Pregnancy Can Affect Axial Spondyloarthritis Activity, Prospective Study Suggests

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by Alice Melao |

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During pregnancy, women with axial spondyloarthritis experience stable, low disease activity that tends to peak during the second trimester, according to a recent study in Norway.

The study, “Disease activity during and after pregnancy in women with axial spondyloarthritis: a prospective multicentre study,” was published in the journal Rheumatology.

Axial spondyloarthritis is a progressive, inflammatory disease that affects the spine. As with many inflammatory disorders, alterations to the body’s normal balance, such as stressful situations, may promote increased inflammatory activity.

Previous studies have evaluated the impact of pregnancy on axial spondyloarthritis activity, but the results have been contradictory. While some studies have shown increased pain and disease activity, particularly during the second trimester, others have revealed reduced activity during pregnancy.

To further evaluate the impact of pregnancy in axial spondyloarthritis, a research team evaluated 166 patients before and after their pregnancies. Clinical data were collected from RevNatus, a Norwegian database created in 2006 by the National Advisory Unit on Pregnancy and Rheumatic Diseases.

The researchers reviewed information from 179 pregnancies in axial spondyloarthritis patients.

Evaluation of disease activity before, during, and after pregnancy based on the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) showed that patients had low and relatively stable disease activity throughout. However, during the second trimester, 45 percent of patients had a higher BASDAI score — which measures active disease — showing a tendency to decrease to a lower value at six weeks postpartum.

Patients also reported significantly worse pain during the second trimester.

An analysis of inflammatory status, as determined by blood levels of C-reactive protein (CRP), showed no significant changes during the study’s duration. The lowest mean CRP value was observed before pregnancy, and the highest was seen one year after birth. No association between CRP values and disease activity scores was found.

Patients experienced decreased functionality, as measured by the Bath Ankylosing Spondylitis Functional Index, during the second and third trimesters compared to six weeks after birth. Functionality one year after delivery was found to be similar to that experienced before pregnancy.

The use of nonsteroidal anti-inflammatory drugs increased during the second trimester, which correlates with the period of increased pain and disease activity.

Although 78 women (44 percent) used TNFi — a disease-modifying antirheumatic drug — before pregnancy, only eight women (5 percent) used TNFi during pregnancy.

“When including TNFi in pregnancy as a covariate in the mixed model analysis, we found that women using TNFi tended to have lower disease activity, but no statistically significant difference,” researchers wrote. “Considering that the changes in BASDAI during pregnancy were so small, despite 40% of the women discontinuing TNFi, we cannot exclude a potential beneficial effect of pregnancy,” they added.

Although disease activity was highest in the second trimester, axial spondyloarthritis activity was low and stable in the period from planning a pregnancy to one year after delivery.

However, whether the deterioration demonstrated in the second trimester represents a true increase in disease activity during pregnancy remains unanswered. “The deterioration in the second trimester could be related to the discontinuation of TNFi before/at confirmed pregnancy,” the authors stated.

Researchers highlighted the need for additional studies to further confirm these findings. The differences in disease activity and inflammation reported during the study period were small, and it remains unclear if they are clinically relevant or due to changes in treatment regimens. Also, studies addressing the impact of pregnancy in different subgroups of the disease (radiographic and non-radiographic, for example) are still warranted, they said.