Active Lupus Nephritis Raises Fetal Loss, Pregnancy Complication Risks

Poor pregnancy outcomes were more common in Black women, study showed

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Active lupus nephritis — kidney inflammation as a result of lupus — is associated with a much higher risk of pregnancy complications, such as fetal loss and preeclampsia, according to a new analysis.

The study also showed pregnancy complications are more common in Black women with lupus than among their white peers.

“Our results support previous studies demonstrating active nephritis is a risk factor for adverse pregnancy outcomes among women with [lupus],” the researchers wrote.

The findings were detailed in the study, “The association of lupus nephritis with adverse pregnancy outcomes among women with lupus in North America,” published in Lupus.

Lupus nephritis is a common and serious complication of systemic lupus erythematosus (SLE), the most common form of the condition. Both have been linked to an increased risk of complications during pregnancy, though most studies assessing these connections have been done at single centers with relatively homogeneous patient populations.

Scientists in the U.S. and Canada analyzed data pooled from three groups of women with SLE who were treated during pregnancy at centers in North America from 1995 to 2015. One group was from Duke University, one from Johns Hopkins University, and a third from the University of Toronto.

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The analysis included data from 393 pregnant women with SLE who had a mean age of 30.6 years at the time of delivery. About two-thirds were white, the remaining 38% were Black. Most received some form of immune-suppressing therapy to manage their condition during their pregnancy.

“A strength of this study is the high proportion of Black pregnant women with SLE, a group that is often under-represented in clinical research,” the scientists wrote.

More than one in three (37%) women had a history of lupus nephritis, though only 8% had active lupus nephritis during pregnancy. The condition was more common in Black women than in white women.

Poor pregnancy outcomes

Adverse pregnancy outcomes of any kind were very common and were reported in nearly half (43%) the women. Specifically, 13% had fetal loss, 26% had a preterm birth, and 14% developed preeclampsia, a condition marked by high blood pressure during pregnancy.

While rates of preterm birth, preeclampsia, and overall poor pregnancy outcomes were more common in Black women, rates of fetal loss were similar in Black and white women.

“Our results are consistent with previous studies that demonstrate a disproportionate amount of Black and Hispanic women with LN and higher disease severity compared to White women,” the researchers wrote. “Our study provides additional insight regarding race and adverse pregnancy outcomes, though we do not have complete data on the other social determinants of health that could be modifying the risk posed by race,” they wrote.

Further studies in nonwhite populations are needed to better understand why poor pregnancy outcomes occur in women of color and what can be done to address them, the researchers said.

Women with a history of lupus nephritis were nearly twice as likely to experience fetal loss, preterm birth, or preeclampsia, statistical models showed.

“Much of this increase in adverse outcomes, however, was due to very high rates of complications in women with active [lupus nephritis], not inactive [lupus nephritis],” the researchers wrote.

Among women with active lupus nephritis, the risk of fetal loss was increased by more than six times and the overall risk of pregnancy outcomes was more than three times higher compared with women without a history of lupus nephritis. There was no increased risk of adverse pregnancy outcomes among women with inactive lupus nephritis, however.

Researchers also called for more studies to understand the causes of these discrepancies and to develop strategies to improve pregnancy outcomes for people with SLE.