The Clinical Utility of Measuring Complement and Anti-dsDNA Antibodies During Pregnancy in Patients with Systemic Lupus Erythematosus

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.