Comparing Letrozole with Natural Cycle for Intrauterine Insemination

Intrauterine Insemination With Letrozole Versus Intrauterine Insemination in Natural Cycle. A Muticenter Randomized Controlled Trial

Not applicable Interventional Peking University Third Hospital · NCT04169451

This study tests if using letrozole to stimulate ovaries can help couples with unexplained infertility or mild male factor infertility have a baby through IUI, compared to doing it naturally.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment982 (estimated)
Ages20 Years and up
SexFemale
SponsorPeking University Third Hospital Academic / other
Locations1 site (Beijing, Beijing Municipality)
Trial IDNCT04169451 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to evaluate the effectiveness of ovarian stimulation with letrozole compared to natural cycle intrauterine insemination (IUI) in couples facing unexplained infertility or mild male factor infertility. The study will be conducted as a multicenter randomized controlled trial across five reproductive medical centers in China. The primary objective is to determine if letrozole increases the live birth rate without significantly raising the risk of multiple pregnancies. Couples meeting specific eligibility criteria will be enrolled to assess the outcomes of the two treatment approaches.

Who should consider this trial

Good fit: Ideal candidates include couples diagnosed with unexplained infertility or mild male factor infertility who have at least one patent fallopian tube and normal or mildly impaired semen quality.

Not a fit: Patients with double-sided tubal pathology, irregular cycles, or significant male infertility may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could enhance fertility outcomes for couples struggling with unexplained infertility.

How similar studies have performed: Previous studies have suggested that ovarian stimulation may improve live birth rates in similar populations, indicating potential success for this approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion criteria

In order to be eligible to participate in this study, a participating couple must meet all of the following criteria:

* Being diagnosed with unexplained or mild male infertility
* At least one sided tubal patency, established according to local protocol
* Normal or mild impairment of semen quality defined as total motile sperm count (TMSC) no less than 5million, based on at least one recent semen analysis

Exclusion criteria

A potential participant who meets any of the following criteria will be excluded from study participation:

* Woman with double sided tubal pathology
* Women with irregular cycles, PCOS or other endocrine disorders
* Man with impaired semen quality: total motile sperm count (TMSC) less than 5million

Where this trial is running

Beijing, Beijing Municipality

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Intrauterine InseminationUnexplained Infertility
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.