Does the addition of clomiphene citrate or letrazole to gonadotropin treatment enhance the oocyte yield in poor responders undergoing IVF?

Comparison of luteal phase and follicular phase in-vitro maturation in women with oocyte maturation abnormalities

RESEARCH QUESTION

Are there differences in immature oocyte retrieval following luteal phase in-vitro maturation (IVM) compared with follicular phase IVM in women with oocyte maturation abnormalities (OMAs).

DESIGN

From January 2019 to May 2023, a retrospective cohort study at a private IVF centre included 36 women with 53 IVM cycles in Group 1 (follicular phase) and 24 women with 32 IVM cycles in Group 2 (luteal phase). Additionally, nine women had both follicular and luteal phase IVM cycles for intracycle variability analysis.

RESULTS

There were no differences in oocyte maturation stages between the groups at collection. Group 1 and Group 2 exhibited comparable median metaphase II oocyte rates per patient at 48 h after collection [40.0%, interquartile range (IQR) 0.0-66.7% versus 22.5%, IQR 0.0-52.9%] (P = 0.53). The median fertilization rate in Group 1 (66.7%, IQR 50.0-66.7%) was found to be comparable with that in Group 2 (66.7%, IQR 50.0-66.7%). There were no significant differences in the yielded embryo grades and pregnancy rates between the groups. Comparing follicular and luteal phase IVM within the same menstrual cycle in nine patients, no differences were observed in metaphase II oocyte maturation rates (P > 0.05).

CONCLUSIONS

This study found no significant differences in oocyte maturation, fertilization rate, embryo quality or pregnancy outcomes between luteal phase and follicular phase IVM in women with OMAs. These findings suggest that luteal phase IVM can be used similarly to follicular phase IVM, offering a potential avenue to enhance embryo yield for women with OMAs.

Oocyte in-vitro maturation primed with letrozole-HCG versus FSH-HCG in women with oocyte maturation abnormalities: a retrospective study

RESEARCH QUESTION

Are there differences between in-vitro maturation (IVM) primed with letrozole-human chorionic gonadotrophin (HCG) and IVM primed with FSH-HCG in women with oocyte maturation abnormalities (OMAs), defined as at least two failed IVF cycles where immature oocytes were retrieved?

DESIGN

This retrospective study was conducted at a private fertility clinic from January 2009 to April 2023. The final analysis included 75 women in Group 1 (IVM primed with FSH-HCG) and 52 women in Group 2 (IVM primed with letrozole-HCG).

RESULTS

A significantly higher median number of oocytes was obtained in Group 1 compared with Group 2 {9 [interquartile range (IQR) 1-5] versus 5 (IQR 1-18); P < 0.001}. However, no differences in oocyte maturation stage at collection were found between the groups (P > 0.05). At the end of IVM, Group 1 had 73/666 mature oocytes and Group 2 had 106/322 mature oocytes, and the median metaphase II oocyte rate per patient was higher in Group 2 [33.3% (IQR 66.7-100.0%) versus 0.0% (IQR 0.0-22.2%); P < 0.001]. Moreover, Group 2 demonstrated a higher median fertilization rate [66.7% (IQR 50.0-100.0%) versus 50.0% (IQR 0.0-66.7%); P = 0.027]. Group 2 had a higher proportion of Grade 2 embryos (58.5% versus 6.3%), and Group 1 had a higher proportion of Grade 3 embryos (93.8% vs 24.4%; P < 0.001). Notably, all pregnancies obtained in the study were in Group 2 (5 versus 0; P = 0.042).

CONCLUSIONS

IVM primed with letrozole-HCG in women with prior failed IVF cycles due to OMAs may result in mature oocytes, clinical pregnancies and live births. The effectiveness of letrozole priming for the subtypes of OMAs needs further investigation, with studies including greater numbers of cases.

Letrozole-induced endometrial preparation improved the pregnancy outcomes after frozen blastocyst transfer compared to the natural cycle: a retrospective cohort study

Background

Letrozole treatment is considered an effective option in endometrial preparation for frozen embryo transfers in patients with ovulation disorders or irregular menstruation; however, the effectiveness of letrozole-induced endometrial preparation remains unclear in ovulatory patients. Furthermore, there is no comparative study reporting on pregnancy complications and congenital anomalies after frozen embryo transfers comparing natural and letrozole-assisted cycles. This study examined whether letrozole-induced endometrial preparation affected pregnancy outcomes, perinatal outcomes, and congenital anomalies after single vitrified-warmed blastocyst transfers (SVBTs) in ovulatory patients, as compared with the natural cycle.

Methods

This historic cohort study included only patients with unexplained infertility. Overall, 14,611 patients who underwent SVBTs between July 2015 and June 2020, comprising both natural and letrozole-assisted cycles, were included. Multiple covariates that impact outcomes were used for propensity score matching; 1,911 patients in the letrozole group were matched to 12,700 patients in the natural group, and the clinical records of 1,910 patients in each group were retrospectively analysed. Cycle characteristics, pregnancy outcomes (clinical pregnancy, ongoing pregnancy, and live birth), and incidence of pregnancy complications and congenital anomalies were statistically compared between the two groups.

Results

Multivariate logistic regression analysis showed that letrozole administration during SVBT cycles significantly improved the live birth rate (P = 0.0355). Gestational age, birth length, birth weight, and infant sex, as well as the incidence of pregnancy complications and birth defects, were statistically comparable between the two groups. Furthermore, multivariate logistic regression analysis revealed that the perinatal outcomes were not affected by letrozole-induced endometrial preparation.

Conclusions

Letrozole-induced endometrial preparation improved the live birth rate compared with the natural cycle, without adverse effects on perinatal outcomes and congenital anomalies after SVBTs. Therefore, letrozole-induced endometrial preparation might be a safe and more effective strategy, especially for patients with insufficient luteal function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05174-0.

The impact of estradiol on pregnancy outcomes in letrozole-stimulated frozen embryo transfer cycles

OBJECTIVE

To assess the impact of low estradiol (E2) levels in letrozole-stimulated frozen embryo transfer (FET) cycles on pregnancy and neonatal outcomes.

DESIGN

Retrospective cohort.

SETTING

University-affiliated fertility center.

PATIENTS

All patients who underwent letrozole-stimulated FET cycles from January 2017 to April 2020 (n = 217). The "Low E2" group was defined as those with E2 serum levels on the day of trigger <10th percentile level (E2 <91.16 pg/mL, n = 22) and the "Normal E2" group was defined as those with E2 serum levels ≥10th percentile level (E2 ≥91.16 pg/mL, n = 195).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Pregnancy outcomes including rates of clinical pregnancy, clinical miscarriage, and live birth. Neonatal outcomes including gestational age at delivery, birth weight, and Apgar score.

RESULTS

The mean ± SD estradiol level was 66.8 ± 14.8 pg/mL for the "Low E2" group compared with 366.3 ± 322.1 pg/mL for the "Normal E2" group. There were otherwise no substantial differences in cycle characteristics such as endometrial thickness on the day of ovulation trigger and progesterone levels in early pregnancy. The "Low E2" group had a significantly higher clinical miscarriage rate (36.4% vs. 8.8%, adjusted odds ratio 8.06) and lower live birth rate (31.8% vs. 57.9%, adjusted odds ratio 0.28). Neonatal outcomes such as gestational age at delivery, mean birth weight, Apgar scores, and incidence of newborn complications were not clinically different between the groups.

CONCLUSION

Low E2 levels were associated with a significantly higher miscarriage rate and lower live birth rate, suggesting that E2 levels in the follicular phase may have an effect on cycle outcomes. Given the rise in use of FET, further studies are needed to confirm our findings and understand the mechanisms.

Randomised controlled trial on the effect of clomiphene citrate and gonadotropin dose on ovarian response markers and IVF outcomes in poor responders

STUDY QUESTION

Does the gonadotropin (GN) starting dose and the addition of clomiphene citrate (CC) during the early follicular phase influence oocyte yield in poor responders undergoing ovarian stimulation for IVF treatment?

SUMMARY ANSWER

The number of retrieved oocytes was similar regardless of the starting dose of GN (150 versus 450 IU) with or without the addition of CC (100 mg from Day 3 to 7 versus placebo).

WHAT IS KNOWN ALREADY

ART in poor responders is a challenge for patients and clinicians. So far, randomised controlled studies addressing interventions have shown that neither the GN dose nor the addition of oral medication has any significant effect on the clinical outcome of ART in poor responders. There is limited knowledge about the effect of GN starting dose in combination with CC during the early follicular phase of ovarian stimulation on ovarian response markers and ART outcome.

STUDY DESIGN, SIZE, DURATION

This single-centre randomised double-blinded clinical trial was conducted from August 2013 until November 2017. Using the Bologna criteria, 220 of 2288 patients (9.6%) were identified as poor responders and 114 eligible participants underwent ovarian stimulation in a GnRH-antagonist protocol for ART.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The participants were equally randomised to one of four treatment arms: Group A (n = 28) received 100 mg CC (Day 3-7) and a starting dose of 450 IU HMG, Group B (n = 29) received 100 mg CC and a starting dose of 150 IU HMG, Group C (n = 30) received placebo and a starting dose of 450 IU HMG and Group D (n = 27) received placebo and a starting dose of 150 IU HMG. Serum levels of FSH, LH, estradiol and progesterone were measured on Day 1 and 5 and on the day of ovulation induction. Available embryos were cultured up to the blastocyst stage and were always transferred in the same cycle. The primary outcome was the number of oocytes collected after ovarian stimulation. Other outcome measures were response to ovarian stimulation, embryo development and obstetrical outcome.

MAIN RESULTS AND THE ROLE OF CHANCE

All study participants (n = 114) fulfilled at least two of the Bologna criteria for poor responders. Median age of the study population was 38.5 years. There were 109 patients who underwent oocyte retrieval. The number of oocytes retrieved was similar among the groups (±SD; 95% confidence intervals); A: 2.85 (±0.48; 2.04-3.98), B: 4.32 (±0.59; 3.31-5.64); C: 3.33 (±0.52; 2.45-4.54); D: 3.22 (±0.51; 2.36-4.41); P overall = 0.246. However, ovarian stimulation with 150 IU plus CC resulted in a higher number of blastocysts compared to ovarian stimulation with 450 IU plus CC (±SD; 95% confidence intervals); A: 0.83 (±0.15; 0.58-1.2), B: 1.77 (±0.21; 1.42-2.22); P overall = 0.006. Mean FSH serum levels were lower in the groups with a starting dose of 150 IU. Adding CC did not affect mean serum FSH levels. There were no differences in estradiol concentrations among the groups. Endometrial thickness was lower in the groups receiving CC. The overall live birth rate (LBR) was 12.3%, and the cumulative LBR was 14.7%.

LIMITATIONS, REASONS FOR CAUTION

The trial was powered to detect differences in neither the number of blastocysts nor the LBR, which would be the preferable primary outcome of interventional trials in ART.

WIDER IMPLICATIONS OF THE FINDINGS

We found that ovarian stimulation with 150 IU gonadotrophin in combination with 100 mg CC produced more blastocysts. The effect of adding CC to GN on LBR in poor responders remains to be proven in randomised trials. High GN doses (450 IU) resulted in high FSH serum levels but increased neither the estradiol levels nor the number of retrieved oocytes, implying that granulosa cell function is not improved by high FSH serum levels. Lower starting doses of GN lead to a reduction of costs of medication. The small but significant difference in blastocyst formation and the lower FSH levels in the treatment groups receiving less GN may be an indication of better oocyte quality with higher developmental competence.

STUDY FUNDING/COMPETING INTEREST(S)

The costs for the HMG used for ovarian stimulation were provided by IBSA Switzerland. The study was also supported by the Repronatal Foundation, Basel, Switzerland. The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

NCT01577472.

TRIAL REGISTRATION DATE

13 April 2012.

DATE OF FIRST PATIENT’S ENROLMENT

August 2013.

Does the additional use of clomiphene citrate or letrozole for in vitro fertilization deserve more attention?

BACKGROUND

Adding clomiphene citrate (CC) and/or letrozole (LE) to in vitro fertilization (IVF) cycles for mild ovarian stimulation is a general approach. Although lots of researches have demonstrated partial benefits of the strategy, all-around effects of oral medications remained deficient. This paper aims to assess whether an addition of oral medication will result in considerable outcomes on T-Gn (total dose of gonadotropin), Gn days, total retrieved ova, high quality embryos, blastocyst number, ovarian hyperstimulation syndrome (OHSS) rate, clinical pregnancy rate and cumulative pregnancy rate, even if it was not conventional mild/minimal stimulations.

RESULTS

Participants were categorized to three diverse populations as high responders, normal responders and poor responders according to basal antral follicle count. T-Gn in patients treated with CC/LE distinctly decreased from 2496.96 IU/d to 1827.68 IU/d, from 2860.28 IU/d to 2119.99 IU/d, and from 3182.15 IU/d to 1802.84 IU/d, respectively. For high ovary responders and normal responders, the OHSS incidence rate also declined from 29.2 to 4.3% (P < 0.001) and from 1.1 to 0.0% (P = 0.090). Other, there was no statistical difference with respect to the T-retrieved ova (total retrieved ova), high quality embryos, cultured blastocyst and blastocyst number in high responders. For normal responders and poor ovary responders, T-Gn, Gn days, T-retrieved ova, high quality embryos, cultured blastocyst and blastocysts number in oral medications group all apparently decreased. Clinical pregnancy rate per fresh cycle of poor responders with prior oral medications was significantly decreased (25.7% vs. 50.8%, P = 0.005), and no significant differences in high responders and normal responders were expressed (52.5% vs. 44.2%, P = 0.310; 51.9% vs. 42.4%, P = 0.163) between two groups of participants. The numbers of cumulative pregnancy rates were lower in the conventional group compared to the add group for high (75.90% versus 81.03%, P = 0.279), normal (62.69% versus 71.36%, P = 0.016) and poor (39.74% versus 68.21%, P < 0.001) responders.

CONCLUSIONS

The addition of CC/LE to the ovulation induction during IVF has certain efficacy in terms of low cost, low OHSS incidence. CC/LE deserves more recommendations as a responsible strategy in high responders due to advantageous pregnancy outcomes. For normal responders, the strategy needs to be considered with more comprehensive factors.

Therapeutic Potentials of Low-Dose Tacrolimus for Aberrant Endometrial Features in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a major anovulatory infertility affecting a great proportion of women of childbearing age and is associated with obesity, insulin resistance and chronic inflammation. Poor endometrial receptivity and recurrent implantation failure are major hurdles to the establishment of pregnancy in women with PCOS. The accumulating body of evidence obtained from experimental and clinical studies suggests a link between inherent adaptive and innate immune irregularities and aberrant endometrial features in PCOS. The use of conventional therapeutic interventions such as lifestyle modification, metformin and ovarian stimulation has achieved limited clinical success in restoring ovulation and endometrial receptivity in women with PCOS. Unlike other immunosuppressive drugs prescribed in the clinical management of autoimmune and inflammatory disorders that may have deleterious effects on fertility and fetal development, preclinical studies in mice and in women without PCOS but with repeated implantation failure revealed potential therapeutic benefits for the use of low-dose tacrolimus in treating female infertility. Improved systemic and ovarian immune functions, endometrial progesterone receptor and coreceptor expressions and uterine vascular adaptation to pregnancy were among features of enhanced progesterone-receptor sensitivity in the low-dose tacrolimus-treated mouse model of the disease. In this review, we have compiled available experimental and clinical data in literature on endometrial progesterone resistance and current therapeutic options, as well as mechanisms of actions and reported outcomes relevant to the potential therapeutic benefits for the use of low-dose tacrolimus in treating PCOS-associated female infertility.

A review of the physiology behind letrozole applications in infertility: are current protocols optimal?

Letrozole is a targeted aromatase inhibitor which has primarily been used in post-menopausal women with breast cancer. Recently, it has been utilized in infertile pre-menopausal women because of its ability to enhance FSH production for ovulation induction. However, the ovarian follicle’s response to FSH is only a part of the endocrine events occurring in a developing follicle. The health of the small antral follicles is driven primarily by androgens, which contribute to granulosa cell mitosis, sensitivity to FSH, and resistance to atresia. In contrast, elevated androgens in the late antral to pre-ovulatory follicle have a negative impact on follicle health and lead to atresia and cystic follicle formation. This ovarian physiologic data suggests that current applications of letrozole to infertility may be squandering some of the primary benefits available in using letrozole to promote follicle development. Four applications of letrozole to infertility that have appeared in the medical literature are reviewed. Androgen-related benefits are reviewed and various questions put forward about how letrozole could be more effectively used to help patients in these settings.

The addition of clomiphene citrate to ovarian stimulation protocols for poor responders

Poor ovarian response (POR) is one of the most challenging problems in assisted reproduction. Several strategies have been used to improve pregnancy rates. The use of Clomiphene Citrate (CC) has been shown to improve ovarian stimulation outcomes and decrease gonadotropin requirements in women of advanced reproductive age. However, the combination of CC and gonadotropins to improve pregnancy rates after in IVF in poor responders is still unexplored due to the small number of trials with few participants. This is a prospective cohort trial involving 12 patients diagnosed with poor ovarian response who underwent ovarian stimulation during the period between June 2015 and September of 2017. All patients were treated with the maximum dose of gonadotropins (hMG, 300 IU/day, hMG group) according to a short gonadotropin/GnRH antagonist protocol. In a subsequent cycle those patients underwent the same stimulation protocol with the addition of 100 mg of CC from day 3 to day 7 (CC-hMG group). Supplementation with 100 mg of CC resulted in a statistically significant increase in estradiol levels, number of follicles and number of oocytes retrieved, as well as an increase in the number of total embryos available for transfer. Furthermore, a significant reduction was observed in cancellation rates in the CC-hMG group. Two clinical pregnancies, which resulted in two live births and 3 biochemical pregnancies were achieved in the CC/hMG group. Furthermore, by employing open-source, biological data we identified a common gene (Estrogen Receptor 1, ESR1) between genetic targets of clomiphene treatment and POR which could explain the benefits of clomiphene in this group of patients. In conclusion, the addition of CC 100 mg to the stimulation regimen in women diagnosed with POR and previous failed IVF cycles could improve stimulation results, but this study could not demonstrate any benefit in terms of clinical pregnancies and live births. The effectiveness of this treatment requires further investigation.

Effect of simultaneously started clomiphene citrate and gonadotropins in antagonist regimes, on cumulative live births, fresh-cycle live births and cost of stimulation in IVF cycles

AIM

The aim of the study was to compare simultaneously started clomiphene citrate (CC) and gonadotropins (Gn) with gonadotropins alone in conventional antagonist regimes with respect to fresh-cycle live births, cumulative live births and cost of ovarian stimulation per started cycle.

METHODS

This was a single-center prospective cohort study conducted over 1 year. Women undergoing autologous in vitro fertilization (IVF) treatment in antagonist protocols and who consented to participate in the study were divided into two cohorts. The CC cohort (n = 86) received 50 mg CC for 5 days and individualized Gn daily until the hCG trigger, both starting from day 2 and antagonist daily from day 8 of menstrual cycle. The Gn-only cohort (n = 349) received individualized Gn from day 2 and the antagonist from day 7 of menstrual cycle. IVF outcomes and cost of stimulation were compared between two cohorts across expected ovarian response categories.

RESULTS

The CC cohort used a mean lower dose of Gn (1741.38 ± 604.46 vs 1980.54 ± 686.42; MD = -239.16; 95%CI = -348.03 to -189.24; P = 0.003) over fewer days (8.54 ± 1.86 vs 9.25 ± 1.97; MD =-0.71;95% CI = -1.17 to -0.25; P = 0.0026) to achieve similar retrieved oocytes, (9.19 ± 5.92 vs 9.36 ± 6.96; MD = -0.17; 95%CI -1.77 to + 1.43; P = 0.83), positive bhCG rates (40% vs 29.6%, MD = 10.4%; OR = 1.65, 95%CI = 0.95-2.86; P = 0.078) and live births in fresh cycles (32.31% vs 21.30%; MD = 11.01%; OR = 1.76; 95%CI = 0.97-3.19; P = 0.06) and cumulative live births per initiated cycle (30.23% vs 20.34%; MD = 9.89%; OR = 1.697; 95%CI = 0.99-2.88; P = 0.0501). The dose lowering achieved a 28-40% reduction in the cost of stimulation, which was most noticeable in the hyper-responder category for both hMG cycles, (Rs.11 602.3 ± 3365.9 vs 19615 ± 2677.1; MD = -8012.7; %age reduction: 40.8%; P = 0.0007) and recombinant FSH cycles (Rs. 22 459.6 ± 6255.3 vs 33 022.1 ± 9891.2; MD: -10 562; %age reduction: -32%; P = 0.0001).

CONCLUSION

CC started simultaneously with Gn in antagonist regimes helps lower the cost of stimulation without affecting IVF outcomes.

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.

Effectiveness of corifollitropin alfa used for ovarian stimulation of poor responder patients

Purpose

To evaluate the efficiency and efficacy of corifollitropin alfa (follicle-stimulating hormone–carboxy terminal peptide) in the treatment of poor responder patients.

Methods

A total of 85 poor responder patients with a mean age 40.2±3.9 years entered our assisted fertilization program. The patients were prospectively randomized into two groups based on the ovarian stimulation regimen used: group A (study group) (n=42) received clomiphene citrate and corifollitropin alfa for the first 7 days of stimulation followed by recombinant follicle stimulating hormone (rFSH) in a gonadotropin-releasing hormone antagonist protocol, and group B (control group) (n=43) received clomiphene citrate and a daily injection of rFSH in a gonadotropin-releasing hormone antagonist protocol. We analyzed the stimulation outcome, the number of retrieved oocytes, cleaving embryos, and pregnancy and implantation rates as well.

Results

Comparable results were observed between the two groups in terms of demographic data, stimulation outcome, and the number of canceled cycles. There were no differences evident between groups A and B with respect to the number of retrieved oocytes (3.0±0.8 and 2.7±0.7, respectively) and the number of cleaving embryos (1.8±0.6 and 1.7±0.7, respectively). Higher, though not statistically significant, differences were observed in favor of group A compared to group B in terms of pregnancy rate per cycle (19% and 16.3%, respectively), pregnancy rate per transfer (21.6% and 17.9%, respectively), and implantation rate (14.7% and 13.4%, respectively). Also, miscarriage rate was similar between patients treated with corifollitropin alfa and those treated with daily rFSH injection (12.5% and 14.2%, respectively).

Conclusion

The results show that ovarian stimulation with corifollitropin alfa appears to be as efficacious and efficient as daily injection rFSH regimen to treat patients with poor ovarian response.

Poor ovarian reserve

Poor ovarian reserve (POR) is an important limiting factor for the success of any treatment modality for infertility. It indicates a reduction in quantity and quality of oocytes in women of reproductive age group. It may be age related as seen in advanced years of reproductive life or may occur in young women due to diverse etiological factors. Evaluating ovarian reserve and individualizing the therapeutic strategies are very important for optimizing the success rate. Majority or women with POR need to undergo in vitro fertilization to achieve pregnancy. However, pregnancy rate remains low despite a plethora of interventions and is associated with high pregnancy loss. Early detection and active management are essential to minimize the need for egg donation in these women.

A randomized, single-blind, prospective trial comparing three different gonadotropin doses with or without addition of letrozole during ovulation stimulation in patients with poor ovarian response

OBJECTIVE

The aim of this randomized controlled trial (RCT) was to investigate whether IVF outcomes would differ between patients with POR who received three different gonadotropin doses with or without the addition of letrozole during ovulation stimulation.

STUDY DESIGN

Only those who fulfilled two of the three Bologna criteria were included to the study. 95 patients met the inclusion criteria and agreed to participate in the study. In the first group, 31 patients were treated with 450IU gonadotropins. In the second group, 31 patients were treated with 300IU gonadotropins. The third group comprised 33 patients and was treated with 150IU gonadotropins in combination with letrozole.

RESULTS

The results indicate that differences in doses of hMG and rFSH in patients with POR result in a similar number of retrieved MII and fertilized oocytes, similar fertilization rates, number of transferred embryos, implantation, cancelation, chemical, clinical, and ongoing pregnancy rates.

CONCLUSIONS

Increasing the dose of gonadotropins during ovulation stimulation is an intuitively appealing approach when the patient is a poor responder. However, increasing the dose does not necessarily improve the reproductive outcome. Using a mild stimulation with addition of letrozole was as effective as stimulation with higher doses of gonadotropins alone in this patient population.

The association of serum estradiol level with outcomes of clomiphene citrate/human menopausal gonadotropin ovarian stimulation for in vitro fertilization and embryo transfer

BACKGROUND

The purpose of this study was to test the hypothesis that estradiol (E2) level on day 3 may be associated with in vitro fertilization (IVF) outcomes.

METHODS

The records of patients who received clomiphene citrate 100 mg/day plus human menopausal gonadotropin 150 IU/day from day 3 and received frozen-thawed embryo transfers were reviewed. Patients were divided into three groups: group A (E2 ≤30 pg/ml), group B (30< E2 ≤50 pg/ml), and group C (E2 >50 pg/ml). A total of 1080 cycles from 941 patients were included.

RESULTS

The number of eggs and MII oocytes were less in group C than group A (both, P = 0.001). The embryo implantation (P = 0.006) and clinical pregnancy rates (P = 0.036) were lower in group C than group B, and the rates were similar between group A and B.

CONCLUSION

Maintaining the serum E2 level from 30 to 50 pg/ml may result in a higher clinical pregnancy rate in IVF cycles.

Comparison of The Effectiveness of Clomiphene Citrate versus Letrozole in Mild IVF in Poor Prognosis Subfertile Women with Failed IVF Cycles

BACKGROUND

Our objective was to evaluate the effectiveness of clomiphene citrate (CC) vs. letrozole (L) plus human menopausal gonadotropin (hMG) in gonadotropin releasing hormone (GnRH) antagonist protocol in poor prognosis women with previous failed ovarian stimulation undergoing intracytoplasmic sperm injection (ICSI).

MATERIALS AND METHODS

This retrospective cohort study included cycles with CC and L plus hMG/GnRH antagonist protocols of 32 poor responders who had failed to have ideal follicles to be retrieved during oocyte pick-up (OPU) or embryo transfer (ET) at least for 2 previous in vitro fertilization (IVF) cycles with microdose flare protocol or GnRH antagonist protocol from January 2006 to December 2009. Main outcome measures were implantation, clinical pregnancy and live birth rates per cycle. Duration of stimulation, mean gonadotropin dose used, endometrial thickness, number of mature follicles, serum estradiol (E2) and progesterone (P) levels on the day of human chorionic gonadotropin (hCG) administration, number of retrieved oocytes and fertilization rates were also evaluated.

RESULTS

A total number of 42 cycles of 32 severe poor responders were evaluated. Total gonadotropin consumption was significantly lower (1491 ± 873 vs. 2808 ± 1581 IU, P=0.005) and mean E2 level on the day of hCG injection were significantly higher in CC group than L group (443.3 ± 255.2 vs. 255.4 ± 285.2 pg/mL, P=0.03). ET, overall pregnancy and live birth rates per cycle were significantly higher in CC than L protocol (27.2 vs. 15%, 13.6 vs. 0% and 4.5 vs. 0%, respectively, P<0.05).

CONCLUSION

Severe poor responders who had previously failed to respond to microdose or GnRH antagonist protocols may benefit from CC plus hMG/GnRH antagonist protocol despite high cancellation rate.

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.

In vitro fertilisation treatment and factors affecting success

The efficacy of assisted reproductive technologies has improved significantly over the past decades. The main indications for in vitro fertilisation include tubal obstruction, severe male-factor infertility, severe endometriosis, ovulatory dysfunction, diminished ovarian reserve, and infertility of unexplained cause. In vitro fertilisation has also become an effective treatment option for couples wishing to undergo pre-implantation genetic diagnosis or screening, and for those wishing to cryopreserve their oocytes or embryos for preservation of fertility. The management of women in late reproductive age poses a major challenge; the optimum in vitro fertilisation treatment for poor responders remains elusive. The success of in vitro fertilisation treatment can be optimised by taking an individualised, patient-centered approach to controlled ovarian hyperstimulation. Key components involve selection of an appropriate controlled ovarian protocol, close-cycle monitoring, adjustment of gonadotropin dosage to avoid hyper-response, and individualised timing of human chorionic gonadotropin injection. Future directions of assisted reproductive technologies include development of non-invasive embryo selection methods, use of transcriptomics, proteomics, metabolomics, and time-lapse imaging technologies.