0900 GMT January 26, 2021
A study by experts at Newcastle University highlights the importance of antenatal scans.
Normally, only identical twins share a placenta, even then each twin may have its own. Identical twins are known to have an increased risk of congenital heart disease compared to single births, scifeeds.com said.
The research, undertaken by PhD student Kate Best and led by Professor Judith Rankin, used information of more than 400,000 pregnancies occurring between 1998 and 2010.
Scientists found that 13 in every 1,000 twins were born with some type of congenital heart disease, compared to seven in every 1,000 single births.
It was also identified that twins who share a placenta in the womb are particularly at risk, with 20 in every 1,000 twins sharing a placenta being born with a congenital heart disease compared to 11 in every 1000 twins with separate placentas.
Judith Rankin, professor of Maternal and Perinatal Epidemiology at Newcastle University, said: "The unique information from two surveys in the North of England has enabled us to show the higher risk of a congenital heart disease for twins and, in particular, for those that share a placenta. This information will be incredibly helpful to parents and health professionals.
"Not all congenital heart diseases can be detected before birth but for those that can, this research demonstrates the importance of antenatal scans and the information they can provide to prepare for the best care possible when the baby is born."
Around two thirds of identical twins share a placenta, and this depends upon when the fertilized egg splits to form two embryos after conception.