A Preliminary Study on Reduced Dose (33 or 25 G) Gonadotropin- Releasing Hormone Agonist Long Protocol for Multifollicular Ovarian Stimulation in Patients With High Basal Serum Follicle-Stimulating Hormone Levels Undergoing in Vitro Fertilization-Embryo T
By Ku, Seung-Yup; Choi, Young Sik; Jee, Byung Chul; Suh, Chang Suk; Et al
Abstract
The aim of the present study was to evaluate the clinical efficacy of half-dose (50 g) and further reduced dose (33 or 25 g) gonadotropin-releasing hormone agonist (GnRH-a; triptorelin) long protocols for multifollicular ovarian stimulation (MFOS) for patients with high basal serum follicle-stimulating hormone (FSH) level undergoing in vitro fertilization and embryo transfer (IVF- ET). One hundred and two IVF-ET cycles performed in 84 infertile patients with high basal serum FSH (> 10.0 mIU/ml) were included in this retrospective study. Study subjects were assigned to two groups: continuous half-dose GnRH-a long protocol (group A, n = 63) vs. further reduced dose GnRH-a long protocol (group B, n = 39) from half-dose at the start of GnRH-a to one-third or one-quarter dose after pituitary downregulation. Exogenous FSH or human menopausal gonadotropin was administered for MFOS in step-down mode, four or fewer embryos were transferred, and the outcomes of MFOS were compared between the two groups. Serum estradiol (E^sub 2^) level on the day of human chorionic gonadotropin administration was significantly higher in group B (mean standard deviation (SD): 1318.3 1120.4 vs. 2054.9 1773.5 pg/ml, p = 0.015). The number of transferable and good-quality embryos was also significantly higher in group B (mean SD: 2.9 1.7 vs. 3.7 2.0, p = 0.027; 1.8 1.4 vs. 2.7 2.0, p = 0.020). No statistically significant difference in the outcomes was observed with respect to the dose of gonadotropins administered, the number of oocytes retrieved or the clinical pregnancy rate. In conclusion, GnRH-a long protocol with a reduced dose, tapered from the starting half-dose to a third or a quarter of the normal dose after pituitary suppression, may be beneficial for MFOS in IVF-ET patients with a high basal serum FSH level. A further prospective randomized controlled study on a larger scale is needed to confirm these findings.
Keywords: Gonadotropin-releasing hormone agonist, reduced dose, long protocol, controlled ovarian hyperstimulation
Introduction
The introduction of gonadotropin-releasing hormone agonists (GnRH- a) in multifollicular ovarian stimulation (MFOS) has contributed to a marked improvement in the results of in vitro fertilization and embryo transfer (IVF-ET). The use of GnRH-a in MFOS improves the synchronization of follicular growth and prevents premature luteinizing hormone (LH) surges, which result in a reduced number of cancelled cycles. In many cases, this treatment allows more oocytes to be retrieved and increases the number of transferable embryos, thus increasing the pregnancy rate and enabling programmed egg collection [1]. Presently, despite the development of GnRH antagonists, GnRH-a are still widely used for MFOS.
Patients with high serum follicle-stimulating hormone (FSH) concentrations on day 3 have a higher risk of having a ‘poor response’ to ovarian stimulation [2-4]. Various treatments have been proposed in the literature for ovarian stimulation in poor responders. Among these treatments, protocols avoiding the use of GnRH-a have produced disappointing results in poor responders and have been associated with the risk of premature luteinization and cancellation [5]. Use of lower dosages of GnRH-a could have some advantages, based upon dose-finding studies [6,7]. It has been demonstrated that once the pituitary has been suppressed, the dose of GnRH-a needed to prevent the LH surge decreases with the length of treatment [8]. Reducing the dose of GnRH-a administered daily for MFOS has been successful in poor responders, without having an adverse effect on the quality of ovarian response to stimulation [9]. However, in a recent comparative study, the cancellation rate was significantly higher without a favorable pregnancy rate in those receiving a microdose GnRH-a protocol [10].
Despite the above controversial results, studies on the GnRH-a long protocol in which the starting half-dose (50 g/day) is reduced further after pituitary suppression in the expected poor responders are rare. In the present preliminary study, we aimed to evaluate the clinical efficacy of continuous half-dose and further reduced dose GnRH-a long protocols, in FVF-ET patients with high basal serum FSH levels, using a reduced dose of half-dose at the start tapering to one-third or one-quarter dose (33 or 25 g/day) after completion of downregulation.
Patients and methods
Patients
Eighty-four patients (102 cycles) with a basal serum FSH level > 10 mIU/ml were included in this retrospective study. All underwent IVF-ET using half-dose GnRH-a for MFOS at the Infertility Clinic, Seoul National University Hospital. Study subjects were assigned to one of two groups: continuous half-dose GnRH-a long protocol (group A, n = 63) and further reduced dose GnRH-a long protocol (group B, n = 39) from half-dose at the start of GnRH-a to one-third or one- quarter dose after pituitary suppression.
Multifollicular ovarian stimulation regimens and in vitro fertilization procedures
Ovarian stimulation was performed, as described in our previous reports [11,12], using FSH (Metrodin-HP; Serono, Switzerland) or human menopausal gonadotropin (Pergonal; Serono) in a step-down fashion after pituitary desensitization with GnRH-a (Decapeptyl; Ferring, Sweden) with a long protocol. In group A, treatment with triptorelin at 50 g/day began on day 21 of the preceding cycle and continued until the day of administration of human chorionic gonadotropin (hCG), while in group B the triptorelin dose was further reduced from 50 g/day at the start to 25 or 33 g/day after pituitary suppression according to the physician’s preference. Ovarian response was monitored frequently by transvaginal ultrasonography. When the leading follicle reached 18mm in mean diameter, or there were three or more 16mm follicles with a serum estradiol (E^sub 2^) level of 200 pg/ml per follicle, 10 000IU of hCG (Profasi; Serono) was administered. Transvaginal oocyte retrieval was performed 36 h after hCG injection. Intracytoplasmic sperm injection (ICSI) was performed according to the conventional protocol and only on metaphase II oocytes. Up to four embryos were transferred vaginally on the second or third day after retrieval. The luteal phase was supported by 50 mg of progesterone in oil (Progest; Samil Pharmaceutical, Korea) or 8% progesterone gel (Crinone; Serono) from the day of embryo transfer. Clinical pregnancy was defined by the presence of intrauterine gestational sac(s) with pulsating heart beats on transvaginal ultrasound scan at 5-6 weeks’ gestation with increasing serum β-hCG levels.
Statistical analysis
The MFOS and IVF-ET outcome variables were compared for the two groups. The primary outcomes were the results of MFOS such as cancellation rate, duration of MFOS, number of oocytes retrieved, and numbers of transferable and good-quality embryos. Good-quality embryos were denned as those with embryo grades of I/V to III/V. The secondary outcomes were clinical pregnancy and implantation rates. Results are presented as mean standard deviation. Where appropriate, the χ^sup 2^ test and Student’s t test were employed using SPSS for Windows version 11.0 (SPSS Inc., Chicago, IL, USA). A value of p < 0.05 was considered to be statistically significant.
Results
Eighty-four women (102 cycles) were included in this study, 50 (63 cycles) in group A and 34 (39 cycles) in group B. Their clinical characteristics are summarized in Table I. No difference was evident in the distribution of infertility causes between the two groups, and no statistically significant differences were observed between the two groups in terms of age, basal serum FSH level, body mass index (BMI) or the proportion of patients who underwent ICSI. In group A, five cycles were cancelled; testicular sperm extraction failed in one cycle and four cycles showed fertilization failure. In group B, two cycles were cancelled; idiopathic thrombocytopenic purpura was aggravated in one patient and the other cycle failed fertilization.
The results of MFOS and IVF-ET are shown in Tables II and III. Compared with group A, in group B serum E^sub 2^ level on the day of hCG administration was significantly higher (1318.3 1120.4 vs. 2054.9 1773.5 pg/ml, p = 0.015), as were the numbers of transferable (2.9 1.7 vs. 3.7 2.0, p = 0.027) and good-quality (1.8 1.4 vs. 2.7 2.0, p = 0.020) embryos. There were no statistically significant differences in the outcomes such as dose of gonadotropins administered, duration of controlled ovarian hyperstimulation, number of follicles 14mm or more on hCG day, number of oocytes retrieved, fertilization rate, cancellation rate, implantation rate and clinical pregnancy rate per cycle.
Table I. Comparison of clinical characteristics between the two study groups.
Table II. Outcomes of multifollicular ovarian stimulation and in vitro fertilization – embryo transfer.
Table III. Odds ratios (OR) and 95% confidence intervals (CI) comparing various outcomes between half-dose and dose reduction groups.
Discussion
The present study showed that, after completing luteal-phase pituita\ry desensitization using the GnRH-a long protocol, reducing the GnRH-a dose from the starting half-dose to one-third or one- quarter of the usual dose can be beneficial in patients with high basal FSH, compared with fixed half-dose of GnRH-a. The further reduced dose group showed higher peak E^sub 2^ level and numbers of obtained and good-quality embryos (Table II). Our results may provide a useful reference for the management of older patients with a high basal FSH level. In our study, the average age of participants was 37.0 5.1 years and their mean basal FSH was 16.3 7.5mIU/ml, and they benefited from the reduction to a third or a quarter of the usual dose by acquiring 0.8 more embryos (0.9 good- quality embryos).
The optimal dose of GnRH-a has been searched for since the early 1980s [13,14]. In the case of triptorelin, 100 g has been adopted for MFOS. Due to a slower and lower ovarian response to complete desensitization of the pituitary (especially in low responders), several authors have suggested that dose reduction of GnRH-a should be possible [6,7,15,16]. Until recently, a number of studies have focused on reducing GnRH-a doses in normal responders. Simon and co- workers compared continuous 0.5mg triptorelin with tapering from a starting dose of 0.5mg to 0.1mg following downregulation, and found that this method enabled them to reduce the dose of GnRH-a without any adverse effects on ovarian response or clinical results [17]. Elgendy and colleagues reported that they could retrieve more oocytes and obtain more embryos with intranasal nafarelin 200 mg three times daily followed by a reduction to twice daily after downregulation, vs. continuous 200 mg three times daily until hCG day [18]. In a recent report by DaI Prato and associates, partial desensitization with reduced GnRH-a dose was superior to long- acting depot form [19]. Desensitization using 100 g triptorelin followed by 50 g significantly reduced the duration of MFOS and gonadotropin doses compared with the group on 3.75mg depot triptorelin.
The efficacy of < 100 g triptorelin was suggested by Janssens and co-workers in their two dose-finding studies [6,7]. They found that 15, 50 and 100 g were effective doses that induced adequate desensitization [6], and that more oocytes and embryos were obtained with 50 and 100 g compared with 15 g or placebo [7], in women with tubal, idiopathic or male infertility whose basal FSH levels were < 10mIU/ml.
Another aspect of GnRH-a dose reduction was addressed by an earlier report that warned of the possible occurrence of ovarian hyperstimulation even when using subtherapeutic doses of GnRH-a [20]; however, this possibility may not apply to those who are poor or low responders. Thus, it is believed that a reduced GnRH-a dose may avoid profound pituitary suppression and improve ovarian responsiveness to gonadotropin.
In poor responders with high basal FSH, the reduction of the GnRH- a dose in the following cycles can be successful. Feldberg and colleagues compared three doses of triptorelin administered during a long luteal protocol in women with a previous poor response and high basal serum FSH (>15mIU/ml): 3.75mg in a single intramuscular dose; 500 g/day decreased to 100 g/day; and 100 g/day decreased to 50 g/ day [21]. In the lowest dose group, they found higher peak serum E^sub 2^ levels and larger number of oocytes retrieved, as well as a lower cancellation rate and a higher, although not significantly so, pregnancy rate. Olivennes and co-investigators studied IVF patients with a high basal FSH (>6.5mIU/ml) who had received a long protocol with triptorelin in the depot formula over the previous 6 months [22]. These patients were treated with low-dose leuprolide, which was reduced from 500 g at the start to 250 g after the pituitary suppression protocol. The use of a low-dose agonist protocol reduced the number of gonadotropin ampoules used and the duration of stimulation, increased the number of mature oocytes, and reduced the cancellation rate. Even though there was no previous literature report evaluating the efficacy of triptorelin doses smaller than 50 g, like ours that compared 50 g with 33 or 25 g, the above studies also provide good evidence of the benefit we could get by decreasing the dose of GnRH-a when MFOS is performed in poor responders or in those with high basal FSH levels.
Reduction of the GnRH-a dose to 33 g (n = 27) or 25 g (n=12) was determined by physician’s preference. These two doses were not analyzed separately due to further reduced sample sizes. No statistical difference was observed between these two doses in terms of the outcomes of MFOS or pregnancy (data not shown). Neither did the two dose groups differ in terms of age or basal FSH levels of patients. Regarding BMI, the 25 g group tended to have lower BMI than the 33 g group (20.5 2.3 vs. 22.1 2.4kg/m^sup 2^), although this difference did not reach statistical significance. This finding suggests that body habitus might have influenced the physician’s dose preference. Our presumption that there would be no significant major difference between these two doses (higher than 15 g) is supported by a study by Janssens and associates, which showed that adequate desensitization can be achieved with a dose as low as 15 g of triptorelin [6].
In summary, we used a reduced dose GnRH-a luteal long protocol to improve ovarian responsiveness in women with a high basal FSH level. We started MFOS in the mid-luteal phase at triptorelin 50 g/day, which avoided the premature LH surge without profound pituitary suppression. GnRH-a was continued with the above half-dose until the day of hCG administration (group A) or reduced to one-third or one- quarter (33 or 25 g/day), higher than 15 g/day known as the lowest dose for desensitization (group B). As a result, the peak serum E^sub 2^ level and the numbers of transferable and good-quality embryos were higher in group B. Although this reduced GnRH-a dose protocol yielded higher numbers of embryos, it does not seem to improve the pregnancy outcomes. However, in terms of number of embryos acquired, cost and convenience, the results of our study suggest that GnRH-a long protocol with a dose reduction from half- dose at the start to a third or a quarter after pituitary suppression may be more beneficial for MFOS in IVF-ET patients with high basal serum FSH level, and should be considered as an alternative to a continuous half-dose GnRH-a long protocol. However, because of the limitation that this study was retrospective, further comparative studies in a cumulative way and prospective randomized controlled studies on a larger scale will be necessary to confirm our findings.
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SEUNG-YUP KU1, YOUNG SIK CHOI1, BYUNG CHULJEE1, CHANG SUK SUH1,2, YOUNG MIN CHOI1,2, JUNG GU KIM1, SHIN YONG MOON1,2, & SEOK HYUN KIM1,2
1 Department of Obstetrics and Gynecology, College of Medicine, Seoul National University, Seoul, South Korea, and 2 Institute of Reproductive Medicine and Population, Medical Research Center, Seoul National University, Seoul, South Korea
(Received 16 March 2005; revised 22 June 2005; accepted 19 July 2005)
Correspondence: S. H. Kim, Department of Obstetrics and Gynecology, College of Medicine, Seoul National University, Yonkeun- dong, Chongno-gu, Seoul 110-744, South Korea. Tel: 82 2 2072 3773. Fax: 82 2 762 3599. E-mail: seokhyun@plaza.snu.ac.kr
Copyright CRC Press Oct 2005