Gestational diabetes: the test, the diet, and what it means for the baby

The test

The oral glucose tolerance test (GTT) is done between 24 and 28 weeks, and earlier for women at higher risk. India's national guidance uses a single-step test with a 75 g glucose drink; many private practices use a fasting-plus-timed-samples protocol. Follow whichever your doctor orders.

Practically: fasting from the night before where required, then the glucose drink, then blood samples at set times — two to three hours in total. No walking around, eating or drinking between samples. Take something to read and a snack for afterwards.

Indian women have a substantially higher risk of gestational diabetes than many other populations, which is why the test is universal here and not risk-based. Skipping it because you feel well is the classic mistake — gestational diabetes has essentially no symptoms.

What a diagnosis means

First, what it does not mean: it is not caused by eating sweets, and it is not your fault. Pregnancy hormones work against insulin in every pregnancy; in some women the body cannot compensate.

Left unmanaged, high blood sugar crosses to the baby, who grows larger than they should — which makes delivery harder, raises the chance of caesarean and shoulder problems at birth, and causes low blood sugar in the newborn afterwards. It also raises the mother's risk of pre-eclampsia.

Managed, the outlook is good: most women with well-controlled gestational diabetes have normal pregnancies and deliveries. The management is the whole story.

Diet, monitoring and medication

The diet is the same Indian food, rearranged: smaller frequent meals (three meals and two or three snacks), never skipping meals, fibre and protein at every meal, and carbohydrates spread through the day rather than concentrated. Whole grains — jowar, bajra, ragi, hand-pounded rice — instead of refined ones, and vegetables and dal before rice at a meal.

Cut out: sugary drinks, sweets, fruit juices, refined flour snacks, and large portions of white rice at one sitting. Keep: fruit in moderation with the skin, dairy, dals, eggs and nuts. Ask for a referral to a dietitian — a personalised plan works far better than general advice.

Walking after meals — even fifteen to twenty minutes — makes a measurable difference to post-meal sugar. It is the cheapest and most effective addition available.

Monitoring: a home glucometer with readings fasting and after meals, as directed. If diet and activity do not control the numbers, insulin is added — it is safe in pregnancy, does not cross to the baby, and is not a failure. Some doctors use metformin in specific situations. Neither is a sign that you did something wrong.

Delivery and afterwards

With good control, delivery is usually planned at term. Growth scans monitor the baby's size, and the timing and mode of delivery depend on those and on control. A large baby is not an automatic caesarean, but it is a factor.

After birth, the baby's blood sugar is checked in the first hours — babies of mothers with diabetes can have low blood sugar — and early breastfeeding helps prevent it. The mother's own blood sugar usually returns to normal within days.

The long-term part that gets forgotten: gestational diabetes raises the mother's lifetime risk of type 2 diabetes substantially — a majority develop it within a decade or two without intervention. A glucose test at six to twelve weeks postpartum and then yearly, plus weight, diet and exercise, genuinely changes that trajectory.

Breastfeeding lowers the risk for both mother and baby — one more reason to protect it.

When to see a doctor

Same-day: blood sugar readings far outside the target range your doctor has given, repeated readings you cannot bring down, symptoms of very low sugar on insulin (shaking, sweating, confusion — treat immediately with sugar and then call), reduced fetal movements, severe headache with visual changes, sudden swelling, or any bleeding or leaking.

And do not skip the postnatal glucose test at six to twelve weeks — it is the single most important follow-up appointment after a gestational diabetes pregnancy.

This article is general information, not medical advice, and is no substitute for personal medical advice. For any decision about your or your child's health, please consult your doctor.

Frequently asked questions

Q: Can I avoid it by cutting sweets before the test? — Restricting food before the test distorts the result rather than preventing the condition — and a false-negative leaves a real problem unmanaged. Eat normally in the days before, and follow the fasting instructions only.

Q: I have gestational diabetes. Will my baby have diabetes? — Not at birth. There is a raised lifetime risk for the child of obesity and type 2 diabetes, which is influenced by feeding, activity and family diet — which is another reason the whole household's eating habits are worth adjusting.

Q: Do I have to give up rice? — No. Portion and pairing matter more than elimination: a smaller portion of rice, eaten after dal and vegetables, with protein alongside, affects blood sugar very differently from a large plate of rice alone. A dietitian will help you keep familiar food.

Q: Is insulin harmful to the baby? — No. Insulin does not cross the placenta, and uncontrolled blood sugar is what harms the baby. Where diet and exercise are not enough, insulin is the standard, safe treatment.