Oocyte maturation rate: an indicator of clinical outcome

Abstract

OBJECTIVE: Indirect markers to assess the developmental potential of an oocyte cohort after controlled ovarian hyperstimulation are limited. Our objective was to evaluate the effect of in vivo oocyte maturation rate on implantation and birth rates. DESIGN: Data were prospectively collected over a 6-year period. Patients were divided into four groups based on the percentage of mature oocytes. Clinical and laboratory end points were analyzed using t-test and Fisher's exact test. MATERIALS AND METHODS: Patients undergoing ICSI (n=2191) ≤37 years old were included. Oocyte maturation was assessed by extrusion of the first polar body at ICSI, 6-10 hours post retrieval. Injected oocytes were cultured in sequential G-1/G-2™ media under low oxygen tension (5%). Epididymal or testicular sperm, donor oocytes and patients with no mature oocytes were excluded. RESULTS: There was a higher implantation, clinical pregnancy and birth rate as the number of retrieved mature oocytes increased. No difference was noted between groups for average number of oocytes retrieved, number of embryos transferred and patient age.TableEffect of oocyte maturation rate on clinical outcome.% Mature OocytesnAvg. AgeAvg. Oocytes RetrievedAvg. Embryos Trans.Clinical Preg. Per ET (%)Ongoing/Birth Rate (%)Implant. Rate (%)<5010032.815.12.142 (42)¤Different character symbols within columns indicate significant differences (P<0.05).38 (38)¤Different character symbols within columns indicate significant differences (P<0.05).61/213 (28)¤Different character symbols within columns indicate significant differences (P<0.05).50-6945832.515.32.2237 (52)¤Different character symbols within columns indicate significant differences (P<0.05).217 (47)¤Different character symbols within columns indicate significant differences (P<0.05).355/1034 (34)¤Different character symbols within columns indicate significant differences (P<0.05).70-89105132.415.72.2630 (60)¥Different character symbols within columns indicate significant differences (P<0.05).569 (54)¥Different character symbols within columns indicate significant differences (P<0.05).936/2310 (40)¥Different character symbols within columns indicate significant differences (P<0.05).≥ 9058232.815.02.2379 (65)§Different character symbols within columns indicate significant differences (P<0.05).350 (60)§Different character symbols within columns indicate significant differences (P<0.05).583/1262 (46)§Different character symbols within columns indicate significant differences (P<0.05).¤ ¥ § Different character symbols within columns indicate significant differences (P<0.05). Open table in a new tab CONCLUSIONS: These results suggest that achieving high maturation rates after ovarian hyperstimulation are of paramount importance for a positive treatment outcome. Incomplete cytoplasmic maturation in the oocyte cohort could be one of the causes for the poorer clinical success for patients with a lower number of mature oocytes retrieved.