Gestational diabetes
Gestational diabetes is hyperglycaemia first recognized during pregnancy that does not meet criteria for overt diabetes outside pregnancy. It often causes no symptoms, so detection depends on antenatal testing rather than how a person feels.
At a glance
Quick facts
- Category
- Diabetes in pregnancy
- Symptoms
- Often none
- Typical testing
- 24–28 weeks in many systems
- Diagnosis
- Blood glucose testing / OGTT
- Management
- Nutrition · activity · monitoring · medication
- After pregnancy
- Follow-up for future type 2 diabetes risk
Dr. Sony Sherpa
Obstetrics & Gynecology · Patan Academy of Health Sciences
Reviewed for clinical accuracy, safety language and gynecology context.
Names & terminology
How this entity may be named or searched
- Canonical name
- Gestational diabetes mellitus (GDM).
- Broader term
- Hyperglycaemia in pregnancy also includes pre-existing diabetes and diabetes first detected in pregnancy that meets overt-diabetes thresholds.
- Important distinction
- Diagnostic criteria and screening strategies differ between health systems.
- Current guideline context
- WHO issued global management guidance in 2025 and began updating screening and diagnostic criteria in 2026.
Structured entity profile
Clinical profile
Overview
Pregnancy naturally increases insulin resistance. Gestational diabetes develops when pancreatic insulin production is not sufficient to keep glucose in the target range during pregnancy. It often has no symptoms and is usually found by blood glucose testing. [1] [2]
WHO's 2025 global guideline emphasizes intensified monitoring and treatment because diabetes during pregnancy increases risks for the pregnant person and baby. In September 2026 WHO also announced work to update recommendations on screening and diagnostic criteria, so exact thresholds should always be interpreted in the context of the guideline used locally. [1] [4]
Symptoms and warning signs
Most people with gestational diabetes do not notice symptoms. When symptoms occur, they may be mild and nonspecific, such as increased thirst or urination. Symptoms cannot reliably rule GDM in or out, which is why antenatal screening or diagnostic testing is used. [2]
SYMPTOM MATRIX
Why testing matters more than symptoms
Gestational diabetes is commonly asymptomatic.
- No symptoms
- Detected on routine antenatal testing
- Normal day-to-day wellbeing
- More thirst than usual
- More frequent urination
These are nonspecific and are not enough to diagnose GDM.
- Very high glucose or symptoms suggesting overt diabetes
- Reduced fetal movement or other pregnancy concerns
- Illness with vomiting, dehydration or inability to eat
Acute symptoms in pregnancy require clinical assessment rather than self-adjustment of treatment.
Diagnosis
Blood tests are used to diagnose gestational diabetes. NIDDK notes that testing commonly occurs between 24 and 28 weeks; people at increased risk may be tested earlier. Depending on the health system, testing may use a one-step oral glucose tolerance test (OGTT) or a screening test followed by an OGTT. [2]
Thresholds differ by guideline. NICE uses a 75 g 2-hour OGTT for women with defined risk factors and its own diagnostic cut-offs. WHO is updating its global criteria in 2026, so this reference intentionally does not present one universal threshold as if it applied everywhere. [3] [4]
Diagnostic pathway
From risk assessment to confirmed hyperglycaemia
The exact sequence varies by country and guideline.
Diagnostic thresholds vary between current pregnancy-diabetes frameworks; interpret results using the guideline adopted locally. Source [1] Source [3]
Why gestational diabetes matters
Hyperglycaemia in pregnancy is associated with complications including preeclampsia, large-for-gestational-age birth, neonatal hypoglycaemia and birth injury. Good management can reduce pregnancy risk, and follow-up matters because GDM also identifies increased future risk of type 2 diabetes. [1] [4]
Treatment and management
Management starts with individualized nutrition advice, appropriate physical activity and glucose monitoring. If glucose targets are not achieved, medication may be needed. NICE recommends metformin after a short trial of diet and exercise when targets are not met, and insulin when metformin is unsuitable or insufficient; other health systems may use different medication sequences. [3]
Medical nutrition therapy and lifestyle measures are the usual first step. If glucose targets are not reached after a short trial, medication may be needed.
Timing and mode of delivery should be individualized according to glycemic control and maternal and fetal circumstances rather than determined by gestational diabetes alone.
WHO's 2025 guideline provides global recommendations for diabetes during pregnancy and stresses individualized monitoring and treatment. Medication decisions must be made with the maternity/diabetes team rather than copied from non-pregnancy diabetes care. [1]
Treatment & care hub
Control glucose while supporting a healthy pregnancy
Care plans combine lifestyle measures, self-monitoring and medication when needed.
Individualized eating plan
Meal pattern and carbohydrate intake are tailored to glucose response, nutrition needs and pregnancy.
Pregnancy-safe physical activity
Activity can improve post-meal glucose when there is no obstetric contraindication.
Blood glucose monitoring
Fasting and post-meal measurements are commonly used to guide treatment.
Metformin and/or insulin
Choice depends on guideline, glucose pattern, severity, gestational age and patient preference.
After delivery
Glucose often improves after pregnancy, but a history of GDM is an important marker of future type 2 diabetes risk. Postpartum glucose testing and longer-term periodic screening are therefore part of care, along with support for healthy lifestyle measures. [1] [3]
Global context · WHO / IDF
Hyperglycaemia in pregnancy
Global estimates usually combine gestational diabetes with other forms of hyperglycaemia in pregnancy, so the figures need careful labeling.
Common questions
Frequently asked questions
No. Most cases are found through antenatal blood glucose testing rather than symptoms.
Many systems test at 24–28 weeks, with earlier testing when the chance of pre-existing or gestational diabetes is higher.
No. Screening strategies and glucose thresholds differ between guidelines and are actively being updated internationally.
No. Some people reach glucose targets with nutrition and activity changes; others need metformin, insulin or another guideline-supported approach.
Glucose often returns below the pregnancy diagnostic range after delivery, but the future risk of type 2 diabetes remains higher, so postpartum and long-term follow-up are important.
Sources
- WHO — WHO recommendations on care for women with diabetes during pregnancy (2025)
- NIDDK — Gestational Diabetes: Definition, Symptoms and Diagnosis
- NICE — Diabetes in pregnancy: management from preconception to the postnatal period (NG3)
- WHO — WHO to update recommendations on criteria and diagnosis of hyperglycaemia in pregnancy, 25 September 2026
- IDF — IDF Diabetes Atlas, 11th edition (2025), hyperglycaemia in pregnancy
This article is based on trusted medical sources and has undergone clinician review. It is not a substitute for personalized medical advice.
During assessment I pay particular attention to family history of diabetes, obesity, a previous macrosomic baby and previous adverse pregnancy outcomes because these can raise suspicion for gestational diabetes.