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COVID during pregnancy: Studies underscore urgency of prevention strategies

November 23, 2021

Pregnant individuals infected with COVID-19 are more likely to become severely ill, die or have a stillbirth compared with those who are not pregnant, according to three new reports.

The predominance of the delta variant in the U.S. (after June 27, 2021), exacerbated these risks, highlighting the urgency of prevention strategies including vaccination for this population.

There were 145,791 COVID-19 cases in pregnant women between Jan. 22, 2020, and Nov. 15, 2021, with 229 deaths, according to the Centers for Disease Control and Prevention (CDC) COVID Data Tracker. In September, the CDC issued an urgent health advisory calling for vaccination as soon as possible for those who are pregnant, recently pregnant, or trying to or are likely to become pregnant. Pregnant people also are included in the CDC’s clinical considerations for use of COVID-19 vaccines.

The new reports analyzed maternal or perinatal outcomes in three similar time periods. Factors such as mothers’ underlying health conditions and demographic variables also were considered. One study also looked at vaccination status.

Risk factors in Mississippi deaths

A study aimed to assess characteristics of 15 pregnant Mississippi women who died after contracting COVID-19, with consideration of the timing of infection before and during the rise of the delta variant.

There was an increase in the ratio of deaths associated with COVID-19 per 1,000 cases among pregnant women as the delta variant spread. The study described the characteristics of the women who were either pregnant — or within 90 days of the end of their pregnancy — from March 1, 2020, to Oct. 6, 2021.

None of the women were fully vaccinated. Nine were unvaccinated; five women died before vaccinations became available and one was partially vaccinated.

The median age was 30; 14 of 15 women had underlying conditions; and all had been admitted to the intensive care unit (ICU), with 14 requiring invasive mechanical ventilation. Nine of these patients were Black, three were non-Hispanic Whites and three were Hispanic women.

Seven of the women had emergency Cesarean delivery; 3 died during pregnancy and 12 died after a live birth.

The findings are published in “COVID-19–Associated Deaths After SARS-CoV-2 Infection During Pregnancy — Mississippi, March 1, 2020–October 6, 2021” (Kasehagen L, et al.  MMWR. Nov. 19, 2021).

Risk for stillbirths

Another study sought to assess whether a maternal COVID-19 diagnosis at delivery hospitalization was associated with stillbirth between March 2020 and September 2021, as well as before and during the period of the delta variant’s predominance.

Previous studies looking at whether COVID-19 during pregnancy was associated with an increased risk for stillbirths have reported mixed results.

Analysis of 1.25 million deliveries at 736 hospitals found that compared with women without COVID-19, those infected with the virus were four times as likely to have a stillbirth when delta was the predominant variant.

Vaccination status was not assessed.

The study identified the following conditions that were associated with a higher prevalence of stillbirths in women with COVID-19: chronic hypertension, multiple-gestation pregnancy, adverse cardiac event/outcome, placental abruption, sepsis, shock, acute respiratory distress syndrome, mechanical ventilation and ICU admission.

“Implementing evidence-based COVID-19 prevention strategies, including vaccination before or during pregnancy, is critical to reducing the impact of COVID-19 on stillbirths,” the authors wrote in  “Risk for Stillbirth Among Women With and Without COVID-19 at Delivery Hospitalization — United States, March 2020–September 2021” (De Sisto CL, et al, MMWR. Nov. 19, 2021).

Impact of delta variant, pregnancy status

Using a large sample size, a third study, posted as a preprint, aimed to assess risk for severe COVID-19 among women aged 15 to 44 years by pregnancy status and timing relative to the delta variant.

While noting that the overall risk for severe COVID-19 among women of reproductive age remains low; symptomatic pregnant women are at increased risk for severe outcomes compared with nonpregnant individuals. The risk increased when the delta variable became predominant, according to the report.

Delta also increased the risk for severe illness among the nonpregnant women of reproductive age.

For pregnant women with COVID-19 during the delta period, the report found the following:

  • The risk of ICU admission was 66% higher.
  • The risk of needing a ventilator or special equipment to breathe was 63% higher.
  • The risk of death was more than two times higher than in the pre-delta period.

Researchers were unable to assess the role of vaccination status in the study,  COVID-19 Severity among Women of Reproductive Age with Symptomatic Laboratory-Confirmed SARS-CoV-2 by Pregnancy Status – United States, Jan 1, 2020 – Sep 30, 2021.

The report concludes that the greatest risk for COVID-19 is currently among the unvaccinated, noting that the CDC, American College of Obstetricians and Gynecologists and Society for Maternal-Fetal Medicine recommend COVID-19 vaccination.

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