Background and Aims

To analyse complement variations during SLE pregnancies, focusing on disease flares and adverse pregnancy outcome (APO).

Methods

Retrospective analysis of 246 SLE pregnancies (172 patients, table 1) prospectively-followed in 2 Italian Centers (1987-2018). C3 and C4 normal levels were calculated in general obstetric population (GOP) as previously described¹, and related to maternal and fetal outcome.

Results

Pregnancies with flare (30) showed higher frequency of low C3 and C4 at preconception visit(T0) and of low C4 in every trimester(T1-T2-T3), as compared with pregnancies without flare. At multivariate analysis, low C4 at T0 was associated with flare (OR[95%CI]: 10.34 [2.52-42.39]; p=0.001). Fig.1 shows the variation of complement in SLE pregnancies with and without flare and in GOP. APO were recorded in 47 pregnancies (27 fetal loss: 20 early miscarriage, 7 late pregnancy loss; 11 severe preterm birth; 15 hypertensive disorder: 11 pre-eclampsia and 4 pre-eclampsia+HELLP syndrome). In pregnancies without APO, C3 increased from T0 to T3 and C4 increased from T0 to T2; in fetal death and severe preterm birth C3 and C4 did not increase; in hypertensive disorders C3 and C4 increased only between T0 and T1 (Fig.2).

Conclusions

In SLE pregnancies, monitoring of C3 and C4 is important: its failure to increase can be useful to recognize potential risk situations which deserve particular monitoring.

References ¹Reggia R. et al. Rheumatology 2012;51:2186-2190