Gestational diabetes is a condition where blood sugar levels become too high during pregnancy, affecting both mother and baby. Understanding this temporary form of diabetes and how to manage it can help ensure a healthier pregnancy and reduce risks for both you and your developing child.
Understanding How Common Gestational Diabetes Is
Gestational diabetes affects a significant number of pregnant women around the world. In the United States, approximately 5% to 10% of pregnancies are affected by this condition each year, according to health authorities.[1][2][4] Some estimates suggest the rate could be as high as 8% to 9% of pregnancies, making it a relatively common pregnancy complication that healthcare providers routinely screen for.[2][3]
The picture worldwide shows even higher rates. On average, gestational diabetes affects between 14% and 17% of pregnant women globally.[3] These numbers have been rising in recent years across many countries. The variation in rates between different regions can be influenced by several factors including age of mothers, ethnic background, access to pregnancy care, and geographic location. What’s particularly important to understand is that the rate of gestational diabetes in the United States has been increasing over time, highlighting the growing importance of awareness and proper management of this condition.[3]
What Causes Gestational Diabetes
The root cause of gestational diabetes lies in how pregnancy affects your body’s ability to use a hormone called insulin. Insulin acts like a key that allows sugar from your blood to enter your cells, where it can be used for energy. During pregnancy, your body naturally undergoes many hormonal changes to support your growing baby. The placenta, which is the organ that connects you to your baby and provides nutrients, produces hormones that are essential for your baby’s development.[1][2]
However, these same hormones from the placenta can interfere with how insulin works in your body. They can block insulin’s normal action, creating a condition called insulin resistance. This means your body’s cells don’t respond to insulin as well as they should.[2][4] When this happens, your body tries to compensate by producing more insulin. For most pregnant women, this compensation works just fine. But for some women, their body simply cannot make enough insulin to overcome this resistance, and blood sugar levels rise too high, resulting in gestational diabetes.[2]
The exact mechanisms behind why some women develop gestational diabetes while others do not are still not completely understood. What we do know is that all pregnant women experience some degree of insulin resistance, especially during the later stages of pregnancy. This is actually a normal part of pregnancy that helps ensure your baby gets enough nutrients. However, when this natural process becomes too pronounced and your body cannot keep up, gestational diabetes develops.[4][13]
The condition typically appears during the middle of pregnancy, most commonly between 24 and 28 weeks of gestation.[3][5] This timing relates to when pregnancy hormones are at their strongest levels. It’s important to understand that developing gestational diabetes doesn’t mean you had diabetes before pregnancy, nor does it automatically mean you’ll have diabetes after giving birth. The condition is specifically triggered by pregnancy itself.[2][3]
Who Is at Higher Risk
While any woman can develop gestational diabetes during pregnancy, certain factors increase the likelihood. Understanding these risk factors can help both you and your healthcare provider stay alert and ensure proper screening. Being aware of your risk doesn’t mean you will definitely develop the condition, but it does mean more careful monitoring may be beneficial.[3][4]
One of the most significant risk factors is being overweight or having obesity before pregnancy. Extra weight affects how your body uses insulin, making insulin resistance more likely.[3] Similarly, a personal history of gestational diabetes in previous pregnancies significantly raises your risk of developing it again. If you gave birth to a baby who weighed more than 9 pounds (approximately 4.5 kilograms), this is also considered a risk factor, as it may indicate that your body had difficulty managing blood sugar in that pregnancy.[4][6]
Family history plays an important role as well. If you have a parent or sibling with type 2 diabetes, your risk increases. This suggests there may be genetic factors that affect how your body processes sugar.[4][6] Age is another consideration—women over 40 years old are at higher risk, though being over 25 is also considered a risk factor.[6]
Certain ethnic backgrounds are associated with higher rates of gestational diabetes. Women who are African American, Hispanic or Latino, American Indian, Alaska Native, Native Hawaiian, Pacific Islander, South Asian, Black, African-Caribbean, or of Middle Eastern origin have increased risk, even if they were born in countries where their ethnic group is not the majority population.[4][6]
Other health conditions can also increase your risk. These include having polycystic ovary syndrome (PCOS), which is a hormone disorder affecting the ovaries, having high blood pressure, or having heart disease.[3][4] Women who are carrying twins or multiple babies are also at two to three times higher risk, likely because they have more placental tissue producing hormones that affect insulin.[7]
Physical inactivity before pregnancy and a lack of regular exercise can contribute to higher risk as well. Additionally, women who have had certain weight-loss surgeries, such as gastric bypass, may face increased risk.[6]
Recognizing the Symptoms
One of the challenges with gestational diabetes is that it often doesn’t cause obvious symptoms. Most women who have the condition feel perfectly normal and have no idea their blood sugar levels are elevated. This is precisely why routine screening tests during pregnancy are so crucial—they can detect the condition even when you feel fine.[1][3]
When symptoms do occur, they are typically mild and can easily be mistaken for normal pregnancy changes. The most common possible symptoms include feeling more thirsty than usual and needing to urinate more frequently than normal.[1][4] However, many pregnant women experience these same symptoms as a regular part of pregnancy, which makes them unreliable indicators on their own.
In some cases where blood sugar levels become very high, women might experience additional symptoms such as unusual tiredness, a dry mouth, or blurred vision.[6] There might also be itching in the genital area or recurrent infections like thrush. But again, several of these symptoms can occur during normal pregnancy and aren’t necessarily signs of gestational diabetes.[6]
Because symptoms are so unreliable for detecting gestational diabetes, you should not wait for symptoms to appear before seeking evaluation. Instead, standard pregnancy care includes screening for gestational diabetes between 24 and 28 weeks of pregnancy for all women. If you have risk factors, your healthcare provider may test you earlier in your pregnancy, possibly during your first prenatal visit.[4][5]
How It Affects You and Your Baby
Understanding the potential effects of gestational diabetes on both mother and baby helps explain why proper management is so important. When blood sugar levels remain high during pregnancy, they can lead to various complications, though many of these can be prevented with good care and blood sugar control.[5]
For your baby, high blood sugar levels in your blood can cross through the placenta, causing your baby’s blood sugar to rise as well. This excess sugar gives your baby extra energy that gets stored as fat, which can cause your baby to grow larger than normal. A condition called macrosomia, where babies weigh more than 9 pounds at birth, becomes more likely.[5][6] Very large babies can make delivery more difficult and may increase the likelihood of birth injuries. This also raises the chances that you might need a cesarean section (C-section) rather than a vaginal delivery.[5]
Babies born to mothers with gestational diabetes may experience low blood sugar (hypoglycemia) shortly after birth because their bodies have been producing extra insulin to handle the high sugar levels during pregnancy. Once born and separated from the mother’s blood supply, this extra insulin can cause their blood sugar to drop too low.[5] Some babies may also have breathing difficulties or develop jaundice, which is a yellowing of the skin and eyes that may require treatment.[6]
Poorly controlled gestational diabetes increases the risk of premature birth—delivery before the 37th week of pregnancy. There’s also an increased risk of having too much amniotic fluid surrounding the baby, a condition called polyhydramnios, which can cause premature labor or delivery problems.[6] In severe cases where gestational diabetes is not managed, there is an increased risk of stillbirth, though this is rare when the condition is properly monitored and treated.[5][6]
The effects don’t end at birth. Babies born to mothers with gestational diabetes have a higher likelihood of becoming overweight and developing type 2 diabetes later in their lives.[5]
For mothers, gestational diabetes increases the chance of developing preeclampsia, a serious condition characterized by high blood pressure and protein in the urine during pregnancy. Preeclampsia can cause severe or life-threatening problems for both mother and baby, and the only cure is delivery of the baby.[5] Women with gestational diabetes are also more likely to require a C-section due to their babies’ larger size.[5]
Perhaps most importantly for long-term health, having gestational diabetes significantly increases your risk of developing type 2 diabetes later in life. About half of women who have gestational diabetes go on to develop type 2 diabetes at some point after pregnancy.[4] This means ongoing monitoring of blood sugar levels after pregnancy is important. Over time, chronically high blood sugar can lead to serious health problems including heart disease, kidney disease, nerve damage, and eye problems.[5]
Preventing Gestational Diabetes
While it’s not always possible to prevent gestational diabetes, there are steps you can take before and during pregnancy that may reduce your risk. These lifestyle approaches focus on maintaining a healthy body weight and staying physically active.[4]
Before you become pregnant, achieving and maintaining a healthy weight can help lower your risk if you’re currently overweight or have obesity. Regular physical activity before pregnancy is also beneficial, as exercise helps your body use insulin more effectively. Eating a balanced, nutritious diet that focuses on whole grains, lean proteins, fruits, vegetables, and healthy fats while limiting processed foods and added sugars can support healthy metabolism.[4]
It’s important to note that once you’re already pregnant, you should not try to lose weight, even if you’re overweight. Pregnancy is not the time for weight loss, as your baby needs adequate nutrition to grow and develop properly. Instead, the focus should be on healthy eating and appropriate weight gain for a healthy pregnancy. Your healthcare provider can advise you on how much weight gain is right for your specific situation.[4]
Staying physically active during pregnancy, when safe and appropriate for your situation, can help with blood sugar control. Before starting any new exercise program during pregnancy, discuss it with your healthcare provider to ensure it’s safe for you.[4]
If you’ve had gestational diabetes in a previous pregnancy, you’re at higher risk for developing it again in future pregnancies. In this case, your healthcare provider will likely screen you earlier in pregnancy and may recommend particularly careful attention to diet and activity levels. However, having had gestational diabetes before doesn’t mean you’ll definitely have it again—many women have normal blood sugar in subsequent pregnancies.[3]
After you’ve given birth and your gestational diabetes has resolved, taking steps to prevent type 2 diabetes becomes important. This includes maintaining a healthy weight, eating a nutritious diet, exercising regularly, and having your blood sugar checked as often as your doctor recommends to catch any problems early.[4]
How Gestational Diabetes Changes Your Body’s Normal Function
To understand gestational diabetes, it helps to know what happens in a normal pregnancy and how this condition changes those processes. Pregnancy naturally transforms your body’s metabolism—the way you process and use nutrients from food. These changes are designed to ensure your growing baby receives a constant supply of nutrition.[7]
In a normal pregnancy, all women gradually develop some degree of insulin resistance as pregnancy progresses. This is actually a beneficial adaptation. When your cells become less responsive to insulin, more sugar remains in your bloodstream rather than being taken up by your cells. This higher circulating blood sugar ensures a steady supply of nutrients crossing the placenta to nourish your baby. In essence, your body becomes less efficient at using sugar so that your baby can have more of it.[4][7]
The placenta plays a central role in this process. As it grows, it produces increasing amounts of hormones including human placental lactogen, estrogen, and cortisol. These hormones are essential for your baby’s development, but they also interfere with insulin’s action in your body. They essentially block insulin from working as effectively as it normally would.[2][7]
In women who don’t develop gestational diabetes, the pancreas—the organ that produces insulin—compensates by making much more insulin than usual. This extra insulin overcomes the resistance and keeps blood sugar levels in the normal range. The pancreas of a pregnant woman without gestational diabetes can produce up to three times more insulin than normal to meet this increased demand.[7]
In gestational diabetes, however, the pancreas cannot produce enough insulin to overcome the resistance created by pregnancy hormones. Some women enter pregnancy already having some insulin resistance due to factors like excess weight or genetics. When the additional insulin resistance of pregnancy is added to this pre-existing resistance, their pancreas simply cannot keep up with the dramatically increased insulin needs. As a result, blood sugar levels rise higher than they should.[2][7]
This metabolic imbalance affects how your body stores and uses energy. Normally, after you eat, your blood sugar rises, insulin is released, and cells throughout your body take up the sugar to use for energy or store for later use. With gestational diabetes, this process is disrupted. Sugar stays in the bloodstream longer and at higher concentrations, crossing the placenta to the baby. The baby’s pancreas then produces extra insulin to handle this excess sugar, causing the baby to store the extra energy as fat and grow larger than normal.[7]
The condition typically becomes apparent in the second half of pregnancy, particularly between weeks 24 and 28, because this is when pregnancy hormones reach their peak levels and insulin resistance is strongest. This timing is why screening for gestational diabetes is routinely done during this period.[3][5]
The good news is that these changes are usually temporary. For most women, once the baby is born and the placenta is delivered, the source of the hormone interference is removed. Insulin resistance decreases, the pancreas can produce adequate insulin again, and blood sugar levels typically return to normal soon after delivery. However, the fact that the body couldn’t handle the metabolic stress of pregnancy indicates an underlying susceptibility to diabetes that may become apparent again later in life.[1][7]
