This prospective cohort study aims to establish a cut-off threshold for pre-washed total rapidly motile sperm count (TRMSC) based on WHO 2021 criteria to predict the live birth rate following intrauterine insemination (IUI). The study seeks to answer two key questions:

1. Is there a correlation between TRMSC, as per the WHO 2021 criteria, and the live birth rate after IUI?
2. What is the appropriate cut-off threshold of TRMSC to predict a positive live birth outcome after IUI? Couples undergoing ovulation induction and IUI for indicated reasons will participate in the study. On the day of insemination, the pre-washed semen from the husband will be assessed according to the WHO 2021 criteria. The outcomes of the IUI procedure will be documented.

Eligible patients will be enrolled in the study on the day of intrauterine insemination (IUI). Both spouses will receive detailed information about the study and provide informed consent. Sperm motility will be evaluated according to the WHO 2021 guidelines before filtration and washing.

Ovarian stimulation will be conducted using human menopausal gonadotropins (hMG) with regular ultrasound monitoring of follicular development. Once the lead follicle reaches a size of 18mm, ovulation will be induced using hCG. If six or more follicles reach a size of 14mm, the patient will be advised to cancel the cycle or consider in-vitro fertilization (IVF). IUI will be performed 36-38 hours after hCG injection.

For patients who prefer non-injection-based ovarian stimulation, an oral agent using letrozole will be offered. Letrozole with a dosage of 5 to 7.5 mg will be administered orally from days 2-5 of the menstrual cycle, and ovarian follicle development will be assessed through ultrasound on day 10.

Sperm samples will be collected through masturbation at the hospital after a period of 2-5 days of ejaculation abstinence. Motility analysis will be performed based on the WHO 2021 guidelines, which classify sperm as rapid progressive (A), slow progressive (B), non-progressive (C), or immotile (D), using the formula: percentage of rapid progressive sperm x density x volume. Semen parameters, including volume, density, and normal morphology ratio, will also be evaluated according to the WHO 2021 guidelines.

The collected sample will undergo processing using the density gradient method, following the WHO 2021 guidelines. The processed semen will be used for IUI, and its concentration and motility will be examined.

During the insemination procedure, a Gynétic soft catheter will be used. After the procedure, the patient will rest for 15 - 20 minutes, followed by luteal-phase support using vaginal micronized progesterone for 14 days. The presence of hCG in the blood will be tested after 14 days to determine a biochemical pregnancy. Confirmation of clinical pregnancy will be based on ultrasound observation of a gestational sac at 7 weeks of gestational age. Prenatal care until delivery will be provided either at specified hospitals or through regular contact.

During delivery, data on labour, delivery, and any complications experienced by the participant or newborn will be collected. Participants who cannot attend prenatal care at the designated hospitals will be contacted regularly for data collection. Descriptive analysis will be used to describe the background characteristics of the study population, presenting continuous variables as means and standard deviations (SD) and comparing them using appropriate statistical tests. Categorical variables will be presented as percentages and compared using relevant statistical tests such as Pearson's chi-square or Fisher's exact test.

Inclusion Criteria:

• Patient undergoing IUI
• Undergone <4 previous IUI cycles
• Total progressive motility sperm count before sperm preparation: > 5million
• Agree to participate in the study

Exclusion Criteria:

• Using frozen semen

Live babies born in couples undergo intrauterine insemination