In May, a mother in Canada who tested positive for coronavirus had a cesarean delivery of a baby who did not test positive for the virus. Just this week in Mexico, an asymptomatic woman gave birth to triplets who tested positive. A new study attempts to pinpoint the possible pathways of mother to child transmission during pregnancy.
Dean Blumberg, the chief of pediatric infectious disease at UC Davis, said, 'There is concern that mother's infection during pregnancy may result in transmission to the baby.' Dr. Blumber continued, 'We are pleased to have the opportunity to offer a framework to look at different possible transmission pathways.' Although it hasn't been established if direct transmission occurs from the mother to the fetus, they ruled out three potential mechanisms of viral transfer.
The first type of intrauterine transmission (mother to fetus) that can occur could occur at any time during the pregnancy. If the mother is viremic or is infected through the blood during acute infection, COVID-19 may travel to the fetus via the placenta. This direct transfer is called vertical transmission.
Vertical Transmission
Vertical transmission may occur through the placenta, breast milk, or direct contact from the birth mother to the baby. It's very similar to how pregnant women with HIV give birth to children with the same infection. The latest point of infection during the pregnancy may occur also occur at the time of delivery.
One other possible way of a newborn baby contracting the virus is if the mother or someone in close physical contact with the woman and baby had coronavirus in the time period of two weeks before delivery and two days after giving birth. If the mother is actively infected, maternal blood or other secretions may result in a positive test for the baby between two and 14 days after delivery since the virus may become incubated within the baby's environment at this time.
The third is transient viremia or superficial exposure of coronavirus. The newborn may have a false negative result of the test. The mother may contract the virus during the last two weeks of her pregnancy or right after giving birth.
Doctors can then take samples of the amniotic fluid, or the blood from the umbilical cord, or take a blood sample from the newborn. However, if the mother's secretions test positive for the SARS-CoV-2, the baby may test negative.
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Pregnant with COVID-19
'In case of the mother's confirmed infection with SARS-CoV-2, we recommend as a minimum procedure a swab of the respiratory tract of the newborn in the first and second 24-hour periods,' said Satyan Lakshminrusimha, physician-in-chief of UC Davis Children's Hospital. 'If initial SARS-CoV-2 swab tests negative, it may be repeated if the baby shows symptoms.
There may be a role for antibody testing in selected patients to diagnose past infection."Due to the first case in Toronto, the rare case meant that the virus not only infected the respiratory system, where the most common symptoms occur but also other areas of the body.
Dr. Adi Davidov, a gynecologist at Staten Island University Hospital said that mother to fetus transmissions are a rare phenomenon. 'Nonetheless, it is important for clinicians to be aware of this situation and to screen all newborns for COVID-19.'
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