Table 3

Risk factors of pregnancy-related attack using univariate and multivariate Poisson regression

Variable
(number of pregnancies)		Univariate analysisMultivariate analysis
OR (95% CI)P valueOR (95% CI)P value
Age at disease onset (76)0.97 (0.94–1.00)0.045*—0.787
Age at delivery/abortion
 33–40 (12)1.001.00
 26.5–33 (39)12.62 (1.89–84.10)0.009**10.17 (1.55–66.62)0.016*
 20–26.5 (25)12.96 (1.93–87.01)0.008**8.45 (1.26–56.71)0.028*
Time interval from disease onset to pregnancy (76)1.01 (0.96–1.07)0.573——
Time interval from last attack to pregnancy (76)1.00 (1.00–1.01)0.253——
Treatment during pregnancy and after delivery/abortion
 Adequate treatment† (10)1.001.00
 Inadequate treatment‡ (66)5.07 (1.44–17.89)0.011*4.32 (1.34–13.94)0.014*
AQP4-ab titre
 <1:100 or negative (45)1.001.00
 ≥1:100 (31)1.89 (1.22–2.91)0.004**1.56 (1.03–2.37)0.036*
Relapse within 1 year before pregnancy
 No (58)1.00
 Yes (18)0.75 (0.39–1.42)0.376——
ARR before pregnancy (76)0.70 (0.41–1.20)0.198——
EDSS score before pregnancy (76)0.99 (0.82–1.20)0.952——
Counts of concomitant auto-antibodies§
 <1 (42)1.00
 ≥1 (34)1.13 (0.72–1.79)0.593——
Counts of concomitant auto-antibodies§
 <2 (51)1.00
 ≥2 (25)1.16 (0.71–1.90)0.558——

  • *P<0.05; **p<0.01.

  • †Adequate treatment was defined as (1) usage of relatively higher dose oral prednisone (>10 mg/day), (2) usage of immunosuppressant (azathioprine 100 mg/day or tacrolimus 3 mg/day) combined with or without oral steroid, (3) a dose of rituximab (375 mg/m2) within 6 months before conception and shortly after delivery.

  • ‡Inadequate treatment referred to (1) no treatment at all, (2) usage of low-dose oral prednisone (≤10 mg/day) as single therapy.

  • §Including antinuclear antibody, extractable nuclear antigen antibody, double-stranded DNA antibody, antineutrophil cytoplasmic antibody, anticardiolipin antibody, thyroid peroxidase antibody and thyroglobulin antibody.

  • AQP4-ab, aquaporin-4 antibody; ARR, annualised relapse rate; EDSS, Expanded Disability Status Scale.