This pilot study evaluates how progesterone levels change after hCG-triggered ovulation in modified natural cycles. Forty women preparing for frozen embryo transfer will have blood tests over 6 days to monitor hormone levels. The goal is to understand whether hCG affects the timing of the luteal phase and embryo implantation.
At least 1 follicle of 14 mm or more
Endometrium of 6 mm or more
Plasma luteinizing hormone (LH) less than 2 times basal level (measured at the beginning of the cycle between D1 and D4) and progesteronemia less than 1.5 ng/mL
For whom ovulation induction with recombinant hCG (Ovitrelle) is then proposed (standard care).
Patient whose venous capital contraindicates repeated blood sampling over a short period of time over a short period.
Patient treated with exogenous natural progesterone (vaginal or injectable) which may interfere or synthetic progesterone, which may interfere with endogenous progesterone secretion.
Patient who has not given written consent to participate in the study.
Patient not fluent in French.