Administering Tdap vaccination -- tetanus, diphtheria, acellular pertussis -- to pregnant women may not increase children's risk of developing autism spectrum disorder, claims a study of more than 80,000 children born.The study showed that the autism spectrum disorder rate in children was 1.5 per cent in the maternal Tdap vaccinated group and 1.8 per cent in the maternal unvaccinated group."Infants are at the highest risk of hospitalization and death among any population subgroup after contracting a pertussis infection, a highly contagious respiratory disease also known as the whooping cough," said lead author Tracy A. Becerra-Culqui, a post-doctoral research student at Kaiser Permanente -- a US-based health care company."Pregnant women can be reassured by this study that there is no indication of an increased risk of autism spectrum disorder in children after being exposed prenatally to the Tdap vaccine," Becerra-Culqui added.The study, published in the journal Pediatrics, looked at the autism diagnosis for nearly 82,000 children.The Advisory Committee on Immunisation Practices, which provides guidance on the use of vaccines for the US, recommends pregnant women receive the Tdap vaccine to prevent pertussis infection, but some women still hesitate."The link between vaccination and development of autism has been refuted by many rigorous scientific investigations. Unfortunately, the misconceptions still generate concerns," the researchers said.