Luteal phase after ovarian hyperstimulation

Ovarian stimulation for IVF and endometrial receptivity--the missing link

The contemporary approach to ovarian stimulation for IVF treatment results in supraphysiological concentrations of steroids during the follicular and luteal phases of the menstrual cycle. These sex steroids act directly and indirectly to mature the endometrium, influencing receptivity for implantation. Corpus luteum function is distinctly abnormal in IVF cycles, and therefore luteal support is widely used. Various reasons may underlie the defective luteal phase, including (i) ovarian hyperstimulation per se, (ii) gonadotrophin-releasing hormone (GnRH) analogue co-treatment and (iii) the use of human chorionic gonadotrophin (HCG) to induce final oocyte maturation. The recent introduction of GnRH antagonist co-treatment for the prevention of a premature LH rise during the late follicular phase allows for different approaches to ovarian stimulation for IVF. However, a recent meta-analysis showed that implantation rates may be compromised by using GnRH antagonists in currently employed regimens. The development of endometrium receptive to embryo implantation is a complex process and may be altered by inappropriate exposure to sex steroids in terms of timing, duration and magnitude. New approaches to the assessment of endometrial receptivity are now required. Novel approaches to ovarian stimulation aimed at adjusted GnRH antagonist regimens and achieving a more physiological luteal phase endocrinology are now appearing in the literature and may represent an important step in the improvement of the overall health economics of IVF.

Alterations in luteal phase progesterone and estradiol production after leuprolide acetate therapy before ovarian stimulation for in vitro fertilization

The impact of pituitary suppression with a gonadotropin-releasing hormone agonist (GnRH-a) on the luteal phase of in vitro fertilization (IVF) cycles was examined in 21 women who underwent identical stimulation regimens with and without leuprolide acetate pretreatment. The areas under the serum progesterone curves, measured over the 1st 10 days of the luteal phase, were significantly greater in the GnRH-a cycles compared with the non-GnRHa cycles, but when calculated per oocyte retrieved were similar in GnRH-a and non-GnRH-a cycles. In contrast, the areas under the luteal phase serum estradiol curves were significantly less in the GnRH-a cycles. These data suggest that GnRH-a treatment is accompanied by potentially beneficial alterations in the systemic steroidal milieu of the luteal phase of IVF cycles.

Pulsatility of serum-luteinizing hormone during hyperstimulation with clomiphene citrate and human menopausal gonadotropin for in vitro fertilization

The pulsatile pattern of gonadotropin secretion regulates follicular growth and corpus luteum function in normal cycles, but the role of endogenous gonadotropin pulses in hyperstimulated cycles is unclear. We studied pulsatility of serum-luteinizing hormone (LH) in the late follicular and midluteal phases in four women after hyperstimulation with clomiphene citrate, human menopausal gonadotropin, and human chorionic gonadotropin, and in five women with normal untreated cycles. In the late follicular phase, the number, interval, amplitude, and area of LH pulses did not show significant differences between hyperstimulated and control cycles. In the midluteal phase, the long-lasting (greater than 90 minutes) LH pulses typical for the normal luteal phase, were not found after hyperstimulation. As the length of the luteal phase in these cases was normal, the significance of this finding remained obscure.