April 22 (UPI) -- Pregnant women with COVID-19 are at increased risk for complications, such as high blood pressure, pre-eclampsia and preterm delivery, compared to those without the disease, a study published Thursday by JAMA Pediatrics found.
Expecting mothers with the virus are 76% more likely to develop pre-eclampsia, or high blood pressure during pregnancy, and nearly 60% more likely to have premature babies, compared to uninfected women, the data showed.
In addition, they have about double the risk for seeing their babies die during pregnancy and are themselves 22 times more likely to die during pregnancy than those free of COVID-19.
However, on that latter number, just 11 of the 706 infected women -- less than 2% -- of the women included in the analysis died during pregnancy, which equates to 159 deaths for every 10,000 childbirths, according to the researchers.
Pregnant women also have a more than three-fold higher risk for severe illness from COVID-19 and are five times as likely to need intensive care unit treatment compared to those who did not have the virus.
"If you are pregnant, contracting COVID-19 has important consequences," study co-author Dr. Aris Papageorghiou told UPI in an email.
This includes "direct risks of the virus itself -- needing to go to intensive care and have respiratory support, higher risks of hypertension and pre-eclampsia and effects of medical interventions such as preterm birth," said Papageorghiou, a professor of fetal medicine at the University of Oxford in England.
The findings are based on an analysis of 706 pregnant women with COVID-19, and more than 1,400 without the virus, treated at 43 hospitals across 18 countries.
Last June, a Centers for Disease Control and Prevention report on the effects of the virus on expecting mothers in the United States found that they had about a two-fold higher risk for severe illness.
A separate CDC study found that the risk for preterm delivery was 25% higher among infected women.
Conversely, in data released Wednesday and published by the New England Journal of Medicine, 14% of pregnant women who received the COVID-19 vaccine had a pregnancy loss and less than 10% reported preterm delivery.
These percentages are comparable to those found in studies of pregnancy outcomes nationally conducted before the pandemic, the CDC researchers said.
In their analysis, Papageorghiou and his colleagues found that pregnant women with COVID-19 who experienced fever and shortness of breath as a result of infection were nearly three times as likely to experience health complications.
In addition, their babies had a more than five-fold risk for health complications if they experienced these common symptoms of the virus, the data showed.
Women who suffered mild illness with no symptoms of the virus still had a 24% higher risk for health complications during pregnancy, the researchers said.
These risks are likely the result of a "combination of immune changes due to pregnancy," according to Papageorghiou.
"There is a degree of immune suppression, to ensure 'tolerance' of the fetus [and] changes in how inflammation affects the body during pregnancy,' Papageorghiou said.
"The key [to minimizing risk] is to avoid infection, so the two main options are to self-isolate and take the standard precautions or to have the vaccine," he said.