 10 to 15 minute walk after each meal lowers the 1-hour post-meal glucose by roughly 20 to 30 mg/dL. ACOG recommends 150 minutes a week of moderate activity in uncomplicated pregnancies.

Check with your obstetric provider first if you have placenta previa, cervical insufficiency, preeclampsia, bleeding or preterm labor, and stop for dizziness, chest pain, contractions or fluid leakage.

Mediterranean-style eating pattern

Moderate evidence

In the ESTEEM trial of 1,252 pregnant women with metabolic risk factors in the UK, a Mediterranean-style diet (extra-virgin olive oil, 30 g of nuts a day, more fish, legumes and vegetables, less red and processed meat) started in early pregnancy reduced gestational diabetes by 35 percent and gestational weight gain by about 1.2 kg compared with usual care. After a diagnosis, replacing refined grains and sugary drinks with whole grains, vegetables and protein, and spreading carbohydrate across three meals and two to three snacks, is the core of medical nutrition therapy and keeps about 70–85 percent of people off medication.

Reaching a healthier weight before pregnancy or between pregnancies

Moderate evidence

Pre-pregnancy BMI is the strongest modifiable predictor of gestational diabetes. In a large US cohort, women who lost at least 2 BMI units (about 5–6 kg) between pregnancies after having gestational diabetes cut their odds of recurrence by about 70 percent, while gaining 3 or more units roughly doubled them. Keeping gestational weight gain within Institute of Medicine ranges (11–20 lb for BMI 30 or over, 15–25 lb for BMI 25–29.9) is associated with lower rates of large babies and later type 2 diabetes.

Weight loss during pregnancy itself is not recommended; the lever is before conception and between pregnancies.

Myo-inositol

Preliminary evidence

Myo-inositol, a glucose-like molecule involved in insulin signaling, has been tested at 4 g a day (usually with 400 µg folic acid) from the first trimester in women at high risk (obesity, PCOS, family history). Pooled trials, mostly small and from Italy, show roughly a 40 to 60 percent reduction in gestational diabetes diagnoses, but a 2023 Cochrane review rated the evidence low certainty and it is not yet in US guidelines. It does not change the result of a test already scheduled; the trials started supplementation at 12–13 weeks.

Discuss with your obstetric provider before starting any supplement in pregnancy; mild nausea and loose stools are the main side effects.

Correcting vitamin D deficiency

Preliminary evidence

Low 25-hydroxyvitamin D (under 20 ng/mL) is associated with about a 40 to 50 percent higher risk of gestational diabetes in observational studies, and a Cochrane review of supplementation trials found it may reduce gestational diabetes (low-certainty evidence), with doses of 1,000 to 2,000 IU a day being typical. The effect, if real, is likely limited to people who are deficient; routine high-dose supplementation has not been shown to help.

Keep total intake at or below 4,000 IU a day unless a clinician is monitoring your level.

When to see a clinician promptly

  • A 1-hour result of 200 mg/dL or more: contact your prenatal clinic within a day or two so management can start without waiting for a 3-hour test.
  • Any positive screen with symptoms of high glucose (marked thirst, frequent urination, blurred vision, unexplained weight loss) or if a random glucose has been over 250 mg/dL: same-day review, as pre-existing diabetes may be present.
  • Persistent vomiting that stops you keeping fluids down, with dizziness or reduced urination, whether from the test drink or pregnancy nausea: dehydration in pregnancy needs prompt assessment.
  • Reduced fetal movements at any time after about 28 weeks, regardless of glucose results: go to labor and delivery the same day.
  • Severe headache, visual disturbance, pain under the right ribs or sudden swelling of the face and hands with a diagnosis of gestational diabetes: possible preeclampsia, which is more common in gestational diabetes and is an emergency.
  • Shakiness, sweating and confusion that do not settle after eating, especially once on insulin or glibenclamide (glyburide): possible significant hypoglycemia.

Frequently asked questions

What is a normal result for the 1-hour glucose test?

Below 140 mg/dL (7.8 mmol/L) at most US practices, and below 135 or 130 at some. A normal result means your risk of gestational diabetes is low enough that no further testing is done unless something changes later in pregnancy. Ask your clinic which cut-off it uses; a result of 134 is a pass under a 140 threshold and a fail under a 130 threshold.

What happens if I fail the 1-hour glucose test?

You are scheduled for the 3-hour, 100 g oral glucose tolerance test, usually within a week. You fast overnight, have a fasting blood draw, drink 100 g of glucose, and have blood drawn at 1, 2 and 3 hours; two or more values at or above 95, 180, 155 and 140 mg/dL diagnose gestational diabetes. About three in four people who failed the 1-hour test pass the 3-hour test. If your 1-hour result was 200 mg/dL or more, many clinicians skip the 3-hour test and diagnose gestational diabetes directly.

Do you have to fast for the 1-hour glucose test?

No. The 1-hour glucose challenge test is designed to be done at any time of day without fasting, which is part of why it is the screening test. Eat your normal meals; many clinics suggest avoiding a very large meal or sugary drink in the hour or two before, not smoking, and sitting quietly during the hour. Fasting is required only for the 3-hour diagnostic test, and for the one-step 2-hour test if your practice uses that instead.

What should I eat before the 1-hour glucose test in pregnancy?

Your usual diet. Do not cut carbohydrates in the days before, because that makes the result higher, not lower. On the day, a normal balanced breakfast or lunch 1 to 2 hours beforehand (for example eggs and whole-grain toast, or yogurt with fruit) is fine; skip the orange juice, soda, pastries or a big dessert immediately before, since those add glucose to the load. Bring a protein-containing snack to eat straight after the blood draw to head off the shaky, lightheaded dip some people feel.

Is 140 a fail on the 1-hour glucose test?

At a practice using the 140 mg/dL threshold, 140 is at the cut-off and counts as a positive screen (the usual rule is 'at or above'). It is a mildly positive result: people in the 140s pass the 3-hour test about 75 percent of the time. At a practice using 130 or 135, it is clearly positive. Either way the next step is the same, the 3-hour test, and the result does not by itself mean you have gestational diabetes.

Can I eat jelly beans or candy instead of drinking the glucola?

Some practices allow 50 g of carbohydrate from jelly beans (about 28 beans) or a similar standardized candy for people who cannot tolerate the drink, and it causes less nausea. However, in the trial that compared them, jelly beans detected only about 40 percent of gestational diabetes cases versus 80 percent for the glucose drink, because the sugar mix and absorption differ, so a pass is less reassuring. If the drink makes you vomit, ask about a smaller volume, a chilled drink, a different flavor, or going straight to the fasting diagnostic test.

What if I throw up the glucose drink?

If you vomit within the hour, less than the full 50 g was absorbed and the test is invalid, so it is rescheduled; it does not count as a fail. Sipping the drink cold over the allowed 5 minutes, having a light meal an hour or two beforehand rather than arriving fasting, and sitting still afterward all reduce nausea. If you vomit a second time, options include a fasting glucose plus A1C, the one-step 75 g test (which is often better tolerated because of the fasting state), or home glucose monitoring for a week or two.

Why is the glucose test done at 24 to 28 weeks?

Insulin resistance from placental hormones rises steadily through the second trimester and is high enough by 24 to 28 weeks to unmask gestational diabetes in most people who will develop it, while still leaving 10 to 14 weeks in which treatment can prevent excess fetal growth and newborn complications. Testing earlier catches pre-existing diabetes but misses many gestational cases, which is why people tested early for risk factors are re-tested at 24 to 28 weeks if the first test was normal.

References

  1. Glucose screening tests during pregnancy. MedlinePlus Medical Encyclopedia, US National Library of Medicine (2024)
  2. American College of Obstetricians and Gynecologists Committee on Practice Bulletins—Obstetrics. ACOG Practice Bulletin No. 190: Gestational diabetes mellitus. Obstetrics & Gynecology (2018)
  3. American Diabetes Association Professional Practice Committee. 2. Diagnosis and classification of diabetes: Standards of Care in Diabetes—2025. Diabetes Care (2025)
  4. American Diabetes Association Professional Practice Committee. 15. Management of diabetes in pregnancy: Standards of Care in Diabetes—2025. Diabetes Care (2025)
  5. US Preventive Services Task Force. Screening for gestational diabetes: US Preventive Services Task Force recommendation statement. JAMA (2021)
  6. HAPO Study Cooperative Research Group; Metzger BE, Lowe LP, Dyer AR, et al.. Hyperglycemia and adverse pregnancy outcomes (HAPO). New England Journal of Medicine (2008)
  7. Crowther CA, Hiller JE, Moss JR, McPhee AJ, Jeffries WS, Robinson JS. Effect of treatment of gestational diabetes mellitus on pregnancy outcomes (ACHOIS). New England Journal of Medicine (2005)
  8. Landon MB, Spong CY, Thom E, et al.. A multicenter, randomized trial of treatment for mild gestational diabetes. New England Journal of Medicine (2009)
  9. Hillier TA, Pedula KL, Ogasawara KK, et al.. A pragmatic, randomized clinical trial of gestational diabetes screening. New England Journal of Medicine (2021)
  10. Lamar ME, Kuehl TJ, Cooney AT, Gayle LJ, Holleman S, Allen SR. Jelly beans as an alternative to a fifty-gram glucose beverage for gestational diabetes screening. American Journal of Obstetrics and Gynecology (1999)
  11. Davenport MH, Ruchat SM, Poitras VJ, et al.. Prenatal exercise for the prevention of gestational diabetes mellitus and hypertensive disorders of pregnancy: a systematic review and meta-analysis. British Journal of Sports Medicine (2018)
  12. H Al Wattar B, Dodds J, Placzek A, et al.. Mediterranean-style diet in pregnant women with metabolic risk factors (ESTEEM): a pragmatic multicentre randomised trial. PLoS Medicine (2019)

Related markers

Related conditions

Evidence guides

Worried about your number?

Ask AskMN what your GCT result could mean in the context of your other results, symptoms and medications. Free, unlimited, no account needed.

Ask about my GCT

This page is educational and is not medical advice or a diagnosis. Lab results have to be interpreted together with your history, symptoms and other results by a clinician who knows you. Do not start or stop a supplement to change a lab value before the cause is known.