Most women who get infected with Covid-19 when pregnant pass antibodies to their unborn babies, reveals a study.
Antibodies to infections are known to be transferred from mother to baby during the last three months of pregnancy, providing the baby with some protection against that particular illness when they are born. Little is known, however, about how well Covid antibodies are transferred from mother to child, either in vaccinated or unvaccinated populations.
Italian researchers from the University of Bologna, studied more than 4,000 women who gave birth in Bologna between July 1, 2020 and March 31, 2021.
About 136 of the women (3.4 per cent) had antibodies to Covid in their blood, and 26 per cent of them had both IgG (older infection) and IgM (more recent/current infection) antibodies, while 74 per cent of the women had IgG antibodies but were IgM negative.
All 73 babies had negative PCRs when tested shortly after birth, indicating they didn’t have Covid and that the antibodies had been passed to them by their mother, rather than being made by themselves.
“This study of pregnant women and their newborns, which was carried out in the pre-vaccination era, found that 3.4 per cent of the women had Covid-19 during pregnancy,” said Dr Liliana Gabrielli and colleagues at the IRCCS St. Orsola Polyclinic, at the varsity.
Most of these women passed antibodies to their babies. However, the protection provided by these antibodies will gradually decrease over time and disappear within 100 days of birth in most cases, Gabrielli said.
The study presented at this year’s European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) being held in Portugal showed that antibodies are likely to wane in about 100 days after birth, increasing the risk.
Thus vaccination is important in pregnant women, as studies have shown that antibodies produced by vaccination pass from mother to child via breastfeeding. Pregnant women are advised vaccination as it decreases the risk of severe complications like stillbirth and premature delivery, if they contract Covid.