Investigating the effect of repeated Letrozole doses on mature follicles status and pregnancy rate in women with polycystic ovary syndrome resistant to the initial Dose: a randomized controlled trial.

Determining the effect of repeated letrozole dose on mature follicle and pregnancy rate in women with polycystic ovary syndrome resistant to the initial dose.

A clinical trial with a control group with parallel, single-blind, randomized, phase 3, on 124 patients with polycystic ovary syndrome resistant to the initial dose of letrozole. The sealed envelope site was used for randomization.

Infertile women with polycystic ovary syndrome, referring to one of the private clinics in Rasht, who will be treated with letrozole in a dose of 5 mg/for 5 days. Then, on day 13-14 of the cycle, they will undergo transvaginal sonography, and if all follicles are less than 12 mm, they will be considered as not responding to letrozole.all these patients (resistant to the initial dose of letrozole) were randomly selected .They will be assigned to two intervention and control groups.study is single blinded.

Inclusion criteria: All infertile women with polycystic ovary syndrome resistant to letrozole primary treatment , with full consent to participate in the study, under the age of 35, With the indication of using oral medicine (not received 6 cycles of ovulation induction medication) Exclusion criteria: Obstruction of the fallopian tubes, absence of a normal uterine cavity , ovarian cysts , metabolic diseases and any disease with a negative effect on ovulation, chronic heart, liver and kidney diseases, abnormal sperm analysis, using other ovulation induction drugs at the same time

The intervention group, will take 2 letrozoles per day for 5 days from the 14th (with repeated letrozole dose) The control group:without receiving letrozole again

The size of mature follicle equal to 17 mm in ultrasound evaluation on day 22-23 of the cycle

124 PCOS women resistant to initial dose of letrozole are divided into 2 groups of 62 people (intervention and control). Group 1 (control) is named A and group 2 (intervention) is named B. Random block classification is assigned to the research units based on the randomized list by the sealed envelope website. Then a table that has 31 rows called block and each block will have 4 parts and each part will be named with A and B will be considered In the next step, the numbers are placed in each house in order. After all the numbers have been placed in the blocks, the people who had numbers in house A will receive packages with code A, and the people who have numbers in house B will receive packages with code B. Concealment is done using a sealed envelope method that is given to a third person outside the research team..

The study is single blinded, the final ultrasound to evaluate the diameter of the follicle is performed by the main researcher (project manager) who is not aware of the grouping. Also, for data analysis, a statistician who is separate from the study process and is unaware of all the performed processes will be used.