Effect of letrozole on moderate and severe early-onset ovarian hyperstimulation syndrome in high-risk women: a prospective randomized trial

Effect of aromatase inhibitors for preventing ovarian hyperstimulation syndrome in infertile patients undergoing in vitro fertilization: a systematic review and meta-analysis

PURPOSE

To summarize the findings of relevant randomized controlled trials (RCTs) and conduct a meta-analysis to investigate the potential effect of aromatase inhibitors on preventing moderate to severe ovarian hyperstimulation syndrome (OHSS) in infertile women undergoing in vitro fertilization (IVF).

METHODS

We searched for relevant RCTs in electronic databases, including MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov (from inception to August 2023). In addition, we manually searched the related reviews and reference lists of included studies for further relevant studies. We included RCTs where aromatase inhibitors prescribed either during controlled ovarian stimulation (COS) or in early luteal phase. The meta-analysis was performed using RevMan 5.4.1 software. The primary outcome was the incidence of moderate to severe OHSS. A descriptive analysis was conducted in cases where a meta-analysis was not feasible due to heterogeneity or lack of comparable data.

RESULTS

2858 records were retrieved and 12 RCTs were finally included. Letrozole was administered in the treatment group during COS in seven RCTs, whereas in the early luteal phase in five RCTs. Compared with the control group, the risk of moderate to severe OHSS significantly reduced by 55% in the letrozole group (RR 0.45, 95% CI 0.32 to 0.64, I2 = 0%, 5 RCTs, 494 patients). Moreover, serum estradiol (E2) levels on hCG trigger day significantly decreased with the administration of letrozole during COS (MD -847.23, 95% CI -1398.00 to -296.47, I2 = 93%, 5 RCTs, 374 patients). And serum E2 levels on the 4th, 5th and 7th to 10th day after hCG trigger were also significantly lower than those in the control group when letrozole was administered in the early luteal phase.

CONCLUSIONS

Patients with high risk of OHSS probably benefit from letrozole, which has been revealed to reduce the incidence of moderate to severe OHSS by this systematic review. However, the very limited number of participants and the quality of the included studies does not allow to recommend letrozole for the prevention of severe OHSS.

Current research of Assisted Reproductive Technology for women with early endometrial cancer and atypical endometrial hyperplasia after conservative treatment

As the incidence of endometrial cancer (EC) and atypical endometrial hyperplasia (AEH) has been increasing, and has shown young trend. It is crucial to study the fertility-preserving treatment of endometrial lesions and fertility-promoting protocols. Age, obesity, and irregular ovulation are not only high-risk factors for endometrial lesions but also key factors affecting female fertility. Assisted reproductive technology (ART) can significantly improve pregnancy outcomes in patients with AEH and EC after conservative treatment. Based on the existing studies, this article reviews the progress of research on pregnancy outcomes of ART and its influencing factors in such patients. It helps physicians in providing optimal fertility guidance.

Prevention of moderate and severe ovarian hyperstimulation syndrome: a guideline

Ovarian hyperstimulation syndrome is a serious complication associated with assisted reproductive technology. This systematic review aims to identify who is at high risk for developing ovarian hyperstimulation syndrome, along with evidence-based strategies to prevent it and replaces the document of the same name last published in 2016.

Cocktail treatment by GnRH-antagonist, letrozole, and mifepristone for the prevention of ovarian hyperstimulation syndrome: a prospective randomized trial

OBJECTIVE

This study is aimed to determine the efficacy of a cocktail style treatment by combining GnRH-antagonist, letrozole, and mifepristone on the prevention of ovarian hyperstimulation syndrome (OHSS) in high-risk women.

METHODS

This prospective, randomized controlled clinical trial was performed between January 2018 and December 2018. A total of 170 women who identified as high risk of OHSS during the ovarian hyperstimulation and underwent cryopreservation of whole embryos. On the day of oocyte retrieval, the combination group received 0.25 mg Cetrorelix for 3 d, 5 mg letrozole for 5 d, and 50 mg mifepristone for 3 d, the mifepristone group received 50 mg mifepristone for 3 d. A total of 156 cases were included in final analysis. All the frozen embryo transfer (FET) cycles were followed up until December 2021.

RESULTS

The combination group showed significantly decreased incidence of moderate and severe OHSS than mifepristone group (20.5% vs. 42.3%), with remarkably reduced serum estradiol level on hCG + 3 and + 5 d, decreased ovarian diameter, and shortened luteal phase. Oocyte retrieval number, levels of estradiol on hCG + 0 and VEGF, and ovarian diameter on hCG + 5 were associated with the severity of the symptoms. There was no significant difference in cumulative live birth rates (LBRs) between the combination and mifepristone group (74.4% vs. 76.9%).

CONCLUSIONS

The combination treatment effectively reduces the incidence of moderate/severe OHSS in high-risk women.

Ovarian hyperstimulation syndrome and pregnancy luteoma mimicking malignant ascites: a rare case report

BACKGROUND

During pregnancy, both ovarian hyperstimulation syndrome (OHSS) and pregnancy luteoma could manifest as massive ascites, enlarged ovaries, or elevated serum levels of cancer antigen 125 (CA125), and atypical cells may be found in the ascitic fluid of OHSS patients. Whether this should be treated aggressively as peritoneal carcinomatosis is controversial.

CASE PRESENTATION

A 35-year-old G2P1A1 woman with secondary infertility had a successful pregnancy after one cycle of assisted reproductive technology. The patient complained of lower abdominal distension, oliguria, and poor appetite 19 days after embryo transplantation. She was diagnosed with late-onset OHSS. Although the size of the ovaries decreased bilaterally to the normal range at 12 weeks of gestation after prompt medical care, the ascites increased again after an initial decreasing trend. Elevated serum levels of CA125 (191.1 IU/mL), and suspected adenocarcinoma cells were observed in the ascitic fluid. Although further magnetic resonance imaging examination or diagnostic laparoscopy was recommended, the patient was provided with supportive treatment and closely monitored upon her request. Surprisingly, her ascites diminished, and serum level of CA125 started to decline at 19 weeks of gestation. During cesarean section, pathological examination of the solid mass in the right ovary revealed pregnancy luteoma, which was presumably the other cause of the intractable ascites.

CONCLUSIONS

Caution should be exercised in cases of suspicious malignant ascites during pregnancy. This may due to OHSS or pregnancy luteoma, in which abnormalities usually regress spontaneously.

Letrozole and Ovarian Hyperstimulation Syndrome (OHSS): A Promising Prevention Strategy

Ovarian Hyperstimulation Syndrome (OHSS) is an uncommon but serious complication occurring in patients undergoing ovarian stimulation. It is characterized by ovarian enlargement, nausea, vomiting, abdominal pain/distension, and reduction in urine output. However, OHSS may rarely evolve into a life-threatening condition with ascites, hemoconcentration and hypercoagulability. Prevention of OHSS consists of an integrated approach that associates behavioral aspects with administration of pharmacological compounds. Among drugs used to manage OHSS, Letrozole has recently been proposed as an effective option for prevention of the syndrome. However, despite the promising findings reported by several studies, to date Letrozole is not yet officially mentioned in the guidelines for "Prevention and Treatment of moderate and severe ovarian hyperstimulation syndrome". In this scenario, the current study discusses Letrozole approaches scientifically available to prevent OHSS.

Letrozole increases preantral follicle growth and decreases estradiol production without impairing follicle survival

BACKGROUND

Letrozole has been reported to be effective in treating anovulation, preventing ovarian hyperstimulation syndrome (OHSS), and retrieving oocytes in breast cancer patients. However, the role and mechanism of letrozole in follicular development remain unclear.

RESULTS

We treated mouse preantral follicles with various treatments; we found no significant difference in follicle survival rates in the letrozole (LET) group compared with the control group, but the average diameter of follicles in the LET group tended to be larger (CTRL vs. LET 30, p = 0.064; CTRL vs. LET 100, p = 0.025). The estradiol concentrations in culture media of the LET group were significantly lower than those observed in the control group (CTRL vs. LET 30, p = 0.038; CTRL vs. LET 100, p = 0.025). We further found a marked increase in follicle-stimulating hormone receptor (FSHR) gene expression in response to letrozole treatment (CTRL vs. LET 30, p = 0.075; CTRL vs. LET 100, p = 0.034). This result suggested that increased FSHR expression promotes follicle development. Letrozole inhibited aromatase activity, but the effect was limited. Letrozole did not significantly reduce vascular endothelial growth factor (VEGF) gene expression.

CONCLUSIONS

Letrozole may promote follicle development by increasing the expression of FSHR. Letrozole may be useful for fertility preservation of patients with estrogen-dependent cancers such as breast cancer and various other cancers. Whether letrozole has a direct effect in reducing OHSS requires further investigation.

The impact of letrozole on oocyte quality in assisted reproductive technology (ART); a randomized double-blind clinical trial

OBJECTIVE

To examine the effect of letrozole on oocyte quality and pregnancy outcome in assisted reproductive technology (ART).

METHODS

This double blind placebo controlled clinical trial was conducted in Vali-Asr Infertility Center. Infertile women candidate for IVF that underwent antagonist protocol were selected. Eligible women randomly allocated into treatment (letrozole/Let group) and control (placebo) group. Participants received letrozole 5 mg/day or placebo at the time of gonadotropin start until trigger day in the same manner. Number of oocyte retrieved, metaphase II oocyte number, high grade oocyte number (G1), high quality embryo, Chemical and clinical pregnancy rate and OHSS (ovarian hyperstimulation syndrome) rate was recorded. 216 infertile women (104 in letrozole and 112 in the control group) were evaluated.

RESULTS

In the Let group estradiol level was significantly lower (p_value < .001) and testosterone significantly higher than in the control group (p_value = .02). The number of retrieved oocytes, MII oocytes, G1 oocytes, and 2PN was significantly lower in the Let group (p < .05). No significant difference was found in the day of stimulation, total gonadotropin dose, OHSS rate, and clinical pregnancy rate between the two groups (p > 0.05).

CONCLUSIONS

According to the results, letrozole may reduce oocyte quality and cause poor IVF outcomes as well.

Evaluation of The Effect of Letrozole in the Ovarian Hyperstimulation Syndrome Prevention in Participants at Risk of Treatment with Ovulation-Stimulating Drugs:A Randomized Controlled Trial

Background

This study aims to evaluate the effect of Letrozole (LE) in reducing ovarian hyperstimulation syndrome (OHSS) in high-risk participants with polycystic ovary syndrome (PCOS) treated with In vitro fertilization (IVF).

Methods

This study was a randomized clinical trial in which participants were randomly divided into two groups (n= 25 per group). Based on GnRH-antagonist protocol, recombinant follicle-stimulating hormone 150 units/day subcutaneously and human menopausal gonadotropin 75 units/ day intramuscularly used from day 2 of the menstrual cycle. In the study group, Letrozole 5 mg daily was added simultaneously with gonadotropin during the first five days of the IVF cycle and in the control group placebo was added.

Results

There were statistically significant differences among the groups in terms of Estradiol level on Trigger Day (p= 0.04). The total days of stimulation and cumulative Gonadotropin dose were significantly lower in the Letrozole group (p= 0.00). There were no significant differences between the groups in terms of the number of oocytes retrieved, numbers of implanted embryos, and clinical pregnancy rates (p-value> 0.05). There was only one moderate case in the intervention group and 9 moderate symptoms in the control group (p= 0.04).

Discussion

Administration of Letrozole with GnRH antagonist protocol, conventional protocol in PCOS cases in IVF cycle, had a significant effect on reducing the incidence of OHSS. So, if the future studies prove LE co-administration may lessen the incidence of OHSS, LE will be a highly potent drug for preventing OHSS in PCOS cases.

Comparison of the Effectiveness of Various Medicines in the Prevention of Ovarian Hyperstimulation Syndrome: A Network Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Previous studies have described the effects of different drugs in preventing ovarian hyperstimulation syndrome (OHSS). However, the efficacies of those drugs in preventing OHSS remain inconclusive.

METHODS

We searched the PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. A network meta-analysis of randomized controlled trials (RCTs) was performed up to August 2021. We investigated the following drugs in our study: aspirin, albumin, metformin, calcium, cabergoline, quinagolide, letrozole, hydroxyethyl starch (HES), and glucocorticoids. The primary outcome was the incidence rate of moderate-to-severe OHSS, with the results presented as risk ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

The incidence of moderate-to-severe OHSS was significantly reduced by calcium administration (risk ratios [RR] 0.14, 95% confidence interval [CI]: 0.04, 0.46) (grade: high), HES (RR 0.25, 95% CI 0.07, 0.73) (grade: high), and cabergoline (RR 0.43, 95% CI 0.24, 0.71) (grade: moderate). The surface under the cumulative ranking curve (SUCRA) indicated that calcium (SUCRA, 92.4%) was the most effective intervention for preventing moderate-to-severe OHSS. These drugs were safe and did not affect clinical pregnancy, miscarriage, or live birth rates.

CONCLUSION

Calcium, HES, and cabergoline could effectively and safely prevent moderate-to-severe OHSS, with calcium as the most effective intervention.

Letrozole Supplementation and the Increased Risk of Elevated Progesterone Levels on Trigger Day

Although using letrozole (LE) during in vitro fertilisation and intracytoplasmic sperm injection (IVF/ICSI) has many advantages, it remains unclear whether LE induces an increase in progestogen during the late follicular phase. The objective of this study was to investigate whether progesterone levels increased under antagonist protocols supplemented with LE on the trigger day using a retrospective cohort study. The study included 1,133 women who underwent IVF/ICSI cycles from January 2018 to June 2020. After propensity score matching (PSM) for baseline characteristics, 266 patients with gonadotropin-releasing hormone-antagonist (GnRH-ant) were matched to 266 patients with letrozole + GnRH-ant (LE GnRH-ant) (PSM 1 cohort), and 283 patients with gonadotropin-releasing hormone-agonist (GnRH-a) were matched to 283 patients with LE GnRH-ant (PSM 2 cohort). In the PSM 1 cohort, patients in the LE GnRH-a group presented higher progesterone levels (1.22 ± 0.95 ng/mL vs 0.86 ± 0.60 ng/mL, P < 0.001), with a higher proportion of patients with progesterone level > 1.5 ng/mL (24.81% vs 7.52%, P < 0.001). In PSM 2 cohort, patients in the LE GnRH-a group presented higher progesterone levels on trigger day (1.23 ± 0.91 ng/mL vs 0.98 ± 0.61 ng/mL, P < 0.001), with a higher proportion of patients with progesterone level > 1.5 ng/mL (25.45% vs 12.70%, P < 0.001). In the PSM 1 cohort, progesterone levels on the trigger day increased by 0.05 ng/mL, with an increase in every retrieved oocyte in the LE GnRH-ant group (β 0.05 ng/mL [95% CI 0.04, 0.06], P < 0.001), whereas an increase of 0.02 ng/mL was observed in the GnRH-ant group (β 0.02 ng/mL [95% CI 0.01, 0.03], P < 0.001), with P for interaction being 0.0018. In the PSM 2 cohort, progesterone levels on the trigger day increased by 0.05 ng/mL with an increase in every retrieved oocyte in the LE GnRH-ant group (β 0.05 ng/mL [95% CI 0.04, 0.06], P < 0.001), whereas an increase of 0.02 ng/mL was observed in the GnRH-a group (β 0.02 ng/mL [95% CI 0.01, 0.03], P < 0.001), with P for interaction being 0.0002. LE supplementation on the antagonist protocols may increase progesterone levels in the late follicular stage.

Twenty-first century oocyte cryopreservation—in vitro maturation of immature oocytes from ovarian tissue cryopreservation in cancer patients: A systematic review

Objectives:

Our review aimed to consolidate the latest update on the application of in vitro maturation among immature oocyte harvest in combination with ovarian tissue cryopreservation known as ovarian tissue oocyte–in vitro maturation.

Methods:

A thorough search for relevant studies was conducted via PubMed, Google Scholar, EMBASE, and clinical.gov databases up to December 2020. The primary outcome was the oocyte maturation rate, which measured the number of immature oocytes (geminal vesicle stage) that progressed to mature oocytes (meiosis II stage) following in vitro maturation. The secondary outcomes were the fertilization rate following intracytoplasmic sperm injection/in vitro fertilization of these oocytes for the embryo cryopreservation cohort. Our review included pre-pubertal girls and women with cancer who underwent ovarian tissue oocyte–in vitro maturation as fertility preservation.

Results:

The primary search identified 207 studies. Twelve manuscripts were selected for inclusion in our review following duplication assessment, title and abstract screening, and full-text evaluation tailored to our inclusion criteria. All the population belonged to a cancer group and underwent concurrent ovarian tissue oocyte–in vitro maturation. A total of 5724 immature oocytes were obtained following ovarian tissue cryopreservation. Approximately 33.84% of the immature oocytes successfully matured via in vitro maturation, which were cryopreserved as oocytes or fertilized as embryos and subsequently stored for future use.

Conclusion:

Our review proposed the potential application of ovarian tissue oocyte–in vitro maturation in increasing the number of mature oocytes. The acceptable improvement in oocyte maturation rate following in vitro maturation indicates that improving oocyte outcomes is an excellent cost-effective strategy for fertility preservation among women with cancer.

Impact of an oral gonadotropin-releasing hormone antagonist on severe ovarian hyperstimulation syndrome in a patient with breast cancer who received a sustained-release gonadotropin-releasing hormone agonist: A case report

Postoperative hormone therapy for hormone-sensitive patients with breast cancer is important to prevent a recurrence. As hormone therapy does not induce infertility in patients, fertility-preserving therapy is not provided during treatment. Here, however, we performed controlled ovarian stimulation and embryo freezing for fertility preservation under the influence of a sustained-release gonadotropin-releasing hormone agonist in a patient with breast cancer whose postoperative treatment plan was changed from hormone therapy to chemotherapy. After oocyte retrieval, the patient developed treatment-resistant severe symptomatic ovarian hyperstimulation syndrome. Following treatment with oral gonadotropin-releasing hormone antagonist, her symptoms immediately improved, and she could receive chemotherapy on schedule.

Severe hemoperitoneum resulting from restart of letrozole after oocyte retrieval procedure: a case report

BACKGROUND

In the field of oncofertility, patients with breast cancer are often administered letrozole as an adjuvant drug before and after oocyte retrieval to prevent an increase in circulating estradiol.

CASE PRESENTATION

We report a case of abdominal hemorrhage due to an ovarian rupture in a 29-year-old Japanese patient who restarted letrozole 2 days after an oocyte retrieval procedure in which 14 mature oocytes were retrieved. The patient had sought embryo cryopreservation as a fertility preservation option before undergoing treatment for recurrent breast cancer. A day after restarting letrozole treatment, the patient unexpectedly developed severe abdominal pain. Laparoscopic hemostasis was performed to manage the ovarian swelling and hemorrhage.

CONCLUSIONS

The ovaries can be restimulated by restart letrozole after an oocyte retrieval procedure. Therefore, reproductive-medicine practitioners should understand the potential complications of letrozole administration in such cases and take steps to ensure that they are minimized.

Effect of GnRH-antagonist, mifepristone and letrozole on preventing ovarian hyperstimulation syndrome in rat model

RESEARCH QUESTION

Can luteolysis-targeted drugs, gonadotrophin-releasing hormone antagonist (GnRH-ant), mifepristone and letrozole, administered separately or in combination, prevent the progression of ovarian hyperstimulation syndrome (OHSS) in a rat model?

DESIGN

Thirty-six female Wistar rats were randomly divided into six groups, including control group (OHSS group, ovarian hyperstimulation-induced OHSS); GnRH-ant group (OHSS with GnRH-ant treatment); mifepristone group (OHSS with mifepristone treatment); letrozole group (OHSS with letrozole treatment); combination group (OHSS with GnRH-ant, mifepristone and letrozole treatment in combination). The main outcomes were the alterations in OHSS-related indices, including ovarian weight, vascular permeability, serum oestradiol and progesterone levels, corpus luteum proportion and diameter, ovarian vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), caspase-3 and cleaved caspase-3 levels.

RESULTS

No significant difference was found in body weight gain among the six groups. Compared with the control group, the OHSS group showed significant increases in all OHSS-related indices. GnRH-ant treatment showed decreases in vascular permeability, serum oestradiol level, corpus luteum diameter, ovarian VEGF /IL-6 mRNA levels, and increases in ovarian caspase-3 and cleaved caspase-3 levels. Mifepristone treatment demonstrated reduction in serum progesterone level and corpus luteum diameter, and elevation in ovarian caspase-3 and cleaved caspase-3 levels. Letrozole treatment displayed a decline in serum oestradiol level and corpus luteum diameter, and up-regulation in ovarian caspase-3 and cleaved caspase-3 levels. The combination treatment by GnRH-ant, mifepristone and letrozole showed enhanced synergistic effect on reducing OHSS-related indices.

CONCLUSIONS

GnRH-ant, mifepristone and letrozole are beneficial in preventing the progression of OHSS through different luteolytic mechanisms. Cocktail style treatment shows enhanced synergistic effect on preventing the progression of OHSS.

Whether Letrozole could reduce the incidence of early ovary hyperstimulation syndrome after assisted reproductive technology? A systematic review and meta-analysis

Background

Letrozole can significantly decrease the estrogen level, and has been administrated to prevent the incidence of early ovary hyperstimulation syndrome (OHSS). However, the effect of Letrozole on prevention of OHSS reached to controversial conclusions. The present meta-analysis aim to examine whether Letrozole could reduce the incidence of early OHSS after assisted reproductive technology (ART).

Methods

An exhaustive electronic literature search was conducted on MEDLINE, Google Scholar, CNKI and WANFANG MED ONLINE, from inception until May 2018. We include clinical trials that examined the effect of Letrozole on the prevention of early OHSS. The main outcome measures were the incidence of total early OHSS, mild early OHSS, moderate early OHSS, and severe early OHSS.

Results

Eight studies included in the review. Of these, five publications evaluated the effect of Letrozolel on the prevention of total, mild, moderate, and severe OHSS, respectively. The results indicated that there was a significantly decreased incidence of total OHSS with Letrozole compared with control group, and there were no significantly differences in the incidence of mild, moderate, and severe OHSS between study group with Letrozole and control group. Eight studies reported the incidence of moderate + severe OHSS. We found a significant decrease in incidence of moderate + severe OHSS in high-risk women with Letrozole.

Conclusions

Letrozole has no beneficial effect on the prevention of mild, moderate, and severe OHSS, individually; Letrozole should not be considered as the first-line treatment for prevention of OHSS. Further cohort studies are required to explore the effect of Letrozole on the prevention of OHSS.

Plain English Summary

This study aimed to examine whether Letrozole could reduce the incidence of early OHSS after assisted reproductive technology (ART). A meta-analysis including 8 studies was conducted. There were no significantly differences in the incidence of mild, moderate, and severe OHSS between study group with Letrozole and control group. Letrozole has no beneficial effect on the prevention of mild, moderate, and severe OHSS, individually.

Oocyte cryopreservation in the setting of a vascular endothelial growth factor (VEGF)-producing paraneoplastic syndrome: a case report and review of literature

BACKGROUND

Many reproductive aged women with new oncologic diagnoses choose to undergo emergency oocyte or embryo cryopreservation prior to initiating potentially gonadal toxic oncologic therapies. Ovarian hyperstimulation syndrome (OHSS) is a potential complication of these treatments and can be particularly dangerous in these patients due to their underlying medical illness and by delaying lifesaving oncology treatment. This case report details a multipronged approach to OHSS prevention in a patient with a paraneoplastic syndrome defined by overproduction of vascular endothelial growth factor (VEGF), which is also primarily responsible for OHSS.

CASE PRESENTATION

A 29 year old nulligravid woman was diagnosed with a rare multisystem paraneoplastic syndrome (Polyradiculoneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder and skin changes, known as POEMS) and presented for fertility preservation consultation prior to autologous stem cell transplant. She successfully underwent oocyte cryopreservation without complications due to aggressive OHSS prophylaxis with both a dopamine agonist and aromatase inhibitor during and after stimulation and a gonadotropin releasing hormone agonist (GnRH-A) for final oocyte maturation, without delay in her subsequent oncology treatment.

CONCLUSIONS

This is the first report of a patient with POEMS undergoing controlled ovarian hyperstimulation (COH). Oocyte cryopreservation was successful and without complications due to a combination of prophylactic measures against OHSS (cabergoline, letrozole and GnRH-A trigger) and close collaboration between reproductive endocrinology and oncology. This case demonstrates the use of combined measures in targeting VEGF overproduction and OHSS risk during COH.

New clinical targets of d-chiro-inositol: rationale and potential applications

INTRODUCTION

Inositols have a key role in ovarian physiology and the literature reports a wealth of studies about the major isomer, myo-inositol (MI). However, information about d-chiro-inositol (DCI) is still scarce, despite the ratio MI:DCI is tissue-specific and actively maintained by an insulin-dependent epimerase enzyme.

AREAS COVERED

This expert opinion provides an overview of the physiological contribution of DCI in regulating steroidogenesis. DCI indeed mediates the intracellular signaling of insulin, which induces the biosynthesis of androgens. Studies on second messengers of insulin also revealed that DCI has a specific role in modulating the activity of aromatase enzyme. Specifically, recent findings demonstrated that DCI influences the enzyme gene expression, thus reducing the conversion of androgens into estrogens.

EXPERT OPINION

Available evidence suggests that the effects of DCI administration may be similar to those of aromatase inhibitors, but without causing hypo-estrogenic states. Therefore, DCI treatments should be evaluated for either estrogen-dependent gynecological conditions or low testosterone states in male subjects.

Effect of adding letrozole to gonadotropin on in vitro fertilization outcomes: An RCT

Background

Aromatase inhibitors prevent the aromatization of androgens into estrogens, which reduces the negative feedback of estrogen on the hypothalamic-pituitary axis. It is clear that increasing the secretion of follicle-stimulating hormones results in an increased follicular growth.

Objective

This study aimed to evaluate the effect of adding letrozole to gonadotropin on in vitro fertilization outcomes in normal responders.

Materials and Methods

In this randomized clinical trial, 100 normal responder women candidate for controlled ovarian stimulation were randomly enrolled in two groups (n = 50/each). In the case group letrozole was added to gonadotropin in the antagonist protocol. The control group received the conventional antagonist protocol. The main outcome was clinical and chemical pregnancy; and the second outcomes were the number of mature oocytes, the fertilization rate, estradiol level, and the total dose of gonadotropins.

Results

Basic clinical and demographic features were comparable between the groups. Estradiol level on the day of human-chorionic-gonadotropin administration and the total gonadotropin consumption were significantly higher in the control group than the case group (p = 0.045). In addition, the number of MII oocytes was higher (but not significantl) in the case group than the control group (p = 0.09). Moreover, the endometrial thickness was significantly lower in the case group. There were no significant differences in fertilization rate and chemical and clinical pregnancy rates between the two groups.

Conclusion

Although adding letrozole to gonadotropin in normal responders reduces the total dose of gonadotropin, it does not improve the pregnancy outcomes.

Ovarian hyperstimulation syndrome: a clinical retrospective study on 565 inpatients

The aim of this study was to analyze clinical manifestations of 565 ovarian hyperstimulation syndrome (OHSS) inpatients in the largest Obstetrics and Gynecology hospital in China from year 2010 to 2017, to get more understanding of epidemiologic features of this disease, and to provide some insight on the diagnosis, treatment, and preventions of OHSS. It is a clinical retrospective study. In the 565 cases that developed OHSS over an eight-year period between 2010 and 2017 were reviewed, we assessed patients' general characteristics, clinical manifestations, treatment, prognosis, and the relationship between different indicators and the severity of OHSS. Totally 12 kinds of ovulation induction protocols (Protocol 1: CC; Protocol 2: Gn; Protocol 3: hCG; Protocol 4: GnRh-a; Protocol 5: CC & Gn; Protocol 6: CC & hCG; Protocol 7: Gn & hCG; Protocol 8: GnRh-a & Gn; Protocol 9: CC & Gn & hCG; Protocol 10: GnRh-a & CC & Gn; Protocol 11: Letrozole & Gn & hCG; Protocol 12:GnRh-a & Letrozole & Gn) were analyzed and the Odds Ratio (OR) of each protocol were calculated. Five hundred and sixty-five patients were reviewed in our study. In all these patients, the number of hospitalizations, mean age, primary infertility rate, and pregnancy rate did not differ through the last 8 years. From which we may infer that the incidence rate of OHSS may not change over the last 8 years. Older patients tend to develop into more severe stage easily. The pregnancy rate was much lower in mild stage patients, but no difference was found between patients in moderate, severe and critical stage. Oocytes retrieval is strongly associated with severity. PCOS history, irregular menstrual cycle and infertility type do not seem to affect the severity of OHSS. Twelve kinds of ovulation induction protocols were analyzed, OR of different protocols were calculated, what is noteworthy is that patients who used GnRh easily developed more severe OHSS than the patients who received oocytes retrieval. We suggest that we may choose ovulation induction protocols according to the OR table while treating women with high-risk factors.

The role of Letrozole (LE) in controlled ovarian stimulation (COS) in patients at high risk to develop ovarian hyper stimulation syndrome (OHSS). A prospective randomized controlled pilot study

BACKGROUND

Recently, it has been shown that PCOS patients with extremely high anti-Mullerian hormone (AMH) level are more likely to experience OHSS during IVF, compared to PCOS patients with lower AMH level. While recent data questioned the effect of Letrozole (LE) on the occurrence of OHSS in non-PCOS patients, it role in PCOS patients with very high AMH level was never investigated in a prospective manners. Hence, our main objective was to evaluate the clinical outcome of PCOS patients at very high risk for OHSS undergoing two different COS protocols (with or without LE).

METHODS

A prospective randomized controlled study (RCT) of 51 patients with specifically high levels of AMH undergoing one of two COS protocols. The control group (group A) consisted of 24 PCOS women who received low-dose gonadotropins using the multiple-dose GnRH-antagonist protocol, GnRH agonist-triggered and "freeze all". The study group (group B) consisted of 24 women with PCOS who received the same protocol combined with LE. High risk criteria for OHSS were: PCOS patients with low BMI, young age, and extremely high level of serum AMH (inclusion criteria for AMH > 50 pmol/L).

RESULTS

Cumulative live birth rates per retrieval were similar in both groups. While no single case of severe OHSS was observed in, in the study group (group B), the rate of moderate and mild OHSS was 5 times lower compared to the control group (P < 0.05).

CONCLUSION

In PCOS patients with extremely high AMH levels the LE co-administration to GnRH-Ant protocols results in reduced incidence of OHSS than conventional GnRH-Ant protocols. LE co-administration may prove to be highly effective in preventing OHSS, even in the women who are at high risk to these dangerous complications.

Ovarian manipulation in ART: going beyond physiological standards to provide best clinical outcomes

Current knowledge on ovarian physiology has challenged the traditional concept of folliculogenesis, creating the basis for novel ovarian stimulation protocols in assisted reproduction technology. The purpose of this review was to evaluate the efficacy of novel clinical interventions that could aid clinicians in individualizing their protocols to patients' characteristics and personal situations. We conducted a literature review of the available evidence on new approaches for ovarian stimulation from both retrospective and prospective studies in the PubMed database. Here, we present some of the most important interventions, including follicle growth in the gonadotropin-independent and dependent stage, manipulation of estradiol production throughout ovarian stimulation, control of mid-cycle gonadotropin surges, and luteal phase support after different stimulation protocols and trigger agents. The latest research on IVF has moved physicians away from the classical physiology, allowing the development of new strategies to decouple organ functions from the female reproductive system and challenging the traditional concept of IVF.

A Retrospective Study of Letrozole Treatment Prior to Human Chorionic Gonadotropin in Women with Polycystic Ovary Syndrome Undergoing In Vitro Fertilization at Risk of Ovarian Hyperstimulation Syndrome

Background

Women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF) are given letrozole before a trigger injection of human chorionic gonadotropin (hCG) to lower estrogen (E₂) levels, but can experience ovarian hyperstimulation syndrome (OHSS). The aim of this study was to evaluate the effect of oral letrozole, prior to administration of hCG, on the outcome of IVF and development of OHSS.

Material/Methods

Retrospective clinical review included 181 cases of women with PCOS who underwent IVF cycles with intracytoplasmic sperm injection (ICSI) and embryo transfer (ET) (IVF/ICSI-ET). The day before the use of hCG, cases were divided into a letrozole-treated group (N=78) and a non-letrozole group (N=103). An oral dose of 2.5 mg qd of letrozole was given when the peak level of E₂ was ≥4000 pg/ml during ovarian stimulation and ceased before the day of egg retrieval.

Results

The letrozole-treated group had a significant increase in the number of retrieved oocytes, viable embryos, and fresh ET rate (P>0.05); peak levels of E₂, and E₂ levels on the day of the egg retrieval, were significantly higher, and the fertilization rate was significantly lower (P<0.001). No significant differences were found in the rates of pregnancy, abortion, or ectopic pregnancy between the two groups (P>0.05). The incidence OHSS was lower in the letrozole-treated group, but this difference did not reach statistical significance (P>0.05).

Conclusions

Women with PCOS who underwent IVF, oral treatment with letrozole a day prior to treatment with hCG lowered E₂ levels, but did not significantly reduce the incidence of OHSS.

The VEGF and PEDF levels in the follicular fluid of patients co- treated with LETROZOLE and gonadotropins during the stimulation cycle

BACKGROUND

Previous studies have shown that androgens, in addition to serving as precursors for ovarian estrogen synthesis, also have a fundamental role in primate ovarian follicular development by augmentation of FSH receptor expression on granulosa cells. Recent studies have shown that aromatase inhibitor, letrozole, improves ovarian response to FSH in normal and poor responder patients, possibly by increasing intraovarian androgen levels. Studies in mice also showed an effect of letrozole to increase pigment epithelium-derived factor (PEDF) and to lower vascular epithelial growth factor (VEGF), which might be expected to reduce the risk of ovarian hyperstimulation syndrome (OHSS) with stimulation. The aim of this study was to compare the VEGF and PEDF levels in the follicular fluids of normal responders treated with letrozole and gonadotropins during the ovarian stimulation with patients treated with gonadotropins only.

METHODS

A single center, prospective clinical trial. We collected follicular fluid from 26 patients, on a GnRH antagonist protocol, dual triggered with hCG and GnRH agonist. The patients in one group were co-treated with letrozole and gonadotropins during the ovarian stimulation and the patients in the other group were treated with gonadotropins only. VEGF, PEDF, estrogen, progesterone and testosterone levels were measured by ELISA kits.

RESULTS

The age of the patients, the total dose of gonadotropins and the number of oocytes were comparable between the two groups. In the follicular fluid, the estrogen levels (2209 nmol/l vs. 3280 nmol/l, p = 0.02) were significantly decreased, and the testosterone levels (246.5 nmol/l vs. 40.7 nmol/l, p < 0.001) were significantly increased in the letrozole group compared to the gonadotropin only group. The progesterone levels (21.4 μmol/l vs. 17.5 p = NS) were comparable between the two groups. The VEGF levels (2992 pg/ml vs. 1812 pg/ml p = 0.02) were significantly increased and the PEDF levels (9.7 ng/ml vs 17.3 ng/ml p < 0.001) were significantly decreased in the letrozole group.

CONCLUSIONS

Opposite to observations in the mouse, we found that VEGF levels were increased and PEDF levels were decreased in the follicular fluid in patients treated with letrozole during the stimulation cycles. Further investigation is required to determine if patients treated with letrozole during the IVF stimulation protocol are at increased risk for developing OHSS as a result of these findings.

In vitro fertilization treatments with the use of clomiphene citrate or letrozole

There has been increasing interest in combining the oral agents clomiphene citrate (CC) and letrozole with gonadotropins in IVF: for poor responders to reduce the amount of gonadotropins used, and in normal responders to reduce the incidence of ovarian hyperstimulation (OHSS). In normal responders, mild stimulation with the use of CC and gonadotropins was found to decrease the number of oocytes retrieved and result in good pregnancy rates, but in most studies the cumulative pregnancy rate was lower compared with conventional ovarian stimulation when frozen embryo transfers were considered. Coadministration of letrozole and gonadotropins has mainly been used in patients with breast cancer to prevent the massive elevation of serum E₂ concentrations with the use of standard controlled ovarian hyperstimulation. CC and letrozole have both been used with gonadotropins in poor responders and have been shown to reduce the amount of gonadotropin used without reducing the pregnancy rate. Letrozole use with gonadotropins in IVF cycles may increase endometrial receptivity by increasing integrin expression in the endometrium and by lowering estrogen concentrations to more physiologic levels.

Recent advances in in vitro fertilization

The field of assisted reproductive technology is rapidly progressing with many new advances in the last decade. The present review discusses methods to improve oocyte quality in older women and new stimulation protocols that may improve the number of mature oocytes retrieved during an in vitro fertilization cycle. We will discuss the present use of pre-implantation genetic screening (PGS) and finally focus on some new methods to determine endometrial receptivity. The focus of this review is to point out areas of technology that may be controversial or are new enough to require proper controlled studies for validation.

Does daily co-administration of letrozole and gonadotropins during ovarian stimulation improve IVF outcome?

BACKGROUND

For the last year we have been treating normal responders with gonadotropins and letrozole during the whole stimulation in order to improve response to FSH by increasing the intrafollicular androgen concentration, and to reduce circulating estrogen concentrations. The aim of this study was to compare the IVF outcome of normal responders treated with letrozole and gonadotropins during ovarian stimulation with patients treated with gonadotropins only.

METHODS

A single centre retrospective cohort study of 174 patients (87 in each group).

RESULTS

The age of the patients was comparable between the groups. Estradiol levels were significantly higher in the control group (6760 pmol/L vs. 2420 pmol/L respectively, p < 0.01), and the number of follicles ≥15 mm at the trigger day was significantly lower in the control group (7.9 vs. 10, p = 0.02). The number of retrieved oocytes (10 vs. 14.5, p < 0.01), MII oocytes (7.9 vs. 11.2, p < 0.01) and blastocysts (2.7 vs. 4.0, p = 0.02) was significantly higher in the study group. We found no significant differences in the cumulative pregnancy outcome between the two groups (65.2% vs 58.3% p = NS).

CONCLUSIONS

We conclude that co-treatment with letrozole improves the IVF outcome in normal responders in terms of increased number of blastocysts obtained without increasing the pregnancy rate or the risk of OHSS.