Biologic Use in Pregnancy Does Not Increase Infant Infection Risk

Using a biologic medication to manage rheumatoid arthritis during pregnancy does not appear to significantly increase an infant’s risk of serious opportunistic infections after birth, according to new research presented at the ACR/ARHP Annual Meeting in San Diego.

Although the use of biologic therapies for rheumatoid arthritis during pregnancy has become more common, there has been concern that infants prenatally exposed could be at increased risk for infection after birth. This concern has been greater with later pregnancy exposure, when placental transfer of the immune suppressing medication is increased.

The findings were presented in the second Plenary Session on November 6 by Dr Christina Chambers, Co-Director of the Center for Better Beginnings, Professor at the University of California in San Diego, and a study coauthor.

The study
This observational cohort study, conducted by the Organization of Teratology Information Specialists (OTIS) Autoimmune Diseases in Pregnancy Project, included data from pregnant women in the United States and Canada from 2004 to 2016.

In 502 pregnancies, the mother with rheumatoid arthritis had been treated with a biologic at some point during her pregnancy (in some cases with other disease-modifying antirheumatic drugs). This group was compared with 231 pregnancies in which the mother had rheumatoid arthritis but did not use any biologics during pregnancy and 423 pregnancies in which the mother had no chronic disease.

Data were collected through phone interviews and medical records, and follow-up data on infection rates were collected from the infants’ pediatricians up to 1 year after birth. The serious or opportunistic infections tracked included neonatal sepsis, invasive fungal infection, x-ray proven pneumonia, meningitis, bacteremia, pneumocystis, septic arthritis, osteomyelitis, tuberculosis, herpes, listeria, legionella, mycobacteria, systemic cytomegalovirus, and abscess.

The findings
Serious or opportunistic infections occurred in 4.0% of the infants born to mothers with rheumatoid arthritis who took biologics during pregnancy, compared with 2.6% of infants born to mothers with rheumatoid arthritis who did not use biologics during pregnancy and 2.1% of infants born to healthy mothers. Thus, no significant increased risk of serious opportunistic infections with exposure to biologics was identified.

The researchers also examined infection rates among infants potentially exposed in the third trimester, when most experts think placental transfer of medications is increased. Among the pregnant mothers with rheumatoid arthritis who used biologics, 43.2% took their last dose in the first or second trimester and 56.8% took their last dose in the third trimester.

For infants born to mothers whose last biologic dose was after 24 weeks gestation, 3.5% of mothers reported infections in their infants. For infants born to mothers whose last biologic dose was after 32 weeks gestation, 2.7% reported infant infections.

These findings represent about the same risk as that in women with rheumatoid arthritis who did not use any biologic during pregnancy. Consequently, there does not appear to be an increased risk of serious or opportunistic infections even with exposure to biologics in the third trimester of pregnancy.

Implications for physicians
Dr Chambers recognized in her presentation that this study does not take any direct measure of infant immune function and does not address whether there is an increased risk of less serious infections. In the Q&A portion, she acknowledged that this study does not answer the question of whether live vaccines should be avoided after birth if infants have been exposed to biologics during pregnancy. Additional data are still needed to answer these questions.

Still, the evidence is reassuring for women with rheumatoid arthritis who need to be treated with a biologic throughout pregnancy.

References:

American College of Rheumatology Press Release. “Biologic Use During Pregnancy May Not Increase Opportunistic Infection Risks in Infants.” November 4, 2017.

Presentation Number 1785. “Serious or Opportunistic Infections in Infants Born to Pregnant Women with Rheumatoid Arthritis and Treated with a Biologic Medication.” ACR/ARHP Annual Meeting, November 6, 2017.