Objective: The importance of low complement and anti-dsDNA during pregnancy in patients with systemic lupus erythematosus (SLE) is poorly defined. We investigated the effect of these laboratory tests and clinical SLE activity on pregnancy outcomes.
Methods: We conducted a study of all pregnancies in patients with SLE followed from 1986 to 2002 in a cohort of patients with SLE. At each visit, the physician's estimate of activity (PEA), complement, and anti-dsDNA antibody were measured. We assessed the combination of moderate to severe SLE clinical activity (defined as PEA ≥ 2) and these serologic measurements on pregnancy outcomes. Pregnancies electively terminated were excluded from our study.
Results: Regardless of SLE activity, low complement or positive anti-dsDNA in the second trimester was associated with a higher rate of pregnancy loss and preterm birth. Patients with the combination of either high clinical activity of SLE and low complement or positive anti-dsDNA had the highest rate of pregnancy loss and preterm birth.
Conclusion: Women with the combination of high clinical activity with serologic markers of SLE activity are at highest risk for pregnancy loss and preterm delivery. While hypocomplementemia and positive anti-dsDNA alone are predictive of poor pregnancy outcomes in the second trimester, the risks are far higher for the women in whom this is coupled with clinically active SLE.