Effect of letrozole at 2.5 mg or 5.0 mg/day on ovarian stimulation with gonadotropins in women undergoing intrauterine insemination

Ovulation induction using sequential letrozole/gonadotrophin in infertile women with PCOS: a randomized controlled trial

RESEARCH QUESTION

Is sequential letrozole/human menopausal gonadotrophin (HMG) superior to letrozole alone in ovulation induction and pregnancy promotion among infertile women with polycystic ovary syndrome (PCOS)?

DESIGN

This open-label randomized controlled trial comparing sequential letrozole/HMG and letrozole alone included 174 participants enrolled from August 2019 to January 2020 at the Union Hospital of Tongji Medical College, Huazhong University of Science and Technology. Infertile women aged between 18 and 40 years who met Rotterdam criteria for PCOS and without other known causes of infertility were selected for this study. Patients were randomly assigned at a 1:1 ratio to receive 2.5 mg letrozole on cycle days 3-7 (n = 87) or 2.5 mg letrozole on cycle days 3-7 with a sequential injection of 75 IU HMG on cycle days 8-10 for one treatment cycle (n = 87). The pregnancy outcome was recorded after one treatment cycle.

RESULTS

Women receiving sequential treatment achieved a significantly higher ovulation rate than those in the letrozole group (90.8% versus 70.1%, P = 0.001) and the live birth rate of the sequential group was significantly higher than that of the letrozole protocol (23.0% versus 10.3%, P = 0.025); there was no statistical variation with respect to adverse events.

CONCLUSIONS

The data suggest that the sequential letrozole/HMG protocol may be superior to the letrozole alone protocol in terms of ovulation induction and pregnancy promotion among infertile women with PCOS.

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

BACKGROUND

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

OBJECTIVE

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

METHOD

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

Aromatase Inhibitors for Ovarian Stimulation in Patients with Breast Cancer

BACKGROUND

Breast cancer is the most common malignancy diagnosed in women, and its treatment has a high probability of loss of fertility. Oocyte vitrification is the most commonly used technique to preserve fertility before starting oncological treatment. Aromatase inhibitors induce hypoestrogenemia while promoting the release of gonadotropins and constitute an alternative drug for ovarian stimulation in patients with breast cancer.

OBJECTIVE

In this mini-review, we update and describe the current status of aromatase inhibitor use in controlled ovarian stimulation for oocyte vitrification in patients with breast cancer.

RESULTS

Aromatase inhibitors are commonly used in combination with gonadotropins for ovarian stimulation in patients with breast cancer who preserve their fertility through oocyte vitrification. They achieve similar ovarian responses as conventional ovarian stimulation protocols in regards to the number of oocytes, and no additional complications after their use have been reported. Furthermore, aromatase inhibitors seem to be safe not only for offspring, as no more congenital defects occur in newborns from pregnancies achieved after their use, but also for the patients, as no more malignancy recurrence or increased mortality was found in cohort studies.

CONCLUSION

Aromatase inhibitors are elective drugs for ovarian stimulation in patients with breast cancer who decide to preserve their fertility through oocyte vitrification.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION(S)

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

A comparison of the efficacy of two doses of letrozole alone or with continuous recombinant follicle-stimulating hormone for ovulation induction in anovulatory women

AIMS

To determine the efficacy of letrozole alone or with recombinant follicle-stimulating hormone (rFSH) for ovarian induction in anovulatory women.

METHODS

A total of 322 patients undergoing intrauterine insemination (IUI) were included in this retrospective study. Letrozole (2.5 or 5.0 mg) was administered from days 5 to 9 of menses, alone or followed with rFSH started on day 9 until the day of human chorionic gonadotropin administration. A single IUI was performed 24 h after ovulation.

RESULTS

The number of follicles, endometrial thickness and serum estradiol levels were significantly higher in the letrozole + rFSH groups than in the letrozole-alone groups (p < 0.05), but no significant difference was found between the two doses of letrozole, whether alone or with rFSH. Women treated with 5.0 mg/day of letrozole + rFSH required a total dose of rFSH similar to women treated with 2.5 mg/day of letrozole + rFSH (230.77 ± 118.29 vs. 258.55 ± 130.13 IU, respectively; p = 0.205). There was no significant difference in pregnancy rates between the two doses of letrozole, whether alone or with rFSH.

CONCLUSION

Treatment with letrozole + rFSH was more efficacious than letrozole alone for pregnancy in the IUI program; however, the effect of 5.0 mg/day of letrozole versus 2.5 mg/day of letrozole on ovulation was equivalent, regardless of whether rFSH was used.

Extended high dose letrozole regimen versus short low dose letrozole regimen as an adjuvant to gonadotropin releasing hormone antagonist protocol in poor responders undergoing IVF-ET

OBJECTIVE

To compare the efficacy and cost-effectiveness of extended high dose letrozole regimen/HPuFSH-gonadotropin releasing hormone antagonist (GnRHant) protocol with short low dose letrozole regimen/HPuFSH-GnRHant protocol in poor responders undergoing IVF-ET.

METHODS

In this randomized controlled trial, 136 women who responded poorly to GnRH agonist long protocol in their first IVF cycle were randomized into two equal groups using computer generated list and were treated in the second IVF cycle by either extended letrozole regimen (5 mg/day during the first 5 days of cycle and 2.5 mg/day during the subsequent 3 days) combined with HPuFSH-GnRHant protocol or short letrozole regimen (2.5 mg/day from cycle day 3-7) combined with HPuFSH-GnRHant protocol.

RESULTS

There were no significant differences between both groups with regard to number of oocytes retrieved and clinical pregnancy rate (5.39 ± 2.08 vs. 5.20 ± 1.88 and 22.06% vs. 16.18%, respectively).The total gonadotropins dose and medications cost per cycle were significantly lower in extended letrozole group (44.87 ± 9.16 vs. 59.97 ± 14.91 ampoules and 616.52 ± 94.97 vs. 746.84 ± 149.21 US Dollars ($), respectively).The cost-effectiveness ratio was 2794 $ in extended letrozole group and 4616 $ in short letrozole group.

CONCLUSION

Extended letrozole regimen/HPuFSH-GnRHant protocol was more cost-effective than short letrozole regimen/HPuFSH-GnRHant protocol in poor responders undergoing IVF-ET.

Ovulation induction with minimal dose of follitropin alfa: a case series study

BACKGROUND

Gonadotropins are used in ovulation induction (OI) for patients with anovulatory infertility. Pharmacologic OI is associated with risks of ovarian hyperstimulation syndrome and multiple pregnancy. Treatment protocols that minimize these risks by promoting monofollicular development are required. A starting dose of 37.5 IU/day follitropin alfa has been used in OI, particularly among women at high risk of multifollicular development and multiple pregnancy. A retrospective case series study was performed to evaluate rates of monofollicular development and singleton pregnancy following standard treatment with 37.5 IU/day follitropin alfa.

METHODS

Spanish centers that had performed at least five OI cycles during 2008 using 37.5 IU/day follitropin alfa as a starting dose were invited to participate. Data could be provided from any cycle performed in 2008 (up to a maximum of 12 consecutive cycles per site). Case report forms were collected during April-November 2009 and reviewed centrally. Descriptive statistics were obtained from all cases, and follicular development and clinical pregnancy rates assessed. Potential associations of age and body mass index with follicular development and clinical pregnancy were assessed using univariate correlation analyses.

RESULTS

Thirty centers provided data on 316 cycles of OI using a starting dose of 37.5 IU/day follitropin alfa. Polycystic ovary syndrome was the cause of anovulatory infertility in 217 (68.7%) cases. Follitropin alfa at 37.5 IU/day was sufficient to achieve ovarian stimulation in 230 (72.8%) cycles. A single follicle≥16 mm in diameter developed in 193 cycles (61.1%; 95% confidence interval [CI] 55.7-66.4%). Seventy-eight women (24.7%; 95% CI 19.9-29.5%) became pregnant: 94.9% singleton and 5.1% twin pregnancies. Fourteen started cycles (4.4%) were cancelled, mainly due to poor response. Univariate correlation analyses detected weak associations.

CONCLUSIONS

Monofollicular growth rate was comparable with optimal rates reported elsewhere and the pregnancy rate exceeded that in other studies of OI using gonadotropins. A starting dose of 37.5 IU/day follitropin alfa is an effective option in selected cases to prevent ovarian hyper-response without loss of efficacy. The analysis could not identify a single selection criterion for individuals who would benefit from this treatment approach; this merits further investigation in prospective studies.

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

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

Aromatase inhibitors for female infertility: a systematic review of the literature

Ovulation induction remains a milestone in the treatment of women with anovulatory infertility. Clomiphene citrate (CC) is considered the first line treatment for induction of ovulation in women with polycystic ovary syndrome (PCOS), while it may be used for ovulation induction in unexplained infertility. Aromatase inhibitors (AI) have been introduced as a new treatment option that could challenge CC for ovulation induction. A systematic review of the literature was conducted in order to highlight the efficacy and safety of AI in female infertility. Current data from randomized and non-randomized trials suggest that AI may have a role in ovulation induction regimens in PCOS patients, as well as for ovarian stimulation, since they achieve comparable clinical pregnancy rates to CC. Furthermore, when combined with gonadotrophins, AI improve the ovarian response of poor responders and reduce the gonadotrophin dose required. However, the current review is based on small trials with a limited number of patients. If solid data from future large adequately powered randomized trials support current evidence regarding efficacy and safety, AI might offer a new treatment choice for infertile women.

Current trends in the treatment of polycystic ovary syndrome with desire for children

Polycystic ovary syndrome (PCOS), one of the most frequent endocrine diseases, affects approximately 5%–10% of women of childbearing age and constitutes the most common cause of female sterility regardless of the need or not for treatment, a change in lifestyle is essential for the treatment to work and ovulation to be restored. Obesity is the principal reason for modifying lifestyle since its reduction improves ovulation and the capacity for pregnancy and lowers the risk of miscarriage and later complications that may occur during pregnancy (gestational diabetes, pre-eclampsia, etc). When lifestyle modification is not sufficient, the first step in ovulation induction is clomiphene citrate. The second-step recommendation is either exogenous gonadotrophins or laparoscopic ovarian surgery. Recommended third-line treatment is in vitro fertilization. Metformin use in PCOS should be restricted to women with glucose intolerance.