Pregnancy brings a cascade of changes, and it can be hard to tell what is normal and what might signal a deeper health shift. Gestational diabetes mellitus (GDM), a form of high blood sugar that develops during pregnancy, often begins without obvious symptoms. However, some women notice subtle changes that, when recognized early, can lead to timely screening and better management for both mother and baby.
Here are five warning signs you may notice in the early part of your second trimester—typically between 24 and 28 weeks, though they can appear earlier—that warrant a conversation with your healthcare provider.
1. Unusual thirst that won't quit
We all get thirsty, especially as our blood volume increases during pregnancy. But polydipsia—the medical term for excessive thirst—is different. You might find yourself drinking glass after glass of water and still feeling parched. This happens because your kidneys are working overtime to flush out excess glucose through urine, pulling water with it. If you are waking up multiple times at night with a dry mouth or feel like you cannot satisfy your thirst during the day, this is a classic early clue that blood sugar levels may be elevated.
2. Frequent urination beyond the usual pregnancy bathroom breaks
Frequent urination is a hallmark of early pregnancy due to hormonal changes and increased blood flow. What sets gestational diabetes apart is a noticeable increase in frequency that feels extreme. You may find yourself needing to go every hour, sometimes even more often than before, and noticing larger volumes of urine each time. This is your body’s attempt to excrete the excess sugar that your cells cannot absorb. If your bathroom trips are significantly more frequent than what is normal for you, or if you are waking up three or more times a night, it is worth mentioning to your provider.
A simple rule: if your thirst and urination are interfering with sleep or daily comfort, speak up at your next prenatal visit. Early screening can begin as early as the first trimester if you have risk factors.
3. Fatigue that feels different from typical pregnancy tiredness
Pregnancy fatigue is real—your body is building a whole new human, after all. But gestational diabetes fatigue has a distinct quality. It can feel like a heavy, bone-deep exhaustion that does not lift even after a good night’s sleep. This happens because your cells are not getting the glucose energy they need; instead, sugar stays trapped in your bloodstream. You might feel sluggish after meals, especially carb-heavy ones, or find that your usual morning coffee or short nap does not help. Some women describe it as a mental fog or a feeling of being weighed down.
4. Blurred or fluctuating vision
Blurry vision during pregnancy can be alarming. High blood sugar levels can cause fluid shifts in the lens of your eye, leading to temporary swelling and changes in how clearly you see. This often comes and goes—you may notice it more after eating or in the late afternoon. While pregnancy can change your eyesight for other reasons, gestational diabetes-related blurriness tends to be intermittent and linked to blood sugar spikes. If you are seeing things less sharply, or your vision seems to bounce between clear and fuzzy, do not dismiss it as just another pregnancy quirk. Tell your doctor, and avoid adjusting your eyeglass prescription until after delivery, as your lenses can return to normal once blood sugar is controlled.
5. Recurrent vaginal or urinary infections
Elevated glucose in your tissues and urine creates a favorable environment for bacteria and yeast. If you are noticing an uptick in vaginal yeast infections (characterized by itching, thick discharge, and irritation) or urinary tract infections (burning with urination, pelvic pressure, or cloudy urine), this may be an indirect sign that your blood sugar is running high. Many women with undiagnosed gestational diabetes report having two or more infections during their pregnancy before a glucose test confirms the diagnosis. Persistent infections deserve attention not only because they are uncomfortable but also because they can complicate the pregnancy if left untreated.
What to do if you notice these signs
None of these symptoms alone confirms gestational diabetes. Many pregnant women experience some of them without having high blood sugar. The key is pattern and intensity. If you have one or more risk factors—such as a family history of type 2 diabetes, being over 25, having had GDM in a previous pregnancy, or being overweight before pregnancy—you may be more likely to develop it.
Your doctor can order an oral glucose tolerance test (OGTT) between 24 and 28 weeks, or earlier if you have strong risk factors or symptoms. The good news is that most women with gestational diabetes go on to have healthy pregnancies and babies with the right monitoring, nutrition adjustments, and sometimes medication. Early recognition is your best tool.
Simple steps to stay on top of it
- Track any new or worsening symptoms in a notebook or phone app to share with your provider
- Stay hydrated with water, but avoid sugary drinks that can spike glucose
- Eat balanced meals with protein, fiber, and healthy fats to steady blood sugar
- Move your body gently—a 15-minute walk after meals can help your muscles use glucose more effectively
Trust your instincts. You know your body better than anyone. If something feels off, ask for the test. A simple blood draw can provide peace of mind—or a diagnosis that empowers you to take action.
