Gestational diabetes is a form of diabetes that develops during pregnancy in women who did not have diabetes beforehand. It affects roughly 5 to 9% of pregnancies in the United States, and that share has been rising over the past two decades alongside rising rates of obesity and later childbearing age. It typically resolves after delivery, but it deserves real attention during pregnancy because of the effects it can have on both mother and baby. Here are 8 things worth understanding.
1. What's Actually Happening in the Body
During pregnancy, the placenta produces hormones that help the baby grow, including human placental lactogen, cortisol, and progesterone. Several of these hormones also interfere with the mother's insulin function, a normal part of pregnancy physiology that ensures enough glucose is available to the growing baby, since the fetus relies on glucose crossing the placenta as its primary fuel source. For most women, the pancreas compensates by producing more insulin, sometimes two to three times the pre-pregnancy amount by the third trimester.
Gestational diabetes develops when the pancreas cannot keep up with this increased demand, leaving blood sugar elevated. This is part of why gestational diabetes is typically diagnosed in the second half of pregnancy rather than earlier: placental hormone production, and the insulin resistance it causes, increases progressively as pregnancy advances, peaking in the third trimester. Earlier in pregnancy, before this hormonal shift ramps up, insulin sensitivity is often normal or even slightly improved, which is why the same woman's blood sugar can look completely different at 10 weeks versus 30 weeks.
2. Who's at Higher Risk
Risk factors include being over 25, carrying excess weight before pregnancy, having a family history of type 2 diabetes, a personal history of gestational diabetes in a previous pregnancy, having polycystic ovary syndrome, and certain ethnic backgrounds, including Asian, Hispanic, Black, and Native American women, who carry higher population-level risk for reasons researchers believe involve a combination of genetic and social factors. A previous pregnancy resulting in a very large baby, even without a formal gestational diabetes diagnosis at the time, can also signal elevated risk in a subsequent pregnancy.
That said, gestational diabetes can develop in women without any of these risk factors, which is part of why routine screening is standard regardless of individual risk profile, rather than reserved only for women who fit a particular risk category.
3. Does It Cause Noticeable Symptoms?
For most women, no. Gestational diabetes often causes no symptoms at all, which is exactly why universal screening exists rather than relying on women to report feeling unwell. When symptoms do occur, they tend to mirror general diabetes symptoms: increased thirst, more frequent urination beyond what's typical in pregnancy, and fatigue, though all of these can also simply be normal parts of pregnancy, making them unreliable on their own for either the patient or provider to use as a diagnostic clue.
4. When and How It's Screened
Most women are screened between 24 and 28 weeks of pregnancy. In the United States, the most common approach, recommended by the American College of Obstetricians and Gynecologists, is a two-step process: a 1-hour glucose challenge test, which involves drinking a sugary solution and having blood drawn an hour later without needing to fast beforehand, followed by a longer 3-hour test only if the first result is elevated.
An alternative one-step approach, a single 2-hour test after a larger glucose dose, is used more commonly outside the United States and by some U.S. providers. The two methods matter practically because they diagnose gestational diabetes at meaningfully different rates: the one-step approach identifies gestational diabetes in roughly 11 to 18% of pregnancies screened, compared to about 5 to 7% with the two-step approach. This gap has fueled genuine debate among researchers about whether the one-step method catches real cases the two-step method misses, or whether it leads to overdiagnosis and overtreatment of women who would have had normal outcomes regardless. Which method your provider uses can meaningfully affect whether you receive a diagnosis, which is worth knowing if you're ever comparing notes with someone screened at a different practice.
Women at higher risk are sometimes screened earlier than 24 weeks, since catching gestational diabetes sooner allows more time to manage it throughout the pregnancy, and a second screening is often repeated later if the early test comes back normal but risk remains elevated.
5. Why It Matters for the Baby
Elevated maternal blood sugar crosses the placenta, and the baby's own pancreas responds by producing extra insulin. Since insulin promotes growth, this can lead to excess size, a condition called macrosomia, generally defined as a birth weight above 8 pounds 13 ounces. A larger baby increases the risk of delivery complications, including shoulder dystocia, where the baby's shoulder becomes stuck during delivery, which can require additional interventions and carries some risk of injury to the baby or the mother's pelvic tissues.
Babies born to mothers with unmanaged gestational diabetes are also more prone to low blood sugar immediately after birth, since they're used to producing extra insulin in response to a higher-sugar environment in the womb, and that insulin production doesn't stop the moment the umbilical cord is cut. This can require monitoring and, occasionally, treatment in the hours after delivery. Other short-term risks include a higher chance of jaundice, an excess of red blood cells called polycythemia, and, in some cases, respiratory distress, particularly if delivery happens somewhat early.
Longer term, research has found that children born to mothers with gestational diabetes face a higher lifetime risk of obesity and type 2 diabetes themselves, a pattern researchers attribute partly to the baby's metabolic environment during development, sometimes called fetal programming, not just shared genetics or family habits after birth. This is one of the stronger arguments for taking gestational diabetes management seriously even when a mother feels fine day to day.
6. Why It Matters for the Mother
Gestational diabetes increases the risk of preeclampsia, a serious blood pressure condition during pregnancy, and raises the likelihood of needing a C-section delivery, often related to the baby's larger size or concerns about a safe vaginal delivery. It's also associated with a higher risk of polyhydramnios, an excess of amniotic fluid, which can itself increase the risk of preterm labor and other complications.
In some cases, providers may recommend earlier delivery, sometimes around 39 weeks rather than waiting for a full 40, particularly if blood sugar has been difficult to control or the baby is measuring large, since the risks of continuing the pregnancy can outweigh the risks of a slightly earlier delivery in these situations.
Longer term, women who have had gestational diabetes face a substantially elevated risk of developing type 2 diabetes later in life, with some studies estimating that risk at up to 50% within 5 to 10 years without preventive lifestyle changes. This same population also faces a higher long-term risk of cardiovascular disease, independent of whether type 2 diabetes ultimately develops, which is part of why the postpartum period is treated as a meaningful window for prevention, not just a return to normal.
7. How It's Managed
Diet and exercise changes are the first line of management for most women. This typically means spacing carbohydrate intake across meals and smaller snacks throughout the day rather than eating it all at once, choosing higher-fiber carbohydrate sources that digest more slowly, and monitoring blood sugar at home with a fingerstick test, often four times a day: once fasting, first thing in the morning, and again about an hour after each meal.
Regular moderate exercise, such as a 20 to 30 minute walk after meals, is commonly recommended because muscle activity helps pull glucose out of the bloodstream independent of insulin, directly complementing the dietary changes. Most women, roughly 70 to 85%, are able to manage gestational diabetes with diet and exercise alone. When lifestyle changes aren't enough to keep blood sugar in a healthy range, medication, either insulin or in some cases metformin, is added, and is considered safe for use during pregnancy under medical supervision. Target blood sugar numbers are generally stricter during pregnancy than typical diabetes targets, since even modestly elevated levels can affect the baby, which is part of why monitoring is more frequent than it would be for diabetes outside of pregnancy.
8. Does It Go Away After Birth?
For most women, blood sugar returns to normal shortly after delivery, once the placenta, and the hormones it produces, is no longer present. Providers typically recommend a follow-up glucose test, usually a 2-hour, 75-gram oral glucose tolerance test, 6 to 12 weeks postpartum to confirm blood sugar has normalized and rule out underlying type 2 diabetes that may have been unmasked by the pregnancy, since a small share of women are found to have diabetes that persists rather than resolving.
9. Why Ongoing Follow-Up Still Matters
Because of the significantly elevated future diabetes risk, women who've had gestational diabetes are generally advised to continue periodic blood sugar screening for years afterward, not just at the standard postpartum check, typically every 1 to 3 years depending on other risk factors. Maintaining a healthy weight, staying physically active, and following up with regular screenings can meaningfully reduce that long-term risk, and some research suggests these same steps can meaningfully delay or even prevent a future type 2 diabetes diagnosis rather than simply catching it earlier.
Breastfeeding is also worth mentioning here: several studies have found that breastfeeding is associated with improved glucose metabolism in the months after delivery and a modestly lower risk of developing type 2 diabetes later on, adding one more reason, alongside its many other benefits, to discuss feeding plans with your care team if gestational diabetes was part of your pregnancy.
If you're pregnant or planning to be, CareArc's women's health and primary care teams can help you understand your personal risk and build a monitoring plan that carries you through pregnancy and beyond. Request an appointment to get started.
