Complementemia and obstetric outcome in pregnancy with antiphospholipid syndrome

To investigate the predictive value of serum C3 and C4 complement component levels in relation to pregnancy outcome in patients with antiphospholipid syndrome (APS).

A prospective study of 47 pregnancies associated with APS was performed. Pregnancy outcome was analyzed in terms of: fetal loss, preterm delivery (≤34 gestational weeks), fetal intrauterine growth restriction (IUGR), birth weight <2500 g and preeclampsia. Week at delivery, neonatal birth weight and neonatal birth weight percentile were also investigated. Hypocomplementemia, positivity for anti-dsDNA and triple positivity for antiphospholipid antibodies (aPL) were related to pregnancy outcome.

Forty-three pregnancies ended in live births with a fetal loss rate of 8.5%. Fetal death, preterm delivery and birth weight <2500 g were associated with hypocomplementemia (p = 0.019, p = 0.0002, p < 0.0001 respectively). Lower neonatal birth weight, lower neonatal birth weight percentile and lower week at delivery were associated with hypocomplementemia (p < 0.0001, p = 0.0003, p < 0.0001 respectively) and with triple aPL positivity (p = 0.008, p = 0.014, p = 0.03 respectively). A poor pregnancy outcome was confirmed among primary APS (PAPS) pregnancies with hypocomplementemia. Multivariate analysis confirmed that hypocomplementemia was an independent predictor of lower neonatal birth weight (p = 0.0001) and lower week at delivery (p = 0.002).

Hypocomplementemia could be considered a novel prognostic factor for pregnancy outcome in APS patients.