[Single embryo transfer--possibilities and limits].

Objective: To evaluate the results of single embryo transfers, on a set of patients, for a given period of time.
Design: Retrospective study.
Setting: Pronatal Sanatorium, Prague.
Methods: Between January 2008 and May 2010, we evaluated the results of all cycles with single embryo transfers in our workplace. There were four groups of patients: the first group with elective single embryo transfers (ESET, n=147), the second group with only a single embryo transfer without selection (SET n=269), the third group with transfer of one embryo derived from the native cycle (NC, n=70) and the last group with transfer of only one embryo examinated by preimplantation genetic diagnosis (PGD, n=104). All patients were monitored by age, length of cultivation of embryos, clinical pregnancy rate/transfer (CPR/ET), pregnancy loss (AB) and baby take home rate (BTR). Statistical evaluation was performed using the chi square test.
Results: The group with ESET achieved a significantly higher success rate (50% CPR/ET, p<0.001) compared to the other groups: 22% for SET, 7% of spontaneous cycles and 18% after PGD. A significant difference (p<0.001) was also apparent in the evaluation of BTR: ESET 41%, 16% SET, NC 4%, 12.5% of PGD. Patients that made ESET were significantly younger (p<0.001) compared to the other monitored groups (32.9 ESET, SET 35.2, NC 39.6, 39.1 PGD).
Conclusion: We consider that assisted reproduction is only successful with the birth of one healthy child. For women 38 years old or younger the most successful treatment is to transfer a single high quality embryo and to therefore eliminate multiple pregnancy. The age of a woman and the quality of the embryo are major prognostic factors.