Antagonist/letrozole protocol in poor ovarian responders for intracytoplasmic sperm injection: a comparative study with the microdose flare-up protocol

Aromatase inhibitors for ovulation induction and ovarian stimulation

Aromatase inhibitors (AIs) were originally developed for the treatment of advanced breast cancer in postmenopausal women. Their use in reproductive medicine has been extensively studied in the past decade. We reviewed the current strategies for ovulation induction for anovulatory women, mostly women with polycystic ovarian syndrome (PCOS), and the scientific basis for use of AIs in reproductive medicine. The AI, letrozole, is effective in ovulation induction in women with PCOS resistant to clomifene citrate and ovarian stimulation for intrauterine insemination and in vitro fertilization (IVF). Letrozole is an attractive option with its oral route of administration, cost, safety profile and effectiveness in ovulation induction and ovarian stimulation. Letrozole has the potential to be the first-line treatment option for ovulation induction in PCOS women, while its use in ovarian stimulation for IVF deserves further study.

ESHRE consensus on the definition of 'poor response' to ovarian stimulation for in vitro fertilization: the Bologna criteria

The definition presented here represents the first realistic attempt by the scientific community to standardize the definition of poor ovarian response (POR) in a simple and reproducible manner. POR to ovarian stimulation usually indicates a reduction in follicular response, resulting in a reduced number of retrieved oocytes. It has been recognized that, in order to define the poor response in IVF, at least two of the following three features must be present: (i) advanced maternal age or any other risk factor for POR; (ii) a previous POR; and (iii) an abnormal ovarian reserve test (ORT). Two episodes of POR after maximal stimulation are sufficient to define a patient as poor responder in the absence of advanced maternal age or abnormal ORT. By definition, the term POR refers to the ovarian response, and therefore, one stimulated cycle is considered essential for the diagnosis of POR. However, patients of advanced age with an abnormal ORT may be classified as poor responders since both advanced age and an abnormal ORT may indicate reduced ovarian reserve and act as a surrogate of ovarian stimulation cycle outcome. In this case, the patients should be more properly defined as 'expected poor responder'. If this definition of POR is uniformly adapted as the 'minimal' criteria needed to select patients for future clinical trials, more homogeneous populations will be tested for any new protocols. Finally, by reducing bias caused by spurious POR definitions, it will be possible to compare results and to draw reliable conclusions.

Effect of androgen supplementation or modulation on ovarian stimulation outcome in poor responders: a meta-analysis

Many trials have evaluated the use of androgen supplements and androgen-modulating agents to improve outcome of poor responders undergoing IVF treatment. This study conducted a systematic review and meta-analysis of controlled trials of androgen adjuvants (testosterone, dehydroepiandrostereone) and the androgen-modulating agent (letrozole) in poor responders undergoing IVF treatment. Searches were conducted on MEDLINE, EMBASE, Cochrane Library, ISRCTN Register and ISI proceedings. All randomized and non-randomized controlled trials were included. Study selection, quality appraisal and data extraction were performed independently and in duplicate. The main outcome measure was clinical pregnancy rate. The secondary outcome measures were dose and duration of gonadotrophin use, cycles cancelled before oocyte retrieval, oocytes retrieved and ongoing pregnancy rates. A total of 2481 cycles in women considered as poor responders undergoing IVF/intracytoplasmic sperm injection (ICSI) treatment were included in nine controlled trials. Meta-analyses of these studies did not show any significant difference in the number of oocytes retrieved and ongoing pregnancy/live-birth rates with androgen supplementation or modulation compared with the control groups. There is currently insufficient evidence from the few randomized controlled trials to support the use of androgen supplementation or modulation to improve live birth outcome in poor responders undergoing IVF/ICSI treatment.

Role of androgens in the treatment of patients with low ovarian response

The objective of the current report was to provide a summary of knowledge concerning the treatment of women with poor ovarian response with androgens and androgen modulating agents. This involved a review of the literature. The literature search was performed using PubMed. Information concerning the role of androgens and androgen modulating agents in treating women with poor ovarian response is limited. The search of the literature yielded five studies and one case report concerning the treatment of poor responders with androgens. The variations in patient selection, type of androgens employed and the different duration of exposure preclude drawing any definite conclusions. Aromatase inhibitors block the conversion of androgens to oestrogens, thereby promoting an androgen-rich intrafollicular environment. The evidence presented in this review suggests a potential beneficial role for the use of aromatase inhibitors in treating women who have previously experienced failure of standard IVF protocols. The optimal dose and duration of this treatment is yet to be determined. Although the results of studies concerning LH supplementation in poor responders are conflicting, the latest Cochrane review on the use of recombinant LH for ovarian stimulation supports its use in poor responders, based on pooled pregnancy estimates.

A unique human chorionic gonadotropin antagonist suppresses ovarian hyperstimulation syndrome in rats

Ovarian hyperstimulation syndrome (OHSS) is a complication of in vitro fertilization associated with physiological changes after hCG administration to induce final oocyte maturation. It presents as widespread increases in vascular permeability and, in rare cases, results in cycle cancellation, multi-organ dysfunction, and pregnancy termination. These physiological changes are due primarily to activation of the vascular endothelial growth factor (VEGF) system in response to exogenous human chorionic gonadotropin (hCG). An hCG antagonist (hCG-Ant) could attenuate these effects by competitively binding to the LH/CG receptor, thereby blocking LH activity in vivo. We expressed a form of hCG that lacks three of its four N-linked glycosylation sites and tested its efficacy as an antagonist. The hCG-Ant binds the LH receptor with an affinity similar to native hCG and inhibits cAMP response in vitro. In a rat model for ovarian stimulation, hCG-Ant dramatically reduces ovulation and steroid hormone production. In a well-established rat OHSS model, vascular permeability and vascular endothelial growth factor (VEGF) expression are dramatically reduced after hCG-Ant treatment. Finally, hCG-Ant does not appear to alter blastocyst development when given after hCG in mice. These studies demonstrate that removing specific glycosylation sites on native hCG can produce an hCG-Ant that is capable of binding without activating the LH receptor and blocking the actions of hCG. Thus hCG-Ant will be investigated as a potential therapy for OHSS.

Intracytoplasmic sperm injection outcome of women over 39: an analysis of 668 cycles

PURPOSE

To evaluate intracytoplasmic sperm injection (ICSI) outcome of women over age 39 and to determine when to discourage such couples to undergo IVF using their own oocytes.

METHODS

Four hundred ninety-five consecutive women (n=668 cycles) over age 39 were evaluated by year-by-year age increments to discriminate the independent prognostic factors for the achievement of pregnancy.

RESULTS

Although the ovarian hyperstimulation performance (COH) and embryological data were not too diverse, the clinical pregnancy rates per embryo transfer decreased from 26 to 13% from age 40 to 44. According to logistic regression, the female age seems to be the only variable in order to predict an ongoing pregnancy. The miscarriage rate increased with advancing female age. It was 33% at age 40 but increased to 100% by age 45.

CONCLUSIONS

The performance of COH and embryological data is not discouraging among women over 39 years in ICSI cycles. However, increased miscarriages as well as decreased implantation rate are mainly responsible for the poor performance of patients with advanced female age. Irrespective of the ovarian reserve testing, ICSI may be refused at age 45 and thereafter.