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Biomedical subjects

Kayhan Yakin

Publications and source records attributed to Kayhan Yakin.

14 recordsLinked to original sources
PubMed2006

Utilization of high-security straws for embryo freezing in an in vitro fertilization program: a prospective, randomized study.

OBJECTIVE: To compare the outcome of frozen-thawed ET cycles where embryos had been stored in conventional versus ionomeric resin-based, high-security straws (HSSs). DESIGN: Prospective, randomized study. SETTING: Private assisted-reproduction unit. PATIENT(S): Three hundred and six freeze cycles, and 197 thaw cycles. INTERVENTION(S): Day 3 embryos (n = 1,268) were frozen, and 517 were thawed using HSSs. Alternately, day 3 embryos (n = 1,228) were frozen, and 505 were thawed using conventional straws. MAIN OUTCOME MEASURE(S): Cryosurvival, cleavage and morulae formation rates, and clinical pregnancy, implantation, and multiple pregnancy rates. RESULT(S): Although cycle characteristics did not show any differences, the cryosurvival rate was higher in the HSS group (94.7%) than in the conventional straw group (86%), as was the morulae formation rate (58.7% versus 42.7%). Despite a similar number of embryos being transferred, the clinical pregnancy rate (PR) was higher in the HSS group, but the difference lacked statistical significance (42.5% versus 31.2). Implantation rates (19.4% versus 11.4%) and multiple PRs (41.8% versus 16.6%) were significantly higher in the HSS group than in the conventional straw group. CONCLUSION(S): High-security straws are high effective in human embryo cryopreservation, because they provide higher cryosurvival and implantation rates, as well as a lower risk of cross-contamination compared to conventional straws.

Adult↗
PubMed2006

Impact of fresh-cycle variables on the implantation potential of cryopreserved-thawed human embryos.

OBJECTIVE: To compare the clinical outcomes of cryopreservation according to the indications for freezing and the outcomes of the fresh cycle from which the embryos were derived. DESIGN: Retrospective study. SETTING: Private assisted-reproduction unit. PATIENT(S): Three thousand, three hundred and sixty-eight embryos in 702 frozen-thawed embryo transfer (ET) cycles. INTERVENTION(S): Clinical outcomes of frozen-thawed ET cycles in which embryos were derived from fresh conception cycles (n = 436), from fresh nonconception cycles (n = 180), or where the fresh cycle was cancelled due to impending ovarian hyperstimulation syndrome (OHSS) (n = 86). MAIN OUTCOME MEASURE(S): Cryosurvival, clinical pregnancy, and implantation rates. RESULT(S): Despite similar cryosurvival rates and the transfer of a similar number of embryos, significantly higher clinical pregnancy and implantation rates were obtained in the fresh-conception and OHSS groups. The implantation potential of frozen-thawed embryos that were not selected in a prior fresh cycle was comparable to that of embryos selected for fresh transfer. CONCLUSION(S): The success of frozen-thawed ET depends on the outcome of fresh ET and the indications for cryopreservation. Success is similar to that of fresh ET cycles in patients who had all their embryos frozen due to impending OHSS.

Adult↗
PubMed2006

Laser-assisted hatching increases pregnancy and implantation rates in cryopreserved embryos that were allowed to cleave in vitro after thawing: a prospective randomized study.

BACKGROUND: Cryopreservation of embryos may lead to zona hardening that may compromise in vivo hatching and implantation following thawing and transfer. Assisted hatching (AH) has been advocated as a means of assisting the natural hatching process and enhancing implantation. METHODS: The aim of this study was to assess in a prospective randomized manner the effect of laser-assisted hatching (LAH) on implantation as well as clinical and multiple pregnancy rates (the primary outcome) after the transfer of frozen-thawed embryos. All embryos were thawed the day before transfer, and LAH was performed the next day on embryos that cleaved. Control group consisted of embryos that were transferred without AH. RESULTS: The performance of LAH significantly increased implantation (9.9 versus 20.1%, P < 0.01), clinical pregnancy (27.3 versus 40.9, P < 0.05) and multiple pregnancy rates (16 versus 40.3%, P < 0.07). In the LAH group, significantly more excess embryos that were left in culture hatched in vitro. CONCLUSIONS: LAH improves the outcome of frozen-thawed embryo transfer when performed before transfer on embryos that were allowed to cleave.

Cryopreservation↗
PubMed2006

Randomized comparison of two different blastocyst grading systems.

A more detailed blastocyst grading system provides a better selection of blastocysts with the highest implantation potential. Grading systems will help to decrease the number of blastocysts to be transferred without compromising high implantation and pregnancy rates.

Adult↗
PubMed2006

Ovulatory disorders and infertility.

Ovulatory disorders represent a major cause of infertility. The World Health Organization classification offers a useful frame for diagnosis and treatment. Polycystic ovary syndrome (PCOS) is the most common cause of oligoovulation and anovulation. Treatment of infertility associated with PCOS has changed in the last decade due to the introduction of new medications. Insulin-sensitizing drugs, such as metformin, became an integral part of treatment. Aromatase inhibitors will most probably replace clomiphene citrate in the future. Women who fail to ovulate or conceive after first-line treatment options are often referred for gonadotropin treatment. Laparoscopic ovarian drilling, which has been evaluated in well-designed trials, may be an alternative to gonadotropins. In vitro fertilization, which yields high pregnancy rates, is the final treatment option when all else fails. Hypogonadotropic anovulation is treated with exogenous gonadotropins, and little has changed in its management. Women with hypergonadotropic hypogonadism should be counseled for adoption or in vitro fertilization with donated oocytes as spontaneous and treatment-associated pregnancy rates are very low.

Anovulation↗
PubMed2005

Impact of the presence of one or more multinucleated blastomeres on the developmental potential of the embryo to the blastocyst stage.

A retrospective study of 5,982 embryos in 619 blastocyst-stage embryo transfer cycles revealed that detection of multinucleated blastomeres either on day 2 or 3 signifies a poor prognosis for blastocyst formation and that no good-quality blastocyst can be expected from an embryo with more than one multinucleated blastomere. Patients should be counseled regarding a poor prognosis when multiple embryos with multinucleated blastomeres are present.

Adult↗
PubMed2005

Recurrent implantation failure in assisted reproduction: how to counsel and manage. A. General considerations and treatment options that may benefit the couple.

Recurrent implantation failure is a distressing phenomenon, both for the infertile couple and for the physician responsible for their treatment. Aetiology is often not clear and treatment options are vague. Particularly when transferred embryos are of good quality, recurrent implantation failure may be attributed to less than optimal embryo transfer technique, pathological lesions of the uterine cavity, the presence of hydrosalpinges, fibroids and endometriosis. Poor embryo quality, especially when repetitive, is a major impediment to successful implantation and cannot be corrected at the present time. Molecular abnormalities at the endometrial level and abnormal embryo-endometrium dialogue may be responsible for some cases of recurrent implantation failure. Furthermore, there may be over- or under-expressed genes that may be related to successful implantation. At the present time, the physician confronted with a couple presenting with recurrent implantation failure should discuss openly the potential causes of this phenomenon, with special emphasis on correctable causes, and offer remedies that are evidence based.

Counseling↗
PubMed2005

Recurrent implantation failure in assisted reproduction: how to counsel and manage. B. Treatment options that have not been proven to benefit the couple.

The success of assisted reproduction, although gradually increasing over the years, is still less than satisfactory. Many couples have benefited from this treatment; however, many have also been left frustrated following multiple failed attempts. Couples who fail to conceive after multiple IVF/intracytoplasmic sperm injection (ICSI) treatments often seek treatment options that are new and that have not been offered before. Some of these include immunological testing and treatment, allogenic lymphocyte therapy, intratubal transfer of zygotes and embryos, blastocyst transfer, sequential embryo transfer, assisted hatching, co-cultures, and preimplantation genetic screening for aneuploidy. Although the evidence behind some of these is more robust, most suffer from lack of well designed randomized trials comparing them with other treatment options. Randomized studies are extremely difficult to conduct, as couples will resist being randomized into a treatment group where previously failed procedures will be repeated. In the mean time, assisted reproduction programmes should resist offering treatment options that are not evidence based, or at least they should share with the couple the information that is available and should stress that none of these is a panacea for their problem.

Aneuploidy↗
PubMed2005

Is there a possible correlation between chromosomal variants and spermatogenesis?

AIM: Heterochromatin polymorphism is considered a variant of a normal karyotype but is more frequent in infertile men. The aim of this study was to evaluate the correlation between heterochromatic variants and male infertility and to discuss the possible mechanisms of how heterochromatic polymorphism might affect spermatogenesis. METHODS: Cytogenetic analysis was undertaken in 210 infertile males who had been taken into assisted reproductive techniques and in 183 men with proven fertility. Additionally, C-banding was performed in men with heterochromatin polymorphism. Sperm fluorescence in situ hybridization (FISH) was applied in 54 men with normal karyotype presenting either normal or abnormal sperm parameters as well as in 8 men with heterochromatin polymorphism. The outcomes of assisted reproductive techniques were compared between infertile men with normal karyotype and men with heterochromatin polymorphism. RESULTS: The incidence of heterochromatin polymorphism was higher in infertile men. The most frequent chromosome involved in heterochromatin polymorphism was chromosome 9. Sperm FISH analysis revealed an increased rate of aneuploidy in men with heterochromatin polymorphism. Laboratory and clinical outcomes in assisted reproductive techniques were compromised in men with heterochromatin polymorphism. CONCLUSIONS: An increased rate of heterochromatin polymorphism in infertile males seems to be more than an incidental finding, and must not be considered as a normal variant. Polymorphic heterochromatin may have deleterious effects on the genetic constitution of spermatozoa. More attention must be directed to infertile men with heterochromatin polymorphism.

Adult↗
PubMed2004

Assisted reproduction in the treatment of polycystic ovarian syndrome.

Treatment of patients with polycystic ovary syndrome (PCOS) with assisted reproductive techniques is a great challenge for the infertility specialist. Patients with PCOS demonstrate many problems, such as excessive body weight and hyperinsulinaemia, that render management more complex. Prior to treatment with IVF, the PCOS patient should be thoroughly evaluated for disclosure of endometrial neoplasia, hyperinsulinaemia, and other general health related problems. Ovarian stimulation for IVF carries the risks of overstimulation and severe hyperstimulation, which should be avoidable in most cases with preventive measures. The outcome in terms of pregnancy and implantation rates is similar for patients with PCOS when compared with patients undergoing IVF for other indications. There are some questions regarding oocyte and embryo quality in women with PCOS. This manifests itself in lower fertilization rate and decreased embryo quality in some studies. However, increased numbers of oocytes available for insemination or ICSI compensate for decreased fertilization rates and embryo quality. More recent studies suggest higher cumulative conception rates in women with PCOS when compared with controls. In-vitro maturation (IVM) of oocytes retrieved from non-stimulated or minimally stimulated cycles represents a viable option that should be considered seriously when assisted conception is attempted. Results of IVM, however, should be improved further and generalized before the technique can be advocated as the initial treatment approach in these patients.

Cellular Senescence↗
PubMed2004

Pronuclear morphology predicts embryo development and chromosome constitution.

The relationship between pronuclear morphology on the one hand, and embryo development and chromosomal status on the other, was evaluated in 68 couples scheduled to undergo preimplantation genetic diagnosis because of advanced maternal age or recurrent implantation failure. Zygotes were grouped according to their pronuclear (PN) morphology. During the period from fertilization to embryo transfer, cleavage rate, embryo quality, blastocyst formation and results of the chromosomal analysis of 240 embryos were recorded. Both embryo cleavage characteristics and chromosome constitution were related to PN morphology. Embryos developing from zygotes with the normal PN pattern (pattern 0) cleaved faster and formed embryos with better morphology as compared with zygotes with abnormal PN patterns. Aneuploidy rate of embryos derived from zygotes with the normal PN pattern, with a single PN anomaly and with a double PN anomaly was 25.6, 73 and 83% respectively. Chromosomally normal embryos with the normal PN pattern progressed to the blastocyst stage at a higher rate (90%) than chromosomally normal embryos with a single (61%) or a double (40%) PN anomaly. The same relationship applied to chromosomally abnormal embryos. It is concluded that PN morphology predicts both the risk of embryo developmental arrest and that of chromosomal abnormalities.

Blastocyst↗
PubMed2003

Outcome of blastocyst transfer according to availability of excess blastocysts suitable for cryopreservation.

The purpose of this study was to assess the outcome of blastocyst transfer in relation to the presence or absence of excess blastocysts available for cryopreservation. The study was designed as a retrospective case series in a tertiary care private hospital. The study group consisted of 450 blastocyst stage embryo transfer cycles. In 139 cycles there were excess freezeable blastocysts (group 1), in 78 cycles there were excess but unfreezeable blastocysts (group 2), and in 233 cycles there were no excess blastocysts (group 3). A mean of three blastocysts was replaced in all groups. Treatment cycle characteristics, implantation and pregnancy rates following fresh and cryopreserved blastocyst transfer were assessed in each group. More embryos reached the blastocyst stage in group 1 and more blastocysts were of good quality. In group 1, clinical pregnancy and implantation rates (71 and 41%) were significantly higher compared with groups 2 (56 and 27%) and 3 (43 and 19%). Embryos that were selected for transfer among a cohort of good quality blastocysts yielded the highest implantation and pregnancy rates. Given a clinical pregnancy rate of 71%, an implantation rate per embryo of 41%, and a multiple pregnancy rate of 58%, serious consideration should be given to a single blastocyst transfer in these patients.

Abortion, Spontaneous↗
PubMed2003

Male age is not an independent factor to affect the outcome of assisted reproductive techniques.

Controversy exists whether advanced male age is associated with poor sperm quality and subsequent failure in the assisted reproductive techniques (ART). The purpose of this study was to evaluate the effect of male age on sperm quality and the outcome of ART as well as the association of male age with other relevant factors, particularly with the female age. A retrospective study was performed in order to evaluate the effect of male age on the sperm parameters in 880 routine seminal analyses. Additionally, sperm parameters were also compared among different age groups in 919 cases with male factor infertility who had been included in an ART programme. The laboratory and clinical results of ART (fertilization rate, number and quality of embryos transferred, as well as pregnancy rates) were compared according to different age groups. The results were also evaluated by one-way correlation and also step-wise logistic regression analysis to identify the interactions and correlations between different parameters. There were no statistically significant differences between male age groups in terms of sperm concentration, motility and morphology either in routine seminal analyses or in ART groups. In the ART group, a statistically significant linear correlation was present between male and female ages. Male age was increasing in parallel to female age. Female age was also correlated significantly with ART results. In one-way correlation analysis, male age was found to be correlated with the pregnancy rate, but not with fertilization rate and the quality of the transferred embryos. However, regression analysis revealed that correlation between male age and pregnancy results was simply dependent on the effect of the female age. Seminal parameters did not reveal a significant change with the increasing male age. The effect of male age on ART results in cases with male factor infertility is not a direct effect but a reflection of the negative impact of the parallel increase in the female age.

Adult↗