Predictive factors of fetal and maternal pregnancy outcomes in Japanese patients with systemic lupus erythematosus

Objective The number of pregnant and delivery cases in systemic lupus erythematosus (SLE) patients are increasing due to the advances in therapies. However, there are many problems such as the exacerbation of SLE during pregnancy and the risk of fetal complications. We investigated the impact of both pregnancy on lupus and lupus on pregnancy in Japanese patients. Methods We retrospectively analyzed 64 pregnancies in 39 cases of lupus patients at Kyushu University Hospital, Japan, from October 2002 to July 2018 and then assessed the clinical profiles and maternal and fetal outcomes. Results In terms of the impact of pregnancy on SLE, 29.7% of patients had lupus flare during pregnancy. Multivariate analysis showed that flare rates were significantly higher in patients who discontinued the immunosuppressants when pregnancy was detected or before pregnancy. Pregnancy results were 25.0% for preterm birth, 39.1% for low birth weight infants, and 31.3% for small-for-gestational-age infants. Regarding the effect of SLE on fetal death, the rates of stillbirth were significantly higher in cases whose C3 value at 12 weeks of gestation was lower than before conception. Preterm birth was associated with disease duration and lupus flare during pregnancy. Conclusions Discontinuation of immunosuppressive drugs was a predictive factor for lupus flare during pregnancy. Further, the decrease of C3 levels at 12 weeks of gestation from baseline was a predictive factor for fetal loss. It is essential for lupus pregnant patients to prevent flares, even with the use of immunosuppressive medications.