Embryology. Orientation of the first polar body of the oocyte at 6 or 12 o'clock during ICSI does not affect clinical outcome
Author: Stoddart, N.R.
Source: Human Reproduction, Volume 15, Number 7, July 2000 , pp. 1580-1585(6)
Publisher: Oxford University Press
Abstract:This study was designed to clarify whether orientation of the first polar body (PB) of the oocyte at 6 o'clock rather than 12 o'clock, during intracytoplasmic sperm injection (ICSI), significantly affects a number of clinically important outcome measures including fertilization, zygote cleavage, embryonic morphology, and clinical pregnancy and implantation rates. In all, 114 patients were allocated to one of two groups on the basis of strict alternation, both groups being treated by the same ICSI practitioner. In one group, all oocytes were injected with their first PB at 6 o'clock, whereas in the other, the orientation of the PB was reversed (12 o'clock). In all cases, a normally bevelled injection pipette was inserted into the oocyte in the 3 towards 9 o'clock direction. The orientation of the PB did not significantly affect the proportion of oocytes that failed to survive injection or the proportion scored as having either zero, one, two or three pronuclei. The proportion of normally fertilized zygotes that cleaved was not significantly different between the two groups, nor was the proportion of embryos classified as either grade 1, 2 or 3. However, the proportion of grade 4 embryos (the poorest grade) was significantly lower in the 12 o'clock, compared to the 6 o'clock group. Most importantly, there was no significant difference between the two groups in the proportion of patients having a positive clinical pregnancy test, nor in either the implantation rate or the mean number of fetal hearts detected per patient presenting with a clinical pregnancy.
Document Type: Research Article
Affiliations: Department of Obstetrics & Gynaecology, University Hospital, Nottingham, UK and
Publication date: July 2000
- Human Reproduction features full-length, peer-reviewed papers reporting original research, clinical case histories, as well as opinions and debates on topical issues. Papers published cover the scientific and medical aspects of reproductive physiology and pathology, endocrinology, andrology, gonad function, gametogenesis, fertilization, embryo development, implantation, pregnancy, genetics, genetic diagnosis, oncology, infectious disease, surgery, contraception, infertility treatment, psychology, ethics and social issues. The highest scientific and editorial standard is maintained throughout the journal along with a rapid rate of publication.