medwireNews: Pregnant women with axial spondyloarthritis (axSpA) may experience a small increase in disease activity during the second trimester, but the majority have low disease activity throughout pregnancy, Norwegian researchers report.
Kristin Ursin (Trondheim University Hospital) and colleagues used a national registry to evaluate data from 179 pregnancies in 166 women with axSpA. Patients were aged a mean of 31 years and had a median disease duration of 5 years.
Overall, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores remained largely consistent from preconception to the 12-month postpartum follow-up, with estimated mean scores between approximately 3.5 and 4.0 points at all timepoints, suggesting that disease activity was “low and stable in the period from planning pregnancy to 1 year after delivery,” report Ursin and team in Rheumatology.
However, the mean BASDAI score was highest during the second trimester, and was significantly higher during this period than at 6 weeks postpartum, at 3.97 versus 3.46 points. The lowest average BASDAI score, of 3.35 points, was recorded 1 year after delivery.
“The question of whether the deterioration demonstrated in the second trimester represents a true increase in disease activity midpregnancy remains unanswered,” write the researchers, noting that the worsening of disease activity “could be related to the discontinuation of TNFi [tumor necrosis factor inhibitors] before/at confirmed pregnancy.”
Indeed, 44% of women used TNF inhibitors before conception, but only 5% used them during pregnancy. In a mixed model analysis, patients who used TNF inhibitors during pregnancy had lower BASDAI scores in the second trimester of pregnancy than those who did not (3.59 vs 3.89 points), but the difference did not reach statistical significance.
In accordance with the disease activity results, Bath Ankylosing Spondylitis Functional Index (BASFI) scores were significantly worse during the second and third trimesters of pregnancy than at 6 months postpartum (3.2 and 3.6 vs 2.6 points, respectively), as were RAND-36 physical functioning scores (63.1 and 54.5 vs 71.0 points, respectively).
RAND-36 mental health scores were also significantly worse during pregnancy than at 6 weeks after delivery, but overall patients had “good mental health during and after pregnancy,” say the study authors.
Despite their investigation being “the largest prospective study so far of disease activity during and after pregnancy in women with axSpA,” Ursin and co-investigators note that the number of patients was too small to assess the impact of axSpA subgroups and comorbidities during pregnancy. They also caution that the BASDAI score contains subjective measures of disease activity.
“To date, no disease activity measure for axSpA has been validated in pregnant women,” they add.
And the team concludes: “Future research on pregnancy in women with axSpA should differentiate between subgroups of the disease and aim to include objective assessment of inflammation.”
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