(CNN) – Pregnant women may be at an increased risk for severe illness from Covid-19 compared with women who are not expecting, according to a new report from the US Centers for Disease Control and Prevention.
Pregnant women who get infected are more likely to be hospitalized, admitted to an intensive care unit and put on a ventilator, the CDC said in its weekly report on Thursday.
The CDC previously has said on its website: "Although there are currently no data showing that COVID-19 affects pregnant people differently than others, we do know that pregnant people are at greater risk of getting sick from other respiratory viruses than people who are not pregnant."
Now the new MMWR report has provided data, but there are some important limitations.
CDC researcher: ‘Pregnant women were 50% more likely to be admitted to the intensive care unit’
The study included information on 326,335 women ages 15 to 44 who tested positive for the coronavirus.
"This new report includes the largest US cohort of pregnant women with lab-confirmed SARS-CoV-2 infection," Sara Oliver of the CDC's National Center for Immunization and Respiratory Diseases said during a meeting of the Advisory Committee on Immunization Practices on Wednesday.
Data on the women were reported to the CDC between January 22 and June 7 either electronically using a case report form or through the National Notifiable Diseases Surveillance System as part of nationwide Covid-19 surveillance efforts.
What is not clear is whether the pregnant women were hospitalized because of complications related to their coronavirus infections or if they were hospitalized for pregnancy-related reasons and just happened to also have coronavirus.
When it came to Covid-19 symptoms, the experiences were similar among the pregnant and nonpregnant women -- cough and shortness of breath -- but pregnant women less frequently reported headache, muscle aches, fever, chills and diarrhea than did nonpregnant women.
However, more than 31% of pregnant women who caught coronavirus were hospitalized, compared to 5.8% of nonpregnant women, the report found.
"Pregnant women were 50% more likely to be admitted to the intensive care unit and 70% more likely to receive mechanical ventilation," Oliver said in her presentation. "Sixteen deaths were reported among pregnant women, in a similar proportion to nonpregnant women."
Specifically, pregnant women were admitted more frequently to the intensive care unit, at 1.5%, than nonpregnant women, at 0.9%.
Similarly, 0.5% of pregnant women required mechanical ventilation compared with 0.3% of nonpregnant women, according to the report.
Among both pregnant and nonpregnant women, about 0.2% died.
The data also showed racial disparities among pregnant women with coronavirus infection: 46% were Hispanic, 22% were Black and 23% were White. The researchers noted that those proportions differ from pregnancy data from 2019, showing that among women who gave birth last year, 24% were Hispanic, 15% were Black and 51% were White.
This suggests Black and Hispanic women are more likely to be hospitalized with coronavirus, something that has been seen in other research.
Houston responds to report
According to Dr. Kjersti Aagaard, a professor at Texas Children’s Hospital and Baylor College of Medicine, the results support what health professionals already suspected.
“We don’t want pregnant women getting infected with SARS-Cov-2 anymore than we want anyone else, but they are especially susceptible to having the worst outcomes,” she said.
Referring to the CDC’s study as crucially important, Aagaard said the findings placed an emphasis on expectant mothers taking precaution amid the pandemic.
“Follow the recommendations around masking and social distancing and encourage your household members to do the same,” she said.
That’s where Aagaard strays from the CDC study findings. According to her, it is too early to draw a conclusion regarding mortality rates.
“In the midst of a pandemic, it is not the right time to determine the exact mortality rate or risk of death,” said Aagard.
The actions pregnant women can take
CDC researchers included some steps pregnant women can take to help prevent their risk of severe illness from Covid-19.
"Although additional data are needed to further understand these observed elevated risks, pregnant women should be made aware of their potential risk for severe illness from COVID-19," the CDC researchers wrote in the report.
"Specific actions pregnant women can take include not skipping prenatal care appointments, limiting interactions with other people as much as possible, taking precautions to prevent getting COVID-19 when interacting with others, having at least a 30-day supply of medicines, and talking to their health care provider about how to stay healthy during the COVID-19 pandemic," the researchers wrote.
"To reduce severe outcomes from COVID-19 among pregnant women, measures to prevent SARS-CoV-2 infection should be emphasized, and potential barriers to the ability to adhere to these measures need to be addressed."
A ‘different level of risk’
The American College of Obstetricians and Gynecologists released a statement on Wednesday noting that the new CDC information suggests "a different level of risk for pregnant patients than was previously indicated by earlier data."
ACOG said it is reviewing its clinical materials and resources for patients related to Covid-19.
"During this public health crisis, it is critical that medical care be informed by evidence and data. The COVID-19 pandemic continues to be a rapidly evolving situation, and as new research and data become available, clinical care recommendations should be refined to reflect the most current information," Dr. Christopher Zahn, vice president of practice activities for ACOG, said in the statement.
"As the pandemic continues, ACOG urges its members to encourage pregnant patients who test positive for COVID-19 to consider enrolling in an appropriate COVID-19 registry, such as the COVID-19 PRIORITY Registry, to help the medical community better understand the impact of COVID-19 on pregnancy outcomes," Zahn said.
Early talks around pregnancy and Covid vaccine
"The new information from the CDC highlights the importance of pregnant patients being prioritized for a coronavirus vaccine once it becomes available," Zahn said.
Pregnant women are among the groups being considered to possibly get priority for a coronavirus vaccine, if one gets developed. Members of the CDC's Advisory Committee on Immunization Practices discussed priority groups in its virtual meeting on Wednesday.
"Our issue now is that we need to start planning," , said during the meeting.
"Part of the reason we want this discussion early about how you'd recommend we prioritize is that then we want to turn it into operational planning with state and local health departments," Messonnier told committee members. "But until we can articulate the groups to prioritize, we can't move on to the next step."
Messonnier added that the nation's goal is still to have a vaccine available to everyone by next year but identifying priority groups could help guide vaccine distribution plans.
“The question is, I don’t think we can tell you today when those quantities of vaccine will be available and which vaccines it will be, but if that gives you some sense of the scheme -- by next year, enough for everybody,” Messonnier said.