Rate of Pregnancy Complications in Women with Axial Spondyloarthritis Has Decreased Over Time

A cohort study published in The Lancet Rheumatology reported a “reassuring” trend of improvement in pregnancy outcomes in patients with axial spondylarthritis between 2007 and 2020.

“Evidence on the risks associated with pregnancy and childbirth in women with axial spondyloarthritis is scarce and conflicting, with more research needed to guide policy and clinical practice,” the authors wrote of the reasoning behind this study.

The investigators conducted an analysis of registry data on births in Sweden between April 2007 and December 2020, comparing the risk of adverse pregnancy outcomes between women with axial spondyloarthritis compared with the general population. Additionally, the team evaluated how outcomes changed over time in relation to the use of antirheumatic treatments, such as disease-modifying antirheumatic drugs (DMARDs) and non-steroidal anti-inflammatory drugs (NSAIDs).

The cohort of women with axial spondyloarthritis, which comprised 1,580 patients, was matched 1:10 to general population comparators. Matches were made based on year of delivery, maternal age, and parity.

Between April 1, 2007, and Dec 31, 2020, 1580 births in women with axial spondyloarthritis recorded in MBR fulfilled the inclusion criteria and were matched with 15 792 comparator births. Overall, there were higher risks of several complications among women with axial spondyloarthritis compared to the general population:

  • pre-term birth (risk ratio [RR]: 1.43; 95% confidence interval [CI]: 1.13–1.8);
  • pre-eclampsia (RR: 1.44; 95% CI: 1.08–1.92)
  • elective caesarean delivery (RR: 1.59; 95% CI: 1.37 – 1.84)
  • serious infant infection (RR: 1.29; 95% CI: 1.0

However, the risks of several complications decreased over time. The risks of pre-term birth, infant infection, and caesarean delivery decreased around 0.5% annually. At the same itme, the use of tumor necrosis factor inhibitors increased over the study period.

The risks of preterm birth, infant infection, and caesarean delivery decreased by around 0·5 percentage points annually during the study period, while the use of tumour necrosis factor inhibitors during pregnancy increased.

Of these results, the study authors wrote, “In view of remaining concerns regarding safety of the use of biological DMARDs during pregnancy, we saw a reassuring trend in which pregnancy outcomes improved over time in the axial spondyloarthritis group, concurrent with increased use of biological DMARDs. If the current rate of improvement is maintained, women with axial spondyloarthritis treated in accordance with clinical guidelines might eventually not be at an increased risk of adverse pregnancy outcomes.”