Clinical review 81: Gonadotropin-releasing hormone analogs in ovulation induction: current status and perspectives.
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OBJECTIVES: To clarify the endocrine mechanisms underlying the outcome of different ovulation induction regimens with gonadotropins and GnRH agonists (GnRH-a). DESIGN: Prospective study. SETTING: Reproductive Endocrinology Center, University of Bologna. PATIENTS: Forty eumenorrheic women randomly assigned to four groups of 10 subjects each. INTERVENTIONS: Ovulation induction regimens: group A, purified FSH only; group B, purified FSH and flare-up GnRH-a; group C, purified FSH and long GnRH-a; and group D, hMG and long GnRH-a. MAIN OUTCOME MEASURES: Pelvic ultrasound and hormone levels in daily serum samples and in follicular fluid drawn immediately before hCG administration. RESULTS: Exogenous gonadotropin dose did not differ among groups. Group B had fewer preovulatory follicles than group C. Group B had higher serum LH, FSH, E2, P, T, and follicular fluid LH, E2, T, and alpha-inhibin than groups C and/or D. Groups C and D did not differ. CONCLUSIONS: Long GnRH-a regimens improved follicle yield and the endocrine milieu in spite of comparable exogenous gonadotropin dose and lower serum FSH and thus appear to be preferable in assisted reproduction. Reduced folliculogenesis found in flare-up GnRH-a regimens could be mediated by the atretic effects of high intraovarian androgens. Efficacy of purified FSH and hMG was comparable.
OBJECTIVES: To compare the effects of depot and daily forms of GnRH analogs in IVF programs. METHODS: One hundred seventeen patients undergoing IVF, with no severe male factor, were randomized between two treatment groups. Pituitary desensitization was obtained in group 1 (60 patients) with a single IM injection of leuprorelin (3.75 mg), and in group 2 (57 patients) with buserelin (0.3 mg SC twice daily). In a subgroup of 10 patients (5 for the depot form and 5 for the daily form) several GnRH tests were performed to investigate pituitary desensitization. RESULTS: No differences were found in the time to reach desensitization. Resumption of pituitary activity occurred in 7 days with the daily form and in about 2 months with the depot form. No significant differences were found in the stimulation pattern, oocyte quality, percentage of fertilization. The pregnancy rate per transfer was slightly, but not significantly, better in the depot group (29.4% vs 25.9%). Implantation rate (11.9% vs 12.3%) and the percentage of miscarriages (26.6% vs 28.5%) were similar. CONCLUSION: Depot and daily forms of GnRH analogs are equally effective in superovulation induction for IVF. Considering improved patient compliance and preference, depot forms are advantageous.
OBJECTIVE: To assess the oral glucose tolerance test (OGTT)-stimulated insulin secretion and its relation to pulsatile GnRH ovulation induction outcome in patients with multifollicular or polycystic ovaries (PCOs). DESIGN: Prospective study. SETTING: Reproductive Endocrinology Center, University of Bologna, Bologna, Italy. PATIENTS: Eight normal and 29 anovulatory women (8 with multifollicular ovaries and 21 with PCOs). INTERVENTION: A standard OGTT was performed in all subjects. In all anovulatory patients, ovulation was induced with pulsatile GnRH (5 micrograms i.v. every 60 minutes). In multifollicular ovary patients, pulsatile GnRH was administered alone, whereas in PCOs it was preceded by GnRH agonist (GnRH-a) suppression. MAIN OUTCOME MEASURES: Glucose, insulin, and C-peptide response to the OGTT, expressed as area under the curve (AUC). Ovulatory rates in response to pulsatile GnRH. RESULTS: Insulin and C-peptide AUC were greater than controls in both multifollicular ovary and PCO patients. Insulin AUC was positively correlated to ovarian volume. Ovulation was achieved in 88% and 57% of multifollicular ovary and PCO patients, respectively. Body mass index and glucose AUC but not insulin and C-peptide AUC were significantly greater in the anovulatory PCO. CONCLUSIONS: [1] Insulin AUC was increased in both multifollicular ovary and PCO patients; [2] derangements of insulin secretion may be present in a greater variety of anovulatory patients than previously thought; [3] insulin levels during the OGTT did not predict a response to pulsatile GnRH in PCOs, suggesting complex insulin interactions at the ovarian level; [4] given the in vitro stimulatory properties of insulin on granulosa cells synergistic with FSH, we propose that excessive insulin levels may contribute to the ovarian enlargement often found in multifollicular ovary and PCO patients.
Pulsatile GnRH (pGnRH) was administered to 292 anovulatory patients in 600 consecutive cycles between February 1984 and February 1993. This represents the largest single pGnRH series ever reported. Patients were divided into the following groups: primary hypogonadotropic amenorrhea (PHA), 73 patients, 161 cycles; other hypogonadotropic hypogonadisms (OHH), 57 patients 107 cycles; multifollicular ovary (MFO), 39 patients 75 cycles; polycystic ovary (PCO), 85 patients 172 cycles; and other hyperandrogenic anovulations (OHA), 38 patients 85 cycles. GnRH was administered iv at a dose of 1.25-20.0 micrograms every 30-120 min; most cycles (505) were performed with a regimen of 2.5-5.0 micrograms GnRH every 60-90 min. In 228 cycles of MFO, PCO, and OHA patients, pGnRH was preceded by GnRH agonist (GnRH-A) suppression. Ovulatory rates were 75%, and pregnancy occurred in 105 cycles (pregnancy rate of 18%/treatment cycle and 23%/ovulatory cycle). Ovulatory and pregnancy rates were higher in PHA, OHH, and MFO and lower in PCO and OHA. Only 4 multiple pregnancies occurred (3.8%), none after GnRH-A suppression. The abortion rate was 30% and was highest in PCO (45%). GnRH-A pretreatment improved ovulatory rates only in PCO (from 49% to 71%; P < 0.001), whereas it had no significant effect on pregnancy and abortion rates in any group. Higher weight and insulin were associated with lower ovulatory and pregnancy rates; higher LH and testosterone were associated with lower ovulatory rates only. We conclude that 1) pGnRH is a highly effective ovulation induction method; 2) pGnRH does not cause ovarian hyperstimulation; 3) low dose pGnRH is associated with a remarkably low incidence of multiple pregnancy; 4) GnRH-A pretreatment improves pGnRH outcome in PCO and further lowers the incidence of multiple pregnancy; 5) pGnRH is associated with relatively elevated abortion rates, particularly in PCO; and 6) pGnRH is less successful in overweight patients and when high baseline LH, testosterone, and insulin levels are present.
The development of superactive analogues of gonadotrophin-releasing hormone (GnRH) represents one of the most important new pharmaceutical contributions of the last 2 decades. This class of drugs is now available worldwide and is successfully employed in the management of precocious puberty, ovulation induction, prostatic cancer, premenopausal breast cancer, endometriosis, uterine leiomyoma, and for the preparation of female patients undergoing laparotomic, vaginal or endoscopic surgery. GnRH agonists are also applied with some success in other clinical conditions such as catamenial disorders, hyperandrogenism and menometrorrhagia. Studies are under way to identify other potential clinical applications such as other forms of cancer.
The pattern of episodic gonadotrophin releasing hormone (GnRH)-driven luteinizing hormone (LH) secretion changes dynamically across the human menstrual cycle. Adherence to a specific regimen of pulse amplitude and frequency is critical for normal ovulation, menstrual cyclicity and reproductive function. Derangements of episodic LH secretion are associated with anovulation. We have shown that in the human slowing of GnRH-induced LH pulses results in lower ovulatory rates and dysfunctions of the mid-cycle LH surge. This information is relevant for the understanding of the endocrine dynamics of the menstrual cycle both in normal and anovulatory subjects.
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Different depot GnRH analogs (GnRH-A) are currently used for the reversible suppression of the pituitary-ovarian axis in several reproductive and neoplastic disorders in women. In spite of anecdotal reports of incomplete suppression by some depot GnRH-A, this issue has never been systematically investigated in adult women. Thus, we elected to study 40 normally cycling women with male-related infertility or benign reproductive disorders; each group of 10 subjects received a different GnRH-A for 3 months: buserelin (group B; 300 micrograms, sc, every 12 h, as a control), goserelin (group G; 3.6 mg, sc, every 28 days), leuprorelin (group L; 3.75 mg, im, every 28 days), and triptorelin (group T; 3.75 mg, im, every 28 days). Depot GnRH-A was administered by one of the investigators. GnRH tests (100 micrograms, iv) were performed before treatment (cycle day 7; test A) and on treatment days 57 (i.e. 1 day after the third depot GnRH-A; test B) and 84 (i.e. 28 days after the third depot GnRH-A; test C). Immunoreactive (i) LH levels were measured with an ultrasensitive immunochemiluminometric assay. Profound suppression of the iLH response to the GnRH test occurred in all subjects during treatment. Conversely, FSH levels in the third month of treatment tended to be higher in the depot GnRH-A groups than in group B, and this difference achieved statistical significance (P < 0.05) in groups G and L during test C. In GnRH test B, while the mean estradiol (E2) level was less than 75 pmol/L (< 20 pg/mL) in all group B subjects, individual E2 levels were greater than 75 pmol/L in five patients receiving depot GnRH-A (two in group G, one in L, and two in T). Finally, individual E2 levels during test C were greater than 75 pmol/L in only two patients of group G, who also reported vaginal spotting. Thus, we conclude that in adult women, 1) iLH was profoundly suppressed in the third month of administration of all GnRH-A tested; 2) FSH suppression with depot GnRH-A was less marked than that with high-dose short-acting sc buserelin; and 3) signs of an incomplete block of ovarian function can be present in the third month of depot GnRH-A administration, particularly when goserelin is employed.
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To accrue systematic information in different ovulatory disorders on the precise relationship among endocrine response, clinical outcome, and the occurrence of complications, we treated 114 patients with pulsatile GnRH (2.5-5.0 micrograms, iv, every 60 min) for 187 cycles and compared them to 20 normal menstrual cycles. Thirty of these patients had primary hypogonadotropic amenorrhea (PHA; 40 cycles), 33 had other forms of hypogonadotropic hypogonadism (HH; 55 cycles), and 51 had polycystic ovary syndrome (PCOS; 92 cycles). Daily blood samples were drawn for hormone determinations. In PCOS, 50 cycles were preceded by GnRH analog suppression. PHA treatment cycles were characterized by the reestablishment of a normal endocrine pattern, almost no dose-related endocrine differences, elevated ovulatory (93%) and conception rates (23%), and no multiple pregnancies. In the HH subjects the ovulatory (91%) and pregnancy rates (31%) were high; however, while the lower GnRH dose elicited a normal endocrine pattern, the 5-micrograms dose induced excessive folliculogenesis and high estradiol levels and was associated with most of the multiple pregnancies of this study (three of four). GnRH analog suppression was successfully used to avoid recurrence of ovarian over-stimulation in two HH subjects. Finally, GnRH analog suppression in PCOS permitted normalization of the follicular phase endocrine pattern, achievement of good ovulatory (76%) and pregnancy (28%) rates, and avoidance of multiple pregnancies; however, luteal phase steroid secretion was abnormal, and the abortion rate remained elevated (43%). Obesity was associated with a reduced ovulatory rate in PCOS, but not in hypogonadotropic, subjects. Thus, we can conclude that in pulsatile GnRH ovulation induction: 1) a profound hypogonadotropic condition, whether spontaneous as in PHA or induced with GnRH analogs as in other ovulatory disorders, is associated with optimal menstrual cycle restoration, high ovulatory and conception rates, and virtually absent risks of multiple pregnancy; 2) residual hypothalamic activity in HH may be responsible for supraphysiological pituitary-ovarian stimulation and result in multiple pregnancy unless a low GnRH dose (2.5 micrograms/bolus) or GnRH analog pretreatment is employed; 3) obesity does not affect treatment outcome in hypogonadotropic patients; and 4) the high spontaneous abortion rate in PCOS may be related to corpus luteum dysfunction.
Several new developments in the field of reproductive endocrinology were published in 1990. Research on inhibin and related peptides appears to be particularly active and developments in this area may provide fundamental new information for the understanding and treatment of reproductive disorders. Exogenous androgens were found to be useful as a pharmacologic form of reversible male contraception. Interesting new data were also published regarding hypothalamic physiology, ovulation induction procedures, and the endocrinology of pregnancy.
Ovulation induction with pulsatile gonadotropin-releasing hormone achieves high ovulatory and pregnancy rates in hypogonadotropic hypogonadism while limiting the occurrence of ovarian hyperstimulation and multiple pregnancy. However, this form of therapy is apparently less effective in polycystic ovary syndrome. The administration of a gonadotropin-releasing hormone analog for 4 to 8 weeks before the initiation of pulsatile gonadotropin-releasing hormone ovulation induction can temporarily correct endocrine abnormalities of polycystic ovary syndrome, such as excessive luteinizing hormone and androgen secretion, and improve ovulatory and pregnancy rates in these patients. For optimal results, this pretreatment should probably be repeated before each pulsatile gonadotropin-releasing hormone ovulation induction cycle. Obesity is associated with a lower success rate, and spontaneous abortion remains a prominent complication in polycystic ovary syndrome even after gonadotropin-releasing hormone analog suppression. With this regimen the risks of ovarian hyperstimulation and multiple pregnancy are virtually abolished. Thus, pulsatile gonadotropin-releasing hormone appears to be highly effective and safe for ovulation induction in patients with polycystic ovary syndrome also, provided that this treatment is preceded by pituitary-ovarian suppression with a gonadotropin-releasing hormone analog.
Pulsatile GnRH therapy has yet to achieve widespread acceptance as an alternative to exogenous gonadotropin therapy in women with hypothalamic amenorrhea and complete GnRH deficiency. However, when a physiologically based replacement regimen of pulsatile GnRH is used, a high rate of ovulation and conception can be anticipated in patients with complete GnRH deficiency and hypothalamic amenorrhea. Women with polycystic ovarian syndrome may also benefit from pulsatile GnRH, although rates of ovulation are lower. Pretreatment with a GnRH agonist may improve these rates considerably, but experience is limited. Whether an iv or sc route of administration is chosen, a simplified clinical monitoring protocol can be created which requires a minimum of patient monitoring while assuring maximum safety. Seventy five nanograms per kg appears to be a reasonable initiating dose, with subsequent increases in those who do not respond. The frequency of GnRH administration is best based on the GnRH pulse frequency in normal women. However, further information is needed to determine whether such a variable frequency is clearly superior to a fixed frequency regimen. When used appropriately, pulsatile GnRH is safe, effective, and offers an excellent alternative to conventional gonadotropin therapy for women with disordered endogenous GnRH secretion. Most importantly, and as opposed to exogenous gonadotropin therapy, pulsatile GnRH can be administered by most physicians in the office setting without the necessity of on-line E2 monitoring. This feature will enable more patients to receive treatment by their local physicians, whereas exogenous gonadotropin therapy should be administered by appropriately equipped referral centers. In the future, further studies will be required to determine which other categories of patients might benefit from pulsatile GnRH.
An adequate frequency of gonadotropin-releasing hormone (GnRH) pulses appears to be important for physiological gonadotropin secretion. However, limited information exists on the exact role of this parameter in the regulation of the human menstrual cycle. Thus we studied gonadotropin and gonadal steroid secretion in 32 women with primary hypogonadotropic amenorrhea who received pulsatile GnRH (60 to 120 micrograms/day) at 60- or 120-min intervals for a total of 64 ovulation induction cycles. Ovulation was achieved in 94% of 60-min and in 70% of 120-min cycles P less than 0.05). In the follicular phase of ovulatory cycles, estradiol (E2) levels did not differ among the four groups; however, mean luteinizing hormone (LH) levels were lower (P less than 0.005), and the midcycle LH surge was severely blunted in cycles of subjects receiving 120 micrograms/day (5 micrograms/bolus) GnRH every 120 min compared with subjects receiving the same dose of GnRH per day or per bolus every 60 min. Luteal progesterone (only in 60 micrograms/day GnRH cycles) and E2 levels were lower in 120-min than in 60-min cycles (P less than 0.05). The use of the higher daily GnRH dose (120 micrograms/day) reduced or abolished the frequency-associated hormone level differences. We conclude that a low frequency of pulsatile GnRH in women 1) decreases mean LH levels and blunts the midcycle gonadotropin surge, 2) does not increase follicle-stimulating hormone concentrations, and 3) is associated with a reduced rate of ovulation.
Pulsatile GnRH administration for induction of ovulation is often ineffective in polycystic ovarian disease (PCOD) patients. To clarify and correct the endocrine mechanisms underlying this deranged response we gave pulsatile GnRH (5 micrograms, iv, every 60 min) to idiopathic hypogonadotropic hypogonadism (IHH) patients with primary amenorrhea for 19 cycles and to PCOD patients for 24 cycles before (pre-A) and for 25 cycles after (post-A) GnRH analog suppression. Compared to IHH, pre-A cycles were characterized by elevated LH, estradiol, and testosterone; reduced luteal phase progesterone; and low ovulatory (38%) and pregnancy rates (8%). Conversely, LH, estradiol, and follicular phase testosterone levels were lower in post-A than in pre-A cycles, while luteal phase progesterone was higher; the endocrine pattern of post-A cycles closely resembled the one of IHH cycles. The ovulatory and pregnancy rates of PCOD patients improved remarkably in post-A cycles (90% and 38%, respectively). Excessive body weight was associated with a lower incidence of ovulation in both pre-A (15%) and post-A cycles (75%). A worse endocrine pattern and a lower ovulatory rate (50%) were obtained when a second consecutive post-A cycle occurred without repeating GnRH analog suppression. No signs of even mild ovarian hyperstimulation and no multiple pregnancies were recorded in the post-A cycles. We conclude that in PCOD 1) deranged pituitary sensitivity, excessive ovarian androgen secretion, and obesity critically affect folliculogenesis and ovulation; 2) pituitary-gonadal suppression with a GnRH analog markedly improves the endocrine and clinical responses to pulsatile GnRH ovulation induction; 3) optimal results can be achieved only when each pulsatile GnRH cycle is preceded by GnRH analog suppression; and 4) pulsatile GnRH is highly effective and safe for ovulation induction, provided that PCOD subjects are pretreated with a GnRH analog.
The use of pulsatile gonadotropin-releasing hormone is an effective means of inducing ovulation, but requires prolonged intravenous (IV) or subcutaneous administration. We hypothesized that the use of self-contained infusion pumps using fluids maintained in a closed system would permit safe peripheral IV administration of gonadotropin-releasing hormone, and possibly other hormones, over prolonged intervals. Thirty-eight female patients undergoing pulsatile IV gonadotropin-releasing hormone therapy were followed for 1958 catheter days (230 catheters). Catheters were removed for signs of local inflammation, at the completion of a treatment episode or, initially, at routine intervals of 7-10 days. There were no episodes of fever (temperature over 37.5C) and three episodes of local inflammation. The incidence of significant catheter-tip cultures was 11%, and none were associated with local inflammation. There were four positive blood cultures (2%), none associated with local or systemic signs of infection. We conclude that the use of a closed system of prolonged peripheral IV cannulation is relatively safe when combined with fastidious care of the catheter site and careful outpatient monitoring for long-term administration of pulsatile gonadotropin-releasing hormone.