A retrospective cohort study published in JAMA found that pregnant and postpartum women with SARS-CoV-2 infection were at a significantly increased risk of maternal mortality or serious morbidity from common obstetric complications.
The authors are clinicians and investigators from the Maternal-Fetal Medicine Units Network, which was created by the National Institute of Child Health and Human Development (NICHD) in 1986.
“We became concerned about the possibility of increased morbidity in patients who acquired the SARS-CoV-2 virus in pregnancy early in the pandemic, due to all the changes in healthcare delivery and delays in presentation to care that we were observing in our practices,” said principal investigator Torri Metz, MD, an associate professor of ob-gyn and vice chair of ob-gyn research at University of Utah Health in Salt Lake City.
The study comprised 14104 pregnant and postpartum patients, mean age 29.7 years, who delivered from March 2020 to December 2020 at 17 U.S. hospitals participating in the NICHD’s Gestational Research Assessments of COVID-19 study.
Overall, 2352 of the included patients tested positive for SARS-CoV-2 infection, based on a positive nucleic acid or antigen test result. The remaining 11752 patients did not have a positive SARS-CoV-2 test and delivered at the same hospitals on randomly selected days.
Among those who were SARS-CoV-2 positive in pregnancy, 80.1% tested positive in the third trimester, 17.6% in the second trimester and 2.3% in the first trimester.
Among the 4.4% of patients who had their first positive test result postpartum, the median timing was 18 days after delivery; only 2.47% tested positive more than 2 weeks after delivery.
The primary outcome was a composite of maternal death or serious morbidity linked to hypertensive disorders of pregnancy, postpartum hemorrhage, or infection other than SARS-CoV-2.
SARS-CoV-2 infection was significantly connected to the primary outcome: 13.4% vs 9.2% for those patients without a positive test result.
All five maternal deaths were in the SARS-CoV-2 group; however, the infection was not significantly associated with the major secondary outcome of cesarean birth: 34.7% vs 32.4%, respectively.
On the other hand, moderate or higher COVID-19 severity was significantly linked to the primary outcome: 26.1% vs 9.2% for patients without a positive test result.
There was also a significant link between infection and cesarean birth among those with moderate or higher COVID-19 severity: 45.4% vs 32.4%, respectively.
But mild or asymptomatic infection was not significantly associated with either the primary outcome or cesarean birth.
“It was surprising to see such a pronounced impact on maternal morbidity and mortality among those with moderate or higher COVID-19 severity,” Metz told Contemporary OB/GYN®. “This could be related to either the effects of the virus itself or to the changes in health care delivery during the time period, or both.”
Metz said study data can be used to counsel pregnant individuals about the risks of SARS-CoV-2 in pregnancy, especially among those with moderate or higher disease severity. “We know that vaccination helps prevent higher severity infections, so these data can also be used to help encourage pregnant people to get vaccinated,” she said.
The authors anticipate that going forward there will be differential effects from different variants of SARS-CoV-2, which will be important to research.
“It will also be valuable to determine if there are long-term ramifications for the mother and offspring with SARS-CoV-2 infection during pregnancy,” said Metz, who noted that MFMU has secured grant funding from the National Heart, Lung, and Blood Institute for such a study.
Metz is a site principal investigator and medical advisory board member for a Pfizer study on SARS-CoV-2 vaccination in pregnancy.