Monozygotic triplets and monozygotic twins after ICSI and transfer of two blastocysts: case report.

There are data regarding the possible influences of extended embryo culture to the blastocyst stage as well as zona pellucida manipulation on the incidence of monozygotic multiples. This is interesting, as one aim of extended culture with embryo selection is to minimize the multiple pregnancy rate. We report, to our knowledge, on the first case of monozygotic twins and monozygotic triplets after ICSI and the transfer of two blastocysts. Monozygotic multiples after ICSI and blastocyst transfer and the resulting problems are another reason to encourage the transfer of only one blastocyst. Theories about risk factors and the pathophysiology of monozygotic multiples will be discussed both in terms of this case report and of the literature. In our opinion, the incidence of 5.9-8.9% monozygotic multiple occurrence after ICSI and blastocyst transfer reported in the literature requires that patients are informed of the uncertainties until this phenomenon and its risk factors are better understood.