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Gestational Diabetes: Signs, Testing, and Management

Gestational diabetes is high blood sugar that develops during pregnancy, usually in the second or third trimester, in someone who did not have diabetes before.

Gestational Diabetes: Signs, Testing, and Management
Pregnancy & Women's HealthGestational Diabetesmanagement
Written By: DocAi Health Editorial Team
Last Updated: 2026-08-23
Medically Reviewed By: DocAi Health Medical Review Team
Medical Disclaimer: This article is for general informational and educational purposes only and is not medical advice. It does not create a doctor-patient relationship and is not a substitute for professional diagnosis or treatment by a qualified healthcare provider. Never disregard or delay seeking professional medical advice because of something you have read here. If you think you may have a medical emergency, call 911 or your local emergency number right away. Health information can change and this guidance is general and US-focused, so consult a licensed clinician in your own country about your specific situation.
Gestational diabetes is high blood sugar that develops during pregnancy, usually in the second or third trimester, in someone who did not have diabetes before. It happens because pregnancy hormones make your body's cells more resistant to insulin, and for some people the pancreas cannot keep up with the extra demand. Most people have no symptoms at all, which is why it is found through a screening test rather than by how you feel. It matters because unmanaged blood sugar can affect how large your baby grows and raise the odds of complications during delivery, but with testing, diet changes, monitoring, and medication when needed, most people carry a healthy pregnancy to term. This article covers the signs, how testing works, and what day-to-day management looks like.

What Gestational Diabetes Is and Why It Happens

During pregnancy, the placenta produces hormones, including human placental lactogen and progesterone, that help your baby get nutrients but also work against insulin's normal job of moving glucose out of your bloodstream and into your cells. This is a normal part of pregnancy physiology, and every pregnant person becomes somewhat more insulin resistant as the pregnancy progresses. Gestational diabetes develops when the pancreas cannot produce enough extra insulin to overcome that resistance, so blood glucose rises higher than it should.
This is different from having diabetes before pregnancy. Type 1 and type 2 diabetes exist before conception and are managed throughout pregnancy, while gestational diabetes is diagnosed because of a screening test done during pregnancy and, in most people, resolves after the baby is born. Some people who are diagnosed with gestational diabetes actually had undetected type 2 diabetes going into pregnancy, which is part of why postpartum testing matters and is covered later in this article.

Who Is More Likely to Develop It

Anyone can develop gestational diabetes, but certain factors raise the likelihood. These include being over age 35, having a body mass index in the overweight or obesity range before pregnancy, having a parent or sibling with type 2 diabetes, having had gestational diabetes in a previous pregnancy, having polycystic ovary syndrome, and belonging to certain ethnic groups, including Hispanic, Black, Native American, Asian American, and Pacific Islander populations, where the condition is documented at higher rates. Having delivered a baby who weighed more than 9 pounds in a previous pregnancy is also a risk marker. None of these factors mean gestational diabetes is certain, and plenty of people with no risk factors are diagnosed with it too, which is why screening is offered to nearly everyone rather than only to those considered high risk.

Signs and Symptoms

The defining feature of gestational diabetes is that it usually causes no noticeable symptoms. Blood sugar can run higher than normal for weeks before a screening test catches it. When symptoms do appear, they tend to be subtle and easy to mistake for ordinary pregnancy discomfort:
  • Unusual thirst that is not relieved by drinking water
  • Needing to urinate more often than the usual pregnancy increase
  • Fatigue that feels heavier than typical pregnancy tiredness
  • Blurred vision
  • Recurrent yeast or urinary tract infections
  • Nausea in some people
Because these overlap so heavily with normal pregnancy symptoms, self-diagnosis is not reliable in either direction. Feeling fine does not rule out gestational diabetes, and having one or two of these symptoms does not mean you have it. Testing is what makes the diagnosis.

How Testing Works

Most people are screened for gestational diabetes between 24 and 28 weeks of pregnancy, since this is the point in pregnancy when placental hormone levels have typically risen enough to reveal insulin resistance in people who are susceptible, while still leaving time to manage it before delivery. If you have significant risk factors, your clinician may test earlier, sometimes at your first prenatal visit, and then repeat testing later if the early result is normal.
The most common approach in the United States is a two-step process. The first step is the glucose challenge test: you drink a sugary liquid containing 50 grams of glucose without needing to fast beforehand, and your blood is drawn one hour later to measure how your body handled the sugar load. If that result comes back above the threshold your clinic uses, you move to the second step, a three-hour oral glucose tolerance test. For this test you fast overnight, have a fasting blood draw, drink a larger 100-gram glucose solution, and have your blood drawn again at one, two, and three hours. Meeting or exceeding two or more of the four thresholds confirms gestational diabetes.
Some clinicians use a one-step approach instead, a two-hour test with a 75-gram glucose drink and blood draws at fasting, one hour, and two hours, where a single above-target value is enough to diagnose gestational diabetes. Which approach your provider uses can depend on the practice and on national guideline differences, so ask which one you are scheduled for and whether fasting is required beforehand.

What Happens After Diagnosis

A gestational diabetes diagnosis means closer monitoring for the rest of your pregnancy, not that something has gone wrong or that you did anything to cause it. Your care team will typically ask you to check your blood glucose with a fingerstick meter several times a day, often fasting in the morning and again one or two hours after meals, and to keep a log they can review at appointments. Ultrasounds to track fetal growth become more frequent, since the main concern is the baby growing larger than average, a condition called macrosomia, which can complicate vaginal delivery.
Most people manage gestational diabetes successfully with diet and exercise alone, and only a portion need medication in addition. Your care team decides this based on how your glucose logs look over the first one to two weeks after diagnosis, not on the diagnosis itself.

Diet and Lifestyle Management

The first line of treatment is usually a referral to a registered dietitian who helps you build a meal pattern that keeps blood sugar spikes down without restricting the calories and nutrients your pregnancy needs. Common strategies include spacing carbohydrates across three meals and two to three snacks rather than eating them in large amounts at once, pairing carbohydrates with protein and fiber to slow how quickly sugar enters your bloodstream, and choosing whole grains, legumes, and non-starchy vegetables over refined sugar and white flour products. Portion size of carbohydrate-heavy foods matters more than eliminating any single food group.
Physical activity also helps, because muscle contraction pulls glucose out of the bloodstream independently of insulin. A 10 to 15 minute walk after meals is a strategy many clinicians recommend specifically because it targets the after-meal blood sugar rise that gestational diabetes makes harder to control. Your clinician can tell you which types of activity are appropriate given the rest of your pregnancy health.

Monitoring and Medication

Blood glucose targets are set by your care team but commonly fall around 95 mg/dL or below fasting and around 120 to 140 mg/dL one to two hours after a meal, depending on which measurement point your clinic uses. If your logged numbers run above target on a regular basis despite consistent diet and activity changes, medication is added, and this is common rather than a sign that you have failed at managing the condition.
Insulin is the medication with the longest track record in pregnancy and does not cross the placenta, which is why many clinicians consider it a first choice when medication is needed. Metformin, an oral medication, is also used in many practices, but it does cross the placenta readily, so your clinician will discuss which option fits your situation. Dosing and timing are individualized and adjusted based on your glucose logs, so this is managed directly with your prenatal team rather than through a fixed formula.

Risks If Blood Sugar Stays High

When gestational diabetes is not well controlled, the extra glucose crossing the placenta prompts the baby's pancreas to produce more insulin, which can lead to the baby growing larger than average. A larger baby raises the chance of a difficult vaginal delivery, shoulder injury during birth, or a cesarean delivery. After birth, a baby who was exposed to high glucose in the womb can have a drop in their own blood sugar in the first hours of life, because their pancreas is still producing extra insulin after the maternal glucose supply is gone, so newborn glucose checks are routine after a gestational diabetes pregnancy. Poorly controlled gestational diabetes is also associated with a higher chance of preeclampsia and with the baby developing breathing difficulty at birth. Consistent monitoring and treatment reduce these risks substantially, which is the entire point of the testing and management described above.

Delivery and After Birth

Most people with well-controlled gestational diabetes deliver around their due date and do not need an early induction, though your clinician may recommend earlier delivery if the baby is measuring very large or if blood sugar control has been difficult. Insulin or oral medication needs typically stop the moment the placenta is delivered, since the hormones driving insulin resistance leave with it, and many people no longer need any diabetes medication by the time they leave the hospital.
Because gestational diabetes signals a higher lifetime chance of developing type 2 diabetes, a glucose test is recommended 4 to 12 weeks after delivery to check whether your blood sugar has returned to a normal range, and then screening again every one to three years afterward. Breastfeeding, maintaining a moderate weight, and staying physically active after delivery are all associated with a lower chance of developing type 2 diabetes later, though none of these guarantee it will not happen.

When to Seek Medical Care

When to Seek Urgent or Emergency Care

Gestational diabetes itself is manageable, but two related situations can escalate fast: a severe low blood sugar reaction from insulin, and a dangerously high blood sugar crisis called diabetic ketoacidosis. Gestational diabetes also raises your chance of preeclampsia, so watch for those warning signs too. This guidance is in addition to, not a replacement for, the general disclaimer above.

Emergency, call 911 or go to the emergency room immediately if:

  • You are on insulin and become confused, unable to speak clearly, unresponsive, or have a seizure, which can signal severe low blood sugar
  • You have nausea, vomiting, deep or rapid breathing, a fruity smell to your breath, or confusion, which can signal diabetic ketoacidosis, a rare but serious complication
  • You have a severe headache that will not go away, vision changes such as flashing lights or blurriness, or pain under your ribs on the right side, which can signal preeclampsia
  • You notice a significant decrease or absence of your baby's usual movement
  • You have sudden, severe swelling of your face or hands along with any of the symptoms above

See a doctor soon (same-day or next available appointment) if:

  • Your fasting or after-meal glucose readings are repeatedly above the target your clinician set, despite following your meal plan
  • You are having frequent low blood sugar readings, even if they resolve on their own with food
  • A urine test at home shows ketones, even without the more severe symptoms listed above
  • You have new or worsening swelling in your legs, hands, or face that is not severe
  • You feel your baby moving noticeably less than usual, even if you are not sure it counts as a significant decrease
  • You have questions about adjusting your insulin or metformin dose based on your glucose log
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Frequently Asked Questions

Does gestational diabetes mean I did something wrong during pregnancy?

No. It develops because placental hormones increase insulin resistance in every pregnancy, and some people's pancreas cannot produce enough extra insulin to compensate. Diet and body weight can influence risk, but genetics, age, and hormone levels play a large role that is outside your control.

Can I have gestational diabetes and feel completely fine?

Yes, and this is the most common experience. Most people diagnosed with gestational diabetes have no symptoms at all and only find out through the routine glucose screening done between 24 and 28 weeks. Feeling well is not a reliable sign that your blood sugar is normal.

Will I need insulin shots if I have gestational diabetes?

Not necessarily. Most people manage their blood sugar with diet changes and physical activity alone. Insulin or an oral medication like metformin is added only if glucose readings stay above target after a couple of weeks of consistent lifestyle changes, and your care team will walk you through that decision if it comes up.

Does gestational diabetes mean my baby will be born with diabetes?

No. Gestational diabetes does not give your baby diabetes at birth. The concern is that high maternal glucose can make the baby grow larger and can cause the baby's own blood sugar to dip briefly after delivery, which is why newborn glucose checks are routine. Gestational diabetes does raise your child's longer-term chance of developing obesity or type 2 diabetes later in life, which is one reason healthy feeding and activity habits are encouraged from infancy.

Will gestational diabetes go away after I give birth?

For most people, yes. Blood sugar typically returns to normal once the placenta is delivered and the hormones driving insulin resistance are gone. A follow-up glucose test 4 to 12 weeks after delivery confirms this, and ongoing screening every one to three years afterward checks for type 2 diabetes, since gestational diabetes raises that lifetime risk.

What foods should I avoid with gestational diabetes?

There is no single food you must eliminate entirely. The general approach is limiting large portions of refined sugar, sugary drinks, and white flour products, and pairing the carbohydrates you do eat with protein and fiber to slow the blood sugar spike. A registered dietitian can build a specific plan around your preferences and your glucose logs.

Can gestational diabetes affect a vaginal delivery?

It can, mainly if blood sugar has run high enough for the baby to grow larger than average. A larger baby raises the chance of a difficult vaginal delivery or a cesarean birth. Well-controlled gestational diabetes lowers this risk considerably, which is a main reason consistent monitoring matters throughout the third trimester.

How soon after eating should I check my blood sugar?

Most care teams ask for a check one or two hours after the first bite of a meal, along with a fasting check each morning. Your clinician will tell you exactly which timing and targets to use, since this can vary slightly between practices.

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