A good glucose level during pregnancy is a fasting reading below 95 mg/dL, below 140 mg/dL one hour after eating, and below 120 mg/dL two hours after eating. These are the targets recommended by the American College of Obstetricians and Gynecologists, and they’re noticeably lower than what most people expect, even those who have managed diabetes for years.
Target Glucose Levels During Pregnancy
Whether you have pre-existing diabetes or gestational diabetes, the blood sugar goals your provider will ask you to hit are the same:
- Fasting (before eating): below 95 mg/dL
- One hour after a meal: below 140 mg/dL
- Two hours after a meal: below 120 mg/dL
These thresholds exist because a developing baby is more sensitive to blood sugar swings than an adult body. Even glucose levels that would be considered perfectly fine outside of pregnancy can cause problems for a fetus over weeks and months of exposure. For context, continuous glucose monitoring of healthy pregnant women without diabetes shows an average fasting glucose of about 88 mg/dL and an overall 24-hour average of about 98 mg/dL. So the clinical targets above are set to keep your numbers close to what a non-diabetic pregnancy looks like naturally.
Why Blood Sugar Rises During Pregnancy
Your body becomes progressively more resistant to insulin as pregnancy advances, especially in the second and third trimesters. The placenta produces hormones, including estrogen, cortisol, and human placental lactogen, that interfere with insulin’s ability to move glucose out of your blood and into your cells. This is a normal part of pregnancy: the purpose is to keep extra glucose available for the growing baby. But when the system tips too far, blood sugar stays elevated longer than it should after meals, and fasting levels creep up overnight.
This is why gestational diabetes typically develops in the second half of pregnancy and why screening happens between 24 and 28 weeks. Women who already had diabetes before becoming pregnant face these same hormonal shifts on top of their existing condition, which often means insulin needs increase substantially as pregnancy progresses.
How Gestational Diabetes Is Diagnosed
Most providers in the U.S. use a two-step screening process. The first step is a one-hour glucose challenge: you drink a sugary solution containing 50 grams of glucose and have your blood drawn an hour later. If your result is elevated, you move to the second step, a three-hour oral glucose tolerance test using 100 grams of glucose. Your blood is drawn at four points, and a diagnosis of gestational diabetes requires two or more values at or above the following cutoffs:
- Fasting: 95 mg/dL
- One hour: 180 mg/dL
- Two hours: 155 mg/dL
- Three hours: 140 mg/dL
Notice that the diagnostic thresholds for the test are higher than the daily management targets. Failing the glucose tolerance test means your body is struggling to process a large sugar load. Once diagnosed, though, the goal shifts to keeping your everyday numbers in the tighter range described above.
What Happens When Glucose Stays Too High
Persistently elevated blood sugar during pregnancy affects both you and the baby. The most common fetal complication is macrosomia, where the baby grows larger than normal because excess glucose crosses the placenta and stimulates the baby to produce extra insulin and store more fat. A larger baby increases the risk of birth injuries, emergency cesarean delivery, and shoulder dystocia.
Beyond size, poorly controlled blood sugar is linked to a range of serious outcomes. Babies born to mothers with uncontrolled diabetes face higher rates of breathing problems at birth, low blood sugar immediately after delivery (because the baby’s own insulin production is still ramped up), and in severe cases, stillbirth. Pre-existing diabetes that is poorly controlled before conception and during the first trimester raises the risk of congenital heart defects and other structural abnormalities. Gestational diabetes that develops later generally causes less severe but still significant complications, including preterm birth and increased risk of the baby developing metabolic problems later in life.
Research also shows a connection between diabetes during pregnancy and neurodevelopmental outcomes. Both pre-existing and gestational diabetes are associated with modestly increased rates of ADHD and autism spectrum disorder in offspring, though the absolute risk remains low.
Continuous Glucose Monitoring in Pregnancy
If you use a continuous glucose monitor, the international consensus target is to spend at least 70% of your time within the recommended range. Studies comparing outcomes in pregnant women using CGM found that those who achieved this 70% threshold had an average glucose of about 109 mg/dL, while those who fell short averaged around 149 mg/dL. That 40-point gap translated into meaningfully different complication rates. A CGM can be especially useful for catching overnight highs and post-meal spikes that fingerstick testing might miss.
When Levels Drop Too Low
While most of the focus during pregnancy is on keeping glucose from going too high, levels that drop too low also matter. The American Diabetes Association defines hypoglycemia as a blood sugar of 70 mg/dL or below. This is more relevant for women taking insulin or certain medications, since dietary management alone rarely causes dangerous lows. Symptoms include shakiness, sweating, confusion, and feeling faint. If you’re on insulin during pregnancy, your provider will likely adjust your doses as your insulin resistance changes from trimester to trimester, which is one reason frequent monitoring matters so much.
Practical Tips for Staying in Range
The daily targets can feel strict, but most women find a rhythm within a week or two of monitoring. Pairing carbohydrates with protein or fat slows digestion and blunts post-meal spikes. Walking for 10 to 15 minutes after eating is one of the most effective and simplest ways to lower your one-hour reading. Eating smaller, more frequent meals rather than three large ones helps keep glucose more stable throughout the day.
Timing matters too. Many women find that breakfast is the hardest meal to manage because cortisol levels are naturally higher in the morning, making insulin resistance worse. Choosing lower-carb breakfasts, like eggs with vegetables rather than cereal or toast, often makes a noticeable difference in morning readings. Fasting levels are trickier since you can’t control what happens while you sleep, but having a small protein-rich snack before bed can help prevent the liver from releasing too much stored glucose overnight.
If diet and activity changes aren’t enough to keep your numbers in range, medication or insulin may be needed. This isn’t a failure. Some women’s hormonal shifts simply outpace what lifestyle changes can manage, and the goal is always the same: keeping blood sugar in a range that protects both you and the baby.