Human Reproduction, Vol. 19, No. 1, 54-58,
January 2004
© 2004 European Society of Human Reproduction and Embryology
GnRH antagonists and mild ovarian stimulation for intrauterine insemination: a randomized study comparing different gonadotrophin dosages
1 Infertility Unit, Department of Obstetrics and Gynaecology, University of Milan and 2 Reproductive Unit, Istituto Scientifico San Raffaele, Milan, Italy
3 To whom correspondence should be addressed at: Infertility Unit, Department of Obstetrics and Gynaecology, University of Milan, Via Manfredo Fanti 6, 20122, Milan, Italy. e-mail: ragni{at}telemacus.it
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Abstract |
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BACKGROUND: The precise role of GnRH antagonists in the armamentarium of drugs for stimulation of ovulation associated with intrauterine insemination remains to be clarified. In this study, we have compared two different protocols employing GnRH antagonists in order to determine the lower effective dose of gonadotrophins to use. METHODS: Sixty-six couples with unexplained infertility or moderate male subfertility were recruited. Starting on day 3 of the cycle, 32 patients were randomized to receive 50 IU of recombinant FSH per day, whereas 34 were treated with 50 IU of recombinant FSH on alternate days. Women received the GnRH antagonist Ganirelix at a dose of 0.25 mg per day starting on the day in which a leading follicle
14 mm in mean diameter was visualized, until HCG administration. Insemination was performed 34 h after HCG injection. RESULTS: The regimen with daily recombinant FSH was associated with a lower rate of mono-ovulation (53.3% versus 78.8%, P = 0.06) but also with a higher clinical pregnancy rate per initiated cycle (34.4% versus 5.9%, P = 0.005). CONCLUSIONS: A protocol of recombinant FSH 50 IU daily and GnRH antagonist may represent an effective and safe regimen for ovulation induction associated with intrauterine insemination.
Key words: GnRH antagonist/intrauterine insemination/ovulation induction/recombinant FSH
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Introduction |
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The incidence of multiple gestation has been rapidly increasing over recent years because of the growing use of infertility treatments, especially ovarian stimulation and IVF techniques (Evans et al., 1995
; Jewell and Yip, 1995). However, these two infertility treatment options have to be considered separately in this regard. Indeed, the rate of multiple gestation can be considerably reduced by transferring only two embryos in IVF programmes, with only a minimal effect on overall pregnancy rate (Templeton and Morris, 1998). Conversely, it has been reported that there is no way to reduce the rate of multiple births after ovarian stimulation without also reducing the rate of conception (Collins, 1994; Dickey, 2003). As a consequence, multiple pregnancies after ovarian stimulation with or without intrauterine insemination (IUI) currently constitute the majority of all iatrogenic multiple pregnancies (Dickey, 2003; Jones, 2003). This aspect has been emphasized recently in two large studies which documented that ovarian stimulation is associated with a 20% incidence of twin pregnancies and a nearly 10% incidence of higher order multiple pregnancies (Guzick et al., 1999; Gleicher et al., 2000). These results are similar to those obtained from a systematic review of the literature (Cohlen, 1998) and have important clinical implications. Indeed, the adverse medical, economic and social consequences of bearing triplets are widely recognized. Moreover, it has been emphasized recently that even twins face greater risks of disability and death than do singletons (Bergh et al., 1999; Cain, 2000).
The considerable human and financial costs of multiple births thus warrant a re-evaluation of the protocols of ovarian stimulation. In this context, a new class of drugs, the GnRH antagonists, recently have become commercially available and are now at an advanced stage of clinical development. These drugs cause a prompt and reversible suppression of gonadotrophin secretion, thus preventing spontaneous ovulation (Huirne and Lambalk, 2001). Their precise role in the armamentarium of drugs for ovarian stimulation remains to be clarified. In particular, considering that a premature LH surge, a condition that may interfere with the adequate timing of IUI, has been reported to occur frequently in stimulated cycles (Cohlen et al., 1998), it might be hypothesized that these drugs may have a role in this specific context. We have conducted a randomized study comparing two different protocols using GnRH antagonists associated with IUI in order to determine the best protocol that may ensure a decrease in multiple birth risk on one hand and an acceptable pregnancy rate on the other.
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Materials and methods |
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Between September 2001 and May 2002, 69 consecutive subfertile patients who were prescribed ovulation induction and IUI were recruited at the Infertility Unit, Department of Obstetrics and Gynaecology of the University of Milan (n = 49, 71.0%) and at the Infertility Unit, San Raffaele Hospital, Milan (n = 20, 29.0%). Patients included in this study suffered from unexplained infertility or mild male factor infertility. More specifically, inclusion criteria were women <38 years of age, primary or secondary infertility lasting for at least 24 months (but <8 years), a body mass index between 19 and 30 kg/m2, normal prolactin levels, normal thyroid function, normal uterine cavity and bilateral tubal patency assessed by hysterosalpingography and/or laparoscopy with chromosalpingography and hysteroscopy, and no previous IUI. Patients with minimal or mild (stage I–II) endometriosis were eligible 6 months after treatment. Patients with polycystic ovarian syndrome were also included if IUI was required. Mild male factor was defined as abnormal semen variables according to the World Health Organization (1999
) criteria for normality, morphology 5% and total number of motile spermatozoa recovered after gradients 5 x 106. The protocol of the study was approved by the local Ethical Committee and all patients gave informed consent. The precise protocol of monitoring and insemination is described elsewhere (Ragni et al., 1999), and is only briefly reported herein.
After inclusion in the study, patients underwent a transvaginal ultrasonography on day 3 of the cycle and were randomized by means of a previously computer-generated list into two groups. Sealed opaque envelopes contaning treatment allocation were opened after ultrasonographic scan. Women were enrolled only for one cycle of treatment. All subjects started the therapy from the third day of the cycle. The therapeutic protocol of the study is illustrated in Figure 1. Patients in group A were administered recombinant FSH (rFSH; Puregon®, Organon, The Netherlands) 50 IU per day, whereas those included in group B were treated with rFSH 50 IU on alternate days. Ovarian stimulation in both groups was monitored by daily transvaginal ultrasound scans starting from the eighth day of the cycle (fifth day of ovarian stimulation).The GnRH antagonist Ganirelix (Orgalutran®, Organon, The Netherlands) at a dose of 0.25 mg per day was started from the day in which a follicle 14 mm in mean diameter was visualized until administration of 5000 IU of HCG (leading follicle with a mean diameter 18 mm). If a leading follicle with a mean diameter 18 mm was detected at the first transvaginal ultrasound scan at the eighth day of the cycle, HCG was administrated the same day without prescribing GnRH antagonist. No luteal phase supplementation was prescribed since we previously have demonstrated a normal hormonal luteal profile in patients treated with rFSH and GnRH antagonists (Ragni et al., 2001). To further prevent multiple gestations, the cycle was cancelled if the total number of follicles with a mean diameter 15 mm visualized at the time of HCG injection was >2. Insemination was performed 34 h after HCG administration. Serum levels of estradiol were assessed daily starting on the first day of GnRH antagonist until the day of HCG administration. Serum levels of progesterone were determined at 0, +2, +4, +6, +8, +10 and +12 days after HCG administration. Finally, LH levels were evaluated on the day of HCG injection. All hormonal assessments were obtained retrospectively and did not influence clinical decisions regarding ongoing cycles. Serum was obtained from blood samples after centrifugation at 800 g for 10 min at room temperature and then stored at –20°C until assessment. All samples were evaluated simultaneously. Commercially available immunoassays for in vitro quantitative determination (Roche Diagnostics GmbH, Mannheim, Germany) were used to assess serum levels of progesterone, estradiol and LH.
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Data were analysed using
2 test, Fisher exact test, Student’s t-test and non-parametric Wilcoxon signed rank test, as appropriate (SPSS/Windows, Chicago, IL). A binomial distribution statistical model was used to determine the 95% confidence interval (95% CI) of pregnancy rate. A sample size of 200 patients per arm of the study was calculated at the usual levels of study power (5% level of significance, power of the study of 80%). This sample size was estimated hypothesizing a pregnancy rate per cycle initiated in the group treated with rFSH 50 IU/day of 
20% and stating as clinically relevant a drop of >10% in the group treated on alternate days. Considering that few data are currently available on the pregnancy rates associated with these protocols, it was decided to perform an interim analysis after the first 60 cases before initiating the study to verify our assumptions. This analysis would have allowed us to exclude differences in the percentage of success of >20%. It was stated that the study would have been be interrupted for ethical reasons if differences between the two arms of the study were statistically significant (P < 0.05). |
Results |
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The trial profile is shown in Figure 2. The study was interrupted after the first 66 available cases considering that a preliminary evaluation of the results revealed a strong difference between the two groups in terms of pregnancy rate. As shown in Table I, basal characteristics of the two groups of patients enrolled in the study were similar. Data regarding the outcome of treatment cycles are reported in Table II. It is of note that a statistically significant higher clinical pregnancy rate per cycle initiated was observed in the group of patients treated with daily rFSH [34.4% versus 5.9%, odds ratio (OR) 8.4, 95% CI 1.7–41.7]. In this group, the 95% CI of the clinical pregnancy rate per cycle initiated was 17.7–51.1%. Conversely, the percentage of cycles with only one follicle was significantly higher in the group of patients treated on alternate days (OR 3.2, 95% CI 1.0–9.8; and OR 3.5, 95% CI 1.2–9.9 considering follicles with a mean diameter
16 mm and 11 mm, respectively). The GnRH antagonists were not prescribed in eight patients (two in group A and six in group B, P = 0.26) since a leading follicle with a mean diameter 18 mm was observed on the eighth day of the cycle and thus HCG injection was administered on the same day. No relevant differences according to the study centre were observed (data not shown).
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No cases of progesterone and/or LH rise on the day of HCG administration were observed. Estradiol serum values during the proliferative phase according to the stimulation protocol are shown in Figure 3. No significant differences were observed. All pregnancies were intrauterine: 10 women delivered healthy babies. Moreover, two spontaneous first trimester abortions (group A) and one induced abortion for nanism and cranial malformation at 20 weeks gestation (group B) were observed. None of the women who became pregnant was lost at follow-up. No multiple pregnancies were observed. Thus, the overall live birth rate per recruited couples was 25.7% (nine out of 35) and 2.9% (one out of 34) in patients treated daily and on alternate days, respectively (OR 11.4, 95% CI 1.4–96.0).
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Discussion |
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In this study, we have evaluated the efficacy of a regimen of ovarian stimulation using a low dose of recombinant gonadotrophin and GnRH antagonist in patients undergoing IUI for unexplained infertility or moderate male subfertility. Results from this trial have documented that a daily dose of 50 IU of rFSH is associated with a remarkably higher pregnancy rate when compared with a regimen of 50 IU on alternate days.
This study suggests that 50 IU of rFSH daily represents the lower dose of gonadotrophins to use that may presumably ensure a decrease of multiple birth risk on one hand and an acceptable pregnancy rate on the other. Further changing the dose of gonadotrophins to 50 IU on alternate days is associated with a further increase in the percentage of mono-ovulatory cycles and thus with a hypothetical lower risk of multiple birth, but also with an unacceptable drop in the success rate. Indeed, the percentage of patients with only one follicle with a mean diameter 16 mm increased from 53.3 to 78.8%, whereas the pregnancy rate decreased from 34.4 to 5.9%. In this context, it has to be noted that, although the worth in terms of follicular growth of a regimen with low dose on alternate days has been documented previously (Buckler et al., 1999), the appropriateness of this scheme in the presence of a GnRH antagonist has not been demonstrated. Since administration of the antagonist may suppress endogenous FSH secretion, it might be hypothesized that this effect may cause a transient insufficiency of FSH levels in the alternate dose regimen. On the other hand, it is worthwhile noting that serum peak levels of estradiol did not differ between patients randomized to receive rFSH daily and those receiving it on alternate days, thus indirectly supporting that follicular development is not significantly impaired in women treated on alternate days.
An important and unexpected finding of this study is that we have documented the possibility of achieving a remarkably high clinical pregnancy rate per initiated cycle (34.4%, 95% CI 17.7–51.1%) combining low dose gonadotrophins and GnRH antagonists. In idiopathic subfertility and in male subfertility, the two major indications for IUI after standard ovarian stimulation, pregnancy rates from 2.3 to 27.4% and from 3.9 to 13.6% per cycle, respectively, have been reported (Goverde et al., 2000). In a recent large randomized clinical trial aimed to assess the efficacy of IUI, the pregnancy rate per cycle was found to be 8.7% (Guzick et al., 1999). This specific study enrolled 932 couples and currently represents the largest prospective series available on this topic. The reported success rate in previous series specifically using low-dose gonadotrophin without GnRH antagonist in IUI cycles ranged from 9.8 to 25.7% (Balasch et al., 1994; Gregoriou et al., 1995; Healy et al., 2003). The strict criteria used to recruit patients in our study, notably an age below 38 years and the absence of previous IUI, may at least in part explain the high success rate observed. On the other hand, it is unlikely that these criteria, which are frequently employed for studies on this topic, may be solely responsible for the observed results. In this context, it might be speculated that the concomitant use of GnRH antagonist may play a critical role. In particular, this drug may allow optimal timing for insemination in relation to ovulation. In this regard, it is worthwhile noting that a premature LH surge, a condition that may interfere with the adequate timing of IUI, has been reported to occur in 24% of stimulated cycles (Cohlen et al., 1998). On the other hand, it also has to be considered that the much lower pregnancy rate observed in the group treated on alternate days which also used the GnRH antagonist suggests that the success rate of the daily regimen may be due to a better follicular development rather than to the use of the antagonist. A prospective trial where daily 50 IU of rFSH is used with or without GnRH antagonist may help to clarify this issue. Considering costs associated with the use of this drug, such a study may be of value in view of future cost-effectiveness analyses. Finally, considering the relatively small number of cases enrolled in this study, it cannot be excluded that an alpha error may also play a role in explaining the extremely high pregnancy rate observed. It has to be noted, however, that the binomial distribution statistical model used to determine the 95% CI of the pregnancy rate indicates that the lower limit of this interval is 17.7% and, thus, that the rate of success should be at least above this still considerably high percentage. Larger trials are, however, warranted to define more precisely the pregnancy rate associated with this protocol.
Reducing the number of multifetal gestations that result from ovarian stimulation with or without IUI is one of the most important challenges in reproductive medicine (Dickey, 2003). Several strategies to prevent multiplets have been proposed. Mild ovarian stimulation, supernumerary follicle aspiration, coasting, conversion to IVF, selective abortion and application of strict cancellation criteria are all possible solutions (Rosenwaks and Chung, 2003). Cost-effectiveness and cost-benefit analyses of these different strategies remain to be conducted. In this study, we have evaluated a strategy that combined a protocol of mild ovarian stimulation with the application of strict cancellation criteria. Indeed, cycles were cancelled if three or more follicles with a mean diameter 15 mm were present. Considering specifically patients who received 50 IU of rFSH daily, the cancellation rate was found to be 6.3%. This percentage appears to be appealing, considering that it has been reported that the consequence of reducing high-order multiple pregnancies using cancellation criteria would be to interrupt one-third of superovulation induction cycles (Rosenwaks and Chung, 2003). The effectiveness of this protocol in preventing multiple gestation cannot be reliably assessed in the present study due to the insufficient sample size. However, some observations suggest that this risk may be low. First, all 11 pregnancies achieved using this scheme were found to be singleton. Secondly, the extremely reduced total number of follicles with a mean diameter 11 mm and the low serum peak levels of estradiol observed strongly support that patients are presumably not exposed to a relevant risk (Dickey, 2003; Fritz and Ory, 2003). These two variables have indeed been demonstrated to be the two most significant variables correlated with the risk of multiple births in a large series of women undergoing ovarian stimulation (Gleicher et al., 2000). In this specific study, serum peak levels of estradiol in women with a twin pregnancy or a high-order multiple pregnancy (3) were 1458 ± 922 pg/ml and 1482 ± 583 pg/ml, respectively. These levels were therefore much higher than those observed in our study (<300 pg/ml for both treatment groups). Similarly, total numbers of follicles were 17.2 ± 10.1 and 25.3 ± 11.3 in women who developed a twin pregnancy and a high-order multiple pregnancy, respectively. Again, these means were markedly higher than those observed in our study (2.4 ± 2.0 and 1.5 ± 0.7 follicles for patients treated with rFSH daily or on alternate days, respectively).
A protocol employing rFSH 50 IU daily and a GnRH antagonist might become an attractive new possibility for ovarian stimulation in IUI cycles once its effectiveness in terms of pregnancy rate and risk of multiple birth has been confirmed in a larger series.
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Submitted on May 6, 2003; resubmitted on July 22, 2003; accepted on September 29, 2003.
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