Objective: To investigate the predictive value of serum C3 and C4 complement component levels in relation to pregnancy outcome in patients with antiphospholipid syndrome (APS).
Materials and methods: 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.
Results: 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).
Conclusion: Hypocomplementemia could be considered a novel prognostic factor for pregnancy outcome in APS patients.