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Roel Schats

Publications and source records attributed to Roel Schats.

12 recordsLinked to original sources
PubMed2006

Ultrasonographic-guided embryo transfer does not enhance pregnancy rates compared with embryo transfer based on previous uterine length measurement.

OBJECTIVE: To compare pregnancy rates (PRs) after ultrasound-guided embryo transfer and embryo transfer based on ultrasonographic length measurement. DESIGN: Prospective intervention group combined with retrospective control group. SETTING: University fertility clinic. PATIENT(S): Patients undergoing IVF and intracytoplasmic sperm injection. INTERVENTION(S): Transabdominal ultrasonographic guidance at embryo transfer. MAIN OUTCOME MEASURE(S): Pregnancy and implantation rates. RESULT(S): In 367 ultrasound-guided embryo transfers clinical PR, ongoing PR, and implantation rate were 35.1%, 31.1%, and 24.3%, respectively. In 363 embryo transfers based on previous ultrasonographic length measurement, the rates were 33.9%, 29.5%, and 24.2%, respectively. There were no statistical significant differences between the groups. CONCLUSION(S): Ultrasonographic guidance does not show any benefit in terms of PR and implantation rate compared to previous ultrasonographic length measurement, an other precise and atraumatic transfer technique.

Adult↗
PubMed2006

The clomiphene citrate challenge test versus the exogenous follicle-stimulating hormone ovarian reserve test as a single test for identification of low responders and hyperresponders to in vitro fertilization.

OBJECTIVE: This study was designed to compare the exogenous FSH ovarian reserve test (EFORT) versus the clomiphene citrate challenge test (CCCT), basal FSH, and basal inhibin B, with respect to their ability to predict poor and/or hyperresponders in an IVF population. DESIGN: Prospective randomized controlled trial. SETTING: Fertility center of a university hospital. PATIENT(S): One hundred ten patients undergoing their first IVF cycle, randomized into two groups. INTERVENTION(S): Fifty-six patients underwent a CCCT, and 54 patients underwent an EFORT. In all patients, the test was followed by an IVF treatment. MAIN OUTCOME MEASURE(S): Ovarian response, expressed by the total number of retrieved oocytes. RESULT(S): Univariate logistic regression showed that the best predictor for poor response is the CCCT (area under receiver operator characteristic curve [ROC-AUC] = 0.87), with maximal accuracy of 0.89. Multiple logistic regression analysis did not produce a better model in terms of improving the prediction of poor response. For hyper response, univariate logistic regression showed that the best predictor is the inhibin B increment in the EFORT (ROC-AUC = 0.92) but with a low maximal accuracy of 0.78. Again, multiple logistic regression analysis did not produce a better model in terms of predicting hyper response. CONCLUSION(S): Our study, the first which compares the CCCT with the EFORT for the prediction of poor and hyperresponders, shows that the CCCT is superior for identification of low responders. The EFORT (inhibin B increment) is superior for prediction of hyper response at the cost of a high rate of false positives. Neither of the two tests seems adequate to act alone for identification of both poor and hyperresponders.

Clomiphene↗
PubMed2006

Optimizing hCG cut-off values: a single determination on day 14 or 15 is sufficient for a reliable prediction of pregnancy outcome.

OBJECTIVE: Optimizing the cut-off level for a single serum hCG determination around day 15 after oocyte retrieval or ovulation. STUDY DESIGN: Retrospective data analysis. RESULTS: 204 hCG samples >5 IU/L between March and October 1999 taken on day 14, 15 or 16 after oocyte retrieval in 204 patients undergoing IVF or ICSI were analyzed. ROC-curves and optimal cut-off levels to discriminate between viable and non-viable pregnancies were calculated for each day separately. Cut-off levels were found at 76, 142 and 223 IU/L for day 14, 15 and 16, respectively, and were verified by 487 hCG samples >5 IU/L taken between January 2000 and June 2004. CONCLUSIONS: A single serum hCG determination on day 14 or 15 is sufficient to discriminate viable pregnancies accurately from non-viable pregnancies.

Adult↗
PubMed2006

Effect of an oral contraceptive pill on follicular development in IVF/ICSI patients receiving a GnRH antagonist: a randomized study.

This randomized controlled study compared the effectiveness of a gonadotrophin releasing hormone (GnRH) antagonist protocol with or without oral contraceptive (OC) pretreatment on the number of oocytes retrieved in IVF or intracytoplasmic sperm injection (ICSI) patients. Sixty-four patients were randomized to start recombinant human FSH (r-hFSH) on day 2 or 3 after OC withdrawal (OC group) or on day 2 of a natural cycle (control group). From stimulation day 6 onwards, all patients were treated with daily (0.5 mg/ml) GnRH antagonist (Antide). OC pretreatment resulted in significantly lower starting concentrations of FSH, LH and oestradiol (P < 0.001) and a thinner endometrium (P < 0.0001). In the early stimulation period, fewer large follicles were found after OC pretreatment, leading to a significantly extended stimulation period (11.6 versus 8.7 days, P < 0.0001) with more follicles on the day of recombinant human chorionic gonadotrophin administration (15.4 versus 12.5, P = 0.02) and more oocytes retrieved (13.5 versus 10.2, P < 0.001) as compared with the control group. GnRH antagonist regimen, pretreated with OC, prevented the early endogenous FSH rise and improved follicular homogeneity, resulting in more oocytes. As a consequence of the extended treatment period, more rhFSH was required.

Adult↗
PubMed2005

Ongoing pregnancy rates in in vitro fertilization are not dependent on the physician performing the embryo transfer.

OBJECTIVE: To analyze the influence of the factor of the physician performing the ET with a standardized procedure on the ongoing pregnancy rates in an IVF-ET program. DESIGN: Prospective observational study. SETTING: Tertiary university hospital. PATIENT(S): Subfertile women with an IVF indication. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Ongoing pregnancy. RESULT(S): Six physicians performed 977 ETs. Ongoing pregnancy rates ranged from 19.1% to 29.0%, with an average rate of 23.1%. Logistic regression analysis revealed that physician is not a statistically significant variable. Differences between the pregnancy rates achieved by the physicians are within the limits of random variation. CONCLUSION(S): The probability of success in IVF is not dependent on the physician, provided the transfer procedure is standardized.

Adult↗
PubMed2004

Dose-finding study of daily GnRH antagonist for the prevention of premature LH surges in IVF/ICSI patients: optimal changes in LH and progesterone for clinical pregnancy.

BACKGROUND: An optimal range of LH concentrations for achieving pregnancy has not been established. The aim of this study was to investigate the effect of various LH levels induced by different GnRH antagonist doses on IVF outcome. METHODS: This was a prospective, single centre study including 144 IVF patients, stimulated with recombinant FSH from cycle day 2, and co-treated with daily GnRH antagonist (antide/Iturelix) (2 mg/2 ml, 1 mg/ml, 0.5 mg/ml, 0.5 mg/0.5 ml or 0.25 mg/ml) from cycle day 7 onwards. Serum samples were taken three times daily. RESULTS: Clinical pregnancies were only observed within a particular range of change in LH levels. The upper and lower thresholds for the mean LH area under the curve (AUC), adjusted for the baseline LH level before the antagonist was started (LH AUC(-S6); S6=stimulation day 6) were -2.2 and 12.4 (IU/l) respectively (a negative value=below baseline levels). There were no clinical pregnancies outside these threshold values. Similar results were found for progesterone, the threshold levels of progesterone AUC(-S6) were 3.98 and -1.21 ng/ml. Moreover, there were no pregnancies with progesterone levels >0.26 ng/ml/follicle on the day of hCG. CONCLUSIONS: Excessive or insufficient suppression of LH and progesterone levels during GnRH antagonist administration and high progesterone/follicle on hCG day seems to be associated with impaired clinical pregnancy rates.

Adult↗
PubMed2004

Dose-finding study of daily gonadotropin-releasing hormone (GnRH) antagonist for the prevention of premature luteinizing hormone surges in IVF/ICSI patients: antide and hormone levels.

BACKGROUND: The aim of this study was to define the minimal effective dose of antide (Iturelix) to prevent premature luteinizing hormone (LH) surges in in vitro fertilization (IVF) patients. METHODS: In a prospective, single centre study, 144 IVF/ICSI patients were stimulated with r-hFSH from cycle day 2 and from cycle day 6 onwards, cotreated with daily 2 mg/2 ml (n=30), 1 mg/ml (n=30), 0.5 mg/ml (n=31), 0.5 mg/0.5 ml (n=23) and 0.25 mg/ml (n=30) GnRH antagonist (antide). Serum samples were taken three times daily during antide administration to assess antide and hormone levels. The minimal effective dose was defined as the lowest dose group with <2 LH surges (LH >12.4 IU/l and progesterone >2 ng/ml). RESULTS: Serum antide levels, mean LH and E2 levels per day and their area under the curves were dose-related to antide. The bioavailability of antide almost doubled after dilution in larger volumes. Pre-injection LH levels gradually increased during GnRH antagonist treatment. LH surges occurred in the lowest dose groups 0.5 mg/ml (3.2%), 0.5 mg/0.5 ml (6.7%) and 0.25 mg/ml (13.3%). Hence, 0.5 mg/ml is considered to be the minimal effective dose. Antide was overall well tolerated and safe. CONCLUSIONS: 0.5 mg/ml antide is the minimal effective dose to prevent an untimely LH surge in IVF patients stimulated with r-hFSH.

Adult↗
PubMed2004

Human embryo implantation: current knowledge and clinical implications in assisted reproductive technology.

A pregnancy rate of approximately 15% per cycle renders the process of human reproduction inefficient. The cycle-dependent expression of molecules involved in the embryo-endometrial dialogue has lead to the identification of a 'window of implantation'. This is the unique temporal and spatial expression of factors that allows the embryo to implant (via signalling, appositioning, attachment and invasion) in a specific time frame of 48 h, 7-10 days after ovulation. Integrin molecules, L-selectin ligands, mucin-1, heparin-binding epidermal growth factor and pinopodes are involved in appositioning and attachment. The embryo produces cytokines and growth factors [interleukins, prostaglandins, vascular endothelial growth factor (VEGF)] and receptors for endometrial signals (leukaemia inhibitory factor receptor, colony stimulating factor receptor, insulin-like growth factors and heparin binding epidermal growth factor receptor). The immune system plays an important role. Immunomodulatory factors such as glycodelin, inhibin and interleukin prevent a graft-versus-host reaction. Angiogenesis controlled by VEGF and prostaglandins is needed for formation of a receptive endometrium and a placenta. Identification of these factors has led to their use as markers of implantation that may identify defects causing subfertility. An ideal marker of implantation is sensitive and specific, and easy to obtain without disturbing implantation. Glycodelin and leukaemia inhibitory factor (serum) and integrins and pinopodes (biopsies) are promising candidates.

Embryo Implantation↗
PubMed2004

Contemporary pharmacological manipulation in assisted reproduction.

Follicle-stimulating hormone (FSH) treatment to induce follicular development in anovulating women and multiple follicular development for assisted conception has been incorporated in almost all reproductive treatment cycles in the form of either urinary, purified urinary or recombinant preparations. Besides improved tolerance and theoretically lower chances of infection by prions, the latter may be more effective in terms of clinical pregnancy rates, FSH requirement and cost effectiveness. The low-dose, step-up protocol to induce monofollicular development, which is applied worldwide, has to compete with the equally effective but health economically beneficial step-down protocol. The long protocol using recombinant FSH 150 IU/day is advocated when using gonadotropin-releasing hormone (GnRH) agonists in in vitro fertilisation (IVF) or intracytoplasmatic sperm injection treatment. However, the current paradigmatic hyperstimulation came under scrutiny after the introduction of the GnRH antagonists, which allow milder and more convenient approaches with acceptable cancellation and pregnancy rates but lower requirements for FSH. Risk of ovarian hyperstimulation syndrome (OHSS) can be further eliminated if recombinant luteinising hormone (rLH) or GnRH agonists are used to trigger oocyte maturation and ovulation; the latter require pituitary responsiveness and are therefore excluded in agonist protocols. FSH and LH are both required for appropriate folliculo- and steroidogenesis. In hypogonadotropic women, the addition of LH (human menopausal gonadotropin, human chorionic gonadotropin or rLH) is therefore obligate to achieve appropriate follicular growth and pregnancy. The role of LH in ovulation induction is still a matter of debate, although in GnRH agonistic protocols there seems to be a 'therapeutic window'; levels that are too high or too low have detrimental effects on IVF outcome. To broaden the pharmaceutical armoury, recent efforts have been directed towards the development of novel GnRH antagonists and FSH preparations with optimal pharmacokinetic, pharmacodynamic and safety profiles. Alternative strategies with fewer adverse effects and higher benefit/cost ratios are under development. However, before the GnRH agonist is abandoned for the antagonist as standard therapy, the cause of the observed possible lower pregnancy rates with the latter need to be clarified. In addition, prospective studies investigating possible direct effects of GnRH analogues, optimal dose-finding studies and treatment regimens under different conditions, with or without pharmacological coadministration and for different indications, should be performed to optimise the efficacy and tailor treatment strategies to individual needs.

Clinical Trials as Topic↗
PubMed2002

GnRH agonists, antagonists, and assisted conception.

Pituitary stimulation with pulsatile gonadotropin-releasing hormone (GnRH) induces both follicle-stimulating hormone and luteinizing hormone (LH). Blockade of pituitary gonadotropin secretion occurs upon desensitization when a continuous GnRH stimulus is provided by means an agonist or when the pituitary receptors are occupied with a competitive antagonist. The most common indication for blockade of pituitary gonadotropin secretion is with assisted reproduction treatment (ART) where it prevents premature luteinization. Originally by lack of clinically available GnRH antagonist, prolonged daily injection of agonist with its desensitizing effect was introduced for this purpose. Today, single- and multiple-dose injectable antagonists are also available to block the LH surge. This review provides an overview of the use of GnRH agonists and antagonists in assisted reproduction.

Fertilization↗
PubMed2002

The impact of the embryo transfer catheter on the pregnancy rate in IVF.

BACKGROUND: The aim was to assess whether the type of embryo transfer set used for embryo transfer affects the ongoing pregnancy rate in IVF. METHODS: The TDT set was compared with the K-soft 5000 in a large, prospective, randomized study. Patients were randomized moments before transfer by drawing a consecutively numbered, sealed, opaque envelope indicating the catheter to be used. RESULTS: 2059 embryo transfers in 1296 patients were analysed. The ongoing pregnancy rate was significantly higher in the K-soft group. If the first transfer of a patient (n = 1296) within this study period was analysed, the ongoing pregnancy rates were 27.1 versus 20.5% (P = 0.006). If the analysis is limited to patients that underwent their very first transfer ever (n = 607), the ongoing pregnancy rates were 30.3 versus 20.0% (P = 0.003) in favour of the K-soft. CONCLUSION: We conclude from these data that the type of embryo transfer set used for embryo transfer does affect the ongoing pregnancy rate and that the impact of the variable transfer catheter on the ongoing pregnancy rate increases when the a priori chance of pregnancy increases.

Adult↗