Monozygotic twin birth after the transfer of a cleavage stage embryo resulting from a single pronucleated oocyte.

PURPOSE: To present a case involving the transfer of a single pronucleated oocyte resulting in a monozygotic twin pregnancy. METHOD: A descriptive case report of a single patient. RESULTS: The patient conceived and was found to have a monochorionic diamnionic pregnancy which resulted in the birth of normal identical twin boys at 32 weeks of gestation. CONCLUSIONS: The case report addresses an issue that has not received proper attention in the literature. It illustrates that observing a single PN in an oocyte at fertilization check should not be an absolute deterrent to transferring the resulting embryo even in an older patient with a high FSH level. This report also suggests that single observations, especially at the assessment of fertilization, in the IVF laboratory are limited when evaluating embryo potential and normalcy.

Accuracy of day 3 criteria for selecting the best embryos.

OBJECTIVE: To assess the accuracy of day 3 morphologic criteria in identifying the best embryos. DESIGN: Prospective observational study. SETTING: University IVF program. PATIENT(S): One hundred cycles in women desiring blastocyst transfer who had > or =3 eight-cell embryos on day 3. INTERVENTION(S): On day 3, the embryologist chose the two embryos that would have been transferred that day. On day 5, embryos were examined to determine the best and second-best blastocysts. MAIN OUTCOME MEASURE(S): Accuracy of day 3 picks as measured in culture on day 5, outcome of nontransferred picks, and cryopreservation rate. RESULT(S): All cycles reached the blastocyst stage and 73% had cryopreservation. The mean number of blastocysts was 4.8 (3.2 on day 5 and 1.6 on day 6). Neither pick was chosen in 39% of cycles; one pick was transferred in 38%; and both picks were transferred in 23%. Of 116 nontransferred picks, 51 were frozen and 65 arrested, with both picks arresting in 9 cycles. The single best blastocyst was chosen from the picks in 39% of cycles. CONCLUSION(S): Morphologic criteria for cleavage-stage embryo selection may fall short when the transfer is limited to two embryos. Culture to blastocyst is warranted in this population to avoid high-order multiples and still be able to choose the two embryos with the highest implantation potential.