Dr Laura Rienzi
Clinica Valle Giulia
Via de Notaris 2B
Embryo development of fresh versus vitrified metaphase II after intracytoplasmic sperm injection (ICSI): a prospective randomised active-controlled parallel group sibling-oocyte study
Non-inferiority trial in order to evaluate the effectiveness of the oocyte vitrification procedure, effectiveness being defined by fertilisation rate after intracytoplasmic sperm injection (ICSI) per warmed oocyte.
Local medical ethics committee (Clinica Valle Giulia, Roma) approved on the 1st September 2008
Randomised active controlled parallel group trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Intracytoplasmic sperm injection cases, oocyte vitrification
After oocyte denudation, MII oocytes with normal morphology were randomly allocated to fresh ICSI insemination or to vitrification procedure. If pregnancy was not obtained a subsequent ICSI cycle was performed with warmed oocytes of the same cohort. In both groups, 3 oocytes were inseminated per cycle by ICSI procedure.
The vitrification and warming procedures were performed according to Kuwayama and co-Authors (2005). Commercial kits were used (Vitrification and Warming KIT, Kitazato BioPharma Co, Japan).
The vitrification procedure was performed at room temperature (RT). Oocytes were equilibrated in the equilibration solution (ES) containing 7.5% ethylene glycol (EG) and 7.5% dimethylsulfoxide (DMSO) in HEPES buffered basic culture medium M-199 with 20% synthetic serum substitute (SSS). To perform the equilibration gradually, the oocytes were first placed in a 20 microlitre drop of M199+20%SSS and, immediately, after mixed with a second 20 microlitre drop of ES. After 3 minutes incubation, a third 20 microlitre drop of ES solution was mixed. Finally, the oocyte were moved in a pure drop of 20 microlitre ES and incubated for an additional 6 - 9 minutes. The oocytes (1 to 3, contemporaneously) were then transferred in 1 ml of vitrification solution (VS) containing 15% EG, 15% DMSO and 0.5M sucrose in M199+20%SSS for 1 minute. The oocytes were then placed on the Cryotop strip in a single small drop of VS. Much care was driven to re-aspirate, as much as possible, the excess of VS in such way to leave just a thin layer around each oocyte. The Cryotop was then immediately submerged into liquid nitrogen. Finally, the plastic cap was pulled over the Cryotop inside the liquid nitrogen and the sample was stored submerged in liquid nitrogen.
The first step of warming procedure was performed at 37°C. The cap was removed in liquid nitrogen and the cryotop was immediately submerged in 1 ml of warming solution containing 1.0M sucrose in M199+20%SSS. After 1 minute, oocytes were placed in 1 ml solution containing 0.5M sucrose, and incubated at RT for 3 minutes. Finally, the oocytes were washed at RT for 6 minutes in 2 different dishes containing 1 ml basic medium M199+20%SSS each, and transferred into 1 ml culture media. Degenerated oocytes were removed from the cohort.
The surviving oocytes were co-cultured at 37°C (6% CO2 and 5%O2) for exactly 2 hours before ICSI.
Primary outcome measure
Non-inferiority in fertilisation rates calculated per warmed and per injected oocyte, assessed 16 - 18 hours post-treatment (ICSI).
Secondary outcome measures
1. Pronuclear morphology
2. Embryo development, assessed 42 - 44 hours post-treatment
3. Patient's baseline characteristics
4. Clinical outcomes
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
Between September 2008 and February 2009 consecutive patients not older than 42 years of age, presenting greater than 6 normal appearing metaphase II (MII) oocytes and undergoing ICSI treatment with ejaculated sperm in the Centre for Reproductive Medicine GENERA in Rome.
Target number of participants
Participant exclusion criteria
1. Female partner older than 42 years old
2. Less than 6 normal appearing MII oocytes retrieved
3. Surgically extracted spermatozoa
4. Very severe oligoastenoteratozoospermia (motile sperm count less than 500,000/ml after preparation)
5. Patients enrolled in our polar body biopsy programme
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
G.EN.E.R.A. - Clinica Valle Giulia (Italy)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
2010 results in http://www.ncbi.nlm.nih.gov/pubmed/19861328
Rienzi L, Romano S, Albricci L, Maggiulli R, Capalbo A, Baroni E, Colamaria S, Sapienza F, Ubaldi F, Embryo development of fresh 'versus' vitrified metaphase II oocytes after ICSI: a prospective randomized sibling-oocyte study., Hum. Reprod., 2010, 25, 1, 66-73, doi: 10.1093/humrep/dep346.