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Running during pregnancy: the first trimester


When I was pregnant with my son, I had a positive pregnant running experience. I always assumed if I got pregnant again, my experience would be the same.

This is my roundabout way of saying I’m pregnant again! In the beginning, things were going great. Then I experienced some complications, and was sidelined from running for five long weeks. Luckily, I’ve come out the other side and am happy to report that I’m running again and having a healthy pregnancy.

However, this experience taught me a lot about first trimester running. If you’re newly pregnant and interested in running throughout pregnancy, high-five mama! Just keep the following in mind as you run during the first tri:

  • Running cannot cause a miscarriage.  Most miscarriages happen because of a chromosomal defect in the fetus. No amount of exercise during pregnancy has been shown to cause a miscarriage. In fact, some experts say that exercise during pregnancy may lower miscarriage risk and make you and your baby healthier. As long as you were running before pregnancy, it’s probably safe to keep up your routine. Just check with your doctor first.
  • It’s OK to stop running for a while. If you have vaginal bleeding, dizziness, or intense vomiting, your doctor may ask you hold off on exercise for a bit for your safety. Even if you need to take some time off, it may be possible to run later in pregnancy.
  • Ignore your pace and embrace walk breaks. Most pregnant runners will see their pace suffer significantly. This is completely normal. During pregnancy, your blood volume increases by about 50 percent. This makes your heart rate jump higher more easily, meaning that your pace is going to slow down whether you like it or not.
  • Watch your body temperature. Overheating during pregnancy is risky — it can cause birth defects and miscarriage — especially in the early weeks of pregnancy. It’s best to avoid activities than can raise your body temperature to 102 degrees Fahrenheit or higher (some doctors recommend not getting your temp above 100 degrees Fahrenheit). This means you have to be careful when running in the heat or humidity. In the summer, only run during early morning or stick to the treadmill.
  • Be extra careful if you have morning sickness. My morning sickness has been bad this time around. This means I can only run when I’m feeling 100 percent. Running after being sick when you have no food in your stomach is just not going to end well. Trust me.
  • Know that running may wear you out. Thanks to rising hormone levels, many moms-to-be experience intense fatigue during the first trimester. So, if you spend some of your precious energy running, you may need to take it easy for the rest of the day. Just be sure to plan accordingly.
  • Do what feels good. For many runners, running during pregnancy simply doesn’t feel good. And that’s OK. Running during pregnancy should be enjoyable. If it doesn’t feel good, find another activity that does. Even if you don’t run during pregnancy, you can still pick the sport up again after the baby is born.
  • Keep in mind that it may get easier. Last time I was pregnant, I found running in the second and early third trimester much more comfortable than first trimester running. There’s a chance that it may only get easier from here!

Moms, what was your first trimester running experience like?

Written by Jen Matz.

Related: Running during pregnancy