Increased Risk of Fetal and Maternal Morbidity in Systemic Lupus Erythematosus

Fetal morbidity and severe maternal morbidity occurred at a higher rate in patients with systemic lupus erythematosus (SLE) when compared with those without, according to a study published in Rheumatic and Musculoskeletal Diseases.¹ Investigators believe these findings can help inform and counsel this patient population prior to and during pregnancy.

Bella Mehta, MD

Credit: Hospital for Special Surgery

Maternal mortality and severe maternal morbidity are currently increasing in the United States (US), due in part to increasing rates of obesity, advanced maternal age, and comorbidities. Historically, maternal and fetal mortality are worse in women with SLE compared with women without SLE.²

“Little is known about morbidity in patients with SLE, despite evidence that maternal and fetal mortality have declined in patients with SLE,” wrote Bella Mehta, MD, rheumatologist at the Hospital for Special Surgery, and colleagues. “The primary objective of this analysis is to quantify indicators of fetal and severe maternal morbidity in patients with SLE compared with patients without SLE.”

Retrospective data from the National Inpatient Sample (NIS), which contains data on in-hospital admissions in the US, was used to identify all delivery-related hospital admissions of patients both with and without SLE between 2008 and 2017. A total of 21 indicators of severe maternal morbidity were identified using standard definitions from the Centers for Disease Control and Prevention (CDC). The fetal morbidity indicators were defined as pre-term delivery and intrauterine growth restriction (IUGR).

Of the 40,000,000 delivery-related admissions, 51,161 patients with a diagnosis of SLE were admitted. Patients with SLE were older (30.1 years vs 28.2 years, respectively), more likely to receive Medicare, (5.3% vs .7%, respectively), and were more often African American (24.7% vs 15.0%, respectively) when compared with patients without SLE. More patients with SLE were treated at an urban teaching hospital (70.5% vs 56.2%, respectively) and underwent care at a medium- or large-size hospital (90.7% vs 86.3%, respectively).

Compared with those without SLE, those with SLE had a higher risk of fetal morbidity, including IUGR (8.0% vs 2.7%, respectively) and pre-term delivery (14.5% vs 7.3%, respectively). Mothers with SLE were 4 times as likely to require a blood transfusion (4.0% vs 1.1%, respectively) or develop a cerebrovascular disorder during delivery when compared with patients without SLE.

These patients were 15 times as likely to develop acute renal failure when compared with those without SLE (1.5% vs .1%, respectively), 11 times as likely to experience cardiovascular and peripheral vascular disorders (1.1% vs .01%, respectively), and 3 times as likely to develop eclampsia or disseminated intravascular coagulation (1.2% vs .4%, respectively). Patients with SLE were also more likely to develop general medical issues (1.8% vs .5%, respectively).

Investigators noted the large number of patients, the nationwide data, and the emphasis on delivery-related events as strengths of the study. However, there is a potential for misclassified diagnoses due to the billing information and discharge diagnosis used by the NIS. This bias was reduced by using validated codes for SLE and CDC indicators of severe maternal morbidity. Further, investigators were unable to collect data for early pregnancy losses, miscarriages, and outpatient deliveries. However, as most (98.7%) of deliveries occur in hospitals, this should not be considered as an important defect.

“Our study gives population estimates of an increase in fetal and severe maternal morbidity in patients with SLE compared with those without SLE,” investigators concluded. “Despite extensive efforts over the years, there remains substantial risk for both maternal and fetal complications. This information serves to inform both patients and their doctors, promote individual level counselling, and thereby improve outcomes.”

References

1. ^{Mayo Foundation for Medical Education and Research. (2022, June 16). Polymyalgia Rheumatica. Mayo Clinic. Retrieved April 14, 2023, from https://www.mayoclinic.org/diseases-conditions/polymyalgia-rheumatica/diagnosis-treatment/drc-20376545}
2. ^{CDC. Severe maternal morbidity in the United States. reproductive health, 2021. Available: http://www.cdc.gov/reproductivehealth/maternalinfanthealth/severematernalmorbidity.htmlGoogle Scholar}