by British Medical Journal

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Mothers with the long term autoimmune disorder, systemic lupus erythematosus, or SLE for short, run more than double the risk of giving birth to a premature or growth-restricted baby, finds a 10-year nationwide audit of hospital admissions records in the US and published online in the open access journal RMD Open.

And these mothers are nearly 4 times as likely to need a blood transfusion and 15 times as likely to develop kidney failure during delivery as mothers without the condition, the audit shows.

Rates of death and serious illness among new mothers are increasing in the U.S., likely due to rising rates of obesity, underlying conditions, and older age at motherhood, say the researchers.

But despite evidence that maternal and fetal deaths have fallen among women with SLE, it's not clear if rates of severe illness have also fallen in comparison with women without the condition.

In a bid to find out, the researchers drew on data from the National Inpatient Sample (NIS) for the period 2008 to 2017. The NIS is the largest publicly available inpatient database in the U.S. and contains information on more than 7 million hospital stays every year, representative of more than 35 million admissions.

Between 2008 and 2017 an estimated 51,161 (based on unweighted numbers of 10,297) pregnant women with SLE were admitted to hospital to deliver their babies.

Women with SLE tended to be older (30 vs 28), of African American race (25% vs 15%), and more likely to receive Medicare (5% vs nearly 1%) than women without the condition.

Most were treated at an urban teaching hospital and were cared for at a medium or large sized hospital. And significantly more of them had co-existing conditions, as measured by the Elixhauser Comorbidity Index (45.5% vs 4%).

Pregnant women with SLE were more than 3 times as likely to have eclampsia or abnormal blood clotting throughout the body's blood vessels (disseminated intravascular coagulation), and more likely to have general medical issues. And they were 11 times more likely to have cardiovascular and peripheral vascular disorders.

During delivery, they were about 15 times as likely to have acute renal failure, and 4 times as likely to need a blood transfusion or have cerebrovascular disorders.

Their babies were also more likely to be growth-restricted (8% vs nearly 3%) and to be born premature (14.5% vs 7%) than those of mothers without SLE.

"Despite extensive efforts over the years, there remains substantial risk for both maternal and fetal complications," say the researchers.

They conclude, "Our study demonstrates that fetal morbidity and severe maternal morbidity occur at a higher rate in patients with SLE compared with those without. This quantitative work can help inform and counsel patients with SLE during pregnancy and planning."

More information: Fetal and maternal morbidity in pregnant patients with Lupus: a 10-year US nationwide analysis, RMD Open (2023). DOI: 10.1136/rmdopen-2022-002752

Provided by British Medical Journal