Publications by authors named "İpek Keles"

This guideline was prepared by the Turkish Society of Reproductive Medicine to define the conditions and requirements for an outsourced preimplantation genetic testing (PGT) programme in line with the experience and needs of practitioners. This guideline is intended to be a reference document for assisted reproductive technology centres, genetic diagnosis centres, non-governmental organizations working on reproductive health, legal experts, consultants working on laboratory accreditation, academicians specializing in ethical issues, and policy makers. The Consortium aims to provide recommendations addressing the challenges of genetic testing, especially PGT for monogenic diseases (PGT-M) due to the high rate of consanguineous marriage in Turkey.

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Research Question: Does the trigger to oocyte retrieval interval (TORI) affect oocyte maturation rates differently in progestin-primed ovarian stimulation (PPOS) and gonadotrophin-releasing hormone (GnRH) antagonist cycles?

Design: This was a retrospective cohort study. The interaction between the stimulation protocol and TORI was assessed in a linear mixed effects multivariable regression analysis with oocyte maturation rate as the dependent variable, and stimulation protocol (GnRH antagonist or PPOS), age (continuous), gonadotrophin type (FSH or human menopausal gonadotrophin), trigger (human chorionic gonadotrophin [HCG] or GnRH agonist), TORI (continuous) and days of stimulation (continuous) as the independent variables. Oocyte maturation rate was defined as number of metaphase II oocytes/number of cumulus-oocyte complexes retrieved.

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Purpose: This article aims to assess how differences in maternal age distributions between IVF clinics affect the performance of an artificial intelligence model for embryo viability prediction and proposes a method to account for such differences.

Methods: Using retrospectively collected data from 4805 fresh and frozen single blastocyst transfers of embryos incubated for 5 to 6 days, the discriminative performance was assessed based on fetal heartbeat outcomes. The data was collected from 4 clinics, and the discrimination was measured in terms of the area under ROC curves (AUC) for each clinic.

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Study Question: Are the IVF parameters and the steroidogenic luteal characteristics of random-start IVF cycles different from conventional cycles in cancer patients?

Summary Answer: No; controlled ovarian stimulation cycles randomly started at late follicular phase (LFP) and luteal phase (LP) are totally comparable to those conventional IVF cycles started at early follicular phase (EFP) in terms of the expression of the enzymes involved in cholesterol utilization and steroid hormone biosynthesis pathways, gonadotropin receptor expression and, estradiol (E2) and progesterone (P4) production in addition to the similarities in ovarian response to gonadotropin stimulation, oocyte yield, fertilization rate and embryo development competency in cancer patients.

What Is Known Already: Random start ovarian stimulation protocols are commonly employed for oocyte and embryo freezing for fertility preservation in cancer patients with time constraints who do not have sufficient time to undergo ovarian stimulation initiated conventionally at EFP of the next cycle. No data is available regarding the molecular steroidogenic features of these cycles analyzed together with the clinical IVF characteristics in cancer patients.

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A suggested explanation for the pituitary-suppressive effects of progestin-primed ovarian stimulation cycles (PPOS) is pituitary luteinizing hormone (LH) depletion with progestin exposure during the follicular phase. The GnRH agonist (GnRHa) trigger releases endogenous LH from the pituitary, and if the LH depletion theory is correct, the response to the agonist trigger would be dampened in PPOS cycles. In this study, we compared the performance of the GnRHa trigger after PPOS and GnRH antagonist ovarian stimulation cycles.

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While gonadotrophin releasing hormone (GnRH) antagonists have been the standard of pituitary suppression during ovarian stimulation for ART, progestin primed ovarian stimulation (PPOS) has emerged as an alternative. Progestins can be started simultaneously with gonadotrophins (fixed PPOS) or later in the cycle depending on follicle growth (flexible PPOS). However, the flexible and fixed PPOS regimens have not been directly compared as of yet.

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Background: This study compared outcomes of the standard 6000 IU human chorionic gonadotropin (hCG) trigger with a dual trigger comprised of 6000 IU hCG and 1 mg leuprolide acetate for final oocyte maturation in an intracytoplasmic sperm injection (ICSI) cycle. By convention, ICSI was performed in most cases at the clinic.

Materials And Methods: In this retrospective study, a total of 50 women were included in each arm.

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Research Question: Do live birth rates (LBR), obstetric and perinatal outcomes vary between women who underwent frozen embryo transfer (ET) in the immediately subsequent menstrual cycle, and with those who underwent delayed frozen ET.

Design: Retrospective cohort study (n = 198) consisting of 119 women who underwent immediate transfer within 30 days of oocyte retrieval (OR) and 79 women who underwent delayed transfer which was performed after >30 days following OR. Either flexible antagonist or flexible progestin-primed ovarian stimulation protocols were started after a baseline ultrasonography on the second or third day of menstrual cycle.

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Objective: To investigate the predictive value of endometrial thickness (EMT) for live birth when a lower threshold of EMT is not employed for embryo transfer (ET).

Design: Retrospective study SETTING: Academic assisted reproduction center PATIENT(S): All women who underwent fresh or frozen-thawed ET at the Koç University Hospital Assisted Reproduction Unit between October 2016 and August 2019 INTERVENTION(S): After ruling out endometrial pathology, blastocyst transfer was planned regardless of the EMT in the absence of increased serum progesterone level on the trigger day in fresh embryo transfer cycles or before commencing progesterone treatment in artificially prepared frozen-thawed ET cycles.

Main Outcome Measure(s): The primary outcome was live birth.

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The aim of this retrospective cohort study was to compare the effectiveness of the new flexible progestin primed ovarian stimulation (fPPOS) protocol with the flexible gonadotropin-releasing-hormone antagonist (GnRH-ant) protocol in women with decreased ovarian reserve (DOR). Twenty-seven women who underwent fPPOS and 54 age-matched women who received GnRH-ant for pituitary suppression were included in the study. All women had DOR and underwent oocyte cryopreservation.

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Research Question: Does subcutaneous progesterone provide similar live birth or ongoing pregnancy rates as vaginal progesterone in frozen embryo transfer (FET) cycles?

Design: Retrospective cohort study (n = 214 women), consisting of 107 women who received subcutaneous progesterone for FET in artificial cycles and 107 women receiving vaginal progesterone who were matched for age and treatment cycle rank acted as controls. All embryos were transferred in an artificial cycle with 6 mg per day oral oestradiol valerate starting on the second or third day of the menstrual cycle. Patients underwent transvaginal ultrasound on the 10th day of priming, and subcutaneous progesterone (50 mg/day) or vaginal progesterone (180 mg/day) was started if the endometrium had a trilinear pattern regardless of its thickness.

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Study Question: Are there any differences in the molecular characteristics of the luteal granulosa cells (GC) obtained from stimulated versus non-stimulated (natural) IVF cycles that may help explain the defective luteal phase in the former?

Summary Answer: Luteal GC of stimulated IVF cycles, particularly those of agonist-triggered antagonist cycles, are less viable ex vivo, express LH receptor and anti-apoptotic genes at lower levels, undergo apoptosis earlier and fail to maintain their estradiol (E2) and progesterone (P4) production in comparison to natural cycle GC.

What Is Known Already: Luteal function is defective in stimulated IVF cycles, which necessitates P4 and/or hCG administration (known as luteal phase support) in order to improve clinical pregnancy rates and prevent miscarriage. The luteal phase becomes shorter and menstruation begins earlier than a natural cycle if a pregnancy cannot be achieved, indicative of early demise of corpus luteum (premature luteolysis).

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