When someone is pregnant, they may experience hypoglycemia, or low blood sugar, due to changes in how their body regulates and metabolizes glucose.

Hypoglycemia is the term used when someone has low blood sugar. When a person has low blood sugar, it can be difficult to think or concentrate and may cause fainting.

Women who notice symptoms of hypoglycemia while they are pregnant should be tested for diabetes, which is the most common cause of pregnancy-related hypoglycemia.

In this article, we take a close look at hypoglycemia during pregnancy, including the causes, symptoms, risks, and how hypoglycemia may affect the baby.

Share on Pinterest
Natalia Lebedinskaia/Getty Images

Women with diabetes are especially vulnerable to hypoglycemia when pregnant. A 2008 study of pregnant women with type 1 diabetes found that 45 percent experienced episodes of hypoglycemia, particularly during the first and second trimesters.

Insulin is a hormone that helps to control the body’s glucose levels. During pregnancy, a woman’s body requires more insulin because the placenta produces extra glucose. Along with hormonal changes, this can make it difficult for a woman’s body to regulate glucose.

When the body cannot produce enough insulin, a pregnant woman may develop gestational diabetes. Women also tend to become more insulin resistant as their pregnancy continues, which means that the body responds less well to insulin.

As a result of these factors, it is more likely that a pregnant woman will develop hyperglycemia, which is high blood sugar. However, many women may also develop low blood sugar or alternate between the two conditions.

A person’s body has difficulty fueling itself when it has low blood glucose. The result can be weakness, confusion, and other symptoms that someone might expect after missing a meal or two.

Other symptoms may include:

  • shaking
  • sweating
  • a headache
  • blurred vision
  • exhaustion
  • moodiness and anger
  • anxiety
  • difficulty thinking clearly
  • irregular or fast heartbeat
  • pale skin

When someone has severe hypoglycemia, they may experience more serious symptoms, such as seizures, convulsions, or a loss of consciousness.

When a person notices symptoms of hypoglycemia during pregnancy, they should talk to their doctor to find out the exact cause. Two types of hypoglycemia can occur during pregnancy:

  • Reactive hypoglycemia. This form of hypoglycemia happens when blood sugar levels drop within a few hours of a meal. This is common in people with diabetes but can also occur in those without the condition.
  • Fasting hypoglycemia. This occurs when the blood sugar drops dangerously low between meals. This form is more likely in a person with a medical condition other than diabetes.

The causes of low blood sugar during pregnancy include:


Diabetes is the leading cause of hypoglycemia during pregnancy. However, hyperglycemia is more common than hypoglycemia during pregnancy, but both can occur at different stages of pregnancy.

High blood sugar levels are caused by both type 1 diabetes, where the body is unable to produce correct levels of insulin, and type 2 diabetes, where the body has become insulin resistant.

Low blood sugar levels can occur when a person takes diabetes medications or does not eat enough.

Occasionally, hormonal and other changes during pregnancy can cause women with diabetes to develop hypoglycemia even without medication. This is why it is crucial for women with diabetes to eat balanced diets and carefully monitor their blood sugar throughout their pregnancy.

Gestational diabetes

Some women develop gestational diabetes during pregnancy. This condition is due to insulin resistance, hormonal changes, and the increased demands of pregnancy on the body. Gestational diabetes can also cause low blood sugar, particularly in women who take diabetes medication or who do not eat enough.

An estimated 9.2 percent of pregnant women experience gestational diabetes. This condition usually goes away after the baby is born.

Morning sickness

Blood sugar can become very low in people who do not eat enough carbohydrates.

Women with severe morning sickness may develop low blood sugar if they frequently vomit. Women who vomit daily, do not gain weight, or feel light-headed should consult their doctor.

Lifestyle factors

Several lifestyle factors can cause hypoglycemia in pregnancy, more often in women with another risk factor, such as diabetes.

Lifestyle factors include:

  • not eating enough
  • exercising more than usual
  • drinking alcohol
  • having an eating disorder


Diabetes drugs can lower blood sugar levels. When a person does not eat enough or takes too much of a diabetes drug, they may develop dangerously low blood sugar.

Some other medications may also lower blood sugar, including:

  • salicylates or pain relievers, including aspirin, which most doctors do not recommend during pregnancy
  • antibiotics called sulfa drugs
  • pentamidine, a pneumonia medication
  • a malaria medication called quinine

Rare medical disorders

Several rare conditions can cause hypoglycemia. These conditions may affect a developing baby, so it is essential to get an accurate diagnosis and treatment.

Disorders that can cause hypoglycemia include:

  • pancreatic tumors
  • organ failure
  • hormone imbalances, particularly in cortisol and glucagon
  • deficiencies of certain enzymes
  • recent stomach surgery

Mild hypoglycemia is unlikely to harm the developing baby unless it could harm the mother. In most cases, simply eating more or adjusting medication will prevent the risk of any harm.

Women who have severe hypoglycemia may need to be hospitalized or monitored.

Women with gestational diabetes may give birth to unusually large babies. This can make a vaginal delivery more difficult and may increase the risk of injury to mother and baby.

Babies born to mothers with diabetes may also have jaundice, and their blood sugar may drop dangerously low shortly after birth. They may need monitoring during and after delivery.

Most doctors test for gestational diabetes late in the second trimester of pregnancy, but women who show signs of diabetes before or after this may need additional testing.

If a woman does not have diabetes, a doctor may perform additional blood work to find the cause of hypoglycemia. A complete medical history and information about lifestyle can help with a proper diagnosis.

Treatment for diabetes during pregnancy varies. A woman will need to monitor her blood sugar with regular blood glucose readings. She may need to change her diet and exercise more, which can also help balance blood sugar.

If these strategies fail, a woman might need to take insulin or other medications. As diabetes drugs can cause hypoglycemia, it is essential for a person to follow their doctor’s instructions carefully.

If another condition is causing the hypoglycemia, treatment will depend on the cause. For instance, a woman with a tumor that causes a hormonal imbalance may need to have it removed, either during or after the pregnancy.

The most significant complications related to hypoglycemia in pregnancy are due to diabetes.

Pregnant women with diabetes can have difficult labors, and their babies may need additional monitoring. Also, diabetes can be dangerous, leading to heart and organ failure, circulation problems, slow healing, and even death.

Most women with gestational diabetes improve after pregnancy but may experience the condition with subsequent pregnancies. Gestational diabetes is also a risk factor for type 2 diabetes.

Women with type 1 or type 2 diabetes will need to continue managing their diabetes after their pregnancy.

Whatever the cause of hypoglycemia during pregnancy, careful monitoring of mother and baby can reduce the risk of serious complications.

Hypoglycemia during pregnancy can happen for many reasons, including when someone skips a meal. It is essential to get a proper diagnosis because hypoglycemia and diabetes can have adverse effects on labor and delivery.

However, proper medical care and management of blood sugar levels can help keep the mother and baby safe.