Multiple disease-related factors may limit the number of children born to women with systemic lupus erythematosus (SLE). We calculated live births in women with SLE and compared this with general population rates.
We studied women with SLE from a subset of centers participating in the Systemic Lupus International Collaborating Clinics Prospective Inception Cohort Study of SLE. Women diagnosed as having SLE before age 50 years were included. Using age, calendar-period, and country-specific general population birth rates, we calculated the standardized incidence ratio (SIR) of observed to expected live births. We also performed a multivariate analysis with the SIR as the dependent variable to explore potential predictors of live births.
A total of 339 women with SLE were studied. The number of live births over the interval (n = 313) was substantially below that which would be expected (n = 479; SIR 0.65, 95% confidence interval [95% CI] 0.58-0.73). In the multivariate analyses, black race/ethnicity (SIR 1.47, 95% CI 1.08-2.00) and being married or living common-law (SIR 2.04, 95% CI 1.52-2.74) were associated with increased live births (relative to what would be expected). There were trends for fewer live births in women exposed to cyclophosphamide (SIR 0.88, 95% CI 0.56-1.38) and in those with high disease activity (mean SLE Disease Activity Index 2000 update score ≥5; SIR 0.82, 95% CI 0.54-1.25).
Overall, we found that women with SLE have fewer live births compared with the general population. Marital status, race/ethnicity, and possibly clinical factors may mediate this effect.