Interest of Sperm Insemination at 42 Hours Post hCG Compared to 36h in Intrauterine Insemination (SYNcIU)

Interest of Sperm Insemination at 42 Hours Post hCG Compared to 36h in Intrauterine Insemination : a Randomized Controlled Trial. SYNcIU

Intrauterine insemination (IUI) is a common therapeutic option to treate infertility. Typically performed 36 hours post-hCG injection to trigger ovulation. However, research suggests delaying IUI to 42 hours post-hCG may improve egg quality and sperm synchronization for fertilization, leading to higher pregnancy rates. A proposed superiority study aims to compare IUI timing at 36 hours versus 42 hours post-hCG injection to evaluate its impact on live birth rates. The primary objective is to assess the effectiveness (live birth rates) of IUI at two different post-hCG timing intervals (42-43 hours vs 36-37 hours).

Study Overview

• Status: Recruiting
• Conditions: Infertility; Intrauterine Insemination (IUI)
• Intervention / Treatment: Procedure: Insemination between 42 and 43 hours post hCG; Procedure: Insemination between 36 and 37 hours post hCG

Detailed Description

Infertility is a major problem affecting approximately 15% of couples worldwide, with a notable increase due to various factors such as advanced maternal age and unhealthy lifestyles. Intrauterine insemination (IUI) is a common treatment option that aims to increase the chances of conception. It is preceded by ovarian stimulation to promote the growth of the follicles. Traditionally, IUI is performed 36 hours after an hCG injection to trigger ovulation, but research suggests benefits to delaying it. Studies have shown that delaying IUI to 42 hours post-hCG could improve oocyte quality and sperm synchronization for fertilization. Randomized clinical trials have shown higher pregnancy rates with delayed UTIs to 42 hours. We therefore propose a superiority study to compare IU at 36 hours and 42 hours post-hCG, taking into account the origin of the sperm used. This study will be the first to evaluate the effect of hCG-IU delay on live birth rates. In all centers, inseminations will be carried out according to the usual procedure. Patients in the experimental group will be stimulated by gonadotropins, ovulation will be blocked by a GnRH antagonist then triggered by hCG allowing IU to occur between 42 and 43 hours post hCG. These treatments are similar to the control group. Only the timing of the IUI compared to the timing of ovulation triggering is different. In the comparison group, ovulation will be triggered in order to carry out intrauterine insemination between 36 and 37 hours post hCG (as is already the case in clinical practice). Blinding is not possible for this study. On the other hand, the different endpoints will be evaluated without the randomization group being blinded by the evaluating gynaecologists. The monitoring of included patients is similar to the care pathway. The follow-up data (pregnancy test, pregnancy ultrasound, progress of the birth) will be carried out in the same way as the care (for which these data are necessarily collected)

• Study Type: Interventional
• Enrollment (Estimated): 692
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Celia BETTIOL, CRA; Email: bettiol.c@chu-toulouse.fr
• Study Contact Backup: Name: Jessika MOREAU, MD; Phone Number: +33 567771017; Email: moreau.je@chu-toulouse.fr

Study Locations

• France
  • Bordeaux, France
    • Not yet recruiting
    • Chu Bordeaux
    • Contact: Lucie CHANSEL-DEBORDEAUX, MD; Phone Number: +33 05 56 79 56 81; Email: lucie.chansel-debordeaux@chu-bordeaux.fr
    • Principal Investigator: Lucie Chansel Debordeaux, MD
  • La Réunion, France
    • Not yet recruiting
    • CHU La Réunion
    • Contact: Joffrey MONS, MD; Phone Number: +33 02 62 35 95 19; Email: joffrey.mons@chu-reunion.fr
    • Principal Investigator: Joffrey MONS, MD
  • Poitiers, France
    • Not yet recruiting
    • CHU Poitiers
    • Contact: Stéphanie ROBERT BITAUDEAU, MD; Phone Number: +33 05.49.44.39.56; Email: Stephanie.ROBERT-BITAUDEAU@chu-poitiers.fr
    • Principal Investigator: Stephanie ROBERT-BITAUDEAU, MD
  • Toulouse, France
    • Recruiting
    • CHU Toulouse
    • Contact: Jessika MOREAU, MD; Phone Number: +33 567771017; Email: moreau.je@chu-toulouse.fr
    • Principal Investigator: Jessika MOREAU, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Single unmarried woman or heterosexual or homosexual couple in which the woman wishing to carry the pregnancy is aged 18 to 43 and the spouse is aged 18 to 60 at the time of inclusion
• 2 permeable tubes for the woman receiving the insemination
• Spouse's sperm (Number of inseminable sperm ≥ 1 million in prior survival migration test) or sperm donation
• 1st or 2nd intrauterine insemination for this child project
• Ovarian stimulation by gonadotropin with GnRH antagonist (introduced on a fixed day or according to the follicular size criterion of the center)
• Luteal phase support with a progestin until at least the pregnancy test
• Affiliation or beneficiary of a social security scheme or equivalent for both partners of the couple if applicable
• Free and informed consent signed by the unmarried woman or both members of the couple
• Couples and unmarried women meeting the conditions for access to PMA according to the French bioethics law

Exclusion Criteria:

• Endometriosis stage III or IV
• History of ectopic pregnancy
• ≥ 3 spontaneous miscarriages
• Single woman or couple where one of the two partners (or both) is (are) under the protection of justice, under guardianship or under curatorship
• Single woman or couple who have already participated in the study once
• Single woman or couple participating in another interventional clinical study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental group: insemination between 42 and 43 hours post hCG; Patients in the experimental group will be stimulated by gonadotropins, ovulation will be blocked by a GnRH antagonist then triggered by hCG allowing IU to occur between 42 and 43 hours post hCG. These treatments are similar to the control group. Only the timing of the IUI compared to the timing of ovulation triggering is different	Procedure: Insemination between 42 and 43 hours post hCG; Patients will be stimulated by gonadotropins, ovulation will be blocked by a GnRH antagonist then triggered by hCG allowing IU to occur between 42 and 43 hours post hCG
Active Comparator: Control group: insemination between 36 and 37 hours post hCG; In the comparison group, patients will be stimulated with gonadotropin and GnRH antagonist whose ovulation will be triggered and for which intrauterine insemination will be carried out between 36 and 37 hours post hCG (as it is already the case in clinical practice).	Procedure: Insemination between 36 and 37 hours post hCG; Patients will be stimulated with gonadotropin and GnRH antagonist whose ovulation will be triggered and for which intrauterine insemination will be carried out between 36 and 37 hours post hCG

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Delivery rate after 22 weeks of pregnancy with at least one live birth per woman	The live birth rate is the most relevant clinical criterion for judging the effectiveness (success) of the IUI attempt. This criterion will be evaluated according to the usual procedures of the centers via the obligatory collection of post-ART childbirth data and transmission in a regulatory manner to the Biomedicine Agency.	the day of delivery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Biochemical pregnancy rate	Number of β-hCG >100 IU/l	The day of the pregnancy test: 15 days after insemination (T0)
Clinical pregnancy rate	Presence of at least one intrauterine gestational sac with fetal heart activity.	During ultrasound realised at 6 weeks' amenorrhea (SA)
Spontaneous miscarriage rate	Number of pregnancies terminated before 22 weeks of pregnancy/number of biochemical pregnancies	The day of delivery before 22 weeks of pregnancy

Collaborators and Investigators

• Sponsor: University Hospital, Toulouse

Study record dates

Study Major Dates

• Study Start (Actual): September 9, 2025
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: January 9, 2025
• First Submitted That Met QC Criteria: January 27, 2025
• First Posted (Actual): February 3, 2025

Study Record Updates

• Last Update Posted (Actual): May 5, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: infertility; intrauterine insemination; live birth; timing; sperm donation
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Infertility
• Other Study ID Numbers: RC31/24/0309

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No