RECOVER study provides new insights on the relationship between pregnancy and Long COVID
Findings from a recent RECOVER study suggest that women who were pregnant at the time of a SARS-CoV-2 infection had a lower risk of developing Long COVID than women who were not pregnant.
Research studies have often excluded pregnant women from taking part, especially in clinical trials. Including pregnant women and their babies safely in RECOVER observational studies means that the initiative’s research findings can better reflect the experiences of all people affected by Long COVID.
Some research studies that included pregnant women focused on SARS-CoV-2, the virus that causes COVID-19. Their findings suggest that a SARS-CoV-2 infection during pregnancy is associated with different risks. These risks include the mother becoming seriously ill and negative impacts on the baby, such as early birth before the baby is fully developed.
However, less is known about the relationship between pregnancy and Long COVID. Previous RECOVER research—based on data from RECOVER’s adult observational study—found that nearly 1 in 10 women who had a SARS-CoV-2 infection during pregnancy later developed Long COVID symptoms.
In a new study recently published in Nature Communications, RECOVER researchers analyzed the electronic health records (EHRs) of pregnant and nonpregnant women to understand how pregnancy during a SARS-CoV-2 infection impacts a woman’s risk of developing Long COVID.
By using EHRs, RECOVER researchers can study a much larger group of participants. The initiative has access to EHRs from 3 large national healthcare networks within the US, which cover more than 60 million patients’ records.
What did researchers do?
Drawing EHR data from 2 nationwide research networks—the National Patient-Centered Clinical Research Network (PCORnet) and the National COVID Cohort Collaborative (N3C)—researchers identified more than 72,000 women who were pregnant when they had a SARS-CoV-2 infection between March 2020 and June 2023. For comparison, researchers also looked at the health records of more than 207,000 reproductive-age women who had a SARS-CoV-2 infection during the same time period but were not pregnant. By combining these data, researchers created one of the largest studies to date examining pregnancy and Long COVID.
To measure the risk of developing Long COVID, RECOVER researchers examined whether women in the study had the condition 180 days after they had a SARS-CoV-2 infection. The study team identified cases of Long COVID using both diagnoses from healthcare providers in the health records. They also used a computer program called a machine learning algorithm to identify patterns of symptoms that were likely Long COVID cases that may have been misdiagnosed or undiagnosed.
What did researchers find?
Researchers found that among women who had a SARS-CoV-2 infection, those who had an infection while pregnant were less likely to develop Long COVID than nonpregnant women of the same age. Researchers believe that changes in the immune system during pregnancy, which help protect the baby, may also support recovery from COVID-19 and may reduce a woman’s risk of developing Long COVID.
The risk of pregnant women developing Long COVID after having a SARS-CoV-2 infection varied between the 2 research networks used in the study. EHR data from PCORnet showed that 16.47 of every 100 pregnant women (about 16%) who had a SARS-CoV-2 infection developed Long COVID. In comparison, 18.88 of every 100 nonpregnant women (almost 19%) developed Long COVID. EHR data from N3C showed an even lower risk, with 4.37 of every 100 pregnant women (about 4%) who had a SARS-CoV-2 infection developing the condition (compared to 6.21 of every 100–about 6%–nonpregnant women).
Researchers examined other factors during pregnancy that might affect a woman’s risk of developing Long COVID. The study found that pregnant women with certain health conditions and characteristics were more likely to develop Long COVID than others. These risk factors included:
- Race – Women who identified as Black were more likely to develop Long COVID.
- Age – Women who were 35 years or older during pregnancy were more likely to develop Long COVID.
- Trimester – Women who had a SARS-CoV-2 infection during the first or second trimester of pregnancy were more likely to develop Long COVID than those who had a SARS-CoV-2 infection later in pregnancy.
- COVID-19 variant – Women who had a SARS-CoV-2 infection during the Delta or Omicron waves were more likely to develop Long COVID.
- Body mass index (BMI) – Women with obesity were more likely to develop Long COVID.
- Pre-existing health conditions – Women with conditions such as diabetes, high blood pressure, asthma, or other chronic illnesses were more likely to develop Long COVID.
Why are these findings important?
Including pregnant women in RECOVER studies advances maternal health as RECOVER researchers work to better understand, diagnose, prevent and treat Long COVID across the lifespan.
Previous RECOVER research also found that women who had a SARS-CoV-2 infection during pregnancy were less likely to develop Long COVID. However, the previous study included EHRs from 5,397 pregnant women, whereas researchers in this study were able to access EHRs from over 72,000 pregnant women. New collaborations with PCORnet, N3C, and RECOVER’s observational study of pregnant women allowed researchers to include 13 times more pregnant women as participants than the previous study.
Given the scale of the study, researchers examined additional factors that may influence a woman’s risk of developing Long COVID. These additional factors provide important insight into which pregnant women may be more likely to develop Long COVID based on their different backgrounds, circumstances, and health conditions.
This new information can inform future Long COVID studies that include pregnant women and their babies.
