Obstetric and neonatal outcomes in women with Ankylosing spondylitis - an evaluation of a population database

Ankylosing Spondylitis (AS) is a systemic chronic rheumatic disease characterized by involvement of the axial skeletal and sacroiliac joints. Although this disease is not rare amongst women of reproductive age, data regarding pregnancy outcomes have demonstrated conflicting results. We therefore aimed to compare pregnancy and perinatal outcomes between women who suffered from AS to those who did not.

A retrospective cohort study using the Healthcare Cost and Utilization Project, Nationwide Inpatient Sample (HCUP-NIS). Included in the study were all pregnant women who delivered or had a maternal death in the US between 2004 and 2014. Women with an ICD-9 diagnosis of AS before or during pregnancy were compared to those without. Pregnancy, delivery, and neonatal outcomes were compared between the two groups using multivariate logistic regression models adjusting for potential confounders.

A total of 9,096,788 women were inclusion in the analysis. Amongst them, 383 women (3.8/100,000) had a diagnosis of AS and the rest were controls. Women with AS, compared to those without, were more likely to be older; Caucasian; from higher income quartiles; suffer from thyroid disorders, and have multiple pregnancies (p < 0.001, all). After adjusting for confounders, patients in the AS group, compared to those without, had a higher rate of cesarean delivery (CD) (aOR 1.47, 95% CI 1.14-1.91, p = 0.003); gestational diabetes (aOR 1.55, 95% CI 1.02-2.33, p = 0.038); and placenta previa (aOR 3.6, 95% CI 1.6-8.12, p = 0.002). Regarding neonatal outcomes, patients with AS, compared to those without, had a higher rate of small-for-gestational-age (SGA) neonates (aOR 2.19, 95% CI 1.22-3.93, p = 0.009); and intrauterine fetal death (IUFD) (aOR 3.46, 95% CI 1.11-10.83, p = 0.033).

Women diagnosed with AS have an increased risk of obstetric complications, including CD, as well as an increased risk of SGA and IUFD.