Heart defect risk in IVF tied to twinning

The excess risk of congenital heart defects (CHDs) in ART-assisted pregnancies is accounted for by twinning, according to an analysis of more than half a million pregnancies.
In fact, twins, conceived artificially or not, have nearly five times higher prevalence of a CHD than singletons.
The study, published on Tuesday in JAMA Pediatrics, supports the practice of single-embryo transfers in Australia, whereas multiple-embryo transfer elsewhere has reached “epidemic” levels, write the concerned authors.
The Canadian cohort study linked historical records of CHDs in twins and singleton pregnancies conceived with intracytoplasmic sperm injections (ICSI) and in vitro fertilisation (IVF) without ICSI, as well as unassisted pregnancies in Ontario between 2012 and 2015.