Embryo development of fresh “versus” vitrified metaphase IIoocytes after ICSI: a prospectiverandomized sibling-oocyte study Human Reproduction Vol.25 No.1 pp.66-73, 2010 2009/12/24 Ian Huang
March 2004 to May 2009• Italian Law No. 40 regulates ART1. no more than 3 oocytes could be inseminated per cycle.2. all obtained embryos had to be transferred.3. embryo cryopreservation and gamete donation were forbidden.• As a results, oocyte selection and oocyte preservation have been a routine practice in Italian IVF centers.
Recent edict of Italian Constitutional Court (151/2009)• 1. embryo freezing is constitutional, if determined by the health of the patient.• 2. the numbers of oocytes to be inseminated is now chosen by the physician.• The population of this study is from 2008/9/2 to 2009/3/10
Aim• To compare the in vitro performance of fresh and vitrified oocytes post-ICSI procedure.• Measure fertilization, PN morphology, embryo development and embryo morphology of fresh and vitrified sibling oocytes.
Target population• 1. < 42 yrs old• 2. more than 6 normal MII oocytes• 3. MESA/TESE or motile sperm count < 0.5x10^6/ml after preparation are excluded.• 4. PB biopsy is excluded.
Methods• GnRH agonist long protocol and GnRH- antagonist protocol for stimulation.• Oocyte collection at 35 h post-hCG.• Denudation at 37 to 40 h post-hCG.• Oocytes with dark cytoplasm, centrally located granular area, giant with vacuoles, large polar body were excluded.
• radom number assign for normal MII oocyte by computer-generated random list.• 1, 2, 3 for fresh ICSI• others for vitrification(warmed ICSI). (4, 5, 6, ….so on)• fresh ICSI: maximum of 3 oocyte were inseminated, and all obtained embryos are transferred at 44-48 h post ICSI.• warmed ICSI: warmed at 36-40 h post-hCG in nature cycle, surviving oocytes were cultured at 37℃(6%CO2, 5%O2) for 2 h before ICSI.
Discussion• According to the results, embryo development up to Day 2 is not affected by vitrification procedure.• Oocyte survival rate was higher than 95%.• The number of oocytes degenerated during warming procedure was negligible and did not affect the overall fertilization rate.• Although some, non-significant, differences in pronuclear morphology were observed, embryo quality was similar in the two groups.• The percentage of top quality embryos per fertilized oocyte was about 52% in fresh and vitrified group of oocytes.
Discussion• Four ongoing pregnancies (30.7%) were obtained in women aged > 38 years. It cannot be excluded that endometrium receptivity may also be involved in successful implantation of embryos derived from vitrified oocytes.• By transferring embryos in a natural unstimulated cycle, synchronization of embryo and endometrial development can be, in fact, probably better obtained.
Discussion• This results indicate that oocyte vitrification procedure followed by ICSI is not inferior to fresh insemination procedure, with regard to fertilization and embryo developmental rates.• Moreover, ongoing clinical pregnancy is compatible with this procedure, even with a restricted number of oocytes available for insemination.• The promising clinical results obtained, in a population of infertile patients, need to be confirmed on a larger scale.