Ovarian follicular dynamics: from basic science to clinical practice.

The management of low responders (LR) to ovarian stimulation in cycles of assisted reproduction (AR) is a difficult challenge. Aging of the ovary and LR are coincidental in many situations, but LR is also present in young patients undergoing AR. In fact, today it is a recognized cause of infertility. When the aged ovary is considered, there is evidence that the functioning of the granulosa cells as well as the quality of the oocytes and resulting embryos are affected. Similarly, in young LR, the production of inhibin is affected. However, there is no evidence that the quality of the oocyte and/or the resulting embryo is affected. In this study, we have retrospectively analyzed our files and observed that the quality of the oocytes and embryos was similar between younger and older LR and normal responders (NR). Studies using color Doppler vaginal ultrasound have shown that the pulsatility index (PI) and the resistance index (RI) were increased in LR as compared with NR, suggesting that there was some degree of vascular resistance to flow. Treatment of LR is also a difficult challenge. Ovum donation is a successful treatment for LR, since cumulative birth rates are > 85% with four attempts of embryo transfer. The future may be promising for LR once new technologies are introduced into clinical practice. The use of recombinant gonadotropins and genetically engineered human gonadotropin derivatives may be of considerable help for LR. Similarly, non-gonadotropin hormones, such as cytokines or growth factors, may be shown to play a role in the stimulation of the ovary in the near future, and may therefore open new frontiers for treatment of LR.

Evaluation of the ovarian reserve in young low responders with normal basal levels of follicle-stimulating hormone using three-dimensional ultrasonography.

OBJECTIVE: To assess the ovarian content of selectable (2-5 mm) follicles using three-dimensional ultrasonography in low responders to ovarian stimulation for IVF. DESIGN: Prospective case-control study. SETTING: IVF program at the Instituto Valenciano de Infertilidad. PATIENT(S): Ten low responders < or =35 years of age with normal basal serum FSH and eight control patients with normal response in a previous cycle. INTERVENTION(S): Blood was drawn under basal (day 3) conditions. Three-dimensional ultrasound was performed in both ovaries using a vaginal probe. MAIN OUTCOME MEASURE(S): Basal serum E2 and FSH measurements. The ovarian volume and the number of follicles > or =2 mm in each ovary were recorded and compared between the groups. RESULT(S): Low-responder women had significantly higher serum FSH levels than controls despite having FSH values within the normal range. The number of selectable follicles and the total number of follicles with an antrum were significantly decreased in low responders as compared with normal responders. Ovarian volume did not differ between the groups. CONCLUSION(S): This study introduces three-dimensional ultrasound as a novel method for the evaluation of low responders. The results show that the most plausible explanation for low response in young women with normal serum FSH is diminished ovarian reserve.

Endometrial thickness and serum oestradiol concentrations as predictors of outcome in oocyte donation.

Adequate endometrial preparation with exogenous steroids is mandatory for successful ovum donation. This study was undertaken to assess the value of endometrial thickness by ultrasound and serum oestradiol as predictors of ovum donation outcome and to analyse the correlation between serum oestradiol concentrations and the endometrial thickness. Endometrial thickness and serum oestradiol concentrations on the day of oocyte donation were recorded and compared to several in-vitro fertilization parameters. The cycles (n = 465) were classified according to serum oestradiol values and endometrial thickness. Comparison of the groups showed that endometrial thickness was significantly (P = 0.002) higher when serum oestradiol was >400 pg/ml as compared to <100 pg/ml. Pregnancy and implantation rates did not differ among the groups, women with serum oestradiol <50 pg/ml having similar outcome to the remaining cases. Endometrial thickness showed a similar picture in terms of pregnancy and implantation. Also, women with an endometrium <4 mm in size had normal pregnancy and implantation rates. There was a positive correlation (P = 0.0044) between endometrial thickness and implantation, as well as between endometrial thickness and serum oestradiol (P = 0.0184). None of the parameters examined was able to predict ovum donation outcome. It is concluded that endometrial thickness is preferred to serum oestradiol for the monitoring of endometrial development, although neither is able to predict success in oocyte donation.