Pregnancy outcome of systemic lupus erythematosus in relation to lupus activity before and during pregnancy

Background: To analyze the pregnancy complications and pregnancy outcome relating to the disease activity of systemic lupus erythematosus before conception and during pregnancy.

Methods: Seventy-two pregnancies were collected in a single tertiary medical center within a 5-year period. Twelve pregnancies were terminated due to various causes in the first half of pregnancy. Analysis of pregnancy complications and pregnancy outcome relating to the lupus activity before conception and during pregnancy was made among the remaining 60 pregnancies with gestational length > 26 weeks. The assessment of lupus activity was based on the routine monitoring, including urine routine, white blood cell count, hemoglobin and platelet count, erythrocyte sediment rate, serum titers of C3, C4, and double-stranded DNA. Monitoring of renal function with daily urinary protein loss and clearance rate of creatinine was needed when worsened nephropathy was suspected.

Results: The etiologies of the terminated pregnancies were deteriorated nephropathy (6 cases), involvement of central nervous system (1 case), unwanted pregnancy due to drug exposure (3 cases), and two early intrauterine fetal deaths (both during the 23(rd) week of gestation). Pregnancy complications were related to the lupus activity before conception [odds ratio = 0.238, 95% confidence interval (CI) = 0.073, 0.778, p = 0.014] and during pregnancy (odds ratio = 0.153, 95% CI = 0.031, 0.754, p = 0.012). Meanwhile, pregnancy outcome significantly related to the lupus activity of the preconception period and during pregnancy. The gestational length was significantly longer in the pregnancies with remitted lupus activity either before conception (38.2 ± 1.6 weeks vs. 36.3 ± 3.4 weeks, p = 0.011 and 95% CI = -3.454, -0.478) or during pregnancy (38.2 ± 1.6 weeks vs. 35.2 ± 3.8 weeks, p = 0.005 and with 95% CI = -4.988, -1.005). Significant relationships were also found between newborn birth weights and lupus activity preconceptionally (2940 ± 389 g vs. 2448 ± 674 g, p = 0.002 and 95% CI = -792, -192) and after having conceived (2960 ± 383 g vs. 2136 ± 585 g, p < 0.001 and 95% CI = -1081, -568). Multivariate analysis showed that lupus remission during pregnancy was correlated with a significantly longer gestation, since pregnant women with active lupus had a three-fold greater risk of preterm deliveries (hazard ratio = 3.022, 95% CI = 1.261, 7.242) compared with pregnant women without active lupus.

Conclusion: In order to reduce the incidence of pregnancy complication, especially preterm delivery, and to gain good pregnancy outcome, good preparation before conception and good control of the disease during pregnancy are mandatory.