Study: COVID-19 During Pregnancy Associated With Preterm Birth

Among those who had hypertension, diabetes, and/or obesity as well as COVID-19, the risk rose to 160%.

A study by researchers at University of California San Francisco (UCSF) found that individuals who contract COVID-19 while pregnant face a higher risk of having a very preterm birth and any other preterm birth.

The paper highlighted that the risk of very preterm birth, which occurs at less than 32 weeks of gestation, was 60% higher for people infected with COVID-19 at some point during their pregnancy. Meanwhile, the risk of giving birth at less than 37 weeks was 40% higher in those with infection, according to the study. Among those who had hypertension, diabetes, and/or obesity as well as COVID-19, the risk rose to 160%.

“Preterm birth is associated with many challenging outcomes for pregnant people and babies, and very preterm births carry the highest risk of infant complications,” said lead and corresponding author Deborah Karasek, PhD, researcher with the California Preterm Birth Initiative at UCSF, in a press release. “Our results point to the importance of preventative measures to reduce COVID-19 infection among pregnant people to prevent preterm birth, including vaccination. Pregnant people may have concerns about vaccines and the health of their baby, so being able to have an open dialogue that values those concerns, describes evidence about safety, and conveys the risks posed by COVID-19 infection during pregnancy is critically important.”

The study was the first to identify the risks of COVID-19 by specific subtype of preterm birth, as well as race, ethnicity, and insurance status, according to the authors. The data revealed existing disparities in preterm birth rates for Black, Indigenous, and other people of color compared to whites. Disproportionately higher COVID-19 rates during pregnancy were seen in Latinx, American Indian/Alaska Native, Native Hawaiian/Pacific Islander people, and people with public insurance.

“Given that the burden of COVID-19 is greater in these populations, as is the burden of pre-term birth, it really points to the need for an equity approach,” Karasek said in a press release. “With the surge in infections and increase in the Delta variant, we must think about pregnant people, especially Black and Brown populations, as the groups that need to be prioritized, with supportive policies to reduce exposure and stress, and increase access to care.”

All live births between July 2020 and January 2021 were analyzed and documented by California Vital Statistics birth certificates. Out of the 240,157 recorded births, approximately 3.7% indicated a COVID-19 diagnosis in pregnancy. The preterm birth rate among birthing people with a COVID-19 diagnosis was 11.8% compared with 8.7% among those without COVID-19, according to a press release.

The sample included 47.2% Latinx, 26.8% white, 4.9% Black, 13.2% Asian, 0.03% American Indian/Alaskan Native, 0.4% Hawaiian/Pacific Islander, and 7.3% identified as other, unknown, or 2 or more races. Further, 40% of people in the study had public insurance at the time they gave birth, whereas 15.9% had hypertension, diabetes, obesity, or a combination.

Comorbidities along with COVID-19 infection increased the risk of preterm birth, and individuals with hypertension, diabetes, and/or obesity, as well as COVID-19 diagnosis, had a 160% higher risk of very preterm birth and a 100% higher risk of preterm birth compared to those without comorbidities or COVID-19, according to the study.

The research team found that preterm birth rates did not vary by whether the births were spontaneous or medically indicated, which may direct multiple pathways between COVID-19 diagnosis and preterm birth, according to Karasek.

There were limitations with the study, such as not being able to determine when during pregnancy the individuals contracted COVID-19 and how serious the infections were.

REFERENCE

COVID-19 during pregnancy associated with preterm birth. UCSF. August 9, 2021. Accessed August 10, 2021. https://www.ucsf.edu/news/2021/08/421181/covid-19-during-pregnancy-associated-preterm-birth