Pregnancy outcomes in women with systemic lupus erythematosus were better than expected in the largest study of the issue to date, according to a report published online June 22 in Annals of Internal Medicine.

Until now, research examining pregnancy outcomes in systemic lupus erythematosus (SLE) has comprised retrospective or single-center studies with few patients. These studies have failed to include women of diverse ethnic backgrounds and have drawn “controversial” conclusions, Dr. Jill P. Buyon of New York University/Langone Medical Center, New York, and her associates wrote in their report.

Dr. Buyon and her colleagues examined pregnancy outcomes in SLE by analyzing data in the prospective PROMISSE (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and SLE) study. They focused on 385 women who conceived singleton pregnancies while their SLE was inactive or mildly to moderately active during the 8-year study period. The women (48% non-Hispanic white, 15% Hispanic white, 20% African American, 11% Asian American, 3% other, and 3% unknown ethnicity) were enrolled after attaining at least 12 weeks’ gestation, and were followed at eight sites in the United States and one in Canada.

The adverse outcomes of interest in this study were fetal or neonatal death; birth before 36 weeks due to placental insufficiency, maternal hypertension, or preeclampsia; and small-for-gestational-age neonates. Overall, 81% of these pregnancies had none of these complications, and 3% of the women experienced severe SLE flares during pregnancy. “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,” the investigators wrote (Ann. Intern, Med. 2015 June 22 [ doi:10.7326/M14-2235 ]).

One or more adverse outcomes occurred in 19% of the pregnancies, including fetal death (4%), neonatal death (1%), preterm delivery due to placental insufficiency or preeclampsia (9%), and small-for-gestational-age neonates (10%). The rate of adverse pregnancy outcomes was highest among both African Americans and Hispanic whites (26% in each), followed by non-Hispanic whites (15%) and Asian Americans (14%).

Risk factors that predicted adverse pregnancy outcomes included nonwhite ethnicity, the presence of antiphospholipid antibodies, the presence of lupus anticoagulant, higher scores on the Physician’s Global Assessment (PGA) or Systemic Lupus Erythematosus Pregnancy Disease Activity Index, the use of antihypertensive drugs, a low platelet count, and the development of a severe SLE flare during pregnancy.

The rate of adverse pregnancy outcomes was remarkably low – less than 8% – in the large subgroup of women at lowest risk for adverse pregnancy outcomes, which includes those who were white, negative for lupus anticoagulant, had a PGA score of 1 or lower, were not taking antihypertensive medication, had adequate platelet counts, and did not experience a severe SLE flare during the pregnancy, Dr. Buyon and her associates added.

The National Institute of Arthritis and Musculoskeletal and Skin Diseases, the National Institutes of Health, the Mary Kirkland Center for Lupus Research, and Rheuminations supported the study. Dr. Buyon and her associates reported having no conflicts of interest.