Expectant mothers can transmit the raging COVID-19 in the womb, a new report says.
The Pediatric Infectious Disease Journal, the official journal of The European Society for Paediatric Infectious Diseases reports that a baby girl in Texas, US, born prematurely to a mother with the virus, is the strongest evidence that intrauterine (in the womb) transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can occur.
This evidence is coming as acute ischemic strokes (AIS) associated with COVID-19 are said to be more severe, leading to worse functional outcomes and associated with higher mortality.
So says new research published in Stroke, a journal of the American Stroke Association, a division of the American Heart Association.
In “Characteristics and Outcomes in Patients with COVID-19 and Acute Ischemic Stroke: The Global COVID-19 Stroke Registry,” researchers analyzed data on patients with COVID-19 and AIS treated at 28 health care centres in 16 countries this year and compared them to patients without COVID-19 from the Acute Stroke Registry and Analysis of Lausanne (ASTRAL) Registry, from 2003 to 2019.
Researchers sought to determine the clinical characteristics and outcomes of patients with COVID-19 and AIS.
Between January 27 and May 19 this year, there were 174 patients hospitalised with COVID-19 and AIS. Each COVID-19 patient with AIS was matched and compared to a non-COVID-19 AIS patient based on a set of pre-specified factors including age, gender and stroke risk factors (hypertension, diabetes, atrial fibrillation, coronary artery disease, heart failure, cancer, previous stroke, smoking, obesity and dyslipidemia). The final analysis included 330 patients in total.
In both patient groups, stroke severity was estimated with the National Institute of Health Stroke Scale (NIHSS), and stroke outcome was assessed by the modified Rankin score (mRS). When AIS patients with COVID-19 were compared to non-COVID-19 patients:
COVID-19 patients had more severe strokes (median NIHSS score of 10 vs. 6, respectively);
COVID-19 patients had a higher risk for a severe disability following stroke (median mRS score 4 vs. 2, respectively); and COVID-19 patients were more likely to die of AIS.
The researchers noted there are several potential explanations for the relationship between COVID-19-associated strokes and increased stroke severity:
“The increased stroke severity at admission in COVID-19-associated stroke patients compared to the non-COVID-19 cohort may explain the worse outcomes. The broad, multi-system complications of COVID-19, including acute respiratory distress syndrome, cardiac arrhythmias, acute cardiac injury, shock, pulmonary embolism, cytokine release syndrome and secondary infection, probably contribute further to the worse outcomes including higher mortality in these patients. …
‘’The association highlights the urgent need for studies aiming to uncover the underlying mechanisms and is relevant for prehospital stroke awareness and in-hospital acute stroke pathways during the current and future pandemics.”
However, the findings “suggest in utero transmission” of COVID-19 from an infected mother to her infant, according to the case report by Julide Sisman, MD, and colleagues of The University of Texas Southwestern Medical Center, Dallas.
“Numerous infants have now been delivered to pregnant women diagnosed with SARS-CoV-2, with the majority of these infants without respiratory illness or positive molecular evidence for SARS-CoV-2,” comments Amanda S. Evans, MD, one of the lead authors of the new study.
“Our study is the first to document intrauterine transmission of the infection during pregnancy, based on immunohistochemical and ultrastructural evidence of SARS-CoV-2 infection in the fetal cells of the placenta.”
First Documented Intrauterine Transmission of COVID-19
The authors report on an infant delivered to a mother diagnosed with COVID-19, who also had type 2 diabetes.
The infant was born at 34 weeks’ gestation after the mother had premature rupture of the membranes. The baby was born “large for gestational age” (LGA) – an important complication in infants of diabetic mothers. She was treated in the neonatal ICU due to prematurity and possible SARS-CoV-2 exposure.
The infant appeared initially healthy, with normal breathing and other vital signs. On the second day of life, she developed a fever and relatively mild breathing problems. “It is unlikely that the respiratory distress observed in this infant was due to prematurity since it did not start until the second day of life,” the researchers write.
The baby tested positive for SARS-CoV-2 infection at 24 and 48 hours after birth. She was treated with supplemental oxygen for several days but did not need mechanical ventilation.
COVID-19 tests remained positive for up to 14 days. At 21 days, the mother and infant were sent home in good condition.
The researchers examined the placenta, which showed signs of tissue inflammation. In addition, specialised tests documented the presence of coronavirus particles as well as a protein (SARS-CoV-2 nucleocapsid protein) specific for the COVID-19 virus in fetal cells of the placenta.
Together, these findings confirmed that the infection was transmitted in the womb, rather than during or after birth.
Although data on COVID-19 remain very limited, “Intrauterine transmission of SARS-CoV-2 appears to be a rare event,” Dr. Sisman and colleagues conclude.
They highlight several urgent priorities for further research, including the mechanisms and risk factors of in utero SARS-CoV-2 transmission and the outcomes of congenital COVID-19 in infants.
“We wanted to be very careful of our interpretation of this data, but now is an even more important time for pregnant women to protect themselves from COVID-19,” comments Dr. Evans. She adds, “The CDC has thoughtful guidance on ways to reduce risk of infection.”
Two additional case reports in PIDJ also describe “vertical” transmission of SARS-Co-V2 from mother to infant occurring under different circumstances.
Together, the three cases highlight the important but difficult distinction between virus transmission occurring before or during/after delivery (intrauterine versus intrapartum), according to a commentary led by George K. Siberry, MD, of the US Agency for International Development and Associate Chief Editor of PIDJ.
Dr. Siberry and coauthors write: “As these cases illustrate, evaluation for vertical—and especially intrauterine—SARS-CoV-2 infection can be challenging, and assessment is often limited by lack of optimal testing of appropriate specimens obtained at specific timepoints.”