Aromatase inhibitors prevent the estrogen rise associated with the flare effect of gonadotropins in patients treated with GnRH agonists

Efficacy and uterine bleeding patterns in initiating goserelin therapy during different menstrual phases in patients with adenomyosis: a prospective cohort study

OBJECTIVE

We carried out this study to explore the possibility of initiating goserelin therapy during the non-menstrual period in patients diagnosed with adenomyosis.

METHODS

115 premenopausal adenomyosis patients were enrolled and divided into three groups based on their menstrual cycle phase during the initial outpatient visit: menstrual, follicular, and luteal. Each received a 3.6 mg subcutaneous dose of goserelin monthly for three months. The endpoints encompassed alterations in uterine volume, dysmenorrhea Numerical Rating Scale (NRS) score, CA125 level, hemoglobin (HGB) after a 12-week treatment course, and the occurrence and duration of uterine hemorrhage during the first treatment cycle.

RESULTS

Analysis revealed that the timing of goserelin therapy initiation in the menstrual cycle did not significantly impact its effectiveness in reducing uterine size, alleviating pain, lowering CA125 levels, or improving hemoglobin concentrations. However, patients starting treatment during the luteal phase experienced increased uterine bleeding (reference: menstrual period, OR = 4.33, 95% CI 1.23-15.25, p = .023).

CONCLUSIONS

The results suggested non-inferiority of goserelin therapy initiated during the non-menstrual period, but the uterine bleeding rate was higher in the luteal phase group. Therefore, goserelin treatment for outpatient adenomyosis patients should not be limited to starting during the menstrual period; it can also be initiated outside the menstrual period, providing more convenience for patients as most consultations occur outside the menstrual period. However, the use of goserelin during the luteal phase should be avoided to reduce the risk of exacerbated bleeding, especially in anemic patients with heavy menstrual bleeding. This study highlights the importance of individualizing treatment initiation based on the patient's health profile to optimize therapeutic outcomes and minimize adverse effects.

TRIAL REGISTRATION

ChiCTR2200059548.

Good practice with fluid management in operative hysteroscopy

Hysteroscopic surgery requires a balance of continuous controlled irrigation and aspiration to distend the endometrial cavity to a degree that provides the clear and stable visual environment necessary for diagnostic and therapeutic procedures. Whereas the preferred distending solution should be isotonic and isonatremic, radiofrequency (RF) electrosurgery with monopolar instrumentation can only be performed with non-ionic (hyponatremic) solutions. Absorption of as little as 500 mL and certainly more than 1000 mL of non-ionic solutions can result in fluid overload and/or dilutional hyponatremia with potentially serious adverse effects under certain conditions and patient characteristics. Both hysteroscopic RF electrosurgery with bipolar instrumentation and electro-mechanical morcellation and aspiration systems use isotonic and isonatremic solutions. Depending on the clinical context, absorption of more than 1500 mL of isonatremic solutions can also result in serious adverse effects. Automated fluid management systems are preferred and recommended, and surgeons should aim to maintain the maximum allowable intravasation of distending media below 1000 and 1500 mL for non-ionic and ionic fluids, respectively.

Clinical efficacy and safety of trimonthly administration of goserelin acetate 10.8 mg in premenopausal Chinese females with symptomatic adenomyosis: a prospective cohort study

OBJECTIVE

This prospective cohort study aimed to compare the clinical efficacy and safety of goserelin 10.8 mg administered trimonthly with goserelin 3.6 mg administered monthly in premenopausal females with symptomatic adenomyosis.

METHODS

We recruited 139 premenopausal females with adenomyosis who complained of dysmenorrhea and/or menorrhagia. The first group (n = 70) received a single subcutaneous injection of goserelin 10.8 mg, and the second group (n = 69) received monthly subcutaneous goserelin 3.6 mg administered for 3 months. Follow-up was performed at the outpatient department after 12 weeks.

RESULTS

Ultimately, 130 patients completed the study, including 68 and 62 patients in the goserelin 10.8 mg (n = 70) and 3.6 mg (n = 69) groups, respectively. We observed a significant decrease in the dysmenorrhea (NRS) score, uterine volume, and cancer antigen 125 (CA125) levels, and a significant increase in hemoglobin (HGB) levels in both treatment groups. There was no significant difference between the two groups. The sum of the adverse event scores was slightly higher in the goserelin 3.6 mg than in the 10.8 mg group.

CONCLUSIONS

The clinical efficacy of trimonthly administration of goserelin 10.8 mg was equivalent to monthly 3.6 mg dosing and was non-inferior regarding safety and tolerability. Hence, it can be a more cost-effective and convenient alternative treatment option in premenopausal females with symptomatic adenomyosis.

TRIAL REGISTRATION

ChiCTR2200059548.

The Effect of Clomiphene Citrate and Letrozole in Apoptotic Pathways and Cell Cycle in Human Primary Cumulus Cells and the Protective Effect of Estradiol

Clomiphene citrate (CC) and letrozole are ovulatory stimulants that, despite high ovulation rates, achieve low pregnancy rates. This study aimed to investigate the in vitro effects of CC and letrozole, alone or in combination with estradiol, on apoptosis in human cumulus cells. We performed a controlled prospective study using primary cumulus cell cultures from patients undergoing in vitro fertilization (n=22). Alpha-inhibin immunocytochemistry was used to assess cell culture purity and morphology. Cell viability was evaluated by MTT assay, cell cycle status by flow cytometry, and Caspase-3, Bax and SOD-2, and S26 gene expression by qPCR. Cells were treated for 24 hours in 5 conditioned media: CC, CC + estradiol, letrozole, letrozole + estradiol and control. None of the treatments affected cell viability, but letrozole reduced the mean percentage of cells in the S phase compared to control (24.79 versus 21.70, p=0.0014). Clomiphene treatment increased mRNA expression of Bax (4 fold) and SOD-2 (2 fold), which was reversed by co-treatment with estradiol. SOD-2 expression increased in cells treated with letrozole compared to control (4 fold), which was also reversed by estradiol. These findings suggest that clomiphene citrate and letrozole do not significantly affect the viability of human cumulus cells. Still, the expression of genes involved in apoptosis was modulated by these drugs alone and in association with estradiol, suggesting that CC and letrozole may have direct effects on cumulus cells beyond their known mechanisms of action.

Relugolix, an oral gonadotropin-releasing hormone receptor antagonist, reduces endometriosis-associated pain compared with leuprorelin in Japanese women: a phase 3, randomized, double-blind, noninferiority study

OBJECTIVE

To evaluate the efficacy and safety of 40-mg relugolix (REL) compared with those of leuprorelin (LEU) in women with endometriosis-associated pain.

DESIGN

Phase 3, multicenter, randomized, double-blind, double-dummy, active-controlled study in Japanese patients.

SETTING

Hospitals and clinics.

PATIENT(S)

Women aged ≥20 years with regular menstrual cycles (25-38 days) experiencing endometriosis or ovarian endometrioma and reporting pelvic pain.

INTERVENTION(S)

In the REL group, 40 mg of REL was orally administered once a day for 24 weeks. In the LEU group, 3.75 or 1.88 mg of LEU was subcutaneously injected every 4 weeks for 24 weeks.

MAIN OUTCOME MEASURE(S)

The primary endpoint was the change in the maximum visual analog scale score for pelvic pain from baseline until 28 days before the end of treatment.

RESULT(S)

Changes in the maximum visual analog scale score were -52.6 ± 1.3 for REL and -57.5 ± 1.4 for LEU. Ovarian endometrioma decreased by 12.26 ± 17.52 cm³ for REL and 14.10 ± 18.81 cm³ for LEU. Drug-related treatment emergent adverse events with an incidence of >10% for both groups were hot flush, metrorrhagia, headache, and genital hemorrhage. Discontinuations from treatment emergent adverse events were 2.9% for REL and 4.3% for LEU.

CONCLUSION(S)

Relugolix was noninferior to LEU for treating endometriosis-associated pelvic pain. Safety profiles of both medications were comparable, although menses returned earlier in patients taking REL, a huge benefit for women who plan to conceive after treatment.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT03931915.

Disparities in Female Pediatric, Adolescent and Young Adult Oncofertility: A Needs Assessment

Advancements in cancer screening and implementation of targeted treatments have significantly improved survival rates to 85% for pediatric and AYA survivors. Greater than 75% of survivors will live to experience the long-term adverse outcomes of cancer therapies, termed late effects (LE), that disrupt quality of life (QoL). Infertility and poor reproductive outcomes are significant disruptors of QoL in survivorship, affecting 12-88% of survivors who receive at-risk therapies. To mitigate risk, fertility preservation (FP) counseling is recommended as standard of care prior to gonadotoxic therapy. However, disparities in FP counseling, implementation of FP interventions, and screening for gynecologic late effects in survivorship persist. Barriers to care include a lack of provider and patient knowledge of the safety and breadth of current FP options, misconceptions about the duration of time required to implement FP therapies, cost, and health care team bias. Developing strategies to address barriers and implement established guidelines are necessary to ensure equity and improve quality of care across populations.

Role of medical treatment of endometriosis

Endometriosis is a chronic benign disease that affects women of reproductive age. Medical therapy is often the first line of management for women with endometriosis in order to ameliorate symptoms or to prevent post-surgical disease recurrence. Currently, there are several medical options for the management of patients with endometriosis and long-term treatments should balance clinical efficacy (controlling pain symptoms and preventing recurrence of disease after surgery) with an acceptable safety-profile. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of chronic inflammatory conditions, being efficacious in relieving primary dysmenorrhea. Combined oral contraceptives and progestins, available for multiple routes of administration, are commonly administered as first-line hormonal therapies. Several studies demonstrated that they succeed in improving pain symptoms in the majority of patients; moreover, they are well tolerated and not expensive. Gonadotropin-releasing hormone-agonists are prescribed when first line therapies are ineffective, not tolerated or contraindicated. Even if these drugs are efficacious in treating women not responding to COCs or progestins, they are not orally available and have a less favorable tolerability profile (needing an appropriate add-back therapy). Because few data are available on long-term efficacy and safety of aromatase inhibitors they should be reserved only for women with symptoms who are refractory to other treatments only in a research environment. Almost all of the currently available treatment options for endometriosis suppress ovarian function and are not curative. For this reason, research into new drugs is unsurprisingly demanding. Amongst the drugs currently under investigation, gonadotropin-releasing hormone antagonists have shown most promise, currently in late-stage clinical development. There is a number of potential future therapies currently tested only in vitro, in animal models of endometriosis or in early clinical studies with a small sample size. Further studies are necessary to conclude whether these treatments would be of value for the treatment of endometriosis.

Severe ovarian hyperstimulation syndrome associated with long-acting GnRH agonist in oncofertility patients

PURPOSE

To report three cases of severe ovarian hyperstimulation syndrome (OHSS) among oncofertility patients receiving a long-acting GnRH agonist for ovarian suppression after controlled ovarian hyperstimulation (COH) with a GnRH antagonist protocol METHODS: Chart abstraction was completed for three patients at a single academic medical center. Patients included were undergoing fertility preservation prior to gonadotoxic chemotherapy. All patients underwent COH with GnRH antagonist protocol and embryo cryopreservation immediately followed by ovarian suppression with long-acting GnRH agonist. Main outcome measure was development of OHSS.

RESULTS

Despite using GnRH agonist trigger and freezing all embryos, patients developed ascites, intermittent hyponatremia and hemoconcentration consistent with severe early-onset OHSS after receiving long-acting GnRH agonist immediately following oocyte retrieval for ovarian preservation.

CONCLUSIONS

Risk of severe OHSS may be increased when a long-acting GnRH agonist is used for ovarian suppression immediately following oocyte retrieval. A delay in initiating long-acting GnRH agonist after oocyte retrieval in patients at high risk for developing OHSS should be considered.

Options for Prevention and Management of Menstrual Bleeding in Adolescent Patients Undergoing Cancer Treatment: ACOG Committee Opinion, Number 817

ABSTRACT

Obstetrician-gynecologists frequently are consulted either before the initiation of cancer treatment to request menstrual suppression or during an episode of severe heavy bleeding to stop bleeding emergently. Adolescents presenting emergently with severe uterine bleeding usually require only medical management; surgical management rarely is required. Surgical management should be considered for patients who are not clinically stable, or for those whose conditions are not suitable for medical management or have failed to respond appropriately to medical management. When used continuously, combined hormonal contraceptives are effective for producing amenorrhea, although complete amenorrhea cannot be guaranteed. The risk of venous thromboembolism in patients with cancer is compounded by multiple factors, including presence of metastatic or fast-growing, biologically aggressive cancers; hematologic cancers; treatment-related factors such as surgery or central venous catheters; and the number and type of comorbid conditions. Although as a group, patients undergoing cancer treatment are at elevated risk of venous thromboembolism compared with the general population, this risk may be extremely elevated for certain patients and existing guidance on risk stratification should be consulted. The decision to use estrogen in patients with cancer should be tailored to the individual patient after collaborative consideration of the risk-benefit ratio with the patient and the health care team; the patient should be closely monitored for known adverse effects such as liver toxicity and venous thromboembolism.

Effect of GnRH agonist and letrozole treatment in women with recurrent implantation failure

OBJECTIVE

To compare the influence of dual suppression with the use of GnRH agonist plus aromatase inhibitor compared with suppression with the use of GnRH agonist alone or no suppression at all in patients with idiopathic recurrent implantation failure (RIF).

DESIGN

Retrospective cohort study.

SETTING

University-affiliated reproductive center.

PATIENT(S)

A total of 523 infertile women who failed two blastocyst transfers underwent a third frozen blastocyst transfer. Women with known endometriosis were excluded.

INTERVENTION(S)

A total of 204 subjects were not pretreated, 143 received 2 months of GnRH agonist (3.75 mg intramuscular leuprolide acetate monthly) only, and 176 received GnRH agonist and aromatase inhibitor (5 mg oral letrozole daily for 60 days). Demographic and stimulation information was collected and cycle outcomes reported.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rates.

RESULT(S)

Age, antral follicle count, basal FSH levels, duration of infertility, previous pregnancies, and full-term deliveries were similar (P>.05). Clinical pregnancy rates were higher among women who received GnRH agonist plus letrozole compared with women who received GnRH agonist only or women without pretreatment (63%, 42%, and 40%, respectively; P<.0001). Live birth rates were higher among women who received GnRH agonist plus letrozole compared with the other groups (56%, 36%, and 34%; P<.0001). No differences in pregnancy outcomes were noted between patients who did not receive pretreatment and those in the GnRH agonist only group.

CONCLUSION(S)

In patients with RIF, treatment with a GnRH agonist plus letrozole may improve live birth rates in subsequent cycles. We hypothesize that this improvement is due to alterations in the endometrium receptivity or treatment of undiagnosed endometriosis.

Management of recurrent implantation failure by gonadotropin-releasing hormone agonist and aromatase inhibitor suppression, in women without evidence of endometriosis

Endometriosis is common among those with infertility, although many cases go undiagnosed. This study was performed to determine whether empiric treatment with two months of depo-leuprolide 3.75 mg monthly (dep-GnRH-ag) and letrozole 5 mg daily improves pregnancy outcomes in patients with at least two unexplained failed embryo transfers (ETs) but without a previous diagnosis of endometriosis. A retrospective cohort study was performed with subjects who failed at least two good quality ET. The study excluded women with a known history of endometriosis or ovarian cysts (possible endometriomas). Subjects (N = 38) were treated with dep-GnRH-ag and letrozole pre-cycle. Matched women (N = 37) who did not receive either pretreatment served as a control group. Data were compared by non-paired T-tests and multivariate logistic regression to control for confounding effects. Demographic data, hormonal profiles, and ovarian reserve parameters were similar between the two groups. The treated group had failed more embryo transfers (3.5 ± 1.7 vs. 2.0 ± 1.3, p = .01) than the controls. When adjusting for the number of MII oocytes collected, number of blastocysts developed and number of blastocysts transferred, there were more pregnancies (24/38 vs. 11/37, p = .02) and ongoing pregnancies (18/38 vs. 9/37, p = .03) in the treated group. Patients with multiple unexplained failed ET may have undiagnosed endometriosis and may benefit from pretreatment with dep-GnRH-ag and letrozole. These results would benefit from being subjected to a randomized prospective study.

Minimum values for midluteal plasma progesterone and estradiol concentrations in patients who achieved pregnancy with timed intercourse or intrauterine insemination without a human menopausal gonadotropin

Objective

The aim of the study was to assess the lower limits of midluteal plasma progesterone and estradiol concentrations in patients who achieved pregnancy with timed intercourse or intrauterine insemination without a human menopausal gonadotropin stimulation.

Results

We included 297 pregnant cycles of 297 women and assessed midluteal plasma progesterone and estradiol concentrations and pregnancy outcomes, retrospectively. These cycles were compared with the non-pregnant cycles (406 cycles) of the same women who became pregnant. Mean midluteal plasma P4 and E2 concentrations were significantly (P < 0.01) higher in pregnant cycles (14.5 and 188.5 pg/mL) than in non-pregnant cycles (10.7 and 162.6 pg/mL). The 5 percentiles of progesterone and estradiol in pregnant cycles were 5.6 and 70.2 pg/mL, respectively. The lowest progesterone and estradiol levels in pregnant cycles were 2.3 and 23.4 pg/mL, respectively. In non-pregnant cycles, many women had low P4 levels that were less than 5.6 ng/mL. Subgroup analyses showed slight differences among the four groups, which may have been due to the ovarian function of each group. Miscarriage was not related to progesterone and estradiol concentrations. These values may be useful for the evaluation of necessary values for pregnancy with timed intercourse or intrauterine insemination.

New developments in the medical treatment of endometriosis

Endometriosis affects 1 in 10 women of reproductive-age. The current treatments are surgical and hormonal but have limitations, including the risk of recurrence, side effects, contraceptive action for women who desire pregnancy, and cost. New treatments include gonadotropin-releasing hormone analogues, selective progesterone (or estrogen) receptor modulators, aromatase inhibitors, immunomodulators, and antiangiogenic agents. Further research is needed into central sensitization, local neurogenesis, and the genetics of endometriosis to identify additional treatment targets. A wider range of medical options allows for the possibility of precision health and a more personalized treatment approach for women with endometriosis.

Menstrual management and reproductive concerns in adolescent and young adult women with underlying hematologic or oncologic disease

PURPOSE OF REVIEW

Heavy menstrual bleeding is common among adolescent and young adult women, and can affect health-related quality of life. The cause of heavy menstrual bleeding is not uncommonly because of an underlying hematologic or oncologic disease process, which substantially influences the way patients are counseled and treated.

RECENT FINDINGS

Options for menstrual management are more numerous today than ever before and range from minimizing monthly blood loss to suppressing the cycle altogether. However, an underlying bleeding disorder or malignancy can introduce many nuances and limits in individual patient care, which this review highlights. Additionally, because survival rates for adolescent and young adult cancers are improving, more of these patients are planning for lives after their disease, which may include starting or adding to a family. Options for fertility preservation during cancer therapy regimens are solidifying and both primary practitioners and subspecialists should be aware of the possibilities.

SUMMARY

Patients with underlying hematologic or oncologic disease require management of menstrual bleeding, but also deserve a comprehensive evaluation and counseling regarding their individualized contraceptive needs and fertility preservation options during their reproductive years. This review employs the latest evidence from current literature to help guide clinicians caring for this unique demographic.

Medical treatment of ureteral obstruction associated with ovarian remnants and/or endometriosis: report of three cases and review of the literature

STUDY OBJECTIVE

Experience with low-dose intermittent danazol or prolonged gonadotropin-releasing hormone agonist (GnRH-a) with and without add-back therapy in endometriosis-associated ureteral obstruction.

DESIGN

Retrospective case series (Canadian Task Force classification II-2).

SETTING

University-affiliated teaching hospital.

PATIENTS

Three women with endometriosis-associated ureteral obstruction.

INTERVENTION

The regimen of GnRH-a alone or with add-back included (1) leuprolide acetate 3.75 mg intramuscularly monthly; (2) micronized 17α-estradiol 1 mg/day by mouth; (3) pulsed norethinedrone 0.35 mg/day by mouth, 2 days on and/or 2 days off; and (4) letrozole 2.5 mg by mouth for the first 5 days of the first GnRH-a injection. Danazol, 100 mg/day by mouth, was prescribed as a regimen of 3 months on, 3 months off, for 4 years.

MEASUREMENTS AND MAIN RESULTS

The first case was a 50-year-old woman, gravida 3, para 3, body mass index (BMI) 27 kg/m(2), with multiple surgeries, including hysterectomy and bilateral salpingo-oophorectomy (HBSO), and history of a stroke. She presented with right-sided pain and hydro-uretero-nephrosis. Magnetic resonance imaging identified a right adnexal cyst (4.5 × 3.4 × 2.4 cm). She was treated with leuprolide acetate monthly injections and a ureteric stent. The cyst, pain, and hydro-uretero-nephrosis resolved after 12 months. The second case was a 45-year-old woman, G2P2, BMI 28 kg/m(2) with multiple surgeries, including HBSO. She presented with left-sided pelvic pain. Ultrasound identified a left adnexal cyst and hydronephrosis. After 3 months of leuprolide acetate and add-back therapy, the cyst, pain, and hydronephrosis resolved. The third case was a 46-year-old woman, G2P2, BMI 25 kg/m(2), who presented with left flank and pelvic pain. Magnetic resonance imaging indicated moderate left hydronephrosis and left adnexal pelvic side-wall involvement with possible endometriosis. Due to many previous surgeries, this patient was a high-risk surgical candidate, and therefore, she was offered medical therapy. After a normal serum liver and lipid profile, she was started on danazol, 100 mg/day for 3 months. After 3 months of therapy, there was complete resolution of the patient's hydronephrosis and pain. She was then advised to continue with a 3-month on, 3-month off regimen. She discontinued the danazol and remained asymptomatic with no recurrence of hydronephrosis at 3 years.

CONCLUSIONS

Low-dose intermittent danazol or GnRH-a alone or with add-back, may be effective long-term therapies in endometriosis-associated ureteral obstruction when surgery is contraindicated, refused, or difficult to perform.

Aromatase inhibitors for uterine fibroids

BACKGROUND

Uterine fibroids, also called uterine leiomyomas or myomas, are the most common benign tumours in women of reproductive age. Albeit generally benign, uterine fi broids can have a major impact on women's health and quality of life by contributing to abnormal uterine bleeding and causing pelvic pressure symptoms (such as increased urinary frequency, pelvic pain and constipation). Traditional treatments for symptomatic fi broids include a variety of surgical techniques. However, because of the high recurrence rate, as well as possible pain and infertility caused by the formation of postoperative adhesions, this approach may not be advisable. Safer and more effective medical therapy has long been awaited. Both in vitro studies and clinical trials have suggested that use of the aromatase inhibitors (AIs), a class of anti-oestrogens, might inhibit fi broid growth, thereby eliminating the need for surgery.

OBJECTIVES

To evaluate the effectiveness and safety of aromatase Inhibitors (AIs) in women with uterine fibroids.

SEARCH METHODS

We searched the following databases (from inception to August 21, 2013): Cochrane Menstrual Disorders and Subfertility Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, CINAHL and PsycINFO. In addition, the reference lists of included trials were searched, and experts in the field were contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in women of reproductive age comparing the effects of any AI versus placebo, no treatment or any medical treatment/surgery were included.

DATA COLLECTION AND ANALYSIS

Selection of eligible trials, assessment of trial quality and data extraction were performed independently by two review authors. If data were available, we planned to calculate odds ratios (ORs) for analysis of dichotomous data and mean differences for continuous data, with 95% confidence intervals (CIs).

MAIN RESULTS

Only one trial involving 70 participants was included. This trial did not report our primary review outcome (relief of symptoms of fibroids). The only secondary review outcomes reported by this trial were adverse effects (hot flushes) and reduction in fibroid size. Significantly fewer women reported hot flushes in the letrozole group than in the GnRHa group (0/33 vs 26/27, P < 0.05). Use of letrozole reduced fibroid volume by 46% and use of a gonadotrophin-releasing hormone (GnRH) agonist (GnRHa) by 32% after 12 weeks of treatment; these proportions were not significantly different. The included trial did not report data on fibroid volume in a form that permitted calcuation of an odds ratio. Morevoer it was unblinded and included only 60/70 women in analysis.

AUTHORS' CONCLUSIONS

Evidence is insufficient to support the use of AI drugs in the treatment of women with uterine fibroids.

Hormonal, follicular and endometrial dynamics in letrozole-treated versus natural cycles in patients undergoing controlled ovarian stimulation

The objective of this study was to compare letrozole-stimulated cycles to natural cycles in 208 patients undergoing intrauterine insemination (IUI) between July of 2004 and January of 2007. Group I (n = 47) received cycle monitoring only (natural group), Group II (n = 125) received letrozole 2.5 mg/day on cycle days three to seven, and Group III (n = 36) received letrozole 5 mg/day on cycle days three to seven. There were no differences between the groups in endometrial thickness or P₄ on the day of hCG. Estradiol levels had higher variation in the second half of the follicular phase in both letrozole-treated groups compared to the control group. Estradiol per preovulatory follicle was similar in both letrozole cycles to that observed in the natural cycles. LH was lower on the day of hCG administration in the letrozole 2.5 mg/day group vs. the natural group. In summary, letrozole results in some minor changes in follicular, hormonal and endometrial dynamics compared to natural cycles. Increased folliculogenesis and pregnancy rates were observed in the letrozole-treated groups compared to the natural group. These findings need to be confirmed in larger, prospective studies.