Why it happens

Starting around week 24–28 of pregnancy, the placenta produces increasing amounts of hormones that raise the mother's insulin resistance. Normally, the pancreas compensates by producing more insulin. Gestational diabetes develops when this extra compensation isn't enough, and blood glucose levels become persistently elevated.

How common it is

By pooled estimates, gestational diabetes complicates roughly 3–9% of pregnancies worldwide, though the figure varies significantly by age and population: from about 1% of pregnancies in people under 20 to 13% among those over 44. According to the CDC, in the US the share of mothers with diabetes diagnosed during pregnancy rose from 6.0% in 2016 to 8.3% in 2021; among mothers aged 40 and older, the rate (15.6%) is almost six times higher than among mothers under 20 (2.7%). The IDF Diabetes Atlas (2025) estimates that hyperglycemia during pregnancy (a broader category that includes gestational diabetes) occurs in roughly one in five pregnancies worldwide, with about 79% of those cases being gestational diabetes specifically.

Risk factors

  • excess weight or obesity (risk increases, by some estimates, 2 to 8.6-fold depending on severity);
  • gestational diabetes in a previous pregnancy;
  • a family history of type 2 diabetes;
  • polycystic ovary syndrome (PCOS);
  • maternal age 35 or older;
  • belonging to higher-risk groups: South Asian, East Asian, Hispanic/Latino, African American, or Indigenous descent.
In 40–60% of gestational diabetes cases, no obvious risk factor can be identified — which is why routine screening during pregnancy is recommended regardless of whether risk factors are present.

Symptoms

Gestational diabetes most often has no noticeable symptoms and is detected during routine glucose screening. When symptoms are present, they resemble the general signs of diabetes: increased thirst, frequent urination, fatigue, and a greater tendency toward bladder or fungal infections.

Possible effects

For the mother, uncontrolled gestational diabetes is associated with a higher risk of preeclampsia (a hypertensive pregnancy complication), a greater likelihood of cesarean delivery, and an increased risk of postpartum depression. In about 90% of cases the condition resolves after delivery, but an estimated 50–70% of women who had gestational diabetes go on to develop type 2 diabetes within about the next 11 years — making it a marker of future metabolic risk as well. For the baby, possible effects include macrosomia (higher-than-average birth weight), neonatal hypoglycemia immediately after birth, jaundice, and, in severe, untreated cases, an increased risk of stillbirth. Children born after a pregnancy with gestational diabetes also have a somewhat higher long-term risk of childhood obesity and type 2 diabetes.

How it's typically managed

The first line of management is usually dietary adjustment — structuring carbohydrate intake to control post-meal glucose levels — along with regular self-monitoring of glucose several times a day. Moderate physical activity is generally mentioned as a supportive measure. If diet and activity alone aren't enough, medication is used: insulin is the most established option, and metformin is also used in some cases. A pregnancy with gestational diabetes is usually followed with closer monitoring of fetal development, and a follow-up glucose test after delivery is recommended given the increased future risk of type 2 diabetes.

This is a general description of approaches from the medical literature, not personal advice. Managing a pregnancy with gestational diabetes is a decision made individually by an obstetrician.