Multiple pregnancies menotropins are more common and of higher order when menotropins are used for controlled ovarian hyperstimulation as compared to clomiphene citrate cycles or natural cycles. In natural cycles, the twinning rate (in the USA) is about 1 in 90 and the triplet rate is about 1 in 8000. In clomiphene cycles, the twinning rate is about 1 in 10-12 and the triplet rate is about 1 in 150. In menotropin cycles, the twinning rate is about 1 in 4-5, the triplet rate about 1 in 20 (quadruplets or quintuplets less common).
At the point of triplets or more, the combined risks of morbidity or mortality to the pregnant woman and fetuses are generally greater than that of the selective reduction procedure (at a center with significant experience in performing this procedure).
Selective reduction is a procedure that is done to reduce the number of viable pregnancies, typically down to two. Because it does involve terminating one or more viable pregnancies it should be discussed carefully (and respectfully) with (and by) the couple. A decision on selective reduction may involve several moral, ethical, religious, medical, personal and emotional factors.
The decision on whether to employ selective reduction should ideally be made prior to the initiation of a controlled ovarian hyperstimulation cycle, while the couple is able to consider the variables without time limitations or the stress of knowing that there is a viable triplet or greater order multiple pregnancy.