Beijing, Nov 7 : Doctors in China have identified an increased association of SARS-CoV-2 infection during early weeks of gestation with a congenital abnormality called Situs Inversus, where internal organs are mirrored in position. Situs inversus totalis (SIT) is a rare congenital abnormality characterised by a mirror-image transposition of both the abdominal and the thoracic organs. This is a global defect of situs orientation and failure to generate normal left-right asymmetry. Frequency of situs inversus is 1:10,000 to 1:20,000 and is more frequent in males. Writing in a report published in the New England Journal of Medicine, the team stated that cases of foetuses with the rare congenital condition rose four-fold in the first seven months of 2023 post Covid. 'We noted a striking increase in the number of cases of foetal situs inversus that were diagnosed by means of ultrasonography at our hospital several months after the 'zero-Covid' policies in China were lifted,' said the researchers including from Tongji University and Shanghai Jiao Tong University in Shanghai, China. The team of researchers determined the incidence of foetal situs inversus from January 2014 through July 2023 using clinical data from two obstetrical centres in different regions of China. During the first 7 months of 2023, the incidence of situs inversus -- diagnosed by means of routine ultrasonography at a gestational age of approximately 20 to 24 weeks, with no change having been made in the diagnostic protocol or physician training -- at these centres was over four times as high as the mean annual incidence from 2014 through 2022. The incidence peaked in April 2023 and remained elevated through June 2023. Overall, 56 cases of situs inversus were identified from January 2023 through July 2023 (52 cases of situs inversus totalis and 4 cases of partial situs inversus). 'The increase followed the surge of SARS-CoV-2 infections that occurred after the zero-Covid policies were discontinued,' the researchers said. However, 'no conclusions can be made regarding causality', they added. 'Our observations suggest a possible relationship between SARS-CoV-2 infection and foetal situs inversus that warrants further study,' the researchers said. /IANS