Gestational Diabetes: Symptoms, Screening & Treatment Guide

For many expecting mothers, the oral glucose tolerance test (OGTT) done around the 24th to 28th week of pregnancy is just another item on the antenatal checklist. But in Bangladesh, screening studies at tertiary hospitals have found gestational diabetes mellitus (GDM) in anywhere from roughly 8% to over a quarter of pregnant women tested, depending on the population and method used — and a large, countrywide screening effort by the Diabetic Association of Bangladesh (BADAS) found a rate of around 26% among thousands of women screened. Most women with GDM have no symptoms at all, which is exactly why the screening test itself, not how a mother feels, is what catches the condition. This guide explains what gestational diabetes is, how it is diagnosed, what it means for mother and baby, and how it is managed — in Bangladesh and internationally.

What Is Gestational Diabetes?

Gestational diabetes is high blood sugar that is first identified during pregnancy in a woman who did not have diabetes before. It typically develops in the second half of pregnancy, usually after 20 weeks, because the placenta produces hormones that make the body's cells more resistant to insulin. In most pregnancies, the mother's pancreas compensates by producing extra insulin. When it cannot keep up with the increased demand, blood glucose rises — and that is gestational diabetes.

This is different from a woman who already had type 1 or type 2 diabetes before becoming pregnant, or from "overt" diabetes that is discovered early in pregnancy and meets the full diagnostic criteria for diabetes outside of pregnancy (fasting glucose of 126 mg/dL or higher, a random or 2-hour glucose of 200 mg/dL or higher, or an HbA1c of 6.5% or higher). Overt diabetes in pregnancy is managed more intensively from the start and carries somewhat different risks, so doctors distinguish it carefully from true gestational diabetes at the time of diagnosis.

Who Is at Higher Risk?

• Being overweight or obese before pregnancy
• Age over 25, with risk rising further after 35
• A family history of type 2 diabetes in parents or siblings
• Gestational diabetes in a previous pregnancy
• Polycystic ovary syndrome (PCOS)
• Previously delivering a baby weighing more than 4 kg (a "large for gestational age" baby)
• Belonging to a population group with a higher baseline risk of type 2 diabetes — which includes South Asian populations, a point relevant for Bangladeshi women specifically

Women with one or more of these risk factors are usually screened earlier than 24 weeks, sometimes at the very first antenatal visit, because undiagnosed high blood sugar in early pregnancy can affect how the baby's organs develop.

Symptoms: Why Most Women Don't Notice Anything

Gestational diabetes very often causes no symptoms, which is the main reason universal screening in pregnancy exists in the first place. When symptoms do occur, they can include unusual thirst, needing to urinate more often than the usual pregnancy-related frequency, fatigue beyond normal pregnancy tiredness, blurred vision, and recurring vaginal or urinary infections. Because these overlap heavily with ordinary pregnancy symptoms, they are easy to miss — which is why the blood test, not how a mother feels, is the reliable way to detect it.

Screening and Diagnosis: The OGTT

Globally, two main testing approaches are used, and either may be offered depending on the hospital or clinic:

One-step approach (75g OGTT)

A single visit, fasting test using a 75-gram glucose drink, usually done between 24 and 28 weeks. Blood is drawn fasting, then at 1 hour and 2 hours after drinking the glucose solution. Per the criteria widely used by the American Diabetes Association and the International Association of Diabetes and Pregnancy Study Groups (IADPSG), gestational diabetes is diagnosed if any one of these values is met or exceeded:

• Fasting: 92 mg/dL
• 1 hour: 180 mg/dL
• 2 hours: 153 mg/dL

Two-step approach

First, a 50-gram non-fasting screening test (glucose challenge test) is done at any time of day. If the 1-hour reading is elevated, a follow-up fasting 100-gram OGTT is performed, measured at fasting, 1, 2, and 3 hours. Under this approach, a diagnosis typically requires at least two of the following to be met or exceeded: fasting 95 mg/dL, 1 hour 180 mg/dL, 2 hours 155 mg/dL, and 3 hours 140 mg/dL.

Both approaches are medically accepted; which one is used depends on the facility. The specific numeric thresholds can be refined over time as medical bodies update their guidelines, so always follow the interpretation given by the laboratory and treating doctor rather than comparing numbers found online.

In Bangladesh, a major practical challenge is that a meaningful share of women — especially in rural areas with lower-tier health facilities — do not attend antenatal care during the 24–28 week window when screening is usually recommended, so cases are likely under-detected outside major hospitals. Attending antenatal visits on schedule, and specifically asking about the glucose screening test, is one of the simplest ways a mother can make sure gestational diabetes isn't missed.

Why It Matters: Risks If Left Unmanaged

For the mother

• Higher risk of preeclampsia (pregnancy-related high blood pressure)
• Higher chance of needing labor induction or a cesarean delivery
• A substantially increased lifetime risk of developing type 2 diabetes later in life, even after blood sugar returns to normal post-delivery
• Increased long-term cardiovascular risk

For the baby

• Macrosomia — growing larger than average for gestational age, which raises the risk of a difficult delivery and birth injury, including shoulder dystocia
• Neonatal hypoglycemia (low blood sugar) shortly after birth, because the baby's own insulin production has adjusted to the mother's higher glucose levels in the womb
• Newborn jaundice and, less commonly, breathing difficulties
• A higher long-term risk of childhood obesity and type 2 diabetes for the child

With proper monitoring and treatment, most of these risks drop significantly — which is the entire purpose of diagnosing and managing the condition rather than simply noting it.

Managing Gestational Diabetes

Diet and lifestyle — the first line of treatment

For most women, the first step is dietary change: spreading carbohydrate intake across several smaller meals and snacks rather than a few large ones, favoring whole grains, vegetables, and lean protein over refined sugar and simple carbohydrates, and limiting sugary drinks and sweets common in Bangladeshi diets (sweets/mishti, sugary tea, soft drinks). Regular physical activity appropriate for pregnancy — such as a daily walk, especially after meals — helps the body use glucose more effectively. A doctor or dietitian will usually set individual blood sugar targets and may ask the mother to check her blood glucose at home with a glucometer several times a day to see whether diet and activity alone are keeping levels in range.

When medication becomes necessary

If blood sugar targets are not reached through diet and exercise within roughly one to two weeks, medication is added. Oral metformin is one option some obstetric teams use, and a growing body of research supports its safety and effectiveness in pregnancy, though practice varies by hospital and doctor. If targets still aren't met, or if metformin isn't suitable for a particular patient, insulin — given by injection — is the standard and well-established treatment, and various insulin products (including rapid-acting insulin like insulin aspart and premixed human insulin preparations) are available through Bangladeshi pharmacies under a doctor's prescription. Insulin does not cross the placenta in a way that harms the baby and is considered very safe in pregnancy when properly dosed. Some women — for example those with a very high fasting glucose at diagnosis, or whose scans show a larger-than-expected baby or excess amniotic fluid (polyhydramnios) — may be started on insulin right away rather than waiting through a diet trial. Any medication decision in pregnancy must be made by the treating obstetrician or endocrinologist, never self-prescribed.

Monitoring through the rest of pregnancy

Women with gestational diabetes are typically monitored more closely for the remainder of pregnancy, including growth scans to track the baby's size and, depending on how well sugar levels are controlled, a discussion about the timing and mode of delivery with the obstetric team.

After Delivery: What Happens Next

For most women, blood sugar returns to normal soon after the baby and placenta are delivered, and insulin, if used, is usually stopped immediately after birth. However, having had gestational diabetes is a genuine warning sign: these women face a markedly higher lifetime risk of developing type 2 diabetes. Standard practice is a follow-up glucose test — commonly a 75-gram OGTT — around 6 weeks postpartum to confirm blood sugar has returned to normal, followed by periodic screening (commonly every one to three years) for the rest of her life. Breastfeeding is encouraged: it may help lower blood sugar in the short term and some research suggests it may delay the onset of type 2 diabetes. Gestational diabetes also tends to recur in future pregnancies, so maintaining a healthy weight and getting a pre-pregnancy checkup — ideally with blood sugar confirmed normal before conceiving again — is advised for anyone planning another child.

Prevention: What Can Lower the Risk

• Reaching a healthy weight before pregnancy where possible, since excess weight is one of the strongest modifiable risk factors
• Staying physically active before and during pregnancy, within what is safe for each trimester
• Eating a balanced diet with controlled portions of refined carbohydrates and sugar even before conception
• Getting screened earlier than the standard 24–28 week window if known risk factors are present (prior GDM, PCOS, strong family history, obesity)
• Keeping all antenatal visits so screening isn't missed, particularly important in areas where access to antenatal care is less consistent

When to See a Doctor

Any pregnant woman should attend her scheduled antenatal visits and glucose screening regardless of symptoms. She should contact her doctor promptly if she notices unusual thirst, very frequent urination beyond typical pregnancy changes, unexplained fatigue, blurred vision, or recurrent infections — and, after a gestational diabetes diagnosis, if home glucose readings are repeatedly outside the targets her care team has set, or if she notices reduced fetal movement, severe headache, or swelling suggestive of preeclampsia.

Sources: Guidelines and diagnostic criteria from the American Diabetes Association (ADA) and the International Association of Diabetes and Pregnancy Study Groups (IADPSG), along with gestational diabetes screening research conducted at BIRDEM and by the Diabetic Association of Bangladesh (BADAS).