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December 08, 2021
2 min read
COVID-19 appears to have no effect on the brains of the developing fetuses of pregnant women with mild to moderate cases of the disease, according to a study presented at the Radiological Society of North America Annual Meeting.
“Women infected with SARS-CoV-2 during pregnancy are concerned that the virus may affect the development of their unborn child, as is the case with some other viral infections,” author Sophia Stöcklein, MD, of the department of radiology at Ludwig Maximilian University of Munich, said in a press release.
“So far, although there are a few reports of vertical transmission to the fetus, the exact risk and impact remain largely unclear. The aim of our study was to fill this gap in knowledge regarding the impact of a maternal SARS-CoV-2 infection on fetal brain development,” she said.
The researchers used fetal MRI to study 33 patients with COVID-19 infection during pregnancy. The patients were at a mean of 28.4 weeks into their pregnancies (range, 18 to 39 weeks).
Symptom onset occurred at a mean of 18.3 weeks (range, 4 to 34 weeks) into the pregnancy. The most common maternal symptoms were reduced or lost sense of smell (n = 29; 87.9%), reduced or lost sense of taste (n = 26; 78.8%), dry cough (n = 19; 57.6%), fever (n = 9; 27.3%) and shortness of breath (n = 10; 30.3%). Patients were otherwise healthy.
A pair of board-certified radiologists with 3 and 4 years of experience respectively in fetal MRI evaluated the scans, including the brain’s surface, the brain’s fluid-filled spaces, potential signs of brain swelling and brain calcifications. They also quantified brain stem structures.
Based on the analysis, the brain development in the assessed areas was age-appropriate in all fetuses. There were no calcifications, signs of swelling or widening of the brain’s fluid-filled spaces, and no findings indicated fetal brain infection.
“In our study, there was no evidence that a maternal SARS-CoV-2 infection has any effect on the brain development of the unborn child,” said Stöcklein. “This fact should help to reassure affected patients.”
The study only included mothers with mild to moderate symptoms who were not hospitalized, Stöcklein said.
“Since the impact of severe infection on brain development in the fetus has not been conclusively determined, active protection against SARS-CoV-2 infection during pregnancy remains important,” she said.
The researchers noted that the CDC recommends that women who are pregnant or who are thinking about getting pregnant should get vaccinated against COVID-19 to reduce the risk for severe illness.
“So far, vaccination is the most promising protection against COVID-19,” Stöcklein said. “Any potential side effects are manageable, even in pregnant women. Therefore, despite the encouraging results of our study, pregnant women should strongly consider vaccination.”
The researchers said they will continue to recruit new patients and follow them for the next 5 years, including detailed neonatal assessment and assessment of neurological development.
Reference:
- Koliogiannis V, et al. SARS-CoV-2 infection during pregnancy: Does fetal MRI show signs of impaired fetal brain development? Presented at: Radiological Society of North America Annual Meeting; Nov. 28-Dec. 2, 2021; Chicago (hybrid meeting).
Perspective
Irina Burd, MD, PhD
It is reassuring that these researchers did not see any effects in the babies of patients with non-severe COVID-19, which goes along with other studies showing that the virus does not cross the placenta and cause any acute neurologic deficits or MRI abnormalities.
But while the virus had no acute effects on the brain in the 33 babies examined in this study, many other neurologic and psychiatric disorders do not manifest until later. It is very hard to say, just based on these MRIs, that long-term effects are not going to emerge.
We need long-term investigations because inflammation of the placenta could result in a spectrum of neural behavioral outcomes that are not depicted on MRI, including cognitive deficits such as learning disabilities and autism spectrum disorder, or motor deficits such as cerebral palsy.
I’m the primary investigator on a study with the National Institute of Drug Abuse that is following 7,500 children across 25 sites in the United States examining mothers with substance abuse as well as other environmental exposures in pregnancy and their outcomes. Some of these 7,500 children may be born to mothers who have had COVID-19 during pregnancy. The study will go up to 10 years, so we will know their long-term outcomes.
Big studies like this will reveal the long-term outcomes of COVID-19 on pregnancy. We’re not out of the woods, because this sample was only 33 babies. There may have been no acute changes in the fetal brain, but these were only mild to moderate cases.
We don’t know if more severe cases of COVID-19 would have a different impact, but we do need to investigate them. With more severe COVID-19, there’s more maternal inflammation. Specifically, placental inflammation can lead to a spectrum of neurobehavioral and neurological problems.
Autism is not diagnosed at birth, and it cannot be seen with an MRI. Neither can cerebral palsy, which often is diagnosed around age 2 years. If we could pinpoint who is going to develop these diseases, we could potentially prevent many of them. A simple fetal MRI won’t tell us these things. It’s not only about gross anomalies on an MRI but also about connectivity, which can be checked with EEG and neurobehavioral tests.
The results of this small sample of fetal tests are reassuring, but we need more studies in the long term, especially in cases of severe COVID-19 and pregnancy.
Irina Burd, MD, PhD
Director of the Integrated Research Center for Fetal Medicine
Professor of gynecology and obstetrics
Johns Hopkins University School of Medicine
Disclosures: Burd reports no relevant financial disclosures.