Do you feel like you can't get enough air? Are your ankles swollen? Welcome to your third trimester of pregnancy.

What’s the first thing you should do? Stop worrying. Shortness of breath and water retention, or edema, are common in your last weeks of pregnancy. These symptoms can sometimes indicate a condition you should be concerned about, but only rarely. Here’s what’s going on.

What’s Causing Shortness of Breath?

In the last trimester of pregnancy, your growing baby pushes your uterus against your diaphragm (the muscle under your lungs that contracts and relaxes in the breathing cycle). The diaphragm is moved up about 4 cm from its pre-pregnancy position. Your lungs are also somewhat compressed. All this means that you are unable to take in as much air with each breath.

This does not mean, however, that you are getting less oxygen. At the same time that your lung capacity decreases due to the physical constraint of a growing uterus, the respiratory center in the brain is stimulated by progesterone (a hormone released during pregnancy) to get you to take slower breaths. Although each breath may bring in less air, the air stays in the lungs longer so you extract the oxygen you and your baby need. Your body also expands your blood volume during the pregnancy to make sure your baby is also getting enough oxygen.

How to Manage Shortness of Breath

Shortness of breath can be uncomfortable. There are ways that you can breathe more comfortably:

Practice Good Posture

Make sure that you stand up straight with your shoulders back and your head lifted. Visualize a straight line connecting your sternum towards the sky to lift your chest.

Exercise

Aerobic exercise improves your breathing and lowers your pulse. Make sure that any program you begin is approved by your doctor. If you haven’t begun practicing already, now is a good time to start prenatal yoga. Breathing is central to a yoga practice and the extra stretching can improve your posture and give you more room to breathe. Whatever form of exercise you choose, don’t overdo it! Listen to what your body is telling you.

Keep Reading About How to Safely Exercise in the Third Trimester of Pregnancy »

Relax

“Just relax!” While that’s easy for someone who isn’t experiencing shortness of breath to say, it’s also true. The more anxious you become about shallow breathing, the shallower your breathing will become. It’s also important to rest when you need to rest.

Don’t Overdo It

Listen to what your body is telling you and rest when you need a break. Now is not the time to push yourself too hard and it’s important to pay attention to your body’s limits.

The feeling of breathlessness gets better as you approach delivery. As the baby descends in the pelvis, pressure on the diaphragm and lungs is somewhat relieved.

Warning Signs

While it’s good to know nature has a plan for your body, you should look out for warning signs in the unlikely case that your shortness of breath indicates that something is wrong.

Asthma

No doubt you already know if you have asthma before you get pregnant, and you may already know that asthma can get worse during pregnancy. Discuss with your doctor if asthma could be making your shortness of breath worse during the third trimester.

Anemia

In some cases, anemia — insufficient iron in your blood — can cause shortness of breath. Other symptoms of anemia include fatigue, headache, and a bluish tint to your lips and fingertips. To diagnose anemia, your doctor can check your iron levels and may prescribe supplements.

Pain or Persistent Cough

If you feel pain while taking deep breaths, experience fast breathing, or sense an increase in your pulse, contact your doctor immediately. These could be signs you have passed a blood clot to your lung (also known as a pulmonary embolism). Contact your doctor if you have a cough that lasts for more than a few days. You should always contact your doctor or call 911 immediately if you feel chest pain.

What Is Edema?

Edema is a condition in which excess fluid builds up in your body’s tissues. You’ll notice it most in your feet, ankles, and sometimes, in your hands. The fluid tends to pool in parts of your body most affected by gravity.

Many women experience edema during their pregnancy. For most of these women, warm weather and remaining in one position for any length of time contribute to swelling. Edema is at its lowest in the morning and increases throughout the day.

Report any leg pain to your doctor immediately. Tell your doctor if you notice sudden swelling or puffiness in your face or hands. This can be a sign of preeclampsia.

Learn More About Preeclampsia »

How Can I Manage Edema?

Here are some strategies that can help you combat edema:

  • Sit with your feet propped up when possible.
  • Wear support hose. Full pantyhose may not feel good when you’re pregnant, but there are also support knee socks. Choose the size you would have chosen before you were pregnant. Put them on in the morning before you become swollen.
  • Avoid excessive salt intake, which can lead to fluid retention.
  • Drink plenty of water to flush out wastes and help reduce the amount of water you retain.

Outlook

The last trimester of pregnancy is putting new pressures on your body. Some of these decrease in the last weeks as your baby drops down and prepares for delivery. Remember that these changes are all temporary and in the best interest of keeping baby and mother healthy. Continue your prenatal health habits of a balanced diet, as much rest as you can manage, and moderate exercise. Remember to report any severe pains or discomforts to your doctor right away.