The majority of pregnant patients with systemic lupus erythematosus (SLE) have favorable pregnancy outcomes, with few experiencing severe flares, according to the results of the largest prospective study to date investigating pregnancy in women with SLE.
“In patients with inactive disease or stable mild or moderate activity, pregnancy is safer for mother and child than it was previously believed to be, with good outcomes in 81% of patients,” write the researchers, led by Jill P. Buyon, MD, chair of the division of rheumatology at New York University/Langone Medical Center in New York. They published their results in the June 23, 2015 Annals of Internal Medicine.
SLE primarily affects women of childbearing age, and it has been suggested that women with SLE end up with high rates of preterm birth, preeclampsia, and fetal loss.
Previous studies have identified active disease, hypocomplementemia, presence of anti-double-stranded DNA antibodies, prior nephritis, and presence of antiphospholipid antibodies (aPLs) as risk factors for adverse pregnancy outcomes (APOs).
Yet, the researchers point out that the effects of pregnancy on SLE activity and the contribution of disease activity to APOs are unclear. “Currently, patients with SLE are advised to consider pregnancy during periods of minimal and stable disease. However, data supporting this advice are based on retrospective or prospective single-center studies involving few patients, have limited generalizability to multiethnic populations, and are controversial,” they write.
They identified 385 patients, half non-Hispanic white and about one-third with prior nephritis, with SLE in the Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus (PROMISSE) study. PROMISSE is a multicenter, prospective observational study of pregnancies in women with SLE meeting a minimum of 4 revised American College of Rheumatology criteria, women with SLE and aPLs, women with aPLs alone, and healthy women at low risk for APOs.
APOs included fetal or neonatal death; birth before 36 weeks due to placental insufficiency, hypertension, or preeclampsia; and small-for-gestational-age neonate (birthweight below the fifth percentile).
Only 5% of pregnancies ended in fetal or neonatal death, and only 3% of women had severe maternal flares.
“Of note, the rate of APOs was less than 8%, with fetal or neonatal deaths accounting for fewer than half of these events in non-Hispanic white women who were lupus anticoagulant-negative, had a Physician’s Global Assessment score of 1 or lower, were not treated with anti-hypertensives, and had a platelet count of at least 100 × 109 cells/L,” they write.
Certain demographic and risk factors were significant. Non-Hispanic white race was protective. Maternal flares, higher disease activity, and smaller increases in C3 level later in pregnancy also predicted APOs.
For women who either were LAC-positive or were LAC-negative but nonwhite or Hispanic and using anti-hypertensive medications, the APO rate was 58% and fetal or neonatal mortality was 22%.
The researchers suggest that additional biomarkers should be evaluated to identify high-risk patients and define mechanisms of APOs in patients with SLE. They acknowledge that the PROMISSE study did not address first-trimester losses, and the results may not apply to women with high disease activity since they were excluded from the study.
Jane E. Salmon, Jill P. Buyon, et al. Predictors of Pregnancy Outcomes in Patients With Lupus: A Cohort Study. Annals Internal Medicine. Published online June 23, 2015 doi:10.7326/M14-2235. Abstract.