Women with Spondyloarthritis may have an Increased Risk of Small-for-Gestational-Age Births: Study
France: Researchers have found in a prospective cohort study that although most babies born to women with spondyloarthritis (SpA) did well, there was a doubling of risk for small-for-gestational-age (SGA) births compared to the general population. However, rates of other adverse pregnancy outcomes were similar to those in women without SpA.
The findings come from a French national multicentre cohort published in Annals of the Rheumatic Diseases by Sabrina Hamroun of the Rheumatology Department at NOVO Hospital, Pontoise, France, and colleagues. The study aimed to offer contemporary, real-world evidence on pregnancy outcomes among women with SpA—both axial and peripheral forms—and to clarify how these outcomes compare with women from the general population.
The prospective study evaluated 135 pregnancies in 124 women diagnosed with SpA between December 2015 and June 2021. The average age of participants was 32.1 years, and just over half were first-time mothers. Disease duration averaged 6.3 years, and researchers closely tracked maternal characteristics, disease activity, treatments, and pregnancy outcomes throughout gestation.
Pregnancy outcomes in the SpA group were compared with a large control group of French women selected from the 2016 and 2021 National Perinatal Surveys, using a 1:4 matching strategy. This enabled the researchers to assess differences in pregnancy, delivery, and neonatal outcomes under closely aligned demographic conditions.
The key findings of the study were as follows:
- Small-for-gestational-age (SGA) birth was the most common adverse outcome among women with SpA.
- A total of 17.4% of infants born to mothers with SpA were SGA, compared with 9.8% in the general population, indicating nearly double the risk (odds ratio 1.94).
- No clinical or demographic predictors of SGA were identified within the SpA group, pointing toward underlying disease mechanisms rather than modifiable risk factors.
- Other pregnancy outcomes, including preterm birth, caesarean delivery, and additional maternal or neonatal complications, were similar between women with SpA and those without the condition.
These results indicate that, aside from the higher likelihood of SGA, pregnancies in women with SpA generally progress well.
The authors highlighted that earlier studies suggested broader pregnancy risks in women with SpA, but contemporary data—particularly from prospective cohorts—have been limited. This study adds clarity by demonstrating that modern management of SpA may help mitigate many previously reported complications.
However, the researchers acknowledged certain limitations. The sample size restricted the ability to perform detailed subgroup analyses across different SpA subtypes, and recruitment from tertiary care centres may have led to overrepresentation of women with more severe disease. Yet, the absence of increased risks even within this potentially more complex population adds weight to the reassuring nature of the findings.
Overall, the study concludes that while SGA risk is moderately elevated in women with SpA, other major pregnancy outcomes remain similar to those of the general population. The authors emphasise that these results should help guide counselling and support informed decision-making for women with SpA planning a pregnancy, offering renewed confidence for both patients and clinicians.
Reference:
Hamroun S, de Frémont GM, Costedoat-Chalumeau N, Couderc M, Flipo RM, Sellam J, Richez C, Belkhir R, Gossec L, Marotte H, Dernis E, Frazier-Mironer A, Gervais E, Lukas C, Devauchelle-Pensec V, Deroux A, Guern VL, Guettrot-Imbert G, Lelong N, Pannier E, Sentilhes L, Ray CL, Seror R, Molto A; GR2 and the ENP2021 Study Groups. Evaluation of pregnancy outcomes in patients with spondyloarthritis compared to the general population: results from a French national prospective and matched study. Ann Rheum Dis. 2025 Nov 14:S0003-4967(25)04511-X. doi: 10.1016/j.ard.2025.10.024. Epub ahead of print. PMID: 41241656.
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