Embryo selection by the first cleavage parameter between 25 and 27 hours after ICSI.
OBJECTIVE
The objective of this study was to assess first embryo cleavage (FEC) 25-27 h after intracytoplasmic sperm injection (ICSI) as a parameter for the embryo selection process.


METHODS
From January 1998 to December 1999, a total of 670 patients were subjected to the ICSI programme at the Centre for Human Reproduction, Sinhá Junqueira Maternity Foundation, and the FEC parameter was evaluated in three situations.


RESULTS
In the first, a total of 300 zygotes were analyzed on the basis of a score (16-18 h after ICSI) and observed for the presence or absence of FEC (25-27 h after ICSI). A significant (p < 0.02) presence of FEC was observed in zygotes with a score of 15 (ideal score). In the second, a total of 200 patients were selected and divided into two groups matched for age and laboratory performance. Group I (n = 100) was subjected to transfer of embryos with the absence of FEC only (since in this cycle no embryos with FEC were detected within 25-27 h after ICSI) and Group II (n = 100) was subjected to transfer of embryos with the presence of FEC only. The age of Group I patients (33.8 +/- 4.2 years) did not differ significantly (p = 0.50) from that of Group II patients (33.5 +/- 4.3 years). The number of embryos transferred was similar (p = 0.07) for Group I (2.7 +/- 1.1) and Group II (2.9 +/- 0.88). In Group II, the 17.5% implantation rate was significantly higher (p < 0.01) than the 5.9% rate obtained for Group I. The pregnancy rate for Group II was significantly higher (p < 0.01) (33%) than that for Group I (12%). The incidence of abortion was 16.6% in Group I as compared with 6% in Group II. In the third situation, we observed the frequency of embryos with FEC in 36 patients whose implantation rate was 100% (ideal result) and obtained a value of 82%.


CONCLUSIONS
The data suggest that the presence of the FEC parameter that was evaluated 25-27 h after ICSI could be used to select embryos with a higher implantation power. The data reported here may justify routine analysis of embryos with FEC for the process of embryo selection after ICSI.
Petersen
C G
CG
Centre for Human Reproduction, Sinhá Junqueira Maternity Foundation, Rua D. Alberto Gonçalves 1500, 14085-100 Ribeirão Preto, SP, Brazil.
Mauri
A L
AL
Ferreira
R
R
Baruffi
R L
RL
Franco Júnior
J G
JG
D000328:Adult; D002455:Cell Division; D002970:Cleavage Stage, Ovum / Q000166:cytology* / Q000637:transplantation*; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*; D013997:Time Factors; D015053:Zygote / Q000378:metabolism