Bulent Urman

Publications (127) View all

• Article: Single dose GnRH agonist administration in the luteal phase of assisted reproduction cycles: is the effect dependent on the type of GnRH analogue used for pituitary suppression?

  B Ata, B Urman
  Reproductive biomedicine online 01/2010; 20(1):165-6; author reply 167. · 2.04 Impact Factor
• Article: Severe cytoplasmic abnormalities of the oocyte decrease cryosurvival and subsequent embryonic development of cryopreserved embryos.

  B Balaban, B Ata, A Isiklar, K Yakin, B Urman
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  ABSTRACT: Abnormalities of oocyte morphology affect embryo quality and viability. Whether morphological abnormalities of the oocyte influence cryosurvival and further development of derived embryos is not known. The aim of this study was to compare cryosurvival and progression to the blastocyst stage of frozen-thawed embryos derived from normal and abnormal oocytes. A total of 5292 Grade 1 and 2 embryos from 964 women were frozen, thawed and subsequently cultured up to the blastocyst stage. The study was performed on excess embryos from patients who did not opt for cryopreservation. Cryosurvival, progression to the blastocyst stage and hatching were correlated with morphological characteristics of the oocytes that embryos were derived from. Presence of a cytoplasmic abnormality of the oocyte significantly decreased cryosurvival. This detrimental effect was more pronounced in embryos derived from oocytes with vacuolar cytoplasm or with central granulation. Furthermore, these embryos did not have the potential to develop into good quality blastocysts or reach the hatching stage. On the other hand, presence of a single extracytoplasmic abnormality of the oocyte did not affect cryosurvival and the potential to develop into good quality blastocysts. Grade 2 embryos derived from oocytes with irregular shape or a large perivitelline space had decreased cryosurvival. However when these embryos survived cryopreservation, their potential to develop good quality blastocysts or to reach hatching stage was unaffected. Embryos derived from oocytes with vacuolar cytoplasm or central granulation do not seem to bear the potential to develop good quality blastocysts or to reach hatching stage after cryopreservation. The presence of extracytoplasmic abnormalities alone does not affect blastocyst development despite decreasing cryosurvival.
  Human Reproduction 09/2008; 23(8):1778-85. · 4.47 Impact Factor
• Article: A randomized controlled study of human Day 3 embryo cryopreservation by slow freezing or vitrification: vitrification is associated with higher survival, metabolism and blastocyst formation.

  B Balaban, B Urman, B Ata, A Isiklar, M G Larman, R Hamilton, D K Gardner
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  ABSTRACT: The aim of this study was to compare two methods of cryopreservation for the cleavage-stage human embryo: slow freezing and vitrification. A total of 466 Day 3 embryos, donated with consent, underwent cryopreservation by either slow freezing in straws or vitrification using the cryoloop. The vitrification procedure did not include dimethyl sulfoxide, but rather employed ethylene glycol and 1,2-propanediol as the cryoprotectants. Survival, embryonic metabolism and subsequent development to the blastocyst were used to determine the efficacy of the two procedures. Significantly, more embryos survived the vitrification procedure (222/234, 94.8%) than slow freezing (206/232, 88.7%; P < 0.05). Consistent with this observation, pyruvate uptake was significantly greater in the vitrification group, reflecting a higher metabolic rate. Development to the blastocyst was also higher following vitrification (134/222, 60.3%) than following freezing (106/206, 49.5%; P < 0.05). In a separate cohort of 73 patients who had their supernumerary embryos cyropreserved with vitrification, the resulting implantation rate and clinical pregnancy rate were 30 and 49%, respectively. Analysis of metabolism revealed that vitrification had less impact on the metabolic rate of the embryo than freezing, which was reflected in higher survival rate and subsequent development in vitro. Excellent pregnancy outcomes followed the warming and transfer of vitrified cleavage-stage embryos. These data provide further evidence that vitrification imparts less trauma to cells and is, therefore, a more effective means of cryopreserving the human embryo than conventional slow freezing. Clinicaltrials.gov identifier: NCT00608010.
  Human Reproduction 06/2008; 23(9):1976-82. · 4.47 Impact Factor
• Article: GnRH agonist protocol administration in the luteal phase in ICSI-ET cycles stimulated with the long GnRH agonist protocol: a randomized, controlled double blind study.

  B Ata, K Yakin, B Balaban, B Urman
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  ABSTRACT: GnRH agonist administration in the luteal phase was reported to beneficially affect the clinical outcome of intracytoplasmic sperm injection (ICSI) and embryo transfer (ET) cycles. This double blind, randomized, placebo controlled trial evaluates whether a single dose GnRH agonist administered 6 days after ICSI increases ongoing pregnancy rates following ET in cycles stimulated with the long GnRH agonist protocol. Five hundred and seventy women undergoing ET following controlled ovarian stimulation with a long GnRH agonist protocol were included. In addition to routine luteal phase support with progesterone, women were randomized to receive a single 0.1 mg dose of triptorelin or placebo 6 days after ICSI. Randomization was done on the day of ET according to a computer generated randomization table. Ongoing pregnancy rate beyond 20th week of gestation was the primary outcome measure. The trial was powered to detect a 12% absolute increase from an assumed 38% ongoing pregnancy rate in the placebo group, with an alpha error level of 0.05 and a beta error level of 0.2. There were 89 (31.2%) ongoing pregnancies in the GnRH agonist group, and 84 (29.5%) in the control group (absolute difference +1.7%, 95% confidence interval -5.8% to +9.2%). Implantation, clinical pregnancy and multiple pregnancy rates were likewise similar in the GnRH agonist and placebo groups. Single 0.1 mg triptorelin administration 6 days after ICSI following ovarian stimulation with the long GnRH agonist protocol does not seem to result in an increase >or=12% in ongoing pregnancy rates.
  Human Reproduction 03/2008; 23(3):668-73. · 4.47 Impact Factor
• Article: An alternative to PVP for slowing sperm prior to ICSI.

  B Balaban, K Lundin, J M Morrell, H Tjellström, B Urman, P V Holmes
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  ABSTRACT: There is a growing awareness of potential problems in exposing sperm to polyvinylpyrrolidone (PVP) to slow their motility, a procedure commonly used prior to ICSI. The study presented here evaluates an alternative product for slowing sperm motility, which contains hyaluronate, a substance found naturally in the reproductive tract. Computerized sperm motility analysis was used to compare the motilities of sperm exposed to either a PVP-containing product (ICSI-100), or a hyaluronate-containing product (SpermCatch), or control sperm resuspended in a sperm maintenance medium. A subjective assessment was made of the ease with which sperm could be isolated and be drawn into, and expelled from, an injection pipette after having their tails nicked. Sperm exposed to either ICSI-100 or SpermCatch were used for ICSI. Fertilization rate, zygote development, grading, and outcome of transfer were recorded for the two treatment groups. The hyaluronate-containing product slowed sperm motility sufficiently for the sperm to be captured in an injection pipette, was easy to draw into and expel from the pipette, prevented sperm sticking to plastic or glassware, and did not affect post-injection zygote development. Clinical pregnancy rates were similar for the two groups. This product represents an alternative to PVP for slowing sperm motility prior to ICSI.
  Human Reproduction 10/2003; 18(9):1887-9. · 4.47 Impact Factor