The Sassoon General Hospital in Pune, Maharashtra, has claimed to have reported India’s first case of vertical transmission of the coronavirus from a mother to her child through the placenta, PTI reported on Tuesday. Vertical transmission takes place when the baby is in the uterus and the virus crosses the placental barrier.

“During the investigation, it was confirmed that it was a vertical transmission,” said the head of the paediatrics department of the Sassoon General Hospital, Aarti Kinikar. “We waited for three weeks and tested the blood samples of both the mother and child for antibody response.” The doctor said both of them had developed antibodies, which were present in higher quantities in the mother.

Kinikar said the woman had symptoms of Covid-19 for a week before her delivery. But when she was tested for the virus, her reports came back negative. The Indian Council of Medical Research has made it mandatory to test all pregnant women as they fall in the high-risk category.

When the woman gave birth to the girl, swabs of her nose, the umbilical cord and the placenta were tested – the reports for which came out positive, Kinikar said. “The baby was then kept in a separate ward,” she added. “After two to three days of birth, the baby also developed strong symptoms like fever and there were signs of cytokine storm, suggesting severe inflammation.”

A cytokine storm is a physiological reaction in which the immune system causes an uncontrolled and excessive release of pro-inflammatory signalling molecules called cytokines.

The doctor said that after the baby tested positive, she was kept under observation at the hospital’s intensive care unit. After two weeks, the baby’s health settled and she recovered. Since then, both the mother and baby have been discharged, Kinikar added.

While pregnant women are often more susceptible to respiratory infections such as influenza, it is still unclear whether pregnant women are more likely to contract the coronavirus. In March, a study of nine infants in Wuhan, China, published in The Lancet, had concluded that the new coronavirus did not seem to cross from mother to fetus.

However, earlier this month, researchers in Italy said that data on 31 pregnant women hospitalised with Covid-19 “strongly suggested” that the virus could be passed on to unborn infants, AFP reported.

On July 14, doctors in France had also described what they said was the first confirmed case of a newborn infected in the womb with Covid-19 by the mother. The baby boy, born in March, suffered brain swelling and neurological symptoms linked to Covid-19 in adults, but has since recovered, they reported in the journalm Nature Communications.

A study conducted by the Journal of the American Medical Association, or JAMA, in March reporting on a similar number of pregnant Covid-19 patients also found antibodies in newborns that recognise the virus, suggesting that it does get through to the fetus.