Causes of shortness of breath during pregnancy

As pregnancy progresses, a woman may have difficulty catching her breath after carrying out routine tasks, such as climbing the stairs.

According to a 2015 study, an estimated 60 to 70 percent of women experience shortness of breath during pregnancy.

Doctors often attribute this to the growing uterus pushing upward on the lungs and making it difficult to breathe.

This article will explore this and other possible reasons for shortness of breath during pregnancy. We also cover coping strategies and when to see a doctor.


Pregnant woman sitting cross legged on bed holding bump and chest while breathing.
Shortness of breath is a common symptom during pregnancy.

While shortness of breath is a common symptom of pregnancy, it is not always possible for a doctor to pinpoint one single cause.

Shortness of breath during pregnancy appears to be due to a variety of factors, ranging from the growing uterus to changes in the demands on the heart.

Some women may notice changes in their breathing almost immediately, while others see differences during the second and third trimesters.

First trimester

A fetus does not have to be very large to cause breathing changes in a pregnant woman.

The diaphragm, a muscular band of tissue that separates the heart and lungs from the belly, rises by as much as 4 centimeters during the first trimester of pregnancy.

The diaphragm’s movement helps the lungs fill up with air. While some women may not be aware of changes in how deeply they can breathe in, others may notice they cannot take full, deep breaths.

As well as changes in the diaphragm, pregnant women often breathe faster due to increases in the hormone progesterone.

Progesterone plays an essential role in the fetus’s development. It is also a respiratory stimulant, meaning it causes a person’s breathing to quicken.

The amount of progesterone in a woman’s body will increase throughout pregnancy.

While breathing faster does not necessarily cause shortness of breath, some women may notice changes in breathing patterns.

Second trimester

The heart working harder during pregnancy may cause shortness of breath.

Pregnant women may experience more noticeable shortness of breath in the second trimester.

The growing uterus commonly contributes to shortness of breath in the second trimester. However, some changes in the way the heart functions can also cause breathlessness.

The amount of blood in a woman’s body increases significantly during pregnancy. The heart has to pump harder to move this blood through the body and to the placenta.

The increased workload on the heart can make a pregnant woman feel short of breath.

Third trimester

During the third trimester, breathing may get easier or more difficult depending largely on the position of the developing baby’s head.

Before the baby starts to turn and drop further into the pelvis, the baby’s head may feel as if it is under a rib and pressing on the diaphragm, which can make it hard to breathe.

According to the National Women’s Health Resource Center, this type of shortness of breath usually occurs between weeks 31 and 34.

Additional causes

If a pregnant woman is experiencing severe shortness of breath, it is essential to speak to a doctor.

While pregnancy changes can cause some breathlessness, other medical conditions can also contribute to the problem. These include:

  • Asthma: Pregnancy may make existing asthma symptoms worse. Anyone with asthma should speak to a doctor about safe treatments during pregnancy, such as inhalers or medications.
  • Peripartum cardiomyopathy: This is a type of heart failure that can occur during pregnancy or immediately after giving birth. Symptoms include ankle swelling, low blood pressure, fatigue, and heart palpitations. Many women may initially attribute their symptoms to pregnancy, but the condition can seriously affect a woman’s health and often requires treatment.
  • Pulmonary embolism: A pulmonary embolism occurs when a blood clot gets stuck in an artery in the lungs. An embolism can dramatically affect breathing and cause coughing, chest pain, and shortness of breath.

How to cope

Pregnant woman wearing support bandage around bump.
A pregnancy support belt may help improve posture.

Feeling short of breath can be uncomfortable and limit a person’s physical activity.

Fortunately, there are several steps pregnant women can take to make breathing more comfortable, including:

  • Practicing good posture will allow the uterus to move away from the diaphragm as much as possible. Pregnancy support belts can make practicing good posture easier. These belts are available in specialty stores and online.
  • Sleeping with pillows supporting the upper back, which can allow gravity to pull the uterus down and give the lungs more space. Tilting slightly to the left in this position can also help keep the uterus off the aorta, the major artery that moves oxygenated blood through the body.
  • Practicing breathing techniques commonly used in labor, such as Lamaze breathing. Practicing these techniques during pregnancy may help a woman use them during labor as well.
  • Listening to the body and slowing down when needed. It is crucial to take breaks and rest if breathing becomes too difficult. In the later stages of pregnancy, a woman may not be able to do the same level of physical activity as before.

If a woman has another underlying medical condition causing shortness of breath, it is essential to follow the doctor’s recommendations about treatment.

When to see a doctor

While many women experience some shortness of breath during pregnancy, some symptoms require treatment.

Pregnant women should seek immediate medical treatment for the following symptoms:

  • blue lips, fingers, or toes
  • heart palpitations or extremely high heart rate
  • pain when breathing
  • severe shortness of breath that seems to be getting worse
  • wheezing

If shortness of breath is especially bothersome or if someone experiences it for the first time, they should speak to a doctor.

The doctor may want to perform imaging tests, such as ultrasounds on the legs, to rule out a blood clot as a potential cause.

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