In future, most of the 30,000 women who undergo IVF each year will be allowed to have only one embryo implanted, rather than the current two.
The regulator wants to dramatically cut what medical experts say is the unacceptably high number of IVF-assisted multiple births which produce health complications for the mother, the babies or both.
Multiple pregnancies carry a significantly higher risk that babies will be premature and have more health and developmental problems. Premature babies also have a higher risk of dying. Also mothers with multiple pregnancies tend to suffer higher blood pressure and more frequent miscarriages compared with single baby pregnancies.
However, infertile couples will be concerned about the possible increase in cost, time and stress because they would probably have to go through more IVF cycles to achieve a viable pregnancy if fewer embryos are implanted in one procedure.
Approximately one in every four full term pregnancies after fertility treatment results in a multiple birth. This compares to one in 80 natural full term pregnancies.