Introduction
Intrauterine insemination (IUI) is widely used as an infertility
treatment modality. The success of assisted reproductive
technologies is dependent on appropriate patient selection and
adequate development of oocytes. Compared to clomiphene
citrate ovarian stimulation, gonadotropin ovarian stimulation with
IUI results in higher pregnancy rates. Moreover, the combination
of controlled ovarian hyperstimulation (COH) + IUI has been
shown to increase the fecundity of the cycle as compared to IUI
alone.(1,2) There are variations in the reported clinical pregnancy
rates of COH + IUI cycles; these may be attributed to differences
in the aetiology and duration of infertility, sperm preparation
technique, the number of sperms injected, the number of
inseminations per cycle, cycle monitoring, IUI timing and the
ovarian stimulation protocol selected.(2-5)
Although low-dose protocols with recombinant follicle-
stimulating hormone (rFSH) are used during COH + IUI cycles,(6)
multifollicular development may occur and result in a sudden
increase in serum estradiol (E2) levels, which can result in a
premature luteinising hormone (LH) peak (before follicular
maturation) and revocation of the IUI.(7) Gonadotropin-releasing
hormone (GnRH) analogues lead to the desensitisation of pituitary
GnRH receptors and, via this phenomenon, block endogenous
LH increase. The use of GnRH analogues has been reported to
lower premature LH peak to approximately 2% and subsequently
increase pregnancy rates.(8) For more than ten years, the use of
gonadotropins with GnRH agonists has been the most frequently
applied treatment protocol for reducing the incidence of premature
LH peak. (9) However, this treatment protocol, which needs
2–3 weeks of desensitisation time, also increases the amount of
gonadotropins used, the risk of ovarian hyperstimulation syndrome
and the duration of treatment. During the desensitisation period,
patients are also exposed to side effects such as hot flushes,
headaches, vaginal dryness and bleeding. These drawbacks have
resulted in the recent removal of IUI treatment protocols, including
GnRH agonists. A Cochrane review on ovarian stimulation
protocols for IUI advised against the use of GnRH agonists in COH
with low-dose exogenous FSH (i.e. mild COH).(10)
GnRH antagonists, which are produced through the exchange
of amino acids of GnRH with other molecules at multiple points,
bind to GnRH receptors with high affinity.(11) These antagonistic
molecules prevent the release of endogenous gonadotropin and are
currently being considered to replace GnRH agonists due to their
positive pharmacokinetic and pharmacodynamic properties. (11)
The advantages of GnRH antagonists include absence of the first
flare-up effect, reduced risk of oestrogen deficiency syndrome
(since there is no need for long-term desensitisation), sufficient
LH blockage in a short duration of time, dose-dependent effect
Effect of GnRH antagonists on clinical pregnancy rates
in ovulation induction protocols with gonadotropins and
intrauterine insemination
Ramazan Dansuk1, MD, Ali Ihsan Gonenc2, MD, Sinem Sudolmus1, MD, Oguz Yucel2, MD, Osman Sevket1, MD,
Nadiye Köroğlu1, MD
Introduction
Intrauterine insemination (IUI) after controlled ovarian hyperstimulation (COH) was applied to selected
infertile patients to determine the effect of gonadotropin-releasing hormone (GnRH) antagonists in IUI cycles, in which
recombinant follicle-stimulating hormone (rFSH) had been used for COH.
Methods
This study was conducted between April 1, 2009 and June 10, 2009, and involved a total of 108 patients.
These patients had primary or secondary infertility, which resulted in an indication for IUI , and they each received two
cycles of ovarian stimulation treatment with clomiphene citrate. The patients were randomised into two groups – patients
in group A received rFSH + GnRH antagonist (n = 45), while those in group B received only rFSH (n = 63).
Results
The mean age of the patients was 31.84 ± 3.73 years and the mean body mass index (BMI) was 24.40 ± 1.88 kg/m2.
The mean age and BMI of the patients in groups A and B were not significantly different. There was no significant
difference in the mean total rFSH dose administered (988.33 IU in group A and 871.83 IU in group B). When compared
to group B, the mean number of follicles that were > 16 mm on the human chorionic gonadotropin (HCG) trigger day
was significantly higher in group A (1.58 and 1.86, respectively; p < 0.05). When the two groups were compared, there
were no statistically significant differences in the number of cancelled cycles due to premature luteinisation (none in
group A vs. two in group B) and the rate of clinical pregnancy (8.9% in group A vs. 7.9% in group B).
Conclusion
No significant improvement in the clinical pregnancy rates was observed when GnRH antagonists were
used in COH + IUI cycles, despite the significant increase in the number of follicles that were > 16 mm on HCG trigger day.
Keywords
GnRH antagonist, intrauterine insemination, ovarian stimulation, pregnancy rates
Original Article
354
and fast withdrawal from antagonist effects, which make GnRH
antagonists superior to GnRH agonists.(6,12) Furthermore, studies
on in vitro fertilisation (IVF) and intracytoplasmic sperm injection
protocols have shown that treatment duration and the total dose
of gonadotropin used are reduced when antagonists are used in
the protocol.(13) It has also been shown that GnRH antagonists
are associated with a low risk of high-order multiple pregnancies
when standard strict criteria are applied for cycle cancellation.(14)
Although there is controversy regarding the effectiveness
of GnRH antagonists in low-dose ovarian hyperstimulation
protocols, if current and future studies show that these antagonists
are able to improve pregnancy rates, the frequency of their use
may increase in the future. In the present study, we studied the
effect of GnRH antagonists in IUI cycles, in which rFSH had
been used for COH.
Methods
The present study was conducted between 1 April 2009 and
10 June 2009 in Suleymaniye Maternity and Women’s Disease
Research and Teaching Hospital’s outpatient clinics for infertility,
the most visited infertility clinics in Istanbul, Turkey. The study
was approved by the local ethics committee.
Patients who met the following criteria were eligible for
inclusion in the study: (a) indication for treatment with IUI
(e.g. unexplained infertility, mild male factor, minimal or
mild [stage I or II] endometriosis); (b) a history of two cycles
of ovarian stimulation treatment with clomiphene citrate;
(c) determination of tubal patency by hysterosalpingo graphy
(HSG) or laparoscopy; (d) age 18–39 years; (e) body mass index
(BMI) 18–39 kg/m2; (f) regular menstrual cycles (25–32 days);
(g) basal FSH < 10 IU/mL, and normal levels of thyroid-stimulating
hormone and prolactin; and (h) at least 5 million/mL sperm count
and 5% normal morphology on Kruger test. Patients who had
clinically significant systemic or endocrine disease, a diagnosis
of polyp, submucous myoma, uterine septum or any other space-
occupying lesion during HSG or office hysteroscopy evaluation
and previous IUI were excluded from the study.
A total of 126 patients agreed to participate in the study and
informed consent was obtained. However, only 108 patients
were included in the data analysis; 18 patients did not have the
appropriate response to treatment, were lost to follow-up or did
not have timely sonography. If any one of the following criteria
was met, the treatment cycle would be cancelled: (a) premature
luteinisation; (b) progesterone level > 1.7 ng/dL during COH
on the day of human chorionic gonadotropin (HCG) trigger for
ovulation; (c) premature LH peak; (d) LH level > 12.1 mIU/mL
on HCG trigger day; (e) probability of multiple gestations due to
the presence of more than four follicles > 15 mm; and (f) poor
response to treatment (i.e. no follicle > 10 mm).
The patients were randomly divided into two groups (group A
and group B) using an online research randomiser software (www.
randomizer.org). The patients in group A received rFSH and
GnRH antagonist for COH, while those in group B received only
rFSH. In both groups, ovarian stimulation was started on the third
day of the menstrual cycle. We used rFSH (GONAL-f ®; Merck
Serono, Rome, Italy) for ovarian stimulation. When calculating
the starting dose for each patient, the expected ovarian response
was taken into consideration. Most of the patients were prescribed
75 IU/mL rFSH subcutaneous injections around the umbilicus in
the mornings. New dosage was adjusted according to the ovarian
response (examined through follicle number and dimension, and
serum E2 levels on the sixth or seventh day of stimulation) and
stimulation was continued until the day of HCG.
When the dominant follicle reached a diameter of > 14 mm,
once-daily subcutaneous injection of the GnRH antagonist,
Cetrorelix (cetrotide flacon 0.25 mg), was added to the protocol
for group A patients; the use of the GnRH antagonist requires
continuation of gonadotropin. Cetrorelix was continued until
the day of insemination. In both groups, when one, two or three
follicles reached a diameter of 17 mm, 10,000 IU HCG (Pregnyl
ampoule 5,000 IU, 2 ampoules) was injected intramuscularly,
with the aim of triggering ovulation. After a mean duration of
35.5 (range 34–38) hours, IUI was performed. Serum βHCG
was measured 14 days after ovulation, and the βHCG test was
repeated in patients who tested positive. To determine clinical
pregnancy, transvaginal sonography was used to confirm viability
at 5–7 weeks of gestation. In both groups, every couple was
subjected to only one cycle of treatment. The following efficacy
parameters were compared between groups A and B: (a) primary
outcome measure – clinical pregnancy rate; and (b) secondary
outcome measures – duration of induction, total dose of rFSH
used, folliculometry results on HCG day (i.e. number of follicles
> 15 mm) and endometrial thickness on HCG day.
Statistical analyses were performed using Number Cruncher
Statistical System 2007 and Power Analysis and Sample Size 2008
(NCSS, LCC; Kaysville, UT, USA). Student’s t-test was used for
comparing continuous variables that showed normal distribution,
while Mann-Whitney U test was used for variables that did not
follow a normal distribution. To compare qualitative data, chi-
square test and Fisher’s exact test were used. Results were evaluated
using 95% confidence interval and p < 0.05 significance level.
Results
A total of 126 patients agreed to participate in the study – 61 patients
were assigned to group A and 65 were assigned to group B.
In group A, 16 patients were excluded from the data analysis –
seven were either lost to follow-up or did not have timely
sonography, three had insufficient response to treatment (no
development of a dominant follicle), and six patients had cycle
cancellation due to > 4 follicles measuring > 15 mm. In group B,
one patient was lost to follow-up and one did not develop any
follicles. Finally, 45 patients in group A and 63 patients in group B
were included in the assessment.
The mean age of the 108 patients included in the final
analysis was 31.84 ± 3.73 (range 21–37) years and mean BMI was
24.40 ± 1.88 (range 19–26) kg/m2. The differences in mean age
and BMI between groups A and B were not statistically significant.
Table I shows the clinical characteristics, including the duration
of infertility, of the patients in both groups. The mean duration
of rFSH stimulation was 9.49 ± 2.74 days and 9.73 ± 2.82 days
Original Article
355
in group A and group B, respectively. There was no significant
difference in the duration of rFSH stimulation between the two
groups. In other words, the use of GnRH antagonist did not
prolong the duration of rFSH stimulation. Although the mean
total rFSH dose administered was slightly higher in group A than
in group B (988.33 IU vs. 871.83 IU), the difference was not
statistically significant. However, the median number of follicles
> 16 mm on HCG trigger day was significantly higher in group A
than in group B (1.86 vs. 1.58; p < 0.05).
The mean endometrial thickness in group A was 9.26 mm
and that in group B was 9.45 mm; however, this difference was
not statistically significant. No statistically significant differences
were observed in the number of cancelled cycles due to premature
luteinisation (none in group A, two in group B) and the rate of
clinical pregnancy (8.9% in group A, 7.9% in group B).
Discussion
There is no consensus regarding the use of GnRH antagonists
during COH + IUI cycles in the literature. Although earlier
investigations have shown the benefits of these molecules,(6,15-18)
subsequent studies have failed to confirm them. (19-22) In 2005,
Gómez-Palomares et al concluded from their prospective
randomised study that the addition of GnRH antagonists to COH +
IUI cycles significantly increased pregnancy rates. (15) In 2008,
another study by the same authors reported that the markedly
better pregnancy rates seen in patients who were administered
GnRH antagonists could be due to the multifollicular development
of mature (> 18 mm) follicles, as GnRH antagonists allow for the
growth of intermediate follicles without the risk of premature
luteinisation.(17) Subsequent studies, however, have failed to show
the effect of GnRH antagonists on multifollicular development
in COH + IUI cycles.(6,19) In a study by Allegra et al, none of the
women with an LH level > 10 mIU/mL achieved pregnancy, and
the authors concluded that GnRH antagonists improved pregnancy
rates by preventing the occurrence of premature luteinisation.(6)
A study by Lambalk et al showed that although GnRH
antagonists may reduce the incidence of premature luteinisation,
these antagonists do not positively affect pregnancy rate. (16)
Crosignani et al’s study also failed to prove that the use of GnRH
antagonists is beneficial in IUI cycles; the authors speculated
that the benefit of GnRH antagonists in preventing premature
LH surge was countered by the unfavourable effects of GnRH
antagonists, which were not well understood then.(19) In another
study, Martinez-Salazar et al concluded that, while the universal
use of GnRH antagonists in COH + IUI cycles does not increase
pregnancy rates, it may benefit a specific subset of patients who
have premature luteinisation or high progesterone concentrations
in a previous failed IUI.(20) It should be noted that Martinez-Salazar
et al did not evaluate the LH and progesterone levels during
the cycle when GnRH antagonists were used and, therefore,
could not determine the exact effect GnRH antagonists had on
premature luteinisation. (20) In a multicentre, double-blinded,
randomised controlled trial that involved four academic and
eight institutional hospitals, Cantineau et al concluded that the
addition of GnRH antagonists to standard IUI treatment causes
the treatment to be unnecessarily complex, and that GnRH
antagonists should thus not be applied in daily practice.(21) In fact,
a recent trial evaluating the effectiveness of GnRH antagonists
in IUI cycles was discontinued because of the lower pregnancy
rates observed in the GnRH antagonist group. (22) Similarly, the
2011 Cochrane review on ovarian stimulation protocols for IUI
cycles did not reach a definite conclusion on the use of GnRH
antagonists; while the use of GnRH antagonists was not advised
in mild COH cycles, it was recommended that the utility of GnRH
be determined in future trials.(10)
In the present study, we were not able to prove the benefits of
GnRH antagonists in clinical pregnancy rates. However, GnRH
antagonists may still be useful in specific infertile subpopulations,
such as women with polycystic ovarian syndrome or women in
whom COH + IUI cycle has to be converted to an IVF cycle.(23,24)
The use of GnRH antagonists has also been shown to be effective
in manipulating follicular development, so that the insemination
process can be suspended on weekends without an apparent
decrease in pregnancy rates.(25,26)
The present study was not without limitations. The number
of women enrolled in the study small; nevertheless, other studies
investigating the same subject have also enrolled small numbers
of patients.(6,16,19) Another limitation was the difference between
the number of patients in the two groups due to asymmetric
dropouts. This, however, did not affect the significance of the
Results
of statistical analyses performed.
In conclusion, the present study revealed no significant
improvement in clinical pregnancy rates when GnRH antagonists
were used during COH + IUI cycles, despite a significant increase
in the number of follicles > 16 mm on the HCG trigger day. Larger
randomised controlled trials are required to determine whether
liberal use of GnRH antagonists during IUI cycles should be
recommended.
Table I. Clinical characteristics of the patients (n = 108).
Characteristic Mean ± SD p‑value*
Group A (n = 45) Group B (n = 63)
Duration of infertility (yr) 8.39 ± 4.44 8.02 ± 4.60 0.681
No. of follicles > 16 mm on HCG trigger day† 1.86 ± 0.59 (2) 1.58 ± 0.67 (1) 0.016
Duration of rFSH stimulation (day) 9.49 ± 2.74 9.73 ± 2.82 0.659
Total rFSH dose (IU) 988.33 ± 323.41 871.83 ± 343.44 0.078
Endometrial thickness (mm) 9.26 ± 1.66 9.45 ± 1.53 0.535
*Statistical analysis for no. of follicles was performed using Mann-Whitney U test, while statistical analysis for all other parameters was performed using Student’s
t-test. †Data presented as mean ± SD (median). HCG: human chorionic gonadotropin; rFSH: recombinant follicle-stimulating hormone; SD: standard deviation
Original Article
356
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