Extended culture of excess embryos after day 3 embryo transfer (ET) as a pregnancy predictor

Abstract

Objective: In our practice, approximately seventy five percent of all ET occur on day 3 of embryo development and nearly half of the cycles resulting in a day 3 transfer have at least one excess embryo which is placed to extended culture with intention of embryo cryopreservation. Analyzing embryo development and quality following extended culture may be useful with pregnancy prediction. The aim of this study was to determine the significance of this finding. Design: A retrospective study in a private ART center. Materials/Methods: All fresh cycles performed from January 2001 through February 2002 in which day 3 ET occurred with excess embryo(s) available for extended culture (n = 147) were included in this study. Patients underwent down regulation with Lupron prior to controlled ovarian hyper-stimulation with the gonadotropins. Oocyte retrieval occurred 36–38 hours after hCG administration. Insemination of the oocytes (92% by ICSI) was performed 3 to 5 hours after retrieval, and embryos were cultured in G1.2 medium to day 3. The best quality and the most developed embryos were selected for ET. Remaining embryos were placed to G2.2 medium and cultured an additional 2 or 3 days. At this time, embryos were evaluated for their development, quality and freezing suitability according to the Gardner’s method of the blastocyst evaluation, then cryopreserved or discarded. Results: The summary of our findings is presented in the table below.Table 1Embryos cultured after day 3 ET and resulted with:p valueat least 1 good quality blastocystpoor quality or no blastocystsNo. of cycles43104Age (mean ± SD)31.0 ± 4.732.1 ± 4.7NSNo. of oocytes/cycle (mean ± SD)16.0 ± 4.915.4 ± 5.1NSGood quality day 3 embryos∗grade 1 and 2 in the scale 1 to 4,(mean ±SD)7.1 ± 2.85.4 ± 2.5<0.05Transferred embryos (mean ± SD)4.1 ± 1.04.6 ± 1.1<0.05Good quality blastocystsstage 1 to 5 and quality: AA, AB, or BA.(mean ± SD)1.7 ± 1.00.0 ± 0.0N/ANo. of clinical pregnancies (%)30 (69.8)56 (53.8)<0.05∗ grade 1 and 2 in the scale 1 to 4,∗∗ stage 1 to 5 and quality: AA, AB, or BA. Open table in a new tab Conclusions: These data support the hypothesis that embryo quality on day 3 and following extended embryo culture is a positive predictor of cycle outcome. Additionally, those patients with more day 3 good quality embryos are more likely to have spare embryos for cryopreservation. This information may be useful in patient counseling and possible emotional support.