Difficulty breathing during pregnancy is a common concern, but sometimes it can signal something more serious. Here are the symptoms not to ignore

Story by: Sara Thompson; Reviewed by Li Zhou, M.D., Ph.D. on October 3, 2023

Being a little short of breath is normal during pregnancy, especially in the later months. As the body prepares for baby, hormonal shifts, crowded organs and anemia all can contribute to this breathlessness. However, there are some conditions you should be aware of during pregnancy.

Here are some more facts to consider:

• Heart disease (also known as cardiovascular disease) is a leading cause of pregnancy complications and pregnancy-related deaths in the United States.
• According to the Centers for Disease Control and Prevention, over 60 million women (44%) in the United States are living with some form of heart disease. 
• Congenital heart disease (which means you were born with it) is the most common heart disease affecting pregnancies in the United States.
• According to the Journal of the American Heart Association, heart failure is the most common major heart-related health issue arising in pregnancy and in the months after. 

“Many times, in pregnancy, women think their symptoms are normal,” said Li Zhou, M.D., Ph.D., a cardiologist and medical director of the Norton Heart & Vascular Institute Women’s Heart Program. “Sometimes they are, but women’s heart conditions are often overlooked.”

When should I worry about shortness of breath during pregnancy?

Shortness of breath is very common during pregnancy, especially in the first and third trimesters. Doctors can’t always pinpoint a single cause, so this often is considered a symptom of the pregnancy itself. The symptoms can change over the course of the pregnancy and depend on many things, including your overall health.

First trimester

In the first trimester — Weeks 1 through 14 of pregnancy — you will begin to need more oxygen. Pregnant people sometimes breathe faster due to more hormones in the body, such as progesterone and estrogen. Progesterone is also a respiratory stimulant, meaning it causes a person’s breathing to speed up. While breathing faster does not necessarily cause shortness of breath, some people may notice changes in breathing patterns.

The diaphragm, a thick band of tissue that separates the heart and lungs from the stomach, can rise as much as 4 centimeters during the first trimester of pregnancy when the uterus begins to expand upward. The diaphragm helps the lungs fill with air. Some people don’t notice a change in breathing. Others notice they can’t take a full, deep breath.

Second trimester

Many pregnant people may experience noticeable shortness of breath in the second trimester, which lasts from Week 15 until about Week 28.

As the uterus expands with the baby’s growth, more pressure is put on the diaphragm and lungs. It’s not just the expanding uterus that can cause shortness of breath. The amount of blood in a person’s body increases significantly during pregnancy. This means the heart has to pump harder to move this blood through the body and to the placenta.

“The whole body is working harder, especially the heart,” Dr. Zhou said. “This can make you feel out of breath, even when you haven’t been active.”

Third trimester

“The third trimester is easier or harder, all depending on where baby is in the body,” Dr. Zhou said. The baby’s head may feel like it is pressing on your ribs or pushing into the diaphragm.

A few weeks before birth, the baby will begin to turn head down and drop into the pelvis, which can relieve some of the pressure on the diaphragm.

Other reasons for shortness of breath

If you feel out of breath during pregnancy, talk to your health care provider.

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

• Asthma: Pregnancy may make existing asthma symptoms worse. If you have asthma, talk to your doctor about safe treatments during pregnancy, such as inhalers or medications.
• Peripartum cardiomyopathy: This is a type of heart failure that can occur during late pregnancy or within a few months after giving birth. Symptoms include ankle swelling, low blood pressure and fatigue. Many people may assume their symptoms are just from pregnancy, but the condition can seriously affect a person’s health and often requires treatment.
• Pulmonary embolism: This happens 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.

When to worry about shortness of breath during pregnancy

Be sure to visit your pregnancy care provider regularly during your pregnancy. They will take your blood pressure and pulse and make sure you are doing well. Ask any questions you have when you go to these appointments.

If your breathlessness gets worse quickly, doesn’t get better when you change positions (such as moving from sitting to lying on your side), or if you develop sharp pains, call your doctor. Call a health care provider or 911 immediately if you are short of breath and have pain, especially in the chest, or your heartbeat is racing.