title: Pregnancy outcomes in patients with ankylosing spondylitis: a nationwide register study.
abstract: Unlike other chronic inflammatory diseases, little is known about how ankylosing spondylitis (AS) affects outcomes of pregnancy and birth characteristics.
  
  
  
  In a nationwide population-based case-control study, 388 deliveries among women with AS (identified in the Swedish National Patient Register and Medical Birth Register) and deliveries among matched controls (n=1082) from the general population were included. Information regarding pregnancies after AS diagnosis, birth outcomes and possible confounders were retrieved from the national Swedish registers. ORs with 95% CIs were calculated with generalised estimating equations.
  
  
  
  Emergency and elective Caesarean section (CS) were performed in 16.5% and 9.8% of deliveries among women with AS compared with 6.5% and 6.9%, respectively, in population controls, resulting in OR of 3.00 (95% CI 2.01 to 4.46) and 1.66 (95% CI 1.09 to 2.54), respectively. Offspring of women with AS were more often preterm (9.0% vs 4.9%) and small-for-gestational-age (SGA) (3.1% vs 1.5%), resulting in an OR of 1.92 (95% CI 1.17 to 3.15) and 2.12 (95% CI 1.00 to 4.50), respectively. Adjustment for smoking habits, age, educational level, parity and exclusion of women with comorbidities resulted in similar or only slightly lower point estimates of risk. Cases with a more extensive antirheumatic therapy exposures tended to have a higher risk for elective CS and being SGA.
  
  
  
  Women with AS had a higher prevalence for several adverse birth outcomes, with results suggesting an influence by both disease severity and comorbidities.
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
authors.forename: Gustav L
authors.initials: GL
authors.lastname: Jakobsson
authors.affiliation: Division of Obstetrics and Gynecology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Olof
authors.initials: O
authors.lastname: Stephansson
authors.affiliation: Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden Department of Rheumatology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Askling
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
authors.forename: Lennart T H
authors.initials: LT
authors.lastname: Jacobsson
mesh_terms: D001724:Birth Weight; D016022:Case-Control Studies; D002585:Cesarean Section / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000209:etiology; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D013167:Spondylitis, Ankylosing / Q000150:complications*; D013548:Sweden / Q000453:epidemiology
keywords: Ankylosing Spondylitis; Epidemiology; Spondyloarthritis