Dizygotic triplet pregnancy following in-vitro fertilization.

We present a case of dizygotic triplet pregnancy (mono-amniotic twins and a singleton) that, as far as we know, is the first reported one induced by artificial reproductive technology. It ended in the delivery of three healthy normal babies: two monozygotic twin boys and a girl. It appears that zygote splitting is significantly more common in patients treated with ovulation-inducing agents than in the general population. Also, in-vitro conditions of embryonic growth might influence the chances of multifetal gestation and the incidence of identical twinning. This may be due to changes in the physical properties of the zona pellucida and subsequent partial hatching of the pre-embryo. Evaluation of similar cases in the future may shed more light on the mechanism underlying their occurrence following in-vitro fertilization.