based on data from two studies published in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report.
In a study of birth and infant outcomes, rates of preterm birth (less than 37 weeks’ gestational age) were higher among women with confirmed SARS-CoV-2 infections compared with the national average (12.9% vs. 10.2%) wrote Kate R. Woodworth, MD, and colleagues of the CDC COVID-19 Response Pregnancy and Linked Outcomes Team.
The researchers collected information on pregnancy and infant outcomes from 16 jurisdictions through the Surveillance for Emerging Threats to Mothers and Babies Network (SET-NET). The study included 5,252 women with laboratory-confirmed SARS-CoV-2 infection reported during March 29–Oct. 14, 2020.
Overall, 12.9% of the 3,912 live births with known gestational age were preterm. A total of 610 infants were tested for SARS-CoV-2, and 2.6% were positive. Most of these perinatal infections (85%) occurred among infants born to women with SARS-CoV-2 infection within 1 week of delivery.
Half of the infants with positive test results were preterm, possibly reflecting higher screening rates in the ICU, the researchers said. “These findings also support the growing evidence that although severe COVID-19 does occur in neonates the majority of term neonates experience asymptomatic infection or mild disease; however, information on long term outcomes among exposed infants is unknown.”
Address disparities that amplify risk
The study findings were limited by several factors including inconsistent symptom reporting, overrepresentation of Hispanic women, and incomplete information on pregnancy loss, Dr. Woodworth and associates noted. However, the results add to the knowledge about the impact of COVID-19 disease on pregnancy by providing a large, population-based cohort with completed pregnancy outcomes as well as infant testing.
“SET-NET will continue to follow pregnancies affected by SARS-CoV-2 through completion of pregnancy and infants until age 6 months to guide clinical and public health practice,” the researchers noted. “Longer-term investigation into solutions to alleviate underlying inequities in social determinants of health associated with disparities in maternal morbidity, mortality, and adverse pregnancy outcomes, and effectively addressing these inequities, could reduce the prevalence of conditions and experiences that might amplify risks from COVID-19,” they added.
Severe disease and death increased in pregnant women
In a second study published in the MMWR, Laura D. Zambrano, PhD, and colleagues, also of the CDC COVID-19 Response Pregnancy and Linked Outcomes Team, compared data on 23,434 reportedly pregnant and 386,028 nonpregnant women of reproductive age (15-44 years) with confirmed and symptomatic SARS-CoV-2 infections reported to the CDC between Jan. 22, 2020, and Oct. 3, 2020.
After adjustment for age, race, and underlying medical conditions, pregnant women with COVID-19 disease were significantly more likely than were nonpregnant women to be admitted to intensive care (10.5 per 1,000 cases vs. 3.9 per 1,000 cases), to receive invasive ventilation (2.9 vs. 1.1), receive extracorporeal membrane oxygenation (0.7 vs. 0.3) and to die (1.5 vs. 1.2).
“Irrespective of pregnancy status, ICU admissions, receipt of invasive ventilation, and death occurred more often among women aged 35-44 years than among those aged 15-24 years,” Dr. Zambrano and associates noted. In addition, non-Hispanic Black and Black women comprised 14.1% of the study population but accounted for 36.6% of deaths overall (9 in pregnant women and 167 in nonpregnant women).
The findings in the study of characteristics were limited by several factors including the voluntary reporting of COVID-19 cases, potential reporting bias, and inadequate time to assess severe cases, the researchers noted. However, “data from previous influenza pandemics, including 2009 H1N1, have shown that pregnant women are at increased risk for severe outcomes including death and the absolute risks for severe outcomes were higher than in this study of COVID-19 during pregnancy.”
“Pregnant women should be informed of their risk for severe COVID-19–associated illness and the warning signs of severe COVID-19,” Dr. Zambrano and associates said. “Providers who care for pregnant women should be familiar with guidelines for medical management of COVID-19, including considerations for management of COVID-19 in pregnancy.”