WASHINGTON – Women with systemic lupus erythematosus are nine times more likely to develop early-onset preeclampsia during a first pregnancy than are women without the disease, according a study of two Swedish national population-based registries.
The risk of preeclampsia occurring before 34 weeks’ gestation declined with subsequent pregnancies, but it remained significantly elevated above the background risk, Julia F. Simard, ScD, said at the annual meeting of the American College of Rheumatology.
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During the study period, 742 births to women with SLE were matched with 10,484 births to women without the disease. The mean age of the patients was 31 years.
Of the women with SLE, 5% had pregestational hypertension and 3% had pregestational diabetes. Antiphospholipid antibodies were present in 2%. Among the controls, less than 1% had pregestational hypertension, and 1.3% had pregestational diabetes. There were no healthy controls with antiphospholipid antibodies.
In the entire cohort, there were 438 cases of preeclampsia: 82 in the SLE group and 356 in the control group. In the fully adjusted model, this translated to nearly a tripling of relative risk (RR, 2.7).
Preeclampsia more commonly occurred in first births, based on 56 cases in the SLE group and 225 in the control group. SLE patients in their first pregnancy also had a tripling of risk (RR, 3.2). Among subsequent births, there were 157 cases: 26 in the SLE group and 131 in the control group. The relative risk for preeclampsia was lower, but still significantly elevated (RR, 2).
There were 87 cases of early-onset preeclampsia: 32 in the SLE group and 55 in the control group. Women with SLE were more than six times more likely to develop the disorder (RR, 6.3). Early-onset preeclampsia was more common in first births for both groups: 24 in the SLE group and 34 in the control group, for a ninefold increased risk (RR, 9.3).
Again, the incidence decreased with subsequent births in both groups: 8 cases in the SLE group and 21 in the control group. But SLE patients still faced a significant threefold increase in risk (RR, 2.8).
“Antiphospholipid antibodies appear to be an important risk factor that needs to more fully understood,” Dr. Simard said. “But the risk seems to be independent of other traditional risk factors, like pregestational hypertension, body mass index, and smoking.”
She and her associates had no financial disclosures.
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