Axial SpA disease activity remains mostly stable throughout pregnancy

The research team found that, across the span of pregnancy, axSpA disease activity was relatively low and consistent throughout the study. But there was a significant relationship between disease activity and time (P = .029) in which disease activity was highest during the second trimester and proved to be significantly higher than 6 weeks after giving birth (mean BASDAI 3.97 vs. 3.46, P = .005). In fact, 45% of women had active disease in their second trimester (BASDAI of 4 or greater). But among women with data from the second trimester and 6 weeks post partum, 42% had a decrease in BASDAI score of 1 or more, and 22% had an equivalent increase. CRP values remained low and stable throughout the study.

Like the BASDAI scores, physical function and well being seemed to correlate with later time points during pregnancy. The lowest level of physical functioning for most women was during the second and third trimesters, and those periods were significantly worse than 6 weeks after giving birth (mean BASFI of 3.2 during the second trimester and 3.6 during the third vs. 2.6 at 6 weeks post partum). Similarly, patients reported overall worse general health during the second and third trimesters, compared with 6 weeks after giving birth, based on RAND-36 scores (mean physical functioning score of 63.1 in the second trimester and 54.5 in the third vs. 71.0 at 6 weeks post partum).

Use of nonbiologic medications remained relatively stable during pregnancy, while biologic disease-modifying antirheumatic drug (DMARD) use (all tumor necrosis factor [TNF] inhibitors) dropped significantly when pregnancy was confirmed. About 20% used NSAIDs during pregnancy, except for during the third trimester when use decreased to 8%. Prednisolone use remained stable at 5%-8%. A total of 11% had used synthetic DMARDs prior to pregnancy, and this rate stayed at 10%-16% during the three trimesters. Overall, 44% had used a biologic DMARD (TNF inhibitor) prior to pregnancy, but this declined sharply to 6% during the first trimester and 1% in the third.

The main limitations of the study included not having data from all of the women for all the time points. In fact, only 22% were included prior to conceiving, which could suggest that women with low disease activity were less likely to visit their rheumatologist, thereby biasing the sample toward an overestimated disease activity at preconception that could have potentially hidden a “more evident deterioration between the preconception visit and the second trimester,” the authors said.