Corpus Luteum Function and Cardiovascular Adaptation in a Natural MOCK Cycle.

N/ANot Yet RecruitingNCT07648381

Universitair Ziekenhuis Brussel118 enrolled

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.

Study Type

OBSERVATIONAL

Enrollment

118

Conditions

Menstrual Cycle Luteal Phase Progesterone Levels Luteal Phase Adaptation MOCK Cycle

Blood samples for the analysis of biomarkers.DIAGNOSTIC_TEST

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.

Transvaginal ultrasound for follicle and endometrium measurements.DIAGNOSTIC_TEST

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.

Mean Arterial Pressure measurement.DIAGNOSTIC_TEST

The MAP will be measured at cycle day 7 and 7 days post-ovulation induction to follow cardiovascular adaptations.

Ovitrelle injection for ovulation inductionDRUG

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.

Eligibility

Sex: FEMALEMin age: 18 YearsMax age: 40 YearsHealthy volunteers:

Medical Language ↔ Plain English

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).

Outcomes

Primary Outcomes

The relationship between progesterone levels and different follicular sizes on day 7 post ovulation induction.

Progesterone levels will be measured 7 days after ovulation induction to relate them to different follicular sizes.

Time frame: From the start of the menstrual cycle until 7 days after ovulation induction.

Secondary Outcomes

Estradiol evolution throughout the cycle and its relation to luteal progesterone levels.

We will measure the estradiol on different moments throught the menstural cycle, and see how these levels correspond to later (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

We will measure these factors (MAP, progesterone, estradiol, serum sodium, chloride, carbon dioxide and osmolality, prolactin, direct renin, plasma aldosterone, NT-proBNP, relaxin-2 and VEGF) at day 8 of the cycle, as well as 7 days after ovulation-induction. All these factors form a reflection of the body's cardiovascular and renal adaptation, and will be studied to estimate these adaptation at different follicular sizes.