Corpus Luteum Function and Cardiovascular Adaptation in a Natural MOCK Cycle.
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Blood samples for the analysis of biomarkers., Transvaginal ultrasound for follicle and endometrium measurements., Mean Arterial Pressure measurement., Ovitrelle injection for ovulation induction.
- Who it may be relevant to
- Registry conditions: Menstrual Cycle, Luteal Phase Progesterone Levels, Luteal Phase Adaptation, MOCK Cycle. Basic parameters: 18 years — 40 years · Female.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Belgium
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
In infertility treatment, embryos are created in vitro after eggs have been fertilised by sperm using in vitro fertilisation or intracytoplasmic sperm injection techniques. These embryos, resulting from hormonal ovarian stimulation, can be transferred shortly after egg retrieval (fresh transfer) or frozen for later use. Both natural menstrual cycles and artificial cycles (using hormones to mimic a normal cycle) can prepare the uterus for embryo transfer. Patients with regular menstrual cycles often prefer the non-medicated approach. However, these cycles offer less flexibility in timing because they rely on ovulation. As the number of FET cycles increases worldwide, scientists are exploring the possibility of inducing ovulation in smaller follicles to increase the flexibility of natural cycles. However, the safety for future pregnancies is unknown. This study aims to better understand the function of the corpus luteum, the follicle remnant in the ovary after ovulation, by measuring several factors that change throughout the cycle due to substances produced by the corpus luteum. The results of the study will have a direct impact on clinical practice by increasing the flexibility of frozen transfer cycles.
Interventions
- Diagnostic test Blood samples for the analysis of biomarkers.
We will collect several blood samples: * One at day 8 of the cycle: measurements of P, E2, Na, K, CL, CO2, Osmolality, PRL, direct renin, PAC, Nt-proBNP, Relaxin-2 and VEGF. * One for cycle follow up between day 8 and ovulation: measurement of P, E2, LH * One at day 7 after ovulation induction: measurements of P, E2, Na, K, CL, CO2, Osmolality, PRL, direct renin, PAC, Nt-proBNP, Relaxin-2 and VEGF. - Diagnostic test Transvaginal ultrasound for follicle and endometrium measurements.
A transvaginal ultrasound will be performed after day 8 of the cycle to evaluate a 2D measurement of the growing follicle, as well as a measurement of the endometrial thickness to evaluate readiness for ovulation induction. - Diagnostic test Mean Arterial Pressure measurement.
The MAP will be measured at cycle day 7 and 7 days post-ovulation induction to follow cardiovascular adaptations. - Drug Ovitrelle injection for ovulation induction
When patient is deemed ready for ovulation based on follicle size, blood results and endometrium, she will be asked to inject Ovitrelle 250 micrograms to induce ovulation in a controlled and timed manner.
Primary outcome measures
- The relationship between progesterone levels and different follicular sizes on day 7 post ovulation induction. [Time frame: From the start of the menstrual cycle until 7 days after ovulation induction.]
Secondary outcome measures (2)
- Estradiol evolution throughout the cycle and its relation to luteal progesterone levels. [Time frame: From the start of a menstrual cycle until 7 days post-ovulation induction.]
- Indirect factors reflecting cardiovascular and renal adaptation in the luteal phase [Time frame: From the start of the menstrual cycle until 7 days after ovulation induction.]
Eligibility criteria
Inclusion criteria
- Age below 40 years
- Regular menstrual cycles (between 25-35 days)
- Normal BMI between 18.5 and 35
Exclusion criteria
- Underlying renal or cardiac disease
- Hypertension
- Diabetes mellitus
- Contraceptive use less than 3 months before MOCK cycle, including: IUD (hormonal and copper), hormonal patch, contraceptive pill (combination and mini), hormonal intravaginal ring, contraceptive implant, contraceptive injection.
- Ovarian stimulation during the previous three months
- History of recurrent pregnancy loss (defined as 2 or more previous pregnancy losses before 24 weeks gestation).
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Observational model
- Cohort
Study locations
Belgium · 1 center
- UZ Brussel — Jette
Identifiers
NCT: NCT07648381 · EC-2025-445