Drugs given to increase your chances of becoming pregnant fall into two groups: hormone treatment, such as gonadotrophins; and anti-oestrogens, such as clomifene citrate (Clomid) or tamoxifen. Because they increase your chance of becoming pregnant at all, they also increase your chances of multiple pregnancy.
Using anti-oestrogens can make you up to 10 times more likely to have a multiple pregnancy than you would be if you’d conceived naturally. More about anti-oestrogen drugs>>
Because hormone treatment helps to increase the number of eggs produced at one time, it makes it more likely that you will become pregnant with twins or more babies.
More about hormone treatment>>
“Multiple birth is the single biggest risk to the health and welfare of children born after IVF; we can no longer sit back and do nothing about it. IVF babies also deserve the best start in life!”
Prof Peter Braude, King’s College and Guy’s Hospital, London