Use of letrozole challenge test to adjust gonadotropin dose in non–down-regulated cycles

Aging and the environment affect gamete and embryo potential: can we intervene?

Optimal maturation of the oocyte depends on its environment and determines embryo competence, because the embryonic genome is not active until the cleavage stage and new mitochondria are not produced until blastulation. Adverse environmental factors include aging, andropause, oxidative stress, obesity, smoking, alcohol, and psychologic stress, whereas androgen supplementation, a prudent diet, exercise, nutritional supplements, and psychologic interventions have beneficial effects. Mitochondrial function and energy production deteriorate with age, adversely affecting ovarian reserve, chromosome segregation, and embryo competence. In aging mice, the mitochondrial cofactor coenzyme Q10 reverses most of these changes. Early human experience has been encouraging, although only a small study using a shorter duration of intervention compared with the murine model has been carried out. Mitochondrial metabolic stress can result in an abnormal compensatory increase in mitochondrial DNA, which can be assessed in biopsied blastomeres of trophectoderm as a predictive biomarker of implantation failure. Psychologic stress may reduce oocyte competence by shifting blood flow away from the ovary as part of the classic "fight or flight" physiologic response, and methods to reduce stress or the body's reaction to stress improve pregnancy success. Enhancing oocyte competence is a key intervention that promises to reduce the number of euploid embryos failing to produce viable deliveries.

Dosage optimization for letrozole treatment in clomiphene-resistant patients with polycystic ovary syndrome: a prospective interventional study

Objective. Dose adjustment for induction of ovulation is one of the most important problem. Methods. In a prospective interventional study, 44 clomiphene-resistant infertile patients (113 cycles) were selected from the Abolfazl Infertility Clinic of Bushehr University of Medical Sciences. Letrozole was given orally in a dose of 2.5 mg, 5 mg, and 7.5 mg, respectively. If the patient displayed no response, the dosage was increased. Results. In this patients ovulation occurred in 50 cycles (44.24%), clinical pregnancy rate according to number of cycles was 23.89% (27 of 113 cycles) and according to the number of patients was 61.36% (27 of 44 patients). In the 2.5, 5, and 7.5 groups, follicles occurred in 22.9%, 42.1%, and 85.18% of cycles, and pregnancy rate was 14.58%, 28.94% and, 33.33%, respectively. Conclusions. It is better to administer Letrozole at a lower dosage to prevent complications and increase the dose based on sonographic results antral follicular count, anti-Müllerian hormone, LH/FSH, and estradiol.