Mannose-binding lectin levels and repeated pregnancy or implantation failure

Is Plasma Level of Mannose Binding Lectin Associated With Reproductive Failure?

This project will test whether low blood levels of mannose-binding lectin are linked to repeated pregnancy loss, repeated failed embryo transfers after IVF/ICSI/FET, or other unexplained infertility in people with three consecutive pregnancy failures.

Quick facts

• Study type: Observational
• Enrollment: 500 (estimated)
• Ages: 18 Years to 41 Years
• Sex: Female
• Sponsor: Aalborg University Hospital (Academic / other)
• Locations: 1 site (Aarhus)
• Trial ID: NCT05169541 on ClinicalTrials.gov

What this trial studies

This is an observational study measuring plasma mannose-binding lectin (p-MBL) levels in people with recurrent reproductive failure, including recurrent pregnancy loss after spontaneous conception, recurrent pregnancy loss after ART, and recurrent implantation failure after embryo transfer. Participants who meet strict inclusion criteria will have a blood sample taken and their p-MBL level compared with expected background prevalence and across the different reproductive-failure groups. The study excludes people with known chromosomal abnormalities, significant uterine or endometrial pathology, very low ovarian reserve (AMH <4.0 pmol/L unless donor egg used), or pregnancy beyond 9 weeks at sampling. Results will describe how common low or high p-MBL is in these groups and whether patterns differ between RPL, RIF, and ART-related losses.

Who should consider this trial

Good fit: People aged 18–45 who have experienced either three consecutive pregnancy losses after spontaneous conception, three consecutive pregnancy losses after ART, or three failed embryo transfers (each cycle with at least one good-quality embryo), and who do not have exclusionary conditions such as major uterine malformations or known chromosomal abnormalities and have AMH ≥4.0 pmol/L unless donor eggs were used.

Not a fit: People with known causes of reproductive failure (for example parental chromosomal abnormalities, significant uterine or endometrial disease), those with very low ovarian reserve (AMH <4.0 pmol/L without donor eggs), or those unable to attend the Aarhus site are unlikely to benefit from joining this observational project.

Why it matters

Potential benefit: If low p-MBL is tied to certain types of reproductive failure, testing could help identify people who might benefit from tailored diagnostic work-ups or targeted management strategies.

How similar studies have performed: Previous research has reported a higher prevalence of low p-MBL in unexplained recurrent pregnancy loss, but its association with recurrent implantation failure and ART-related losses is less studied and this work expands that inquiry.

Eligibility criteria

Inclusion Criteria:

fulfil one of the following:

* 3 consecutive pregnancy losses after spontaneous conception
* 3 consecutive pregnancy losses after assisted reproductive technology treatment (ART) including IVF, ICSI and FET
* 3 failed embryo transfers characterized by no achieved pregnancy (after 3 cycles with minimum 1 embryo transfer of a good-quality embryo in each cycle.)

Exclusion Criteria:

* Age \<18 or \>45 years
* AMH \<4.0 pmol/l unless donor egg in previous cycles
* Significant uterine malformation
* Known endometrial pathologies including intrauterine endometriosis, adenomyosis, hyperplasia or polyps
* Known chromosomal abnormalities
* Pregnancy \>9 weeks of gestation at the time collecting the blood sample

Where this trial is running

Aarhus

• Aagaard Klinik — Aarhus, Denmark (Recruiting)

Study contacts

• Principal investigator: Caroline Nørgaard-Pedersen, M.D. — Aalborg University Hospital
• Study coordinator: Caroline Noergaard-Pedersen, M.D.

Conditions Mannose-Binding Lectin Deficiency; Recurrent Pregnancy Loss; Recurrent Implantation Failure; Infertility; Habitual Abortion; Recurrent Miscarriage; Recurrent Spontaneous Abortion