# Gestational Diabetes Mellitus

> NEET-PG OBG notes on gestational diabetes mellitus covering DIPSI screening, glucose targets, treatment and fetal risks with exam points.

- Canonical URL: https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/gestational-diabetes-mellitus
- Exam / course: NEET-PG · Subject: Obstetrics and Gynaecology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Gestational Diabetes Mellitus", PrepElephant, https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/gestational-diabetes-mellitus

## Direct answer

Gestational diabetes mellitus (GDM) is glucose intolerance first recognised during pregnancy, screened universally in India at 24-28 weeks. The DIPSI (Diabetes in Pregnancy Study Group India) approach uses a single-step, non-fasting 75 g oral glucose load, with a two-hour plasma glucose of 140 mg/dL or more diagnosing GDM. Management begins with medical nutrition therapy and exercise, adding insulin or metformin when glucose targets are not met.

## What you must remember

- DIPSI method — 75 g glucose given irrespective of fasting status; a two-hour value of 140 mg/dL or more diagnoses GDM; the single-step strategy is the standard adopted across India.
- IADPSG criteria used elsewhere need a fasting 75 g OGTT — fasting 92, one-hour 180, or two-hour 153 mg/dL or more.
- Screen all pregnant women at 24-28 weeks; test earlier for high-risk women (obesity, prior GDM, family history, previous macrosomia, PCOS).
- Medical nutrition therapy with a dietitian plus moderate exercise is first line; drugs are added when targets are unmet despite lifestyle effort.
- Insulin is the traditional gold standard as it does not cross the placenta; metformin is an accepted alternative with reassuring safety data, though it does cross the placenta.
- Common targets — fasting around 95 mg/dL or less, one-hour postprandial 140 or less, and two-hour postprandial 120 mg/dL or less.
- Risks — macrosomia with shoulder dystocia, neonatal hypoglycaemia, hyperbilirubinaemia, respiratory distress and prematurity; maternal pre-eclampsia and a high lifetime risk of type 2 diabetes. Perform a 75 g OGTT at six to twelve weeks postpartum to exclude persistent diabetes.

## Common confusion

GDM is confused with overt (pre-existing) diabetes first detected in pregnancy. Very high values early in pregnancy — fasting 126 mg/dL or more, random 200 or more with symptoms, HbA1c 6.5 per cent or more — indicate overt diabetes, managed as pre-existing disease. Students also mix up the DIPSI and IADPSG numbers; DIPSI needs only the single non-fasting two-hour value of 140 mg/dL — the figure asked in Indian exams.

## Exam-focused takeaway

Expect DIPSI threshold one-liners, the 24-28 week screening window, and drug-choice stems — insulin as the classical gold standard with metformin acceptable. Know the macrosomia-shoulder dystocia chain, neonatal hypoglycaemia as the immediate postnatal worry, and the six-to-twelve-week postpartum OGTT for follow-up.

## Frequently asked questions

### What are the DIPSI criteria for GDM?

A 75 g oral glucose load taken irrespective of fasting, with a two-hour plasma glucose of 140 mg/dL or more diagnosing GDM. It combines screening and diagnosis in a single step.

### When is screening for GDM performed?

Universally at 24-28 weeks of gestation. Women with high-risk factors are tested earlier in pregnancy and retested in the third trimester if initially normal.

### What is the first-line management of GDM?

Medical nutrition therapy and moderate physical activity, with glucose self-monitoring. Pharmacotherapy is added if targets are not achieved.

### Which drugs treat GDM when lifestyle measures fail?

Insulin remains the gold standard because it does not cross the placenta; metformin is a widely accepted oral alternative. Oral sulfonylureas are largely avoided.

### What neonatal complications follow poorly controlled GDM?

Macrosomia with shoulder dystocia and birth injury, neonatal hypoglycaemia, hyperbilirubinaemia, respiratory distress syndrome and prematurity — hence close neonatal glucose monitoring.

### What follow-up is needed after delivery?

A 75 g OGTT at six to twelve weeks postpartum to exclude persistent diabetes, then lifelong periodic screening because of the high risk of type 2 diabetes.