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Showing 13 results for Letrozole

Robab Davar, Abbas Aflatoonian,
Volume 2, Issue 2 (7-2004)

Background: In patients with anovulatory infertility the first choice of treatment for ovulation induction is an antiestrogen, most commonly clomiphene citrate (CC). However, 20-25% of the women are resistant to CC and do not ovulate perhaps due to antiestrogenic mechanism of the CC action, which involves long-lasting estrogen receptor (ER) depletion. Objective: The objective of the study was to mimic the action of CC without depletion of ERs by the administration of an aromatase inhibitor letrozole in a selected group of Poly Cystic Ovary (PCO) patients who demonstrated failure to ovulate after treatment with CC. Materials and Methods: 20 patients with anovulation due to polycystic ovary syndrome (PCOS), who had previously inadequately responded to CC were selected for study. The aromatase inhibitor letrozole was administered orally in a dose of 2.5 mg on days 3-7 of the menstrual cycle. Then, occurrence of ovulation, endometrial thickness, and pregnancy rates were determined. Result(s): Only one patient had one dominant follicle (1.8 cm diameter) on day 14 of the cycle (estradiol = 200 pg/ml). IUI was done; however, no pregnancy took place. In the remaining cases, several sonographies were done between days 9 to 15 of the cycle; however, all cycles were cancelled due to absence of a dominant follicle (>1.4 cm). Conclusion(s): Our study did not confirm the favorable effect of letrozole for induction of ovulation in patients with clomiphene resistant PCO. Article
Robab Davar, Mojgan Javedani, Mohammad Hossein Fallahzadeh,
Volume 9, Issue 1 (7-2011)

Background: Polycystic ovary syndrome (PCOS) is associated with approximately 75% of women who suffer from infertility due to anovulation. Additionally, around 20– 25% of anovulatory women with PCOS do not respond at all to clomiphene citrate and are considered to be “clomiphene– resistant”. Aromatase inhibitors have been suggested as an alternative treatment to clomiphene as the discrepancy between ovulation and pregnancy rates with clomiphene citrate has been attributed to its anti-estrogenic action and estrogen receptor depletion.
Objective: The aim of this study is to compare results of Metformin-letrozole with Metformin-clomiphene citrate in clomiphene resistance PCOS patients undergoing IUI.
Materials and Methods: In this single blind randomized trial, ovarian cycles were studied in 100 clomiphene- resistant patients with PCOS. The inclusion criteria were patients who received 150mg clomiphene citrate daily for 3 cycles and failed to become pregnant. The patients were matched for their age, body mass index (BMI), and infertility period. They were randomly allocated to a metformin-letrozole group (n=50) and a metformin-clomiphene citrate group (n=50). Chemical and clinical pregnancies were assessed after IUI. Abortion rates were determined in both groups.
Results: Regarding pregnancy rate, there was no significant difference between the two groups. One miscarriage (2%) occurred in the metformin-clomiphene citrate group, whereas none was seen in the metformin-letrozole group.
Conclusion: There is no significant difference in pregnancy rate between clomiphene citrate and letrozole groups although it has been 2% in the former and 5% in the latter. Article
Soheila Akbari, Maryam Ayazi Roozbahani, Fatemeh Ayazi Roozbahani,
Volume 10, Issue 1 (7-2012)

Background: Clomiphene citrate (CC) an agonist and antagonist of estrogen, is the first line treatment in ovarian stimulation. Anti-estrogenic effect of CC in endometrial thickness and cervical mucus has negative effect on pregnancy rate. Letrozole is an Aromatase Inhibitor has been seen that has acceptable pregnancy rate compared to CC.
Objective: The aim of this study was to compare the efficacy of letrozole and clomiphene citrate (CC) with gonadotropins for ovarian stimulation in women candidate for intrauterine insemination (IUI).
Materials and Methods: One hundred sixty patients eligible to IUI therapy enrolled in this study. Patients randomized to two groups: group A (received letrozole-gonadotropin) and group B (received CC-gonadotropin). In group A (n=80) letrozole was given on days 3-7 of the menstrual cycles. In group B clomiphen citrate was given like letrozole combined with human menopausal gonadotropin (hMG) administered every day starting on day 8. Ovulation was triggered with urinary HCG when the leading follicle (s) reached 18 mm in diameter. A single IUI was performed 36-40 hours later. The ovarian stimulation response (E2 levels and number of follicles, clinical pregnancy and endometrial thickness) was primary outcome.
Results: Both groups were similar in demographic characteristics. There was a significantly lower peak serum E2 level in the letrozole group compared with CC. (236±86 Vs. 283±106 pg/mL, respectively; p<0.002). The number of mature (>18 mm) preovulatory follicles was significantly higher in CC group than letrozole group (2.2±.68 Vs. 2.02±0.63 respectively; p=0.025). Endometrial thickness measured at the time of hCG administration was significantly higher in letrozole group. (9.08±1.2 mm Vs. 8.1±1.9 mm; p=0.0001). The clinical pregnancy rate was comparable between two groups.
Conclusion: Letrozole is a good and cost-effective alternative to CC in IUI cycles.
Azam Azargoon, Jafar Alavy Toussy, Fakhry Fakhr Darbanan,
Volume 10, Issue 1 (7-2012)

Background: Clomiphen citrate (CC) is the first line therapy for women with infertility and poly cystic ovary syndrome( PCOS). However, 20-25% of women are resistant to CC and do not ovulate.
Objective: The objective of this study was to evaluate the efficacy of sequential treatment of metformin and incremental doses of letrozole in induction of ovulation in cases of CC-resistant PCOS patients.
Materials and Methods: In this prospective before-after study, we enrolled 106 anovulatory PCOS women who failed to ovulate with CC alone from Amir-Almomenin University Hospital in Semnan, Iran. After an initial 6-8 weeks of metformin treatment, they received 2.5 mg letrozole daily on days 3-7 after menes. If they did not ovulate with 2.5 mg letrozole, the doses were increased to 5 to 7.5 mg daily in subsequent cycles. The main outcomes were ovulatory rate, pregnancy rate and cumulative pregnancy rate.
Results: 13.33% of patients conceived with metformin alone. Ovulation occurred in 83 out of remaining 91 patients (91.2%). 78.02% of patients responded to lower doses of letrozole. Cumulative pregnancy rate was 60/ 105 (57.14%).
Conclusion: We suggest that treatment in CC-resistant PCOS patients should begin at first with lower doses of letrozole and could increase to the higher dose depending on the patient response before considering more aggressive therapeutic alternatives such as gonadotropins.
Fariba Seyedoshohadaei, Farnaz Zandvakily, Shole Shahgeibi,
Volume 10, Issue 6 (4-2012)

Background: Unovulation is the most common cause of infertility. The first line oral treatment has been clomiphene citrate. Another anti-estrogen used for ovulation induction is tamoxifen. Many unovulatory infertile women are resistance to anti-estrogens and need another treatment. Alternative treatments are aromatas inhibitors.
Objective: This study was designed to compare the effectiveness of clomiphene, tamoxifen and letrozole in ovulation induction outcomes in isolated non PCOS unovulatory patients.
Materials and Methods: 150 unovulatory infertile women who had isolated non- polycystic ovarian syndrome (PCOS), randomized to 3 groups. Group A received clomiphene 50 mg to maximum 150 mg for 5 days, Group B received tamoxifen 10mg to maximum 30 mg for 5 days, Group C received letrozole 2.5 mg for 5 days, to maximum 7.5 mg until ovulation was induced. If ovulation failed to occur with 5 days treatments, drug continued for 7 days. Treatment has been stopped if they became pregnant or if patient didn’t ovulate with maximum dose for 7 days (resistant to treatment) or failed to concept after six months despite ovulation (failure of treatment). Main outcome measures were: number of mature follicles, endometrial thickness, pregnancy rate, multiple pregnancy rate, live birth and miscarriage.
Results: Overall ovulation rate was 60 (73.4%), this rate in group A was 39 (78%), in group B it was 24 (68%) and in group C was 37 (74%). Pregnancy rate in groups A, B and C were, 32 (64%), 20 (40%), and 25 (50%) respectively, and live birth rate was 22 (44%) in A, 17 (34%) in B and 21 (42%) in C. Miscarriage rate with clomiphene was 10 (20%) while this was 3 (6%) in tamoxifen and 4 (8%) in letrozole group (p=0.05). One twin pregnancy was occurred with clomiphene and one with tamoxifen, while all pregnancies with letrozole were singleton.
Conclusion: Because of higher pregnancy rate with clomiphene citrate than tamoxifen and letrozole, Clomiphene citrate is still the first-line therapy for ovulation induction. Surprisingly, pregnancies after tamoxifen and letrozole have lower miscarriage rate than clomiphene.
Maryam Eftekhar, Farnaz Mohammadian, Robab Davar, Soheila Pourmasumi,
Volume 12, Issue 11 (12-2014)

Background: Poor ovarian response to controlled ovarian stimulation is one of the most important interest points in assisted reproduction. Mild ovarian stimulation seems to be preferable to high dose of FSH regimens in women with a history of poor ovarian response in previous protocol. Clomiphene citrate and letrozole alone or in combination with FSH have been used in mild ovarian stimulation protocol.
Objective: To compare the efficacy of letrozole and clomiphene citrate for mild ovarian stimulation on assisted reproductive technology outcomes in poor responders.
Materials and Methods: In a randomized control study, 184 women aged between 20 and 45 years with the history of poor response to ovarian stimulation who were candidate for ART were randomly subdivided into two groups: group I (n= 80), women who underwent the clomiphene/gonadotropin/antagonist protocol; and group II (n= 87), patients who underwent the letrozole/gonadotropin/antagonist protocol. Groups were compared regarding implantation, chemical and clinical pregnancy rates.
Results: There was a significant difference in the mean endometrial thickness between two groups (9.16±1.2 mm vs. 8.3±0.3 mm). The implantation rate was significantly higher in letrozole group compare to clomiphene group (7.2 vs. 6.6%, p=0.024 respectively). No significant differences were found in chemical and clinical pregnancy rate between two groups.
Conclusion: In mild ovarian stimulation protocol, letrozole and clomiphene have similar value for the poor responder. The optimal treatment strategy for these patients remains debated.
Leila Pourali, Sedigheh Ayati, Shirin Tavakolizadeh, Hourieh Soleimani, Fatemeh Teimouri Sani,
Volume 15, Issue 1 (1-2017)

Background: Clomiphene citrate is one of the effective drugs for infertilitytreatment due to oligo-ovulation or anovulation. Intrauterine insemination (IUI) isone of more adherent methods for treatment of infertile cases which is followed bycontrolled ovarian hyperstimulation (COH).
Objective: the aim of this study was to evaluate Clomiphene citrate versus letrozolewith gonadotropins in IUI cycles.
Materials and Methods: In this prospective randomized trial, 180 infertile patientswho were referred to Milad Hospital were selected. The first group received 5mg/day letrozole on day 3-7 of menstrual cycle. The second group received 100mg/day Clomiphene in the same way as letrozole. In both groups, humanmenopausal gonadotropin was administered every day starting on day between 6-8of cycle. Ovulation was triggered with urinary Human Chorionic Gonadotropin(5000 IU) when have two follicles of ≥16 mm. IUI was performed 36 hr later.
Results: The number of matured follicles, cycle cancellation, and abortion were thesame in both groups. Endometrial thickness was higher at the time of humanmenopausal gonadotropin administration in letrozole group. Chemical and clinicalpregnancy rates were much higher in letrozole group. Ovarian hyperstimulation wassignificantly higher in clomiphene group.
Conclusion: Letrozole appears to be a good alternative to clomiphene citrate withfewer side effects.
Mahbod Ebrahimi, Firouzeh Akbari-Asbagh, Mojgan Ghalandar-Attar,
Volume 15, Issue 2 (3-2017)

Background:Gonadotropin-releasing hormone (GnRH) antagonist protocol has been proposed as a potentially proper option for the patients with limited ovarian reserve. Nevertheless, there is no significant difference in terms of clinical pregnancy between the GnRH antagonist and agonist cycles. The use of aromatase inhibitors such as letrozole was suggested by some studies.
Objective: The object of this study was to evaluate the efficacy of letrozole co-treatment with GnRH-antagonist protocol in ovarian stimulation of poor responder patients undergoing intracytoplasmic sperm injection.
Materials and Methods: A double-blinded randomized control trial was conducted on 70 infertile women with poor ovarian response based on Bologna criteria in two groups: letrozole+GnRH-antagonist (LA) group and placebo+GnRH-antagonist (PA) group (n=35/each). The LA group involved at letrozole 2.5 mg daily over 5 days and recombinant human follicle stimulating hormone 225 IU/daily. The PA group received placebo over 5 days and recombinant human follicle stimulating hormone at the same starting day and dose, similar to LA group. GnRH-antagonist was introduced once one or more follicle reached ≥14 mm. The main outcome measures were the number of oocytes retrieved, fertilization rate, implantation rate, cycle cancellation rate, and clinical pregnancy rate.
Results: There were no significant differences in demographic characteristics between groups. There were no significant differences between groups regarding the number of oocytes retrieved (p=0.81), number of embryos transferred (p=0.82), fertilization rate (p=0.225), implantation rate (p=0.72), total cycle cancelation rate (p=0.08), and clinical pregnancy rate (p=0.12).
Conclusion: The use of letrozole in GnRH-antagonist cycles does not improve clinical outcomes in poor responder patients undergoing intracytoplasmic sperm injection.
Ashraf Aleyasin, Marzieh Aghahosseini, Leili Safdarian, Maryam Noorzadeh, Parvin Fallahi, Zahra Rezaeian, Sedighe Hoseinimosa,
Volume 15, Issue 2 (3-2017)

Background: There are different methods in endometrial preparation for frozen-thawed embryo transfer (FET).
Objective: The purpose of this study was to compare the live birth rate in the artificial FET protocol (estradiol/ progesterone with GnRH-agonist) with stimulated cycle FET protocol (letrozole plus HMG).
Materials and Methods: This randomized clinical trial included 100 women (18-42 years) randomly assigned to two groups based on Bernoulli distribution. Group I received GnRH agonist [Bucerelin, 500μg subcutaneously] from the previous midlutea lcycle, Then estradiol valerat [2 mg/ daily orally] was started on the second day and was increased until the observation of 8mm endometrial thickness. Finally progesterone [Cyclogest, 800 mg, vaginally] was started. Group II received letrozole on the second day of the cycle for five days, then HMG 75 IU was injected on the7PthP day. After observing [18 mm folliclhCG10000 IU was injected for ovulation induction. Trans cervical embryo transfer was performed in two groups. The main outcome was the live birth rate. The rate of live birth, implantation, chemical, and clinical pregnancy, abortion, cancellation and endometrial thickness were compared between two groups.
Results: Implantation rate was significantly higher in group I. Live birth rate was slightly increased in group I without significant difference (30% vs. 26%). The rate of chemical and clinical pregnancy was similar in two groups. The abortion rate was lower in letrozole protocol but the difference was not statistically significant. The mean endometrial thickness was not different between two groups.
Conclusion: Letrozole plus HMG method cannot improve pregnancy outcomes in frozen-thawed embryo transfer but it has only one injection compare to daily injections in artificial method
Tahereh Behrouzi Lak, Masoomeh Hajshafiha, Fariba Nanbakhsh, Sima Oshnouei,
Volume 15, Issue 4 (6-2017)

Background: N-acetyl cysteine (NAC) was proposed as an adjuvant to clomiphenecitratefor ovulation induction in patients with polycystic ovary syndrome (PCOS)without clomiphene citrate resistance.
Objective: To evaluate the effect of NAC on pregnancy rate in PCOS patients whowere candidates for intrauterine insemination.
Materials and Methods: In this randomized clinical trial 97 PCOS women aged 18-38 years were enrolled in two groups, randomly. For the case group (n=49), NAC(1.2 gr) + clomiphene citrate (100 mg) + letrozole (5mg) were prescribed dailyfromthe third day of menstruation cycle for five days. The control group (n=48) had thesame drug regimen without NAC. In order to follicular development, GONAL-Fwas injected on days of 7-11 menstrual cycles in all participants. When the folliclesize was 18mm or more, HCG (10000 IU) was injected intramuscular and theintrauterine insemination was performed after 34-36 hr.
Results: There was no significant difference between study groups regarding BMI(p=0.28), FSH level (p=0.66), LH level (p=0.67), mean endometrial thickness(p=0.14), mean number of mature follicles (p=0.20) and the pregnancy occurrence(p=0.09).
Conclusion: NAC is ineffective in inducing or augmenting ovulation in PCOSpatients who were candidates for intrauterine insemination and cannot berecommended as an adjuvant to CC in such patients.
Ashraf Moini, Zohreh Lavasani, Ladan Kashani, Maryam Farid Mojtahedi, Nazila Yamini,
Volume 17, Issue 9 (9-2019)

Background: Ovarian stimulation (OS) for poor ovarian response (POR) patients is still a major challenge in assisted reproductive techniques. Aromatase inhibitors as co-treatment in antagonist protocol are suggested to these patients, but there are controversial reports.
Objective: To evaluate the effectiveness Letrozole (LZ) as adjuvant treatment in gonadotropin-releasing hormone (GnRH)-antagonist protocol in POR patients undergoing in vitro fertilization/ intracytoplasmic sperm injection cycles.
Materials and Methods: This double-blind randomized clinical trial was conducted in Arash women's hospital. One hundred sixty infertile women with POR based on Bologna criteria were allocated into two groups randomly: LZ + GnRH-antagonist (LA) and placebo + GnRH-antagonist (PA) groups. In the experimental group, the patients received 5 mg LZ on the first five days of OS with 150 IU of recombinant human follicle-stimulating hormone (rFSH) and 150 IU of human menopausal gonadotropin (HMG). The cycle outcomes were compared between groups.
Result: The total number of retrieved oocytes and the metaphase II oocytes in LA-treated group were significantly higher than those in the control group (p = 0.008, p = 0.002). The dosage of hMG used and the duration of OS and antagonist administration in LZ-treated group were significantly lower than those of the control group. The number of patients with no oocyte, in the control group, was higher than the LZ-treated group, and the clinical pregnancy rate in LA-treated group (25%) was higher than the control group (18%); however, the differences were not significant statistically.
Conclusion: Adding 5 mg of LZ to rFSH/hMG antagonist protocol may improve the in vitro fertilization/intracytoplasmic sperm injection cycle outcome in POR patients.
Alamtaj Samsami, Leila Ghasempour, Sara Davoodi, Shaghayegh Moradi Alamdarloo, Jamshid Rahmati, Ali Karimian, Hamide Homayoon,
Volume 17, Issue 12 (12-2019)

Background: The endometrial preparation with stimulating natural cycles for frozen embryo transfer (FET) have benefits like lower cost and ease of use.
Objective: Comparing the clinical outcome of letrozole versus hormone replacement (HR) for endometrial preparation in women with normal menstrual cycles for FET in artificial reproduction techniques.
Materials and Methods: A total of 167 participants who had frozen embryos and regular ovulatory cycles were randomly divided into two groups for endometrial preparation. One group (82 women) was stimulated with letrozole 5mg/day and the other group (85 women) was hormonally stimulated by oral estradiol valerate (2 mg three times a day). All participants were followed serially by ultrasonography. Any patient who did not reach optimal endometrial thickness was excluded from the study. Implantation, biochemical and clinical pregnancy and abortion rate were reported.
Results: There was no significant difference in the mean age, duration, and primary or secondary infertility, cause of the infertility, number, and quality of transferred embryos between the groups. The mean estradiol level on the day of transfer was 643 ± 217 in the HR group and 547 ± 212 in the letrozole group (P = 0.01), which was significantly different. The clinical pregnancy rate was 38.7 in the letrozole group, higher than the HR group (25.3) but not significantly different (P=0.06).
Conclusion: For endometrial preparation in women with a normal cycle, letrozole yields higher pregnancy rate although it is not significant; due to its cost, ease in use, and lower side effects, letrozole is a good choice.
Nayere Khadem Ghaebi, Malihe Mahmoudiniya, Mona Najaf Najafi, Elnaz Zohdi, Matin Attaran,
Volume 18, Issue 2 (2-2020)

Background: The use of frozen embryo transfer (FET) is increasing worldwide in the treatment of infertility by in vitro fertilization. Different methods of endometrial preparation for FET have been suggested.
Objective: The aim of this study was to compare the pregnancy outcomes after treatment with letrozole and those after treatment with the combination of gonadotropin-releasing hormone (GnRH) agonist and estradiol in FET.
Materials and Methods: This randomized controlled trial study was conducted on 142 infertile women with a history of previous FET failure. Participants were randomly assigned to two groups (n = 71 each). The GnRH group received 500 µg of buserelin plus 4mg estradiol (which increased to 8 mg if endometrial thickness was less than 5 mm), and the letrozole group received 5 mg of letrozole plus 75 IU of recombinant human follicle-stimulating hormone). At least two high-quality embryos were transferred to each subject in both groups. The outcome measures were clinical pregnancy rate and fetal heart rate detection.
Results: Subjects in the study groups had similar demographic characteristics and baseline clinical condition. Mean endometrial thickness in the letrozole and GnRH agonist groups were 8.90 ± 0.88 mm and 8.99 ± 0.85 mm, respectively (p = 0.57). The number of positive results of the beta human chorionic gonadotropin test and detection of fetal heartbeat were not significantly different between the groups (p > 0.05).
Conclusion: The administration of letrozole and GnRH may produce similar pregnancy outcomes in FET.

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