A team of French doctors has reported what is believed to be the first confirmed case of in-womb transmission of COVID-19 from mum to unborn baby. While previous studies into transmission during pregnancy have drawn mixed conclusions, the doctors claim this case is a proven instance of the virus crossing the placenta.
The baby boy, who suffered from neurological symptoms similar to those described in some adult patients, has since recovered after spending 18 days in hospital.
According to the case notes published in Nature Communications, the baby's 23-year-old mother presented to hospital in March with a high fever and severe cough. She was 35 weeks pregnant and tested positive to the coronavirus. Days after being admitted to hospital for monitoring, her baby showed signs of distress, with doctors making the decision to deliver him via caesarean section.
At three days old, the baby boy became irritable and was having trouble feeding. The medical team discovered the virus had spread from his mother's blood into the placenta, leading to inflammation on the brain and muscle spasms. "We report a proven case of transplacental transmission of SARS-CoV-2 from a pregnant woman affected by COVID-19 during late pregnancy to her offspring," the authors write in their paper.
According to the team, mum-to-baby transmission is considered proven, "if the virus is detected in the amniotic fluid collected prior to the rupture of membranes or in blood drawn early in life." As such, they note, "our case fully qualifies as congenitally transmitted SARS-CoV-2 infection."
In addition, they found the levels of the virus were "much higher" in the placental tissue than in amniotic fluid or maternal blood.
"Our findings confirm that transplacental transmission is indeed possible in the last weeks of pregnancy," the authors explain. "Although we cannot exclude a possible transmission and fetal consequences earlier during the pregnancy, as there are no definite literature data available yet." The team also highlight that the baby was placed in full isolation, which is "confirmation that we observed an actual neonatal infection, rather than a contamination."
Speaking to The Guardian, co-author Daniele De Luca, medical director of paediatrics and neonatal critical care at the Antoine Béclère hospital in Paris said, "Unfortunately there is no doubt about the transmission in this case. Clinicians must be aware that this may happen. It's not common, that's for sure, but it may happen and it must be considered in the clinical workout."
According to De Luca, the reason it had not been previously demonstrated is due to the amount of samples required, which has been difficult amid the pandemic.
"You need the maternal blood, the newborn blood, the cord blood, the placenta, the amniotic fluid, and it's extremely difficult to get all these samples in a pandemic with emergencies all around.
"There have been some suspected cases, but they remain suspected because nobody had the opportunity to test all of this and check the pathology of the placenta."
De Luca added that the baby is now "clinically fine".
"You can see the glass as half empty or half full. The bad news is that in this case history, the virus is attacking the baby, reaching the baby and causing symptoms. The good news is that at the end of the day, the baby very much recovered.
"Pregnant women should be reassured," he added. "Pregnancy is very controlled and if you have something like this, it can be controlled. In most cases there will be no damage to the baby. There are many things we can do, but we can't close our eyes and say this is never going to happen."
The most recent guidelines from the National COVID-19 Clinical Evidence Taskforce in Australia note that " there is currently no evidence to indicate that caesarean section for women with COVID-19 reduces the risk of vertical transmission to the newborn. Mode of birth should continue as per usual care."
For pregnant women, The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) advises the following preventative measures:
- Hand washing regularly and frequently with an alcohol-based hand rub or soap and water
- Avoidance of anyone who is coughing and sneezing
- Avoid touching eyes, nose and mouth
- Social-distancing and reducing general community exposure
- Early reporting and investigation of symptoms
- Prompt access to appropriate treatment and supportive measures if infection is significant
- Limit support person to one
- If your partner has COVID-19, or is symptomatic, they should not accompany you to the hospital
"Woman should remain reassured, given our extensive knowledge of the impact of the effect of other respiratory viruses, that there is currently no evidence that COVID-19 will harm your baby or cause abnormalities," the college says.