Rheumatoid arthritis tied to birth outcomes

Researchers examine pregnancy outcomes and factors associated with preterm delivery and fetal size.

By
Kathryn Wighton
August 21, 2026
4 min

MDSpire News

Overview

Pregnancies among patients with rheumatoid arthritis (RA) are linked to increased rates of preterm birth and small-for-gestational-age infants compared to the general population. A multicenter study found preterm birth rates of 16% in RA pregnancies versus 8% in controls, and small-for-gestational-age rates of 21% versus 11%, respectively.

Background

Rheumatoid arthritis is a chronic inflammatory disorder that can complicate pregnancy, leading to adverse outcomes. This study provides data on the prevalence of preterm birth and small-for-gestational-age infants in this population.

Data Highlights

Outcome	RA Pregnancies (%)	Control Pregnancies (%)
Preterm Birth	16	8
Small-for-Gestational-Age (<10th percentile)	21	11
Small-for-Gestational-Age (<3rd percentile)	6	2

Key Findings

Preterm birth occurred in 16% of RA pregnancies compared to 8% in controls.
21% of RA pregnancies resulted in small-for-gestational-age infants (<10th percentile) versus 11% in controls.
Nulliparity was associated with small-for-gestational-age births.
Maternal age and glucocorticoid exposure at doses ≥10 mg/day were linked to increased odds of preterm birth.
Moderate or high RA activity was documented in 27% of pregnancies with available disease-activity measurements.
No significant differences were found in gestational diabetes, cesarean delivery, or congenital malformations between the groups.

Clinical Implications

Clinicians should be aware of the increased risks of preterm birth and small-for-gestational-age infants in pregnancies affected by rheumatoid arthritis. Monitoring disease activity and medication exposure during pregnancy is essential for optimizing maternal and fetal outcomes.

Conclusion

The study highlights the elevated risks associated with pregnancies in patients with rheumatoid arthritis, emphasizing the need for careful management and monitoring during this vulnerable period.