What to expect when women with axial spondyloarthritis are expecting: Prevalence of complications of pregnancies in women with axial spondyloarthritis.

Background: Understanding of axSpA is evolving rapidly. Unfortunately, for women with axSpA there is limited data available on pregnancy complications. The Ankylosing Spondylitis Registry of Ireland (ASRI) is a source of epidemiological data on axSpA in Ireland. The aim of this study was to examine the prevalence of pregnancy and fetal complications in axSpA women.

Methods: The ASRI records cross-sectional information on demographics, imaging, treatment, and patient outcomes. A dedicated section collects data on pregnancy, fertility and breastfeeding. For each axSpA woman, data on all pregnancies was recorded. Results were compared to global reference norms (GRN). All patients were diagnosed with axSpA by a Rheumatologist and met the ASAS classification criteria. Informed consent was obtained from all patients, with ethical approval obtained from local hospital ethics committees.

Results: Data was available on 98 women with axSpA. There were 335 pregnancies resulting in 279 live births. Of these pregnancies 51.6% (173) were uncomplicated and 48.5% (162) were complicated, with 13.1% (44) encountering multiple complications. Preterm birth (12.5 % vs 5.2%, p<0.01) and preeclampsia (6.8 % vs 2.8%, p<0.01) were more prevalent in axSpA pregnancies than GRN. Low birth weight was more prevalent in axSpA pregnancies (8.2 % vs 2.9%, p<0.01), however small for gestational age was less prevalent (5.4 % vs 11%, p<0.01).

Conclusions: Preterm birth, preeclampsia and low birth weight are significantly more prevalent in pregnancies of axSpA women. Furthermore, there is a high prevalence of complications in axSpA pregnancies overall. These results provide essential insight into the impact of axSpA in pregnancy and call for further research to understand the pathogenesis of these complications.