Introduction/objectives: The pregnancy rate in systemic lupus erythematosus (SLE) is not fully understood and comparisons of adverse pregnancy outcomes (APOs) with SLE versus the general population are limited. This study aimed to estimate the pregnancy rate and APOs in Korean SLE compared to those without SLE.
Method: Pregnant women were identified using the ICD-10 codes for delivery and abortion in the Korean national health claims database (2013-2015). APOs were classified as fetal loss, intrauterine growth retardation (IUGR), pre-eclampsia/eclampsia, and gestational diabetes. Annual incidence rates (IRs) of pregnancy and APOs were calculated in women with SLE and the general population without SLE and the two groups were compared using age-adjusted incidence rate ratios (IRRs). Age-stratified IRRs were further analyzed.
Results: The annual IRs of pregnancy in SLE were 29.54-30.70 per 1000 persons. The IRRs were lower in women with SLE than in the general population: 0.68 (0.61-0.76), 0.66 (0.60-0.74), and 0.74 (0.66-0.82) in each respective year. The IRRs of fetal loss, IUGR, and pre-eclampsia/eclampsia were 1.30 (1.14-1.49), 4.65 (3.55-6.09), and 3.43 (2.70-4.36), respectively. However, the IRR of gestational diabetes in SLE did not significantly differ from that of women without SLE. Among the APOs, fetal loss, IUGR, and pre-eclampsia/eclampsia showed decreasing tendencies as age increased.
Conclusions: Pregnancy rates in SLE were approximately 30% lower than those in the general population. Except for gestational diabetes, fetal loss, IUGR, and pre-eclampsia/eclampsia were higher in SLE and showed a decreasing tendency with age. Key Points • This population-based cohort study showed that pregnancy rates in SLE were approximately 30% lower than those in the general population. • SLE had a 1.3-fold higher rate of fetal loss, more than 4-fold higher IUGR rate, and more than 3-fold pre-eclampsia or eclampsia rate compared with the general population. • Adverse pregnancy outcomes in SLE showed a decreasing tendency with age.
Keywords: Adverse pregnancy outcomes; Claims; Pregnancy rate; Systemic lupus erythematosus.