Atrial fibrillation (AFib) is a common heart rhythm disorder, called an arrhythmia. If you have AFib, you might need to change how you manage the heart problem during pregnancy. For instance, you might be told not to take some medicines while you're pregnant.

Atrial fibrillation increases the risk of blood clots in the heart. Pregnancy increases the risk of blood clots in the legs. Taking blood thinners, also called anticoagulants, can help reduce these risks. But some blood thinners may not be safe to take during pregnancy. If possible, tell your health care provider about all the medicines you take before you become pregnant.

Pregnancy can make AFib worse. It's also possible to develop the irregular heartbeat while you're pregnant. Talk to your health care team to create the safest treatment plan for you and your developing baby.

The blood-thinning medicine warfarin (Jantoven) should not be used during pregnancy. If you take it, you may be switched to a different blood thinner during all or part of your pregnancy.

Blood thinners called direct oral-acting anticoagulants also are not recommended during pregnancy. These medicines include dabigatran (Pradaxa), rivaroxaban (Xarelto), edoxaban (Savaysa) and apixaban (Eliquis). There aren't enough studies to determine their effects and safety during pregnancy.

Studies show that the blood-thinners heparin and low molecular weight heparin, such as enoxaparin (Lovenox), do not cross the placenta. They may be used during pregnancy when monitored closely. Some pregnant people with atrial fibrillation get low molecular weight heparin shots to prevent blood clots.

Even when taking a blood thinner, blood clots may occur during pregnancy. Watch for symptoms of blood clots, such as chest pain, shortness of breath or leg swelling. Get help right away if you have symptoms of stroke, including changes in vision, trouble speaking and numbness in the face, arms or legs. Get medical help right away if you notice unusual symptoms.

Heparin and other blood-thinning medicines increase the risk of major bleeding, including bleeding where the placenta attaches to the uterus. If you have any bleeding, tell your health care team. Blood thinners are usually stopped during labor and delivery, unless you're at very high risk of blood clots.

You can usually start taking your blood-thinning medicine again after your baby is born. Your health care team gives you specific instructions. Some blood thinners might not be recommended while breastfeeding. Together, you and your care team can decide which blood thinner is safe for you and your baby.