Many types of rheumatoid arthritis medications can harm your developing child during pregnancy. Talk to your rheumatologist and an obstetrician before you become pregnant. It's best to avoid certain rheumatoid arthritis medications for several months before you conceive.

Rheumatoid arthritis occurs when your body's immune system mistakenly begins to attack the tissues around your joints. Many rheumatoid arthritis medications work by suppressing your immune system. Other commonly prescribed drugs control inflammation.

Different types of drugs carry different risks. Some can produce birth defects, while others can cause miscarriage. Some drugs used for rheumatoid arthritis can increase the risk of high blood pressure or diabetes for pregnant women.

The timing of when drugs are taken during the pregnancy also can be important. For example, some medications can cause problems only in the first or third trimester, while others should be avoided completely.

Prednisone (Rayos) use during the first trimester has been associated with cleft palate and cleft lip. However, it's often used during pregnancy in low doses for short periods.

Nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve) used early in pregnancy have been associated with miscarriage in some studies. Used during the third trimester, there's a risk of developing heart problems.

Rheumatoid arthritis medications to avoid during pregnancy and breast-feeding include:

• Methotrexate (Trexall). One of the most commonly used medications to treat rheumatoid arthritis, methotrexate should be stopped three months before trying to get pregnant. It can induce miscarriage early in pregnancy. Taken later in pregnancy, it can cause birth defects affecting the brain and bones.
• Leflunomide (Arava). Doctors recommend avoiding this drug even before conception because it can remain in the body for a long time. Taking cholestyramine (Prevalite) can help speed the elimination of leflunomide from your body.
• Biologic response modifiers. Because there's limited information about the safety of this class of drugs during pregnancy, speak with your doctors if you're taking anakinra (Kineret), rituximab (Rituxin), abatacept (Orencia), tocilizumab (Actemra) or tofacitinib (Xeljanz).

It's important for women who are taking these types of medications to use contraception. If you're planning to become pregnant, talk to your doctor about switching to different types of rheumatoid arthritis medications that are considered relatively safe to use during pregnancy.

Certolizumab pegol (Cimzia), a tumor necrosis factor inhibitor, has a low risk of crossing the placenta and shows up minimally in breast milk.

More studies are needed to assess the safety of these medications during pregnancy.