Women with lupus nephritis — an inflammation of the kidneys caused by lupus — are at increased risk for problem pregnancies, compared to those with systemic lupus erythematosus alone, a new study shows.
The study, “Management and outcomes of pregnancy with or without lupus nephritis: a systematic review and meta-analysis,” was published in the journal Therapeutics and Clinical Risk Management.
It is well known that systemic lupus erythematosus (SLE) negatively affects pregnancy outcomes. However, it is not fully known whether lupus nephritis affects prenatal management and pregnancy outcomes.
One previous study has shown that lupus nephritis is a risk factor for pregnancy loss, particularly in patients with renal impairment. However, no systematic review has been undertaken to answer this question.
So, researchers conducted a systematic review and meta-analysis (an analysis that combines the results of multiple scientific studies) to determine if diagnosis of lupus nephritis correlates with pregnancy outcomes in SLE patients.
Looking at three databases, researchers found 16 relevant studies that compared management and pregnancy outcomes in pregnant SLE patients, with or without lupus nephritis.
Compared to patients without lupus nephritis, those with the condition were 5.7 times more likely to develop gestational hypertension (high blood pressure), and 2.8 times more likely to have preeclampsia (high blood pressure and signs of damage to the liver or kidneys).
Their chances of having SLE flares also were 2.7 times higher compared to patients without lupus nephritis. For renal flares, the risk was 15.2-fold higher. Also, excess protein level in urine — indicating impaired kidney function — was 8.9 times more likely in these patients.
Patients with lupus nephritis also were 2.9 times more likely to have low levels of complement proteins.
The complement system is a part of the immune system that plays a role in the normal development of the placenta and fetus. Low levels of these proteins are linked to nearly one in five pregnancy losses in the first trimester.
Anti-Sjögren’s syndrome-related antigen A/Ro autoantibodies previously have been related to miscarriages and loss of pregnancy. Interestingly, investigators found that pregnant women with lupus nephritis had a lower risk of developing these autoantibodies.
Researchers also showed that pregnant women with lupus nephritis experienced a significant decrease in live births — 38 percent lower than those without lupus nephritis. In addition, preterm births and restriction of fetal growth were more likely to happen in those with the kidney condition.
Regarding prenatal management and pharmacological treatment, pregnant patients with lupus nephritis were treated more often with immunosuppressants and steroids.
“In patients with SLE, [lupus nephritis] increased the risks for adverse pregnancy outcomes and the use of medication. Therefore, special treatment and close monitoring should be allocated to pregnant women with LN.”