Foetal brain unaffected by mild-to-moderate COVID-19 in pregnancy

Mild-to-moderate COVID-19 during pregnancy does not appear to affect the foetal brain, according to a prospective study presented at RSNA 2021.

“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 study senior author Dr Sophia Stöcklein from the Department of Radiology at Ludwig Maximilian University of Munich, Germany.

“[The findings of the study] should help to reassure affected parents,” she said.

The study population comprised 33 pregnant women with gestational age between 18 and 39 weeks (mean 28.4 weeks) and PCR-confirmed SARS-CoV-2 infection. To be included, the women needed to have mild to moderate symptoms of COVID-19, not require hospitalization, and be otherwise healthy. Mean onset of COVID-19 symptoms was at 18.3 weeks gestational age, with the most common symptoms being anosmia or hyposmia (87.9 percent), ageusia (78.8 percent), dry cough (57.6 percent), dyspnoea (30.3 percent), and fever (27.3 percent; mean temperature 38.6°C, maximum 40.8°C).

Foetal MRI was conducted at 1.5 Tesla without the use of a contrasting agent. Two board-certified radiologists with 3–4 years of experience in foetal MRI examined the surface and fluid-filled spaces of the brain and assessed for potential signs of brain swelling and calcification. They also quantified brain stem structures which were then compared to age-adapted reference values.

Brain surface and folding was age-appropriate in all foetuses, as was cerebellar size and size of all brain-stem structures. [RSNA 2021, session SSRI02-3]

The results also showed no calcifications or signs of swelling or widening of the fluid-filled spaces in the brain.

“[A]ll foetuses showed normal brain development, including cortical folding and brain stem segmentation. There were no findings indicative of infection of the foetal brain,” remarked Stöcklein and co-authors.

“Pregnant women are especially vulnerable to SARS-CoV-2 infections with potential complications for the unborn child,” said the authors. “The virus has a high affinity to the placenta [and] reports of transmission of SARS-CoV-2 to the foetus have raised concerns,” they said.

“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,” noted Stöcklein. “[A]lthough there are a few reports of vertical transmission to the foetus, the exact risk and impact remain largely unclear,” she continued, explaining the purpose of conducting the study.

Stöcklein mentioned that follow-up will continue for the next 5 years to assess neonatal and neurological development. She also acknowledged that the current findings only apply to pregnant women with mild to moderate and not severe COVID-19 disease.

“Since the impact of severe infection on brain development in the foetus has not been conclusively determined, active protection against SARS-CoV-2 infection during pregnancy remains important,” said Stöcklein.

“So far, vaccination is the most promising protection against COVID-19. Any potential side effects are manageable, even in pregnant women. Therefore, despite the encouraging results of our study, pregnant women should strongly consider vaccination.”