This is in part due to lack of regulation, but also results from patients and physicians aggressively transferring multiple embryos at once in the hope of achieving any pregnancy. (pacificfertilitycenter.com)
A woman carrying multiple embryos has a greater risk of complications during pregnancy and delivery, which is more likely than a single birth to be by C - section. (scientificamerican.com)
So, patients are in a position where they feel they have to transfer multiple embryos and put them at a higher risk of having a multiple pregnancy. (pregnancymagazine.com)