Aromatase inhibitors in stimulated IVF cycles

Ovarian Hyperstimulation Syndrome (OHSS): A Narrative Review and Legal Implications

BACKGROUND

Infertility is a highly meaningful issue with potentially life-changing consequences, and its incidence has been growing worldwide. Assisted reproductive technology (ART) has made giant strides in terms of treating many infertility conditions, despite the risk of developing ovarian hyperstimulation syndrome (OHSS), a potentially life-threatening complication.

METHODS

This narrative review draws upon scientific articles found in the PubMed database. The search spanned the 1990-2024 period. Search strings used included "OHSS" or "ovarian hyperstimulation" and "IVF" and "GnRH" and "hCG"; 1098 results were retrieved and were ultimately narrowed down to 111 suitable sources, i.e., relevant articles dealing with the condition's underlying dynamics, management pathways, and evidence-based criteria and guidelines, crucial both from a clinical perspective and from the standpoint of medicolegal tenability.

RESULTS

The following features constitute OHSS risk factors: young age, low body weight, and polycystic ovarian syndrome (PCOS), among others. GnRH antagonist can substantially lower the risk of severe OHSS, compared to the long protocol with a gonadotropin-releasing hormone (GnRH) agonist. However, a mild or moderate form of OHSS is also possible if the antagonist protocol is used, especially when hCG is used for the final maturation of oocytes. For women at risk of OHSS, GnRH agonist trigger and the freeze-all strategy is advisable. OHSS is one of the most frequent complications, with a 30% rate in IVF cycles.

CONCLUSION

Providing effective care for OHSS patients begins with early diagnosis, while also evaluating for comorbidities and complications. In addition to that, we should pay more attention to the psychological component of this complication and of infertility as a whole. Compliance with guidelines and evidence-based best practices is essential for medicolegal tenability.

Luteal Phase Stimulation in the Same Cycle Is an Effective Strategy to Rescue POSEIDON Poor Responders with No Embryos after the First Follicular Stimulation

Background

Poor responders may benefit from recruiting a 'second wave' of antral follicles within the same cycle. This concept forms the basis of double stimulation which has been named as 'DuoStim'. This protocol involves ovarian stimulation in both follicular and luteal phases with egg retrieval in each phase, respectively, to increase the number of oocytes and embryos in one menstrual cycle. This can be considered a potentially valuable option for women with poor ovarian reserve/response to maximise the number of oocytes retrieved in a single ovarian cycle in the shortest possible time.

Aims

The aim of this study was to evaluate the efficacy of the DuoStim protocol in women classified as POSEIDON poor responders undergoing in vitro fertilization by comparing the embryological outcomes between the follicular and luteal phase stimulations in the same menstrual cycle.

Settings and Design

This was a retrospective cohort study of 131 patients who enrolled to undergo DuoStim cycles from January 2021 to Sept. 2022, at a IVF center in a tertiary care hospital.

Materials and Methods

The follicular phase stimulation used a standard antagonist protocol for the first oocyte retrieval. Thereafter, the luteal phase stimulation was started 3 days after the first retrieval, with the same dose of gonadotropin along with a daily 10 mg medroxyprogesterone acetate tablet, followed by a second oocyte retrieval. Blastocysts produced in both the phases were subsequently vitrified.

Statistical Analysis Used

The paired t-test was used for comparing means and 95% confidence intervals (CIs) for different parameters. McNemar's test was used to compare paired proportions. The analysis was conducted using R statistical environment 4.2.

Results

The mean number of oocytes retrieved and the mean number of utilizable blastocysts frozen per stimulation cycle were found to be significantly higher in the luteal phase as compared to the follicular phase (5.71 ± 3.95 vs. 4.87 ± 2.79, P = 0.02, and 1.43 ± 1.22 vs. 0.95 ± 1, P = 0.001, respectively). However, the mean fertilization rate and the mean blastocyst utilization rate were found to be similar between both the phases. The length of stimulation was found to be approximately 3 days longer in the luteal phase (12.63 ± 2.43 vs. 9.75 ± 1.85, P = 0.001). Overall, the odds of obtaining a usable blastocyst in the luteal phase was found to be significantly higher than in the paired follicular phase (73.9% vs. 57.7%, P = 0.012, odds ratio: 2.286 [95% CI: 1.186-4.636]). Also importantly, the luteal phase stimulation was able to rescue 68% (32/47) of patients where no blastocysts were formed in the follicular phase.

Conclusion

Our data demonstrate that in women with poor reserve, the addition of luteal stimulation could increase the chances of achieving a pregnancy by significantly increasing the number of eggs and transferable embryos per menstrual cycle compared to follicular stimulation alone. Furthermore, luteal phase stimulation in the same cycle proved to be an effective strategy to rescue POSEIDON poor responders with no embryos after the first stimulation.

The Impact of Suppressing Estradiol During Ovarian Stimulation on the Unsupported Luteal Phase: A Randomized Controlled Trial

CONTEXT

Supraphysiological sex steroid levels at the follicular-luteal phase transition are implicated as the primary cause of luteal insufficiency after ovarian stimulation (OS) for in vitro fertilization.

OBJECTIVE

We aimed to determine the impact of suppressing estradiol levels during OS of multiple dominant follicles on the unsupported luteal phase and markers of endometrial maturation.

METHODS

At 2 university hospitals, 25 eligible egg donors were randomized to undergo OS using exogenous gonadotropins with or without adjuvant letrozole 5 mg/day. Final oocyte maturation was triggered with a GnRH agonist. No luteal support was provided. The primary outcome was the duration of the luteal phase. Secondary outcomes were luteal phase hormone profiles and the endometrial transcriptomic signature 5 days after oocyte pick up (OPU + 5).

RESULTS

The median (interquartile range [IQR]) luteal phase duration was 8.0 (6.8-11.5) days compared with 5.0 (5.0-6.8) days in the intervention and control group, respectively (P < 0.001). Estradiol levels were effectively suppressed in the letrozole group with a median of 0.86 (0.23-1.24) nmol/L at OPU compared to 2.82 (1.34-3.44) nmol/L in the control group. Median (IQR) progesterone levels at OPU + 5 were 67.05 (15.67-101.75) nmol/L in the letrozole group vs 2.27 (1.05-10.70) nmol/L in the control group (P < 0.001). In the letrozole group, 75% of participants revealed endometrial transcriptomic signatures interpreted as post-receptive. In the control group, 40% were post-receptive and 50% noninformative.

CONCLUSION

Suppressing estradiol levels in the follicular phase with adjuvant letrozole significantly reduces the disruption of the unsupported luteal phase after OS.

Predictors and outcomes in breast cancer patients who did or did not pursue fertility preservation

PURPOSE

Breast cancer is the most common cancer in reproductive age women, and treatment can affect fertility; however, there is often concern regarding the safety of increased estradiol (E₂) levels and potential delays in treatment with ovarian stimulation for fertility preservation (FP). The aim of this study was to compare recurrence and survival in breast cancer patients who pursued FP without concurrent letrozole to those who did not (non-FP).

METHODS

We reviewed charts of women with breast cancer who contacted the FP patient navigator (PN) at Northwestern University from 01/2005-01/2018. Oncology and fertility outcome data were collected. Data were analyzed by Chi-square test or regression, as appropriate. Kaplan-Meier curves were used to examine breast cancer recurrence and survival. Statistical analyses were performed with SPSS IBM Statistics 26.0 for Windows.

RESULTS

332 patients were included, of which 157 (47.3%) underwent FP. Median days to treatment after consulting the PN was 35 in the FP group and 21 in non-FP (p < 0.05). Cancer recurrence was noted in 7 (4.7%) FP patients and 13 (7.9%) non-FP patients (NS), and mortality in 5 (3.2%) FP patients and 7 (4.2%) non-FP patients (NS). Within the FP group, no significant differences were found in recurrence or mortality based on ER status, age, BMI, peak E₂ level or total gonadotropin dose. Likelihood of pursuing FP was primarily a function of age and parity, and was not affected by breast cancer stage. To date, 21 have used cryopreserved specimens, and 13 (62%) had a live birth.

CONCLUSIONS

FP is safe and effective in breast cancer patients, regardless of receptor status; E₂ elevations and the 2-week delay in treatment start are unlikely to be clinically significant. These findings are unique in that our institution does not use concomitant letrozole during stimulation to minimize E₂ elevations in breast cancer patients.

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.

Ovarian Stimulation Is Safe and Effective for Patients with Gynecologic Cancer

Purpose: To compare long-term outcomes of gynecologic cancer patients who pursued controlled ovarian hyperstimulation (COH) for fertility preservation (FP) with those who did not. Methods: Retrospective cohort, COH, and health outcomes in gynecologic cancer patients; data were analyzed by chi-square test, t-tests, and logistic regression. Results: Ninety patients with a gynecologic malignancy contacted the FP patient navigator: 45.6% (n = 41) had ovarian cancer, 25.6% (n = 23) endometrial cancer, 18.9% (n = 17) cervical cancer, 5.6% (n = 5) uterine cancer, and 4.4% (n = 4) multiple gynecologic cancers. From this cohort, 32 underwent COH, 43 did not, and 18 pursued ovarian tissue cryopreservation (OTC; 3 patients had both COH and OTC). Median age and type of cancer were not significantly different between the groups. COH patients had a range of 1-35 oocytes retrieved. Days to next cancer treatment in the COH group was 36 days; for those who declined COH, it was 22 days (not significant [NS], p > 0.05). There were two recurrences reported in the stimulation group and four in the no stimulation group (NS). Five deaths were reported, two in the stimulation group, none in the no stimulation group, and three in the OTC group (NS); 34% (n = 11) COH patients returned to use cryopreserved specimens, of which 45% (n = 5) had a live birth. Conclusion: Although time to next treatment was longer in the group of patients who underwent COH, this did not reach statistical significance. It appears that in selected patients with GYN malignancies, COH for oocyte or embryo cryopreservation is safe, with reasonable stimulation outcomes and no difference in long-term outcomes.

Letrozole supplementation during controlled ovarian stimulation in expected high responders: a pilot randomized controlled study

BACKGROUND

Almost all of the previous studies related with co-administration of letrozole in IVF cycles were performed in poor responders and letrozole may reduce the total gonadotropin dose required for ovarian stimulation, and the pregnancy rate did not decrease in poor responders. This study aimed to assess whether high responders co-treatment with letrozole reduced supraphysiological late follicular phase estradiol levels and the incidence of premature progesterone elevated at the end of the follicular phase, thereby impacting positively on endometrial receptivity.

METHODS

A randomized parallel controlled study in a university-affiliated center include 130 high responders between October 2015 and August 2016. The patients were randomized on the first stimulation day of the IVF cycle and from stimulation day 5 receive letrozole (group A) or without letrozole treatment (group B).

RESULTS

Although estradiol levels were significantly lower in the letrozole group (group A) (P < 0.001), progesterone elevation (> 1.5 ng/mL was considered as a rise) on the day of hCG triggering (15.4, 7.7%) was not statistically significant (P = 0.170). RecFSH, the recovery rate of eggs, the high-quality embryo rate, and the thickness of endometrium (P = 0.776) were similar between the letrozole group(group A) and control groups (group B). Clinical pregnancy rates were 53.1% (26/49) and 72.9% (35/48) in the letrozole and control groups, respectively, with a statistical significance (P = 0.043).Live birth rates were 42.9% (21/49) and 62.5% (30/48),showed a marginally significant difference (P = 0.053). The miscarriage rate did not significantly differ between the two groups.

CONCLUSIONS

In this pilot study, letrozole supplementation could not reduce the incidence of premature progesterone rise during the late follicular phase in stimulated in vitro fertilization cycles in expected high responders, producing a harmful effect on the pregnancy outcome.

TRIAL REGISTRATION

China Clinical Trial Registration Center: ChiCTR-IPR-15006211 URL of the trial registry record: http://www.chictr.org.cn/showproj.aspx?proj=10731 . Trial registration date: 8 April, 2015. Date of first patient's enrolment: 5 October, 2015.

Mild ovarian stimulation with letrozole plus fixed dose human menopausal gonadotropin prior to IVF/ICSI for infertile non-obese women with polycystic ovarian syndrome being pre-treated with metformin: a pilot study

BACKGROUND

Letrozole is widely employed as ovulation induction agent in women with PCOS, but its use in mild stimulation (MS) protocols for IVF is limited. Aim of the present study was to evaluate the feasibility of a MS protocol with letrozole plus hMG in non-obese PCOS women undergoing IVF after a metformin pre-treatment.

METHODS

We retrospectively evaluated the data of 125 non-obese PCOS undergoing MS with letrozole plus hMG, 150 IU as starting dose, (group 1, N = 80) compared to those undergoing a conventional IVF stimulation protocols (CS) (group 2, N = 45) prior to IVF. All patients had received metformin extended release 1200-2000 mg daily for three to six months before IVF. GnRH antagonist was administered in both groups when the leading follicles reached 14 mm.

RESULTS

Both groups were comparable for age, BMI and ovarian reserve markers. Both groups showed lower than expected AFC and AMH values as a consequence of metformin pre-treatment. Letrozole-treated patients required a significantly lower amount of gonadotropins units (p < 0.0001), and showed significantly lower day 5, day 8 and hCG day E2 levels compared to patients undergoing the CS protocol (p < 0.0001, p < 0.0001 and p = 0.001 respectively). The oocyte yield, in terms of total (6, IQR 3, vs 6, IQR 4 respectively,) and MII oocytes (5, IQR 3, vs 5, IQR 3, respectively) number, did not differ among groups; the number of total (3, IQR 2, vs 3, IQR 1 respectively) and good quality embryos (2, IQR1 vs 2, IQR 1,5 respectively) obtained was comparable as well in the two groups. The number of fresh transfers was significantly higher in group 1 compared to group 2 (80% vs 60%, p = 0.016). A trend for higher cumulative clinical pregnancy rate was found in women undergoing MS compared to CS (42.5%vs 24,4%, p = 0.044), but the study was not powered to detect this difference.

CONCLUSIONS

The present study suggests that the use of letrozole as adjuvant treatment to MS protocols for IVF may be an effective alternative to CS protocols for non-obese PCOS patients pre-treated with metformin, as it provides comparable IVF outcome without requiring high FSH dose, and avoiding supraphysiological estradiol levels.

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.

Extraovarian gonadotropin negative feedback revealed by aromatase inhibition in female marmoset monkeys

Whereas the ovary produces the majority of estradiol (E2) in mature female primates, extraovarian sources contribute to E2 synthesis and action, including the brain E2-regulating hypothalamic gonadotropin-releasing hormone. In ovary-intact female rodent models, aromatase inhibition (AI) induces a polycystic ovary syndrome-like hypergonadotropic hyperandrogenism due to absent E2-mediated negative feedback. To examine the role of extraovarian E2 on nonhuman primate gonadotropin regulation, the present study uses letrozole to elicit AI in adult female marmoset monkeys. Sixteen female marmosets (Callithrix jacchus; >2 yr) were randomly assigned to ovary-intact or ovariectomy (OVX) conditions and subsequently placed on a daily oral regimen of either ~200 µl vehicle alone (ovary-intact Control, n = 3; OVX, n = 3) or 1 mg ⋅ kg-1 ⋅ day-1 letrozole in vehicle (ovary-intact AI, n = 4; OVX + AI, n = 6). Blood samples were collected every 10 days, and plasma chorionic gonadotropin (CG) and steroid hormone levels were determined by validated radioimmunoassay and liquid chromatography/tandem mass spectrometry, respectively. Ovary-intact, AI-treated and OVX females exhibited elevated CG (P < 0.01, P = 0.004, respectively) compared with controls, and after 30 days, OVX + AI females exhibited a suprahypergonadotropic phenotype (P = 0.004) compared with ovary-intact + AI and OVX females. Androstenedione (P = 0.03) and testosterone (P = 0.05) were also elevated in ovary-intact, AI-treated females above all other groups. The current study thus confirms in a nonhuman primate that E2 depletion and diminished negative feedback in ovary-intact females engage hypergonadotropic hyperandrogenism. Additionally, we demonstrate that extraovarian estrogens, possibly neuroestrogens, contribute to female negative feedback regulation of gonadotropin release.

No increased risk of major congenital anomalies or adverse pregnancy or neonatal outcomes following letrozole use in assisted reproductive technology

STUDY QUESTION

Does letrozole use increase the risk of major congenital anomalies and adverse pregnancy and neonatal outcomes in fresh, single-embryo transfer?

SUMMARY ANSWER

Letrozole significantly decreases the risk of miscarriage and does not increase the risk of major congenital anomalies or adverse pregnancy or neonatal outcomes compared with natural cycles in patients undergoing ART.

WHAT IS KNOWN ALREADY

Letrozole is the most commonly used aromatase inhibitor for mild ovarian stimulation in ART. However, its safety in terms of pregnancy and neonatal outcomes is unclear.

STUDY DESIGN SIZE, DURATION

This retrospective cohort study used data from the Japanese national ART registry from 2011 to 2013.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 3136 natural cycles and 792 letrozole-induced cycles associated with fresh, single-embryo transfer and resulting in a clinical pregnancy were included in the analysis. The main pregnancy outcomes were miscarriage, ectopic pregnancy and still birth, and the neonatal outcomes were preterm delivery, low birth weight, small/large for gestational age and major congenital anomalies. Terminated pregnancies were included in the analysis of major congenital anomalies. Odds ratios (ORs) and 95% CIs were calculated using multivariate logistic regression analysis adjusted for maternal age and calendar year.

MAIN RESULTS AND THE ROLE OF CHANCE

The risk of miscarriage was significantly lower in women administered letrozole (adjusted OR [aOR], 0.37, 95% CI, 0.30-0.47, P < 0.001). There was no significant difference in the overall risk of major congenital anomalies between the two groups (natural cycle 1.5% vs letrozole 1.9%, aOR, 1.24, 95% CI, 0.64-2.40, P = 0.52), and no increased risk for any specific organ system. Subgroup analysis demonstrated that the risk of major congenital anomalies was not increased in patients who underwent either in vitro fertilization or ICSI, or in those who received early cleavage stage or blastocyst embryo transfer. All other pregnancy and neonatal outcomes were comparable between the two groups.

LIMITATIONS REASONS FOR CAUTION

Despite the large sample size, we were only able to rule out the possibility that letrozole might cause large increases in birth-defect risks in ART patients.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that letrozole stimulation reduces the risk of miscarriage, with no increase in the risk of major congenital anomalies or adverse pregnancy or neonatal outcomes compared with natural cycles in women undergoing ART. Letrozole may thus be a safe option for mild ovarian stimulation.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

Not applicable.

Aromatase Inhibitors for Endometriosis-Associated Infertility; Do We Have Sufficient Evidence?

Orally active aromatase inhibitors (AIs) have gained attention for treatment of infertile women with endometriosis in whom aromatase p450 is aberrantly expressed. This review aimed to critically appraise and summarize the available evidence concerning the use of AIs for management of endometriosis-associated infertility. PubMed was searched to May 2015 with the following key words: endometriosis, infertility and aromatase. Priority was given for randomized controlled trials (RCTs) followed by other study designs. Main outcome measures were as follows: rates of clinical pregnancy, miscarriage and live birth as well as endocrine outcomes. Eighty-two abstracts were screened and six original articles were included. A RCT demonstrated that post-operative letrozole treatment did not improve spontaneous pregnancy rate. Another RCT reported no superiority of letrozole superovulation over clomiphene citrate (each combined with intrauterine insemination) in minimalmild endometriosis and previous laparoscopic treatment. Anastrozole significantly inhibited the growth of endometriotic cells and their estrogen production in culture. In assisted reproductive technology (ART) cycles, dual suppression (Agonist/anastrozole) was tested in a pilot study with a pregnancy rate of 45% however, high pregnancy loss (30%) occurred. A retrospective study showed that letrozole may improve endometrial receptivity in endometriotic patients undergoing in vitro fertilization (IVF). An opposite view from an in vitro study showed lower estradiol production and aromatase expression in cultured granulosa cells from endometriotic women undergoing IVF and marked reduction under letrozole. In conclusion, current evidence is limited. More trials are warranted to enhance our knowledge and provide a clear and unequivocal evidence to guide our clinical management of infertile women with endometriosis using AIs.

Luteal-phase ovarian stimulation vs conventional ovarian stimulation in patients with normal ovarian reserve treated for IVF: a large retrospective cohort study

OBJECTIVE

We have previously reported a new luteal-phase ovarian stimulation (LPS) strategy for infertility treatment. The purpose of this study was to systematically assess the efficiency and safety of this strategy by comparing it with conventional ovarian stimulation protocols.

DESIGN

Retrospective cohort study.

SUBJECTS

Patients with normal ovarian reserve undergoing ovum pick-up (OPU) cycles between April 2012 and September 2013 were enrolled: 708 patients underwent the LPS protocol compared with 745 patients who underwent the mild treatment protocol and 1287 patients who underwent the short-term protocol.

MEASUREMENTS

Number of mature oocytes retrieved and top-quality embryos obtained, implantation rate, pregnancy rate, live birth and ongoing pregnancy rate and neonatal outcomes.

RESULTS

The numbers of mature oocytes retrieved and top-quality embryos obtained per OPU cycle were significantly increased in the LPS group (10·9 ± 7·6 and 4·6 ± 4·3, respectively) compared with the mild treatment group (3·7 ± 3·0 and 1·8 ± 1·8, respectively, both P < 0·001) or the short-term group (9·1 ± 5·5 and 3·7 ± 3·1, respectively, both P < 0·001). Moreover, the total gonadotrophin used was also the highest in the LPS group. No significant differences were identified in the implantation rate (35·5% vs 34·8%, P > 0·05), pregnancy rate (46·2% vs 43·7%, P > 0·05) or live birth and ongoing pregnancy rate (44·4% vs 41·7%, P > 0·05) per frozen-thawed embryo transfer (FET) cycle in the LPS and mild treatment groups, respectively. However, the LPS protocol achieved a higher implantation rate (35·5% vs 31·8%, P = 0·012), pregnancy rate (46·2% vs 41·9%, P = 0·041), and live birth and ongoing pregnancy rate (44·4% vs 39·2%, P = 0·012) compared with the short-term protocol. Neonatal outcomes in the LPS group were similar to the other two groups.

CONCLUSIONS

The available data suggest that LPS is a feasible strategy for infertility treatment and complements the available follicular-phase ovarian stimulation strategies.

Controlled ovarian hyperstimulation with sequential letrozole co-treatment in normo/high responders

OBJECTIVE

To investigate the effect of co-administration of letrozole in an ovarian stimulation protocol using recombinant FSH and GnRH antagonists for ICSI in normo/high responders.

METHODS

Computerized data of 320 antagonist ICSI/ET cycles with or without letrozole were retrospectively analyzed. In 105 cases, letrozole (5 mg/day) was started at the second day of the cycle continued for 5 days. At the second day of letrozole, gonadotropins were added. The remaining 215 cases were stimulated with recombinant FSH only. In all cases on day 6, GnRH antagonist was started. Ovarian stimulation protocols with or without letrozole were compared for cycle outcome parameters.

RESULTS

In cycles with letrozole, significantly lower gonadotropin consumption and lower peak estradiol levels were found. In cycles with letrozole, mean number of metaphase II and fertilized oocytes retrieved were significantly higher compared to cycles without letrozole. The pregnancy and clinical pregnancy rates were similar.

CONCLUSION

Should the number of oocytes retrieved being higher in letrozole group might indicate that letrozole might contribute to successful ovarian stimulation with a lower dosage of gonadotropins. Despite the lower peak estradiol levels, pregnancy rates being similar to other group also support the idea that letrozole can contribute to normal potential of implantation.

Comparison of the effects of letrozole and cabergoline on vascular permeability, ovarian diameter, ovarian tissue VEGF levels, and blood PEDF levels, in a rat model of ovarian hyperstimulation syndrome

OBJECTIVE

To evaluate the effects of letrozole and cabergoline in a rat model of ovarian hyperstimulation syndrome (OHSS).

STUDY DESIGN

In this prospective, controlled experimental study, the 28 female Wistar rats were divided into four subgroups (one non-stimulated control and three OHSS-positive groups: placebo, letrozole, and cabergoline). To induce OHSS, rats were injected with 10 IU of pregnant mare serum gonadotropin from day 29 to day 32 of life, followed by subcutaneous injection of 30 IU hCG on day 33. Letrozole rats received with a single dose of 0.1 mg/kg letrozole via oral gavage, on the hCG day. Cabergoline rats received with a single dose of 100 µg/kg cabergoline via oral gavage, on the hCG day. All animals were compared in terms of body weight, vascular permeability (VP), ovarian diameter, ovarian tissue VEGF expression (assessed via immunohistochemical staining), and blood pigment epithelium-derived growth factor (PEDF) levels.

RESULTS

The OHSS-positive placebo group (group 2) exhibited the highest VP, ovarian diameter, extent of VEGF staining, and lowest PEDF level, as expected. No significant difference was evident between the letrozole and cabergoline groups in terms of any of body weight; VP; PEDF level; ovarian diameter; or the staining intensity of, or percentage staining for, VEGF in ovarian tissues.

CONCLUSIONS

Letrozole and cabergoline were equally effective to prevent OHSS, reducing the ovarian diameter, VP, and PEDF and VEGF levels to similar extents.

Polycystic ovary syndrome: chemical pharmacotherapy

INTRODUCTION

Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disease among women of childbearing age. The clinical features are heterogeneous and vary in intensity. Hirsutism, menstrual disorders and infertility are the most frequent conditions observed; however, long-term complications (dyslipidemia, hypertension, cardiovascular disease, type 2 diabetes mellitus, endometrial cancer) are also often described. Each disorder may be managed by tailored strategies, employing sequential or combined pharmacological and/or non-pharmacological treatment.

AREAS COVERED

The authors review the drugs used for PCOS management and discuss new approaches. A systematic MEDLINE search regarding the randomized controlled trials, retrospective and observational studies about medical treatments of PCOS, the Cochrane library for reviews and also search for registered trials on ClinicalTrials.gov is performed.

EXPERT OPINION

A uniform treatment for PCOS patients does not exist. Clinicians should perform an accurate evaluation of patients' characteristics, identifying the phenotypic target and, subsequently, the best-tailored treatment to manage one or more clinical issues. Lifestyle intervention should always be the first recommended approach unless other issues indicate that drug or hormonal interventions are superior.

Addition of growth hormone to the microflare stimulation protocol among women with poor ovarian response

OBJECTIVE

To assess the efficacy of adding growth hormone (GH) to the microflare stimulation protocol among women with poor ovarian response.

METHODS

A parallel, open-label, randomized controlled trial was conducted among patients with poor ovarian response who attended a center in Cairo, Egypt, between July 10 and December 31, 2014. Participants were randomly assigned using a computer program (random block size of 4-8) to undergo the microflare protocol with or without GH. Primary outcomes were the mean numbers of mature oocytes retrieved and fertilized. Analyses were done per protocol: women with cycle cancellations were excluded.

RESULTS

The analysis included 72 women in the GH group and 73 in the microflare only group. The mean number of oocytes collected was 7.2±1.5 in the GH group versus 4.7±1.2 in the microflare only group (P<0.001). The mean number of metaphase II oocytes was 5.2±1.2 in the GH group and 2.8±1.0 in the microflare only group (P<0.001). The mean number of fertilized oocytes was higher in the GH group (4.2±1.1) than in the microflare only group (2.5±0.7; P<0.001).

CONCLUSION

Addition of GH to the microflare stimulation protocol provided some potential benefits to women with poor ovarian response. However, further studies are required before it could be recommended for routine clinical use. ClinicalTrials.gov:NCT02185326.

The Role of Overweight and Obesity in In Vitro Fertilization Outcomes of Poor Ovarian Responders

Objective. Obesity is a worldwide concern with detrimental health effects including decreased fecundity. However, obesity's impact on in vitro fertilization (IVF) is inconclusive and there is little data concerning poor ovarian responders (POR). This study explored the effects of overweight and obesity on IVF outcomes of POR. Design. We retrospectively evaluated 188 POR undergoing IVF cycles. Methods. Patients were categorized into three groups. Group 1 was normal weight POR (18.5–24.9 kg/m², n = 96); Group 2 was overweight POR (25.0–29.9 kg/m², n = 52); and Group 3 was obese POR (≥30.0 kg/m², n = 40). Main measured outcomes included IVF outcomes. Results. The oocyte maturity, total gonadotropin dose-duration, and cycle cancellation rates were similar. Obese women had significantly decreased LH levels. LH < 4 mIU/mL had a sensitivity (62%) and a specificity (86%) for IVF failure (AUC: 0.71). Fertilization rates of obese subjects were significantly lower than normal and overweight subjects (p = 0.04). Obese women's clinical pregnancy rates were significantly lower (15%) than normal weight women (33.3%, p = 0.01). Conclusions. Despite similar counts of recruited mature oocytes, obese POR women had decreased fertilization and clinical pregnancy rates. Obesity rather than overweight significantly decreased IVF outcomes in POR.

Impact of gonadotropins on oocyte maturation, fertilisation and developmental competence in vitro

The aim of the present study was to evaluate the dose-dependent effects of gonadotropins, either singly (Bravelle (B), Luveris (L), Menupur (M), Repronex (R), Gonal-F (G), Follism (F) and Norvarel (N)) or in combination (Menupur+Bravelle; Repronext+Bravelle; and Bravelle+Norvarel), on rates of oocyte maturation, fertilisation and early embryo development in vitro in an animal model. Bovine cumulus-oocyte complexes (COCs) were purchased commercially and cultured in TCM-199 with 10% fetal bovine serum supplemented with varying concentrations of gonadotropin (0, 5, 10, 20, 40IU or United States Pharmacopoeia (USP) mL-1) for 24 and 48h according to current IVF clinical stimulation protocols. All gonadotropins enhanced oocyte maturation in vitro in a dose-dependent manner. Individually, Gonal-F (Merck KGaA, Darmstadt, Germany), Follism (Merck Co, Whitehouse Station, NJ, USA) and Repronext (Ferring, Parsippany, NJ, USA) promoted oocyte maturation; in combination, they effectively enhanced COC expansion and increased the maturation competence of MII oocytes. However, high concentrations of gonadotropins may result in maturation arrest. Specific combinations of gonadotropins may change the rate of early embryonic development (8-16-cells) and morula-blastocyst formation. These data provide support for the responsiveness of bovine oocytes to gonadotropins in vitro and the need to consider variations in the relative concentrations and ratio of combinations (FSH/LH or human chorionic gonadotropin) for optimisation of oocyte developmental competence. The results of the present study could be applied to therapeutic clinical stimulation protocols and help improve IVF success rates.

Clinical use of fertility agents and risk of breast cancer: a recent update for an old problem

PURPOSE OF REVIEW

Female infertility is today a very common, expanding problem and therefore restoring fertility strategies are increasing in the last few years. An association between ovarian stimulation and breast cancer risk has been hypothesized, but the question has not yet been clarified.

RECENT FINDINGS

In the last 2 years, many important studies have been published on this topic. A lot of new combinations of drugs are in experimentation and other recent drugs are already in current use, such as aromatase inhibitors. Furthermore, the data from older studies were investigated by two recent meta-analyses.

SUMMARY

Infertility affects many couples in western countries and the use of fertility stimulation techniques is widespread in the last few years, determining personal anxiety, social costs, and organizing difficulties. It is well known that one of the most important causative agents for the development of breast cancer is the proliferative activity of endogenous and exogenous female hormones. Therefore, it seems appropriate to investigate the risk of breast cancer derived from the use of hormonal therapies in infertile women. The final clarification of this question is very important so that all women can realize their dream of having children, with the certainty of not being exposed to an increased risk of breast cancer.

Cetrotide administration in the early luteal phase in patients at high risk of ovarian hyperstimulation syndrome: A controlled clinical study

The aim of the present pilot study was to assess the feasibility and efficacy of Cetrotide administration in the early luteal phase in patients at high risk of ovarian hyperstimulation syndrome (OHSS), undergoing embryo cryopreservation following superovulation. A total of 135 patients at high risk of OHSS and undergoing embryo cryopreservation were divided into two groups. In the treatment group (n=39), the patients received daily subcutaneous injections of 0.25 mg Cetrotide between days 1 and 5 following ooctye retrieval, and volume expansion and symptomatic treatment were also provided. In the control group (n=96), the patients received routine treatments, including volume expansion therapy. The serum steroid hormone concentrations of the patients were measured on days 2, 5 and 8 following ooctye retrieval, while the incidence of moderate or severe OHSS, self-evaluated clinical symptoms and various clinical indicators were recorded. The serum estradiol (E₂), luteinizing hormone and progesterone levels in the treatment group on days 2, 5 and 8 following oocyte retrieval were not found to differ significantly when compared with the patients in the control group (P>0.05). The incidence of severe OHSS did not differ significantly between the two groups (P>0.05). The average length of hospital stay and length of luteal phase were not found to be significantly different between the treatment and control groups (P>0.05). In conclusion, Cetrotide injections in the early luteal phase did not alter the serum steroid levels of patients at high risk of OHSS undergoing embryo cryopreservation, and were unable to reduce the incidence of severe early OHSS. However, further randomized studies are required to evaluate the effectiveness of Cetrotide in the prevention of OHSS.

Is letrozole needed for controlled ovarian stimulation in patients with estrogen receptor-positive breast cancer?

OBJECTIVE

To assess the advantages and disadvantages of using letrozole for controlled ovarian stimulation (COH) in young patients with estrogen receptor-positive (ER+) breast cancer, wishing to cryopreserve oocytes.

DESIGN

Retrospective cohort analysis.

SETTING

Sixteen Italian units for reproductive medicine and in vitro fertilization.

METHODS

Data of 50 ER+ breast cancer patients undergoing COH to cryopreserve oocytes before gonadotoxic chemotherapy with a letrozole plus gonadotropins (Le+Gn) protocol were compared with those of 25 young women with ER- breast cancer, submitted to COH using a protocol with gonadotropins alone (Gn-only).

RESULTS

The Le+Gn protocol implied a significantly lower total Gn consumption and allowed to maintain significantly lower circulating E2 levels at all checkpoints throughout stimulation (peak E2 value 446 ± 357 versus 1553 ± 908 pg/ml, respectively; p = 0.001). On the other side, the Le+Gn protocol allowed a significantly lower yield of oocytes available for cryostorage (6.6 ± 3.5 versus 8 ± 5, respectively; p = 0.038).

CONCLUSIONS

In breast cancer patients, the association of letrozole to Gn significantly reduces the number of oocytes available for cryostorage in comparison with the use of Gn alone. On the other side, it is associated with significantly lower E2 levels during the whole stimulation cycle, a safety issue that has been traditionally considered advantageous in case of ER+ cancers.

Breast cancer risk after exposure to fertility drugs

In recent years, there has been an increase in the diagnosis of infertility. In industrialized countries, approximately 15% of couples experience this problem today, with a negative impact on quality of life. For this reason, assisted reproductive technologies and other treatments, finalized to overcome infertility, have become very common in clinical practice. For a long time, different ovulation-inducing drugs have been used for ovarian follicle stimulation, either as independent therapies or treatments used during in vitro fertilization cycles. Despite this long-term use, the medical care for infertility gave rise to a lively debate about the potential risk of developing breast cancer that has never been settled. Many studies have been conducted to address this question; but their results have been, and still are, contradictory. The aim of this review is to determine the potential link between the use of fertility drugs and the risk of developing breast cancer in women treated for infertility.

Letrozole increases ovarian growth and Cyp17a1 gene expression in the rat ovary

OBJECTIVE

To evaluate the effects of letrozole on ovarian size and steroidogenesis in vivo, as well as on proliferation and steroidogenesis of theca-interstitial cells alone and in coculture with granulosa cells using an in vitro model.

DESIGN

In vivo and in vitro studies.

SETTING

Research laboratory.

ANIMAL(S)

Immature Sprague-Dawley female rats.

INTERVENTION(S)

In vivo effects of letrozole were studied in intact rats receiving either letrozole (90-day continuous-release SC pellets, 400 μg/d) or placebo pellets (control group). In in vitro experiments, theca cells were cultured alone or in coculture with granulosa cells in the absence or presence of letrozole.

MAIN OUTCOME MEASURE(S)

Deoxyribonucleic acid synthesis was determined by thymidine incorporation assay; steroidogenesis by mass spectrometry; and steroidogenic enzyme messenger RNA (mRNA) expression by polymerase chain reaction.

RESULT(S)

In vivo, letrozole induced an increase in ovarian size compared with the control group and also induced a profound increase of androgen, LH levels, and Cyp17a1 mRNA expression. Conversely, a decrease in Star, Cyp11a1, and Hsd3b1 transcripts was observed in letrozole-exposed rats. In vitro, letrozole did not alter either theca cell proliferation or Cyp17a1 mRNA expression. Similarly, letrozole did not affect Cyp17a1 transcripts in granulosa-theca cocultures.

CONCLUSION(S)

These findings suggest that letrozole exerts potent, but indirect, effect on growth of rat ovary and dramatically increases androgen levels and Cyp17a1 mRNA expression, the key enzyme regulating the androgen biosynthesis pathway. The present findings reveal novel mechanisms of action of letrozole in the rat ovary.

The use of aromatase inhibitors in in vitro fertilization

The use of aromatase inhibitors (AIs) in IVF patients remains controversial. AIs can be considered for ovulation induction for IVF in women who are normal and poor responders, are at risk of ovarian hyperstimulation syndrome or thrombosis, who have endometriosis, and/or are undergoing fertility preservation procedures as a result of estrogen-dependent cancers, primarily breast and endometrial cancers. Although the biologic plausibility of the capacity of AIs in IVF patients is promising, results should be interpreted with caution, because the efficacy of AIs needs to be proven in randomized trials.