Rheumatoid arthritis and pregnancy: are biologics safe for the baby?

This study examined whether biologics (medicines extracted from biological sources, such as cells, that block immune responses) are a risk for pregnant women with rheumatoid arthritis.

A major advance in the treatment of rheumatoid arthritis is the use of biologics including infliximab (Remicade), etanercept (Enbrel), adalimumab (Humira), golimumab (Simponi), and certolizumab pegol (Cimzia). The most commonly used biologics block TNF, a protein known to play a role in inflammation of the joints. These drugs prevent or slow joint damage and have improved patient physical function. This has increased the number of women who feel physically capable of the challenges of pregnancy. However, women have two main concerns with regards to pregnancy. First, will treatment with a biologic before or after pregnancy affect the child. Second, will they be able to control their disease during pregnancy.

This article summarized up-to-date information regarding the use of biologics in women before and during pregnancy.

Biologic use before pregnancy

Women with active rheumatoid arthritis during pregnancy may have an increased risk of complications including preterm delivery and low birth weight babies. For this reason it is recommended that woman achieve low disease activity before pregnancy and try to maintain this throughout the pregnancy.

Here, the authors reassure women that the use of TNF blockers during the time before getting pregnant carries low risk. This is very important as methotrexate (Rheumatrex, Trexall; the most commonly used drug for rheumatoid arthritis) is linked to higher risks for the baby. They suggest that the use of TNF blockers, at least until pregnancy is confirmed, should prevent disease flares in patients who stop methotrexate.

Biologic use during pregnancy

The amount of information on biologic use during pregnancy is limited. To date no difference between the rate of birth defects following exposure to TNF blockers and rates in the general population have been seen. Therefore, the growing consensus is that TNF blocker use appears to carry low risk. Despite this, controversy remains about the best time for women stop taking biologics before giving birth. One recommendation is that biologic should be stopped during weeks 30-34 to minimize high levels building up in the fetus. 

In addition, it is recommended that live virus vaccines be delayed at least 6 months in babies exposed after the 20th week of pregnancy. This is because biologics affect the immune system and could leave babies at risk of developing the infections more easily.

The authors conclude that taking TNF blockers before and during pregnancy carries low risk. However, they report that it may be useful to stop taking them between weeks 30-34 of pregnancy and that live-vaccines should be given later in babies exposed to biologics.