Use of Tumor Necrosis Factor inhibitor (TNFi) during pregnancy is associated with birth of healthier babies with better birth weight to mothers with well-controlled rheumatoid arthritis (RA), reveals a study published in Annals of Rheumatic Diseases.
Small-for-gestational-age (SGA) and hypertensive problems are adverse pregnancy outcomes in women with RA compared to healthy women, particularly in those with active illness throughout pregnancy. In recent years, there have been additional alternatives for prenatal care, including the use of TNF-inhibitors, which has led to better disease outcomes for pregnant RA patients. In order to characterize pregnancy outcomes of children born to RA patients included in the PreCARA-cohort, and in particular to describe the pregnancy outcomes of women who took a TNFi throughout pregnancy while accounting for relevant confounders, Hieronymus T. W. Smeele and team performed this study.

Patients for this trial were selected from the Preconception Counseling in Active RA project, a prospective investigation of pregnancy with RA, and they received care in accordance with a regimen designed to minimize disease activity. The factors influencing birth weight were identified using multivariate linear regression analysis.
The key findings of this study were:
1. 92 (48.9%) of the 188 individuals included in the study had RA and had taken a TNFi while pregnant.
2. At all times throughout pregnancy, the Disease Activity Score in 28 joints C reactive protein (DAS28CRP) was low.
3. Use of TNFi was not linked to a rise in unfavorable pregnancy outcomes such low birth weight cesareans, hypertensive problems, or congenital abnormalities.
4. Use of TNFi decreased the likelihood of large-for-gestational-age births (p=0.73) but did not affect the number of infants born small-for-gestational-age (p=0.05).

5. In women who took a TNFi throughout pregnancy, the mean birth weight was 173 g greater (3.344 kg vs 3.171 kg, p=0.03).
6. Maternal age, TNFi usage ( 0.20, 95% CI 0.066, 0.34, p=0.004), diabetes mellitus, and gestational age were statistically significantly linked to newborn weight in the multivariate analysis.
This study demonstrates a link between TNFi usage throughout pregnancy and higher birth weights in babies of mothers with well-controlled RA. Interestingly, TNFi usage during pregnancy reduces the likelihood of SGA births while leaving LGA births unaffected.
Reference:
Smeele, H. T. W., Röder, E., Mulders, A. G. M. G. J., Steegers, E. A. P., & Dolhain, R. J. E. M. (2022). Tumour necrosis factor inhibitor use during pregnancy is associated with increased birth weight of rheumatoid arthritis patients' offspring. Annals of the Rheumatic Diseases, 81(10), 1367–1373. https://doi.org/10.1136/ard-2022-222679