A randomized trial of letrozole versus clomiphene citrate in women undergoing superovulation

The definition of unexplained infertility: A systematic review

BACKGROUND

There is no consensus on tests required to either diagnose unexplained infertility or use for research inclusion criteria. This leads to heterogeneity and bias affecting meta-analysis and best practice advice.

OBJECTIVES

This systematic review analyses the variability of inclusion criteria applied to couples with unexplained infertility. We propose standardised criteria for use both in future research studies and clinical diagnosis.

SEARCH STRATEGY

CINAHL and MEDLINE online databases were searched up to November 2022 for all published studies recruiting couples with unexplained infertility, available in full text in the English language.

DATA COLLECTION AND ANALYSIS

Data were collected in an Excel spreadsheet. Results were analysed per category and methodology or reference range.

MAIN RESULTS

Of 375 relevant studies, only 258 defined their inclusion criteria. The most commonly applied inclusion criteria were semen analysis, tubal patency and assessment of ovulation in 220 (85%), 232 (90%), 205 (79.5%) respectively. Only 87/220 (39.5%) studies reporting semen analysis used the World Health Organization (WHO) limits. Tubal patency was accepted if bilateral in 145/232 (62.5%) and if unilateral in 24/232 (10.3%). Ovulation was assessed using mid-luteal serum progesterone in 115/205 (56.1%) and by a history of regular cycles in 87/205 (42.4%). Other criteria, including uterine cavity assessment and hormone profile, were applied in less than 50% of included studies.

CONCLUSIONS

This review highlights the heterogeneity among studied populations with unexplained infertility. Development and application of internationally accepted criteria will improve the quality of research and future clinical care.

OUP accepted manuscript

BACKGROUND

Intrauterine insemination with ovarian stimulation (IUI-OS) is a first-line treatment for unexplained infertility. Gonadotrophins, letrozole and clomiphene citrate (CC) are commonly used agents during IUI-OS and have been compared in multiple aggregate data meta-analyses, with substantial heterogeneity and no analysis on time-to-event outcomes. Individual participant data meta-analysis (IPD-MA) is considered the gold standard for evidence synthesis as it can offset inadequate reporting of individual studies by obtaining the IPD, and allows analyses on treatment–covariate interactions to identify couples who benefit most from a particular treatment.

OBJECTIVE AND RATIONALE

We performed this IPD-MA to compare the effectiveness and safety of ovarian stimulation with gonadotrophins, letrozole and CC and to explore treatment–covariate interactions for important baseline characteristics in couples undergoing IUI.

SEARCH METHODS

We searched electronic databases including MEDLINE, EMBASE, CENTRAL, CINAHL, and PsycINFO from their inception to 28 June 2021. We included randomized controlled trials (RCTs) comparing IUI-OS with gonadotrophins, letrozole and CC among couples with unexplained infertility. We contacted the authors of eligible RCTs to share the IPD and established the IUI IPD-MA Collaboration. The primary effectiveness outcome was live birth and the primary safety outcome was multiple pregnancy. Secondary outcomes were other reproductive outcomes, including time to conception leading to live birth. We performed a one-stage random effects IPD-MA.

OUTCOMES

Seven of 22 (31.8%) eligible RCTs provided IPD of 2495 couples (62.4% of the 3997 couples participating in 22 RCTs), of which 2411 had unexplained infertility and were included in this IPD-MA. Six RCTs (n = 1511) compared gonadotrophins with CC, and one (n = 900) compared gonadotrophins, letrozole and CC. Moderate-certainty evidence showed that gonadotrophins increased the live birth rate compared to CC (6 RCTs, 2058 women, RR 1.30, 95% CI 1.12–1.51, I² = 26%). Low-certainty evidence showed that gonadotrophins may also increase the multiple pregnancy rate compared to CC (6 RCTs, 2058 women, RR 2.17, 95% CI 1.33–3.54, I² = 69%). Heterogeneity on multiple pregnancy could be explained by differences in gonadotrophin starting dose and choice of cancellation criteria. Post-hoc sensitivity analysis on RCTs with a low starting dose of gonadotrophins (≤75 IU) confirmed increased live birth rates compared to CC (5 RCTs, 1457 women, RR 1.26, 95% CI 1.05–1.51), but analysis on only RCTs with stricter cancellation criteria showed inconclusive evidence on live birth (4 RCTs, 1238 women, RR 1.15, 95% CI 0.94–1.41). For multiple pregnancy, both sensitivity analyses showed inconclusive findings between gonadotrophins and CC (RR 0.94, 95% CI 0.45–1.96; RR 0.81, 95% CI 0.32–2.03, respectively). Moderate certainty evidence showed that gonadotrophins reduced the time to conception leading to a live birth when compared to CC (6 RCTs, 2058 women, HR 1.37, 95% CI 1.15–1.63, I² = 22%). No strong evidence on the treatment–covariate (female age, BMI or primary versus secondary infertility) interactions was found.

WIDER IMPLICATIONS

In couples with unexplained infertility undergoing IUI-OS, gonadotrophins increased the chance of a live birth and reduced the time to conception compared to CC, at the cost of a higher multiple pregnancy rate, when not differentiating strategies on cancellation criteria or the starting dose. The treatment effects did not seem to differ in women of different age, BMI or primary versus secondary infertility. In a modern practice where a lower starting dose and stricter cancellation criteria are in place, effectiveness and safety of different agents seem both acceptable, and therefore intervention availability, cost and patients’ preferences should factor in the clinical decision-making. As the evidence for comparisons to letrozole is based on one RCT providing IPD, further RCTs comparing letrozole and other interventions for unexplained infertility are needed.

Agents for ovarian stimulation for intrauterine insemination (IUI) in ovulatory women with infertility

BACKGROUND

Intrauterine insemination (IUI), combined with ovarian stimulation (OS), has been demonstrated to be an effective treatment for infertile couples. Several agents for ovarian stimulation, combined with IUI, have been proposed, but it is still not clear which agents for stimulation are the most effective. This is an update of the review, first published in 2007.

OBJECTIVES

To assess the effects of agents for ovarian stimulation for intrauterine insemination in infertile ovulatory women.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL and two trial registers from their inception to November 2020. We performed reference checking and contacted study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

We included truly randomised controlled trials (RCTs) that compared different agents for ovarian stimulation combined with IUI for infertile ovulatory women concerning couples with unexplained infertility. mild male factor infertility and minimal to mild endometriosis.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane.

MAIN RESULTS

In this updated review, we have included a total of 82 studies, involving 12,614 women. Due to the multitude of comparisons between different agents for ovarian stimulation, we highlight the seven most often reported here. Gonadotropins versus anti-oestrogens (13 studies) For live birth, the results of five studies were pooled and showed a probable improvement in the cumulative live birth rate for gonadotropins compared to anti-oestrogens (odds ratio (OR) 1.37, 95% confidence interval (CI) 1.05 to 1.79; I² = 30%; 5 studies, 1924 participants; moderate-certainty evidence). This suggests that if the chance of live birth following anti-oestrogens is assumed to be 22.8%, the chance following gonadotropins would be between 23.7% and 34.6%. The pooled effect of seven studies revealed that we are uncertain whether gonadotropins lead to a higher multiple pregnancy rate compared with anti-oestrogens (OR 1.58, 95% CI 0.60 to 4.17; I² = 58%; 7 studies, 2139 participants; low-certainty evidence). Aromatase inhibitors versus anti-oestrogens (8 studies) One study reported live birth rates for this comparison. We are uncertain whether aromatase inhibitors improve live birth rate compared with anti-oestrogens (OR 0.75, CI 95% 0.51 to 1.11; 1 study, 599 participants; low-certainty evidence). This suggests that if the chance of live birth following anti-oestrogens is 23.4%, the chance following aromatase inhibitors would be between 13.5% and 25.3%. The results of pooling four studies revealed that we are uncertain whether aromatase inhibitors compared with anti-oestrogens lead to a higher multiple pregnancy rate (OR 1.28, CI 95% 0.61 to 2.68; I² = 0%; 4 studies, 1000 participants; low-certainty evidence).  Gonadotropins with GnRH (gonadotropin-releasing hormone) agonist versus gonadotropins alone (4 studies) No data were available for live birth. The pooled effect of two studies  revealed that we are uncertain whether gonadotropins with GnRH agonist lead to a higher multiple pregnancy rate compared to gonadotropins alone (OR 2.53, 95% CI 0.82 to 7.86; I² = 0; 2 studies, 264 participants; very low-certainty evidence).  Gonadotropins with GnRH antagonist versus gonadotropins alone (14 studies) Three studies reported live birth rate per couple, and we are uncertain whether gonadotropins with GnRH antagonist improve live birth rate compared to gonadotropins (OR 1.5, 95% CI 0.52 to 4.39; I² = 81%; 3 studies, 419 participants; very low-certainty evidence). This suggests that if the chance of a live birth following gonadotropins alone is 25.7%, the chance following gonadotropins combined with GnRH antagonist would be between 15.2% and 60.3%. We are also uncertain whether gonadotropins combined with GnRH antagonist lead to a higher multiple pregnancy rate compared with gonadotropins alone (OR 1.30, 95% CI 0.74 to 2.28; I² = 0%; 10 studies, 2095 participants; moderate-certainty evidence). Gonadotropins with anti-oestrogens versus gonadotropins alone (2 studies) Neither of the studies reported data for live birth rate. We are uncertain whether gonadotropins combined with anti-oestrogens lead to a higher multiple pregnancy rate compared with gonadotropins alone, based on one study (OR 3.03, 95% CI 0.12 to 75.1; 1 study, 230 participants; low-certainty evidence). Aromatase inhibitors versus gonadotropins (6 studies) Two studies  revealed that aromatase inhibitors may decrease live birth rate compared with gonadotropins (OR 0.49, 95% CI 0.34 to 0.71; I²=0%; 2 studies, 651 participants; low-certainty evidence). This suggests that if the chance of a live birth following gonadotropins alone is 31.9%,  the chance of live birth following aromatase inhibitors would be between 13.7% and 25%. We are uncertain whether aromatase inhibitors compared with gonadotropins lead to a higher multiple pregnancy rate (OR 0.69, 95% CI 0.06 to 8.17; I²=77%; 3 studies, 731 participants; very low-certainty evidence).  Aromatase inhibitors with gonadotropins versus anti-oestrogens with gonadotropins (8 studies) We are uncertain whether aromatase inhibitors combined with gonadotropins improve live birth rate compared with anti-oestrogens plus gonadotropins (OR 0.99, 95% CI 0.3 8 to 2.54;  I² = 69%; 3 studies, 708 participants; very low-certainty evidence). This suggests that if the chance of a live birth following anti-oestrogens plus gonadotropins is 13.8%, the chance following aromatase inhibitors plus gonadotropins would be between 5.7% and 28.9%. We are uncertain of the effect of aromatase inhibitors combined with gonadotropins compared to anti-oestrogens combined with gonadotropins on multiple pregnancy rate (OR 1.31, 95% CI 0.39 to 4.37;  I² = 0%; 5 studies, 901 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

Based on the available results, gonadotropins probably improve cumulative live birth rate compared with anti-oestrogens (moderate-certainty evidence). Gonadotropins may also improve cumulative live birth rate when compared with aromatase inhibitors (low-certainty evidence). From the available data, there is no convincing evidence that aromatase inhibitors lead to higher live birth rates compared to anti-oestrogens. None of the agents compared lead to significantly higher multiple pregnancy rates. Based on low-certainty evidence, there does not seem to be a role for different combined therapies, nor for adding GnRH agonists or GnRH antagonists in IUI programs.

Poor Endometrial Proliferation After Clomiphene is Associated With Altered Estrogen Action

CONTEXT

Suboptimal endometrial thickening is associated with lower pregnancy rates and occurs in some infertile women treated with clomiphene.

OBJECTIVE

To examine cellular and molecular differences in the endometrium of women with suboptimal vs optimal endometrial thickening following clomiphene.

METHODS

Translational prospective cohort study from 2018 to 2020 at a university-affiliated clinic. Reproductive age women with unexplained infertility treated with 100 mg of clomiphene on cycle days 3 to 7 who developed optimal (≥8mm; n = 6, controls) or suboptimal (<6mm; n = 7, subjects) endometrial thickness underwent preovulatory blood and endometrial sampling. The main outcome measures were endometrial tissue architecture, abundance and location of specific proteins, RNA expression, and estrogen receptor (ER) α binding.

RESULTS

The endometrium of suboptimal subjects compared with optimal controls was characterized by a reduced volume of glandular epithelium (16% vs 24%, P = .01), decreased immunostaining of markers of proliferation (PCNA, ki67) and angiogenesis (PECAM-1), increased immunostaining of pan-leukocyte marker CD45 and ERβ, but decreased ERα immunostaining (all P < .05). RNA-seq identified 398 differentially expressed genes between groups. Pathway analysis of differentially expressed genes indicated reduced proliferation (Z-score = -2.2, P < .01), decreased angiogenesis (Z-score = -2.87, P < .001), increased inflammation (Z-score = +2.2, P < .01), and ERβ activation (Z-score = +1.6, P < .001) in suboptimal subjects. ChIP-seq identified 6 genes bound by ERα that were differentially expressed between groups (P < .01), some of which may play a role in implantation.

CONCLUSION

Women with suboptimal endometrial thickness after clomiphene exhibit aberrant ER expression patterns, architectural changes, and altered gene and protein expression suggesting reduced proliferation and angiogenesis in the setting of increased inflammation.

Pregnancy outcomes following different protocols of controlled ovarian hyperstimulation in couples undergoing intrauterine insemination

Clomiphene citrate (CC), letrozole and cetrorelix acetate are frequently used agents in controlled ovarian hyperstimulation (COH). However, these three agents have not yet been compared to one another regarding their pregnancy outcomes. The present study was designed to retrospectively compare pregnancy outcomes among the three aforementioned agents. This study involved infertile couples with an infertility duration of at least 2 years, ages 18 to 42 years and who were referred to have their first intrauterine insemination (IUI) treatment cycle. All patients underwent COH with recombinant follicle-stimulating hormone (rFSH) plus CC (n = 118), letrozole (n = 81), or cetrorelix acetate (n = 62), followed by IUI. Using the one-way multivariate analysis of covariance to control female patients' ages, patients stimulated with cetrorelix acetate/rFSH or CC/rFSH had higher numbers of preovulatory follicles than women stimulated with letrozole/rFSH (P < .02), whereas women stimulated with cetrorelix acetate/rFSH had a thicker endometrium than women stimulated with CC/rFSH (P < .0005). Biochemical pregnancy rates were similar among the three protocols of COH. However, women stimulated with letrozole/rFSH showed clinical pregnancy rates higher than those stimulated with CC/rFSH (P = .003) or cetrorelix acetate/rFSH (P = .03) and subclinical abortion rates lower than those stimulated with CC/rFSH or cetrorelix acetate/rFSH (P = .009). Of the different protocols of COH, the odds of having a clinical pregnancy was 3.1 times greater for women stimulated with letrozole/rFSH than women stimulated with CC/rFSH (P = .004) and 2.8 times greater for women stimulated with letrozole/rFSH than women stimulated with cetrorelix acetate/rFSH (P = .03). Our observations show that increased numbers of preovulatory follicles or endometrium thickness do not necessarily improve pregnancy outcomes, because pregnancy outcomes are also subjected to the type of COH used agent. In this regard, letrozole produced fewer preovulatory follicles and did not significantly increase endometrium thickness, but significantly improved pregnancy outcomes in comparison to CC and cetrorelix acetate.

Pharmacologic Treatments for PCOS Patients

Polycystic ovarian syndrome is the most common endocrinopathy in reproductive-aged women and has a vast array of clinical manifestations. Common clinical presentations of the disorder include anovulatory infertility, menstrual disorders, cutaneous symptoms secondary to androgen excess, metabolic abnormalities and mental health issues. If the condition is left unaddressed or inadequately treated, long-term sequelae such as endometrial hyperplasia, diabetes mellitus and dyslipidemia may ensue, therefore it is imperative for clinicians to address each component of the syndrome. When initial lifestyle changes and dietary modifications do not suffice or fail, pharmacologic therapy should be considered, and when deemed appropriate treatment should be initiated. This review describes the pharmacologic options available to combat the various sequelae commonly seen in women with polycystic ovarian syndrome.

Letrozole Versus Clomiphene Citrate and Natural Cycle: Endometrial Receptivity During Implantation Window in Women With Polycystic Ovary Syndrome

Objective

Numerous studies have reported on ovulation and pregnancy rates in patients with polycystic ovary syndrome (PCOS). However, relevant data on endometrial receptivity are limited. This study was conducted to compare endometrial receptivity during implantation windows among letrozole (LE), clomiphene citrate (CC), and natural cycle, and to assess the predictive value for pregnancy of observed indicators.

Methods

This randomized controlled trial study enrolled 270 patients with PCOS. Patients were given LE (n=90) at a dose of 2.5mg/day or CC (n=90) at a dose of 50 mg/day on cycle days 5-9 for ovulation induction. Patients in the natural cycle group (n=90) did not receive any drug for ovulation induction. Endometrial ultrasonic parameters, integrin αvβ3, and vascular endothelial growth factor (VEGF) concentrations in uterine secretion were detected during the implantation window. The endometrial receptivity, ovulation rate, pregnancy rates, and predictive value of observed indicators for pregnancy were analyzed.

Results

The successful ovulation rate did not differ between the LE group and CC group (P>0.05). Endometrial ultrasonic parameters [endometrial thickness (ET), endometrial volume (EV), vascularization index (VI), flow index (FI), vascularization flow index (VFI)], integrin αvβ3, and VEGF concentrations in uterine fluid were significantly higher in the LE group compared with the CC group and natural cycle group (P<0.05). The clinical pregnancy and ongoing pregnancy rates of the LE group were significantly higher than in the CC group (P<0.05). Endometrial ultrasonic parameters (VI, FI, and VFI), integrin αvβ3, and VEGF concentrations in uterine fluid of all pregnancy groups were significantly higher compared with the no pregnancy group (P<0.05), and the above parameters in ongoing pregnancy were significantly higher than in biochemical pregnancy (P<0.05). The endometrial FI during the implantation window had the highest predictive value for pregnancy (AUC=0.889). The integrin αvβ3 in uterine fluid had better predictive value (AUC=0.876) than VEGF.

Conclusions

Endometrial receptivity during the implantation window of LE is superior to CC in PCOS women, which may be related to higher clinical pregnancy and ongoing pregnancy rates. Endometrial FI examined by 3-D power Doppler, and integrin αvβ3 in uterine secretion during the implantation window, could be preferable non-invasive predictor markers for pregnancy.

Clinical Trial Registration

www.chictr.org.cn, ChiCTR1900023423.

A comparison of oral versus injectable ovarian stimulation in IUI in women ≥38 years of age with decreased ovarian reserve

PURPOSE

To compare pregnancy rates of oral ovarian hyperstimulation agents (clomiphene citrate (CC) and letrozole) versus injectable agents (gonadotropins) in intrauterine insemination (IUI) in the older reproductive age group with diminished ovarian reserve.

METHODS

A retrospective cohort study was performed among 210 women 38-43 years of age undergoing IUI with controlled ovarian hyperstimulation (COH) at a single academic institution between 2009 and 2018.

RESULTS

A total of 335 IUI cycles met inclusion criteria. Gonadotropins were the most frequently used ovarian hyperstimulation agent (n = 264), followed by CC (n = 38) and letrozole (n = 33). Mean age of the cohort was 40.5 (±1.6) years (range 38-43) did not differ significantly among groups (p = 0.41). Mean AFC and number of mature follicles on day of ovulation trigger also did not differ among groups (p = 0.98, p = 0.10). Overall clinical pregnancy rate was 7.5% per cycle, and rates for CC, letrozole, and gonadotropins respectively were 5.3%, 9.1%, 7.5% per cycle (p = 0.347). There was one multiple gestation pregnancy (twins), which was in a patient stimulated with gonadotropins.

CONCLUSION

This is the first study to compare CC, letrozole, and gonadotropins in older reproductive age women with decreased ovarian reserve. The findings reveal that COH/IUI in older women with decreased ovarian reserve is a viable option (clinical pregnancy rate of 7.5% per cycle), and suggest that oral stimulation agents may be the first-line option, with letrozole having conferred the highest clinical pregnancy rate, 9.1%, which is notable given the typical poor fecundability of this population. However, larger population studies are needed to support this.

Endometrial thickness after ovarian stimulation with gonadotropin, clomiphene, or letrozole for unexplained infertility, and association with treatment outcomes

OBJECTIVE

To study the association of endometrial thickness (EMT) with live birth rates (LBR) in ovarian stimulation with intrauterine insemination (OS-IUI) treatments for unexplained infertility.

DESIGN

Prospective cohort analysis of the Reproductive Medicine Network's Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) randomized controlled trial.

SETTING

Multicenter randomized controlled trial.

PATIENTS

A total of 868 couples with unexplained infertility (n=2,459 cycles).

INTERVENTIONS

OS-IUI treatment cycles (n = 2,459) as part of the AMIGOS clinical trial.

MAIN OUTCOME MEASURES

Live birth rates; unadjusted and adjusted risk ratios (RR) for live birth by EMT category, calculated using generalized estimating equations.

RESULTS

The overall mean EMT on day of human chorionic gonadotropin administration in cycles with a live birth was significantly greater than in those without. Compared to the referent EMT group of 9 to 12 mm, the unadjusted RR for live birth for the EMT groups of ≤5 and 6-8 were 0.48 and 0.92, respectively. The test for trend indicated evidence of decreasing LBR with decreasing EMT. After adjustment for ovarian stimulation medication, a linear trend was no longer supported. Stratified analyses revealed no differences in associations by treatment group.

CONCLUSIONS

In OS-IUI for unexplained infertility, higher LBR are observed with increasing EMT; however, EMT is not significantly associated with LBR when adjusted for OS treatment type. Appreciable LBR are seen at all EMT, even those of ≤5 mm, suggesting that OS-IUI cycles should not be canceled for thin endometrium.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01044862.

IUI for unexplained infertility-a network meta-analysis

BACKGROUND

IUI for unexplained infertility can be performed in a natural cycle or in combination with ovarian stimulation. A disadvantage of ovarian stimulation is an increased risk of multiple pregnancies with its inherent maternal and neonatal complication risks. Stimulation agents for ovarian stimulation are clomiphene citrate (CC), Letrozole or gonadotrophins. Although studies have compared two or three of these drugs to each other in IUI, they have never been compared to one another in one analysis.

OBJECTIVE AND RATIONALE

The objective of this network meta-analysis was to compare the effectiveness and safety of IUI with CC, Letrozole or gonadotrophins with each other and with natural cycle IUI.

SEARCH METHODS

We searched PubMed, MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, CENTRAL and the Clinical Trial Registration Database indexed up to 16 August 2018. We included randomized controlled trials that compared a stimulation regimen with CC, Letrozole or gonadotrophins to each other or to natural cycle IUI among couples with unexplained infertility. We performed the network meta-analysis within a multivariate random effects model.

OUTCOMES

We identified 26 studies reporting on 5316 women. The relative risk (RR) for live birth/ongoing pregnancy rates comparing IUI with CC to natural cycle IUI was 1.05 (95% CI 0.63-1.77, low quality of evidence), while comparing IUI with Letrozole to natural cycle IUI was 1.15 (95% CI 0.63-2.08, low quality of evidence) and comparing IUI with gonadotrophins to natural cycle IUI was 1.46 (95% CI 0.92-2.30, low quality of evidence). The RR for live birth/ongoing pregnancy rates comparing gonadotrophins to CC was 1.39 (95% CI 1.09-1.76, moderate quality of evidence), comparing Letrozole to CC was 1.09 (95% CI 0.76-1.57, moderate quality of evidence) and comparing Letrozole to gonadotrophins was 0.79 (95% CI 0.54-1.15, moderate quality of evidence). We did not perform network meta-analysis on multiple pregnancy due to high inconsistency. Pairwise meta-analyses showed an RR for multiple pregnancy rates of 9.11(95% CI 1.18-70.32) comparing IUI with gonadotrophins to natural cycle IUI. There was no data available on multiple pregnancy rates following IUI with CC or Letrozole compared to natural cycle IUI. The RR for multiple pregnancy rates comparing gonadotrophins to CC was 1.42 (95% CI 0.68-2.97), comparing Letrozole to CC was 0.97 (95% CI 0.47-2.01) and comparing Letrozole to gonadotrophins was 0.29 (95% CI 0.14-0.58).In a meta-analysis among studies with adherence to strict cancellation criteria, the RR for live births/ongoing pregnancy rates comparing gonadotrophins to CC was 1.20 (95% CI 0.95-1.51) and the RR for multiple pregnancy rates comparing gonadotropins to CC was 0.80 (95% CI 0.38-1.68).

WIDER IMPLICATIONS

Based on low to moderate quality of evidence in this network meta-analysis, IUI with gonadotrophins ranked highest on live birth/ongoing pregnancy rates, but women undergoing this treatment protocol were also at risk for multiple pregnancies with high complication rates. IUI regimens with adherence to strict cancellation criteria led to an acceptable multiple pregnancy rate without compromising the effectiveness. Within a protocol with adherence to strict cancellation criteria, gonadotrophins seem to improve live birth/ongoing pregnancy rates compared to CC. We, therefore, suggest performing IUI with ovarian stimulation using gonadotrophins within a protocol that includes strict cancellation criteria. Obviously, this ignores the impact of costs and patients preference.

Comparison of clomiphene and letrozole for superovulation in patients with unexplained infertility undergoing intrauterine insemination: A systematic review and meta-analysis

BACKGROUND

With the medical advancement some studies put forward that letrozole (LE), a specific aromatase inhibitor with the function of reducing oestrogen synthesis, has recently been applied as a potentially better alternative compared with clomiphene citrate (CC), owing to that it has a superior efficacy as compared with CC in patients of unexplained infertility undergoing intrauterine insemination (IUI). However, there is no one study can clear and definite whether LE can replace the CC as first line drug.

OBJECTIVE

Our objective is to compare the LE with CC in the induction of ovulation in patients with unexplained infertility IUI.

METHOD

Searching databases consist of all kinds of searching tools, such as Medline, The Cochrane Library, Embase, PubMed, etc. All the include studies should meet our demand of this meta-analysis: RESULT:: Based on the current meta-analysis, we rigorously consider that LE has a likelihood to improve dominant follicles (MD= -0.56, I= 100%, P= .04; MD= -0.39, I= 73%, P = .0003, respectively) and reduces the miscarriage rate (RR= 0.61, I= 0%, P = .03). There is no significant differences between the 2 groups in The total rate of pregnancy, pregnancy rate per cycle, multiple pregnancy and endometrial thickness. (RR= 1.06, I= 11%, P = .38; RR= 1.09, I= 7%, P = .32; RR= 0.79, I= 0%, P = .46; respectively) CONCLUSION:: Combined with the results of current systematic review and meta-analysis through subgroup analysis and sensitivity analysis, we can be cautious: in general, compared with CC, LE is an effective treatment in the IUI cycle, has a likelihood to improve dominant follicles and reduces the miscarriage rate.

Evidence-based treatments for couples with unexplained infertility: a guideline

OBJECTIVE

To provide evidence-based recommendations to practicing physicians and others regarding the effectiveness and safety of therapies for unexplained infertility.

METHODS

ASRM conducted a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 1968 through 2019. The ASRM Practice Committee and a task force of experts used available evidence and informal consensus to develop evidence-based guideline recommendations.

MAIN OUTCOME MEASURE(S)

Outcomes of interest included: live-birth rate, clinical pregnancy rate, implantation rate, fertilization rate, multiple pregnancy rate, dose of treatment, rate of ovarian hyperstimulation, abortion rate, and ectopic pregnancy rate.

RESULT(S)

The literature search identified 88 relevant studies to inform the evidence base for this guideline.

RECOMMENDATION(S)

Evidence-based recommendations were developed for the following treatments for couples with unexplained infertility: natural cycle with intrauterine insemination (IUI); clomiphene citrate with intercourse; aromatase inhibitors with intercourse; gonadotropins with intercourse; clomiphene citrate with IUI; aromatase inhibitors with IUI; combination of clomiphene citrate or letrozole and gonadotropins (low dose and conventional dose) with IUI; low-dose gonadotropins with IUI; conventional-dose gonadotropins with IUI; timing of IUI; and in vitro fertilization and treatment paradigms.

CONCLUSION(S)

The treatment of unexplained infertility is by necessity empiric. For most couples, the best initial therapy is a course (typically 3 or 4 cycles) of ovarian stimulation with oral medications and intrauterine insemination (OS-IUI) followed by in vitro fertilization for those unsuccessful with OS-IUI treatments.

Effects of letrozole and clomiphene citrate on Wnt signaling pathway in endometrium of polycystic ovarian syndrome and healthy women†

Polycystic ovary syndrome (PCOS) is an endocrine disorder in women of reproductive age. In addition to anovulation, endometrial dysfunction can reduce fertility in PCOS. The cyclical changes of endometrium are controlled by estrogen and progesterone via modulating the Wnt/B-catenin pathway. Clomiphene citrate (CC) and letrozole are used to induce ovulation; unlike letrozole, there is a discrepancy between ovulation and pregnancy rates in CC-treated cycles. Because of the anti-estrogenic effects of CC on endometrium, we compared the expression of the key molecules of the Wnt/B-catenin pathway in the endometrium of women taking CC and letrozole. This study included PCOS and healthy women divided into the groups stimulated with letrozole (5 mg) or CC (100 mg) as well as NO-treatment groups. The endometrial thickness and hormonal profile were measured on day 12 of the menses. Using real-time polymerase chain reaction and western blot, we evaluated mRNA and protein expression of B-catenin, glycogen synthase kinase 3 beta (GSK3B), dickkopf Wnt signaling pathway inhibitor 1 (DKK1), and estrogen receptor 1 (ESR1) in the endometrial samples. Significantly, the mean serum estrogen and progesterone were lower and higher, respectively, in letrozole than CC groups. The endometrial thickness was significantly reduced in CC. The proteins expression of active B-catenin, inactive GSK3B, and ESR1 were significantly decreased in CC-treated groups. The mRNA and protein assessment of DKK1 showed significantly higher expression in CC. Our results indicate that letrozole can provide an acceptable activation of the Wnt/B-catenin pathway, resulting in adequate proliferation of endometrium in the women receiving letrozole compared to CC.

Effect of Letrozole on sperm parameters, chromatin status and ROS level in idiopathic Oligo/Astheno/Teratozoospermia

BACKGROUND

This study investigates the effect of letrozole on hormone profiles, semen parameters, body mass index (BMI), degree of oxidative stress and sperm chromatin integrity in men with idiopathic oligo/astheno/teratozoospermia (iOAT) and T:E₂ ratio ≤ 10.

MATERIALS AND METHODS

This study is a longitudinal, prospective, interventional and open-labelled clinical trial. Semen samples were collected from 20 iOAT men with low serum testosterone (T) to estradiol (E₂) ratio (T:E₂ ratio ≤ 10). The participants were treated with 2.5 mg letrozole orally per day for 3 months. Then, sperm parameters, hormone profiles, BMI, chromatin integrity and intracellular reactive oxygen species (ROS) level were assessed pre- and post- treatment. The chromatin integrity was evaluated by assessment of DNA fragmentation (with TUNEL assay) and protamine deficiency (with Chromomycin A3, CMA3). Also, the intracellular ROS levels were investigated by 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. Finally, the differences between the parameters evaluated before and after letrozole treatment were analyzed with the t-test and the Wilcoxon signed-rank test.

RESULTS

Sperm concentration, percentage of sperm motility and its normal morphology increased significantly after letrozole treatment. Moreover, serum testosterone level increased but estradiol level decreased significantly following treatment. The mean of T:E2 ratio improved 1600%. Also, letrozole treatment significantly reduced the percentage of sperm TUNEL positivity and sperm CMA3 positivity. While no significant difference was observed between intracellular ROS levels and BMI before and after treatment. Finally, as a notable result, four spontaneous pregnancies (20%) were achieved after treatment.

CONCLUSIONS

Letrozole treatment can effectively increase spontaneous pregnancies by improving sperm parameters and sperm chromatin integrity in men with iOAT and T:E2 ratio ≤ 10.

TRIAL REGISTRATION

Trial registration: IRCT, IRCT20191030045283N1. Registered 16 November 2019 - Retrospectively registered, https://fa.irct.ir/user/trial/43484/view.

Letrozole Compared With Clomiphene Citrate for Unexplained Infertility: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the clinical effectiveness, as determined by positive pregnancy test, of letrozole compared with clomiphene citrate for ovarian stimulation in patients with unexplained infertility.

DATA SOURCES

We conducted a systematic review and meta-analysis of data from electronic databases including Ovid-MEDLINE, EMBASE, Scopus, Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, Database of Abstracts of Reviews of Effects, and ClinicalTrials.gov.

METHODS

We searched for concepts of unexplained infertility, letrozole, clomiphene citrate, and clinical outcomes including pregnancy and live birth. Studies were included if they were randomized controlled trials (RCTs) comparing clomiphene citrate with letrozole in patients with unexplained infertility. Eight RCTs including 2,647 patients with unexplained infertility were included. Primary outcome was positive pregnancy test per patient. Secondary outcomes included positive pregnancy test per cycle, clinical pregnancy, live birth, spontaneous miscarriage, twin gestation, mean serum estradiol (E2), endometrial thickness, and number of dominant follicles. The Cochrane Q test and Higgin's I were used to assess heterogeneity. Random effects models were used to obtain pooled relative risks (RR) and 95% CIs.

TABULATION, INTEGRATION, AND RESULTS

In analysis per patient, there was no significant difference in positive pregnancy test between patients treated with letrozole compared with clomiphene citrate (24% vs 23%, pooled RR 1.08, 95% CI 0.85-1.36). Significant heterogeneity was noted between studies (I=60.8%). There were no significant differences in clinical pregnancy (pooled RR 1.15, 95% CI 0.71-1.85), live birth (pooled RR 0.94, 95% CI 0.83-1.08), spontaneous miscarriage (pooled RR 0.92, 95% CI 0.61-1.38), or twin gestation (pooled RR 0.81, 95% CI 0.39-1.68). Mean serum E2 was significantly lower in the letrozole group than in the clomiphene citrate group.

CONCLUSION

Although limited by heterogeneity, studies of ovarian stimulation in women with unexplained infertility show no difference in clinical outcomes between letrozole and clomiphene citrate.

The management of unexplained infertility: an evidence-based guideline from the Canadian Fertility and Andrology Society

Unexplained infertility is a common diagnosis affecting as many as 50% of couples seeking infertility care. As a diagnosis of exclusion, its treatment remains largely empirical. Historically, a step-wise progression in treatment has been initiated with the least invasive, least expensive option followed by a gradual progression to therapies using assisted reproductive technology. In recent years there have been advocates for more rapid-progression IVF. This guideline from the Canadian Fertility and Andrology Society (CFAS) provides comprehensive, evidence-based recommendations for the treatment of unexplained infertility, including expectant management, laparoscopy, intrauterine insemination (IUI) alone, ovarian stimulation with oral agents or gonadotropins alone, ovarian stimulation + IUI, and IVF. The quality of supporting evidence for each recommendation is evaluated using the framework outlined by the Canadian Task Force on Preventive Health Care. This guideline recognizes that the therapeutic approach should be individualized taking into account patient age and duration of infertility, and emphasizes those strategies that are most likely to result in a healthy live birth.

Letrozole versus clomiphene citrate in polycystic ovary syndrome: a meta-analysis of randomized controlled trials

PURPOSE

Polycystic ovary syndrome (PCOS) is a common endocrine disturbance affecting women in the reproductive age group. The present study aimed to compare the effects of letrozole (LE) and clomiphene citrate (CC) for ovulation induction in women with PCOS.

METHODS

The PUBMED, Web of Science, and EMBASE databases were screened systematically for randomized controlled trials (RCTs) published from database inception to July 2017.

RESULTS

Eleven RCTs involving 2255 patients were included, and data were independently extracted and analyzed using 95% risk ratios (RRs) and confidence intervals (CIs) based on a random- or fixed-effect model (as appropriate). Meta-analyses of nine RCTs comparing LE and CC ovulation induction, followed by timed intercourse, indicated that the former significantly increased the ovulation rate (RR = 1.18; 95% CI 1.03-1.36, P = 0.01), pregnancy rate (RR = 1.34; 95% CI 1.09-1.64, P = 0.006), and live birth rate (RR = 1.55; 95% CI 1.28-1.88, P < 0.00001). However, LE and CC did not differ significantly in terms of the multiple pregnancy and abortion rates. Furthermore, LE for ovulation induction significantly improved the pregnancy rate after IUI.

CONCLUSION

LE is superior to CC for ovulation induction in patients with PCOS.

Ovulation induction and controlled ovarian stimulation using letrozole gonadotropin combination: A single center retrospective cohort study

OBJECTIVE

To assess the effect of letrozole in combination with low dose gonadotropins for ovulation induction in anovulatory infertility from polycystic ovary syndrome (PCOS) and controlled ovarian stimulation for endometriosis, and unexplained infertility patients.

STUDY DESIGN

Retrospective cohort study in a setting of private Reproductive Endocrinology and Infertility Clinic affiliated with the University. Three hundred couples (650 cycles) requiring OI/COS for PCOS (92 patients, 195 cycles), endometriosis (89 patients, 217 cycles), and unexplained infertility (119 patients, 238 cycles). Patients received 2.5mg or 5mg letrozole for 5days (D3-D7) and recombinant follicle-stimulating hormone on alternating D3-D7 and human menopausal gonadotropin-highly purified alternating D5-D10 until growth of ideally 2 mature follicles. Ovulation was triggered with 10,000 IU of HCG. Maximum number of cycles per patient was four.

RESULTS

Main outcome measures were clinical pregnancy rates, multiple order pregnancy rates, miscarriage rates, number of follicles and endometrial thickness on the day of HCG administration. The cumulative incidence of pregnancy was estimated as 35% (95%CI: 29%-41%) overall and was highest in patients with PCOS (36.6%), followed by unexplained infertility (34.6%) and endometriosis (32.5%). The pregnancy rates per cycle in PCOS, endometriosis and unexplained infertility patients were 17%, 13.2% and 17.2% respectively, no statistically significant difference between the groups. There were three twin pregnancies in PCOS, and one in unexplained infertility group. Monofolliculogenesis was noted in 48% of patients.

CONCLUSION(S)

Letrozole-low dose gonadotropins combination appears to be effective across different causes of infertility for superovulation. The letrozole-low dose gonadotropin combination resulted in high rate of monofolliculogenesis, low occurrence of multiple gestations and no case of OHSS or cycle cancellation.

Committee Opinion No. 663: Aromatase Inhibitors in Gynecologic Practice

Aromatase inhibitors have been used for the treatment of breast cancer, ovulation induction, endometriosis, and other estrogen-modulated conditions. For women with breast cancer, bone mineral density screening is recommended with long-term aromatase inhibitor use because of risk of osteoporosis due to estrogen deficiency. Based on long-term adverse effects and complication safety data, when compared with tamoxifen, aromatase inhibitors are associated with a reduced incidence of thrombosis, endometrial cancer, and vaginal bleeding. For women with polycystic ovary syndrome and a body mass index greater than 30, letrozole should be considered as first-line therapy for ovulation induction because of the increased live birth rate compared with clomiphene citrate. Lifestyle changes that result in weight loss should be strongly encouraged. Aromatase inhibitors are a promising therapeutic option that may be helpful for the management of endometriosis-associated pain in combination therapy with progestins.

A Study of Controlled Ovarian Stimulation with Clomiphene Citrate or Letrozole in Combination with Gonadotropins and IUI in Unexplained Infertility

Aim:

To compare the effect of clomiphene citrate (CC) + human menopausal gonadotropin (hMG) with letrozole + hMG on size, number of follicles, endometrial thickness, serum levels of oestradiol and progesterone and pregnancy rate.

Settings and Design:

Non-randomised interventional study.

Patients and Methods:

A total number of 60 patients in the age group of 20–35 years with unexplained infertility were divided into two groups, 30 in each. Group A received CC + hMG and group B received letrozole + hMG. In both the groups, ovulation was triggered by hCG followed by intrauterine insemination.

Results:

The number of follicles on day 8 were significantly higher in the CC + hMG group than that in the letrozole + hMG group. Serum oestradiol level was significantly higher in the CC + hMG group on day 10 and on the day of hCG administration. Pregnancy rate in the CC + hMG group was 23.3% and 13.3% in the letrozole + hMG group.

Conclusion:

The sequential protocol was cost-effective. CC + hMG could be a preferred ovarian stimulation protocol in couples with unexplained infertility with the added advantage of having no significant complications in properly monitored cycles.

A New Dawn for Intrauterine Insemination: Efficient and Prudent Practice will Benefit Patients, the Fertility Industry and the Healthcare Bodies

This review addresses the misplaced facts about the IUI procedure within a lucrative fertility industry. Evidence suggests IUI must be a first-line treatment option for most couples except in cases of bilateral tubal blockage and severe oligozoospermia. We introduce the concept of using 'consecutive ejaculation' in men with subfertility and one which can radically alter the male infertility definition, thereby providing a new approach to examining and managing male factor infertility. The review also explores various aspects affecting the IUI procedure, its determinants of success, risks and areas for future improvements. Areas such as choice of patients, clinical management of patients, the type of stimulation regime, timing and the management of sperm usage have significant bearing to whether IUI will succeed. The paper asserts that IUI should be the first choice of fertility treatment.

Letrozole, Gonadotropin, or Clomiphene for Unexplained Infertility

BACKGROUND

The standard therapy for women with unexplained infertility is gonadotropin or clomiphene citrate. Ovarian stimulation with letrozole has been proposed to reduce multiple gestations while maintaining live birth rates.

METHODS

We enrolled couples with unexplained infertility in a multicenter, randomized trial. Ovulatory women 18 to 40 years of age with at least one patent fallopian tube were randomly assigned to ovarian stimulation (up to four cycles) with gonadotropin (301 women), clomiphene (300), or letrozole (299). The primary outcome was the rate of multiple gestations among women with clinical pregnancies.

RESULTS

After treatment with gonadotropin, clomiphene, or letrozole, clinical pregnancies occurred in 35.5%, 28.3%, and 22.4% of cycles, and live birth in 32.2%, 23.3%, and 18.7%, respectively; pregnancy rates with letrozole were significantly lower than the rates with standard therapy (gonadotropin or clomiphene) (P=0.003) or gonadotropin alone (P<0.001) but not with clomiphene alone (P=0.10). Among ongoing pregnancies with fetal heart activity, the multiple gestation rate with letrozole (9 of 67 pregnancies, 13%) did not differ significantly from the rate with gonadotropin or clomiphene (42 of 192, 22%; P=0.15) or clomiphene alone (8 of 85, 9%; P=0.44) but was lower than the rate with gonadotropin alone (34 of 107, 32%; P=0.006). All multiple gestations in the clomiphene and letrozole groups were twins, whereas gonadotropin treatment resulted in 24 twin and 10 triplet gestations. There were no significant differences among groups in the frequencies of congenital anomalies or major fetal and neonatal complications.

CONCLUSIONS

In women with unexplained infertility, ovarian stimulation with letrozole resulted in a significantly lower frequency of multiple gestation but also a lower frequency of live birth, as compared with gonadotropin but not as compared with clomiphene. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01044862.).

Are uterine and ovarian artery Doppler velocimetry values good pregnancy predictors in clomiphene citrate cycles?

Background

We conducted this prospective study to evaluate the prognostic significance of uterine and ovarian artery Doppler velocimetry in clomiphene citrate (CC) cycles.

Materials and Methods

A total of 80 patients with unexplained infertility were given 100 mg/day of CC from day 3 to day 7 of their cycles in this current prospective study. On cycle day 3, before administration of CC, each patient underwent Doppler transvaginal ultrasonography. The Doppler velocimetries of the right and left uterine and ovarian arteries were recorded and analyzed in association with demographic and clinical parameters.

Results

TheThere were 6 out of 80 patients who became pregnant, the overall pregnancy rate in this population was 7.5% for the current study. The cases were divided into two groups according to whether they became pregnant or not. Demographic characteristics showed no statistically significant differences between these groups (p>0.05). However, the duration of infertility did show statistically significant differences between the groups. Doppler velocimetry was not statistically significantly different between the two groups.

Conclusion

Doppler velocimetry of the uterine and ovarian arteries is not a factor in the prognosis for pregnancy in CC cycles.

A Randomized Clinical Trial on Comparing The Cycle Characteristics of Two Different Initiation Days of Letrozole Treatment in Clomiphene Citrate Resistant PCOS Patients in IUI Cycles

Background

There are still many questions about the ideal protocol for letrozole (LTZ) as the commonest aromatase inhibitor (AI) used in ovulation induction. The aim of this study is to compare the ultrasonographic and hormonal characteristics of two different initiation times of LTZ in clomiphene citrate (CC) failure patients and to study androgen dynamics during the cycle.

Materials and Methods

This randomized clinical trial was done from March to November 2010 at the Mashhad IVF Center, a university based IVF center. Seventy infertile polycystic ovarian syndrome (PCOS) patients who were refractory to at least 3 CC treatment cycles were randomly divided into two groups. Group A (n=35) receiving 5 mg LTZ on cycle days 3-7 (CD3), and group B (n=35) receiving the same amount on cycle days 5-9 (CD5). Hormonal profile and ultrasonographic scanning were done on cycle day 3 and three days after completion of LTZ treatment (cycle day 10 or 12). Afterward, 5,000-10,000 IU human chorionic gonadotropin (hCG) was injected if at least one follicle ≥18 mm was seen in ultrasonographic scanning. Intrauterine insemination (IUI) has been done 36-40 hours later. The cycle characteristics, the ovulation and pregnancy rate were compared between two groups. The statistical analysis was done using Fisher’s exact test, t test, logistic regression, and Mann-Whitney U test.

Results

There were no significant differences between two groups considering patient characteristics. The ovulation rate (48.6 vs. 32.4% in group A and B, respectively), the endometrial thickness, the number of mature follicles, and length of follicular phase were not significantly different between the two groups.

Conclusion

LTZ is an effective treatment in CC failure PCOS patients. There are no significant differences regarding ovulation and pregnancy rates between two different protocols of LTZ starting on days 3 and 5 of menstrual cycle (Registration Number: IRCT201307096467N3).

Women who deliver twins are more likely to smoke and have high frequencies of specific SNPs: Results from a sample of African-American women who delivered preterm, low birth weight babies

OBJECTIVES

We examine if there are genetic and environmental differences between mothers of singleton and multiple pregnancies in a sample of African-American mothers.

METHODS

We focus on genomic areas suggested to increase or decrease the odds of multiple pregnancies. We computed the odds ratio (OR) and the 95% confidence interval (CI) for each SNP unadjusted or adjusted with smoking. SNPs' allelic differences between mothers of multiple pregnancies and singletons were also tested using Fisher's exact test. We considered additive terms for the SNPs' genotypes, smoking, and a multiplicative interaction term of two selected SNPs' genotypes.

RESULTS

We found significant interactions between smoking and SNPs of the CYP19A, MDM4, MTHFR and TP53 genes which correlated with higher odds of twinning. We also found a significant interaction between SNPs at the TP53 (rs8079544) and MTHFR gene (rs4846049), where the interaction between the homozygotes (TT for rs8079544, GG for rs4846049) correlated with lowered odds of multiple pregnancy.

CONCLUSIONS

We provide a mechanistic explanation and preliminary evidence for previous reports that mothers of twins are more likely to have smoked, despite seemingly conflicting evidence for the fertility-reducing effects of nicotine. Nicotine, as an aromatase inhibitor, inhibits estrogen synthesis and may allow for greater production of gonadotropins. While smoking may have deleterious effects on fertility across many genotypes, in women of specific genotypes it may raise their odds of producing twins. TP53 involvement suggests the necessity of future work examining relationships between women who bear multiples and cancer risk.

Assessment of multiple intrauterine gestations from ovarian stimulation (AMIGOS) trial: baseline characteristics

OBJECTIVE

To identify baseline characteristics of women with unexplained infertility to determine whether treatment with an aromatase inhibitor will result in a lower rate of multiple gestations than current standard ovulation induction medications.

DESIGN

Randomized, prospective clinical trial.

SETTING

Multicenter university-based clinical practices.

PATIENT(S)

A total of 900 couples with unexplained infertility.

INTERVENTION(S)

Collection of baseline demographics, blood samples, and ultrasonographic assessments.

MAIN OUTCOME MEASURE(S)

Demographic, laboratory, imaging, and survey characteristics.

RESULT(S)

Demographic characteristics of women receiving clomiphene citrate (CC), letrozole, or gonadotropins for ovarian stimulation were very consistent. Their mean age was 32.2 ± 4.4 years and infertility duration was 34.7 ± 25.7 months, with 59% primary infertility. More than one-third of the women were current or past smokers. The mean body mass index (BMI) was 27 and mean antimüllerian hormone level was 2.6; only 11 women (1.3%) had antral follicle counts of <5. Similar observations were identified for hormonal profiles, ultrasound characterization of the ovaries, semen parameters, and quality of life assessments in both male and female partners.

CONCLUSION(S)

The cause of infertility in the couples recruited to this treatment trial is elusive, as the women were regularly ovulating and had evidence of good ovarian reserve both by basal FSH, antimüllerian hormone levels, and antral follicle counts; the male partners had normal semen parameters. The three treatment groups have common baseline characteristics, thereby providing comparable patient populations for testing the hypothesis that use of letrozole for ovarian stimulation can reduce the rates of multiples from that observed with gonadotropin and CC treatment.

CLINICAL TRIAL REGISTRATION NUMBER

NCT 01044862.

Comparison of IVF Outcomes between Minimal Stimulation and High-Dose Stimulation for Patients with Poor Ovarian Reserve

We examined whether treatment with minimum-dose stimulation (MS) protocol enhances clinical pregnancy rates compared to high-dose stimulation (HS) protocol. A retrospective cohort study was performed comparing IVF and pregnancy outcomes between MS and HS gonadotropin-antagonist protocol for patients with poor ovarian reserve (POR). Inclusion criteria included patients with an anti-Müllerian hormone (AMH) ≤8 pmol/L and/or antral follicle count (AFC) ≤5 on days 2-3 of the cycle. Patients from 2008 exclusively had a HS protocol treatment, while patients in 2010 had treatment with a MS protocol exclusively. The MS protocol involved letrozole at 2.5 mg over 5 days, starting from day 2, overlapping with gonadotropins, starting from the third day of letrozole at 150 units daily. GnRH antagonist was introduced once one or more follicles reached 14 mm or larger. The HS group received gonadotropins (≥300 IU/day) throughout their antagonist cycle. Clinical pregnancy rate was significantly higher in the MS protocol compared to the HS protocol (P = 0.007). Furthermore, the live birth rate was significantly higher in the MS group compare to the HS group (P = 0.034). In conclusion, the MS IVF protocol is less expensive (lower gonadotropin dosage) and resulted in a higher clinical pregnancy rate and live birth rate than a HS protocol for poor responders.

Combined letrozole and clomiphene versus letrozole and clomiphene alone in infertile patients with polycystic ovary syndrome

Background

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of childbearing age (6.8%–18%), is among the most common causes of infertility due to ovulation factors, and accounts for 55%–70% of infertility cases caused by chronic anovulation. In this study, we used a combination of letrozole and clomiphene in patients resistant to both drugs individually, and studied the effects of this combination in ovulation and pregnancy in resistant PCOS patients.

Methods

The study population included infertile couples diagnosed as PCOS in the wife. The women used clomiphene for at least six cycles in order to ovulate after failure to form the dominant follicle, and were then put on letrozole for four cycles. Patients who were unable to form the dominant follicle were enrolled on letrozole and clomiphene combination therapy.

Results

One hundred enrolled patients underwent 257 cycles of a combination of letrozole and clomiphene, in which 213 were able to form the dominant follicle (82.9%) and 44 were unable to do so (17.1%). The number of mature follicles was 2.3±1.1. The mean endometrial thickness in patients on the day of human chorionic gonadotropin administration was 8.17±1.3 mm. The pregnancy rate was 42%.

Conclusion

According to the results of this study, it can be proposed that in PCOS patients resistant to clomiphene and letrozole used as single agents, a combination of the two drugs can be administered before using more aggressive treatment that may have severe complications or surgery. This combination may also be used as a first-line therapy to induce ovulation in severe cases of PCOS in order to save time and expense.

Use of clomiphene citrate in infertile women: a committee opinion

This committee opinion describes the use of clomiphene citrate, including indications, use, monitoring, and side effects. There is also a discussion of adjuvants and alternatives to clomiphene citrate therapy.

Is letrozole superior to clomiphene for ovarian stimulation prior to intrauterine insemination?

OBJECTIVE

To compare the efficacy of letrozole with clomiphene citrate for ovarian stimulation prior to intrauterine insemination.

METHODS

A total of 272 patients underwent 362 cycles of stimulation prior to IUI from January 2009 to May 2011. One hundred and twenty-six patients (170 cycles) received letrozole 5 mg and 146 patients (192 cycles) received clomiphene citrate 100 mg for 5 days starting on day 3 of the cycle. Intrauterine insemination was done 36 ± 4 h after hCG injection in 99 patients (131 cycles) in the letrozole group and 115 patients (136 cycles) in the clomiphene group. The number of mature follicles and serum E2 levels was monitored on the day of hCG. Endometrial thickness was noted on the day of hCG and IUI as well. The pregnancy rate, the miscarriage rate, and other parameters were evaluated only for patients who underwent IUI.

RESULTS

The mean number of mature follicles was significantly more in the clomiphene group (1.66 ± 1.69 vs. 1.41 ± 1.53) than in the letrozole group. No significant difference in endometrial thickness on the day of hCG administration was found; however, endometrial thickness was statistically significantly higher in the clomiphene group on the day of IUI (9.28 ± 1.43 vs. 8.77 ± 1.34). Serum E(2) levels on the day of hCG were statistically significantly higher in the clomiphene group (501.09 ± 2.45 vs. 214.79 ± 2.43 pg/ml). Pregnancy rate was 9.2 %/cycle and 12.12 %/patient in the letrozole group, and 8.1 %/cycle and 9.5 %/cycle in the clomiphene group; these differences were not statistically significant.

CONCLUSION

This study found no superiority of letrozole over clomiphene when used for ovarian stimulation and IUI.

A prospective randomized trial comparing the efficacy of Letrozole and Clomiphene citrate in induction of ovulation in polycystic ovarian syndrome

OBJECTIVES:

To compare the efficacy of letrozole and clomiphene citrate (CC) in patients of anovulatory polycystic ovarian syndrome (PCOS) with infertility.

MATERIALS AND METHODS:

This prospective randomized clinical trial included 204 patients of PCOS. 98 patients (294 cycles) received 2.5–5 mg of letrozole; 106 patients (318 cycles) received 50–100 mg of CC (both orally from Days 3–7 of menstrual cycle). The treatment continued for three cycles in both the groups. Main outcome measures: ovulation rate, endometrial thickness, and pregnancy rate. Statistical analysis was done using SPSS 13 software. P value less than 0.05 was considered significant.

RESULTS:

The mean number of dominant follicles in letrozole groups and CC groups was 1.86±0.26 and 1.92±0.17, respectively (P=0.126). Number of ovulatory cycle in letrozole group was 196 (66.6%) versus 216 (67.9%) in CC group (P=0.712). The mean mid-cycle endometrial thickness was 9.1±0.3 mm in letrozole group and 6.3±1.1 in CC group, which was statistically significant (P=0.014). The mean Estradiol [E2] level in clomiphene citrate group was significantly higher in CC group (364.2±71.4 pg/mL) than letrozole group (248.2± 42.2 pg/mL). 43 patients from the letrozole group (43.8%) and 28 patients from the CC group (26.4%) became pregnant.

CONCLUSION:

Letrozole and CC have comparable ovulation rate. The effect of letrozole showed a better endometrial response and pregnancy rate compared with CC.

Letrozole versus clomiphene citrate for superovulation in Egyptian women with unexplained infertility: a randomized controlled trial

OBJECTIVES

To compare the efficacy of letrozole with clomiphene citrate (CC) in Egyptian women with unexplained infertility.

STUDY DESIGN

This randomized controlled trial was conducted at Ain Shams University Hospital and Dar Al Hekma hospital between February 2010 and May 2011.

PATIENTS AND METHODS

Two hundreds and seventy women with unexplained infertility were randomized into two groups using computer-generated randomization plan, and were given letrozole 2.5 mg/day from cycle day 3 to 7 (Letrozole group, n=136) or CC 100 mg/day from cycle day 3 to 7 (CC group, n=134). On day 9, the participants underwent a transvaginal sonography (TVS) every other day to monitor their ovulation and measure both endometrial thickness and Doppler flow indices of uterine and subendometrial vessels. Single injection of 10,000 IU of human chorionic gonadotropin (hCG) was given when the mean diameter of at least one ovarian follicle was ≥18 mm, quantitative βhCG was done 2 weeks after hCG injection to diagnose chemical pregnancy. Clinical pregnancy was confirmed by observing a gestational sac with fetal echoes and pulsation 4 weeks after positive pregnancy test by TVS.

RESULTS

Both groups were comparable with regard to the day of hCG administration (letrozole 13.4±5 vs CC 12.1±4.9, respectively, p=0.06). The mean number of mature follicles was significantly higher in CC group (2±0.9 vs 1±0.0, P=0.02). Serum estradiol was significantly greater in CC group (817±299 vs 364±149 pg/ml, P<0.001). The clinical pregnancy rate was significantly higher in letrozole group (23.07 vs 10.68%, P<0.001). There was statistically significant increase in endometrial receptivity in letrozole group as assessed by endometrial thickness and Doppler flow indices of uterine and subendometrial vessels. No serious side effects were reported in either group.

CONCLUSION

Letrozole has beneficial effect on endometrium, an action that may improve the implantation and pregnancy rates in women with unexplained infertility.

Controlled ovarian hyperstimulation in women with polycystic ovarian syndrome with or without intrauterine insemination

OBJECTIVE

To evaluate the value of intrauterine insemination (IUI) in controlled ovarian hyperstimulation (COH) among couples with polycystic ovary syndrome (PCOS) and normal semen analysis.

DESIGN

Retrospective cohort study.

SETTING

University teaching center.

PATIENTS

PCOS couples with normal semen analysis that underwent COH with IUI or timed intercourse (TIC).

INTERVENTION

COH with clomiphene citrate, letrozole or gonadotropins with or without IUI.

MAIN OUTCOME MEASURES

Clinical pregnancy rates.

RESULTS

Of a total 265 cycles, 151 cycles were with IUI and 114 others with TIC. No significant difference was found in the overall pregnancy rates between the TIC group (17.5%) and the IUI group (16.6%). Analysis of pregnancy rates according to the type of COH treatments did not demonstrate the advantages of IUI over TIC.

CONCLUSION

Compared to timed intercourse, IUI does not increase the pregnancy rate in couples with PCOS and normal semen analysis treated with COH.

Ovarian stimulation and intrauterine insemination at the quarter centennial: implications for the multiple births epidemic

Ovarian stimulation and intrauterine insemination (OS/IUI), a mainstay of current infertility therapy and a common antecedent to IVF, is a significant driver of the multiple births epidemic. Redress of this challenge, now marking its quarter centennial, will require a rethinking of current practice patterns. Herein we explore prospects for prevention, mitigation, and eventual resolution. We conclude that the multiple births attributable to OS/IUI may not be entirely preventable but that the outlook for their mitigation is promising, if in need of solidification. Specifically, we observe that low-dose (≤ 75 IU) gondotropin, clomiphene, and especially off-label letrozole regimens outperform high-dose (≥ 150 IU) gonadotropin counterparts in the gestational plurality category while maintaining comparable per-cycle pregnancy rates. Accordingly we recommend that, subject to appropriate exceptions, high-dose gonadotropin regimens be used sparingly and that whenever possible they be replaced with emerging alternatives. Finally, we posit that OS/IUI is not likely to be superseded by IVF absent further commoditization and thus greater affordability.

Use of the aromatase inhibitor letrozole for ovulation induction in women with polycystic ovarian syndrome

Clomiphene citrate (CC) is the most commonly used oral agent for the induction of ovulation. It is a nonsteroidal selective estrogen receptor modulator that has predominant antiestrogenic action resulting in long-lasting estrogen receptor depletion. Side effects include antiestrogenic effects systemically and on the endometrium and cervical mucous. Letrozole is a potent, nonsteroidal, aromatase inhibitor, originally used for postmenopausal breast cancer therapy, at present its only registered indication. We hypothesized that letrozole could mimic the action of CC without depletion of estrogen receptors. As there is no estrogen receptor antagonism, antiestrogenic effects such as poor cervical mucus and thin endometrium are not expected with aromatase inhibitor treatment. In addition, because estrogen receptors in the brain are not depleted, normal negative feedback occurs with letrozole and generally results in monoovulation. We and others have demonstrated the success of aromatase inhibition in inducing ovulation in women with polycystic ovarian syndrome. Letrozole may be very effective for ovulation induction and pregnancy in cases of CC resistance. When used together with follicle-stimulating hormone (FSH) injections, letrozole resulted in a significant reduction in the FSH dose needed for controlled ovarian hyperstimulation. Aromatase inhibitors likely increase ovarian sensitivity to FSH, and may be useful in poor responders and in women undergoing ovarian stimulation for in vitro fertilization. The safety of letrozole in pregnancy outcome studies has been demonstrated by examination of spontaneous pregnancy loss, multiple pregnancy rates, and congenital anomalies compared with a control group of infertility patients treated with CC. In addition, new data suggest that CC may result in cardiac anomalies and other birth defects and in low birth weight babies. We believe aromatase inhibitors are acceptable alternatives to CC as first line oral agents for ovulation induction or controlled ovarian stimulation.

Dosage optimization for letrozole treatment in clomiphene-resistant patients with polycystic ovary syndrome: a prospective interventional study

Objective. Dose adjustment for induction of ovulation is one of the most important problem. Methods. In a prospective interventional study, 44 clomiphene-resistant infertile patients (113 cycles) were selected from the Abolfazl Infertility Clinic of Bushehr University of Medical Sciences. Letrozole was given orally in a dose of 2.5 mg, 5 mg, and 7.5 mg, respectively. If the patient displayed no response, the dosage was increased. Results. In this patients ovulation occurred in 50 cycles (44.24%), clinical pregnancy rate according to number of cycles was 23.89% (27 of 113 cycles) and according to the number of patients was 61.36% (27 of 44 patients). In the 2.5, 5, and 7.5 groups, follicles occurred in 22.9%, 42.1%, and 85.18% of cycles, and pregnancy rate was 14.58%, 28.94% and, 33.33%, respectively. Conclusions. It is better to administer Letrozole at a lower dosage to prevent complications and increase the dose based on sonographic results antral follicular count, anti-Müllerian hormone, LH/FSH, and estradiol.

Estimating rates of multiple gestation pregnancies: sample size calculation from the assessment of multiple intrauterine gestations from ovarian stimulation (AMIGOS) trial

Infertility afflicts 15% of couples who wish to conceive. Despite intensive evaluation of both male and female partners, the etiology may remain unknown leading to a diagnosis of unexplained infertility. For such couples, treatment often entails ovulation induction (OI) with fertility medications coupled with intrauterine insemination. Complications of this therapy include ovarian hyperstimulation syndrome and creation of multiple gestation pregnancies, which can be complicated by preterm labor and delivery, and the associated neonatal morbidity and expense of care for preterm infants. The Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) study is designed to assess whether OI in couples with unexplained infertility with an aromatase inhibitor produces mono-follicular development in most cycles, thereby reducing multiple gestations while maintaining a comparable pregnancy success rate to that achieved by OI with either gonadotropins or clomiphene citrate. These results will provide future guidance of therapy for couples with unexplained infertility, and if comparable pregnancy rates are achieved with a substantial reduction in multiple gestations, the public health benefit will be considerable.