Table 1

Demographic and clinical data of subjects

Demographics at baseline (n=35)
 Age, years (mean, SD)29.7 (2.62)
 Age>30 years, n (%)12 (34)
 Smoking status, n (%)
  Never29 (83)
  Cessation>3 years2 (6)
  Cessation<3 years3 (9)
  Current smoker1 (3)
 Profession, n (%)
  Physical labour6 (17)
  Non-physical labour27 (77)
  Unemployed/student2 (6)
Clinical characteristics at baseline (n=35)
 Weight, kg (mean, SD)68 (10.9)
 BMI, kg/m² (mean, SD)25 (3.7)
 Weight gain during pregnancy, kg (median, 95% CI)10 (9 to 10)
 HLA-B27 positivity, n (%)1 (3)
 Back pain symptoms, n (%)11 (31)
 Duration back pain, weeks (mean, SD)*13.8 (7.65)
 ≥3 months of back pain (=chronic), n (%)*8 (73)
 VAS back pain at night (median, 95% CI)*0.5 (0 to 2)
 VAS back pain day and night (median, 95% CI)*1 (1 to 3)
 Insidious onset of back pain, n (%)*9 (82)
 Back pain improvement with exercise, n (%)*9 (82)
 No improvement of back pain with rest, n (%)*3 (27)
 Nocturnal back pain, n (%)*5 (46)
 Alternating buttock pain, n (%)*3 (27)
 Morning stiffness, n (%)*1 (9)
 Inflammatory back pain (ASAS criteria), n (%)*4 (36)
 Family history of SpA, n (%)2 (6)
 Arthritis (history or current), n0
 Enthesitis (history or current), n0
 Dactylitis (history or current), n0
 Uveitis (history or current), n0
 Psoriasis (history or current), n (%)3 (9)
 Inflammatory bowel disease (history or current), n0
Current pregnancy and delivery (n=35)
 First pregnancy (G=1), n (%)18 (51)
 First delivery (P=1), n (%)22 (63)
 Duration of labour, hours (median, 95% CI)8 (6 to 12)
 Epidural anaesthesia, n (%)22 (63)
 Male newborn, n (%)17 (49)
 Weight newborn, g (mean, SD)3341 (502)
 Length newborn, cm (mean, SD)50 (2.4)
 Head circumference newborn, cm (mean, SD)34 (1.5)
  • *Only those patients with back pain were retained.

  • ASAS, Assessment of SpondyloArthritis international Society; G, gravida; P, para; SpA, spondyloarthritis; VAS, visual analogue scale.