Follicle-stimulating hormone (FSH) is used in medically assisted procreation, to induce an ovarian stimulation in women. However, the FSH dose that has to be injected is quite hard to adjust, because an excess of exogenous hormone could lead to very severe complications for patient. This hormone acts on its cognate receptor, the FSHR, present on the granulosa cells surface, and which regulation involve the intra-cytoplasmic carboxy-terminus domain.

The investigators first aimed to research in the c-terminus part of the receptor the presence of allelic variants that could explain the variations of response to FSH stimulation.

The investigators also would want to complete the data already known on a functionally determinant single nucleotide polymorphism on 680 position in the c-terminus part of the hFSHR.

Then, the investigators would analyze the entire sequence of the hFSHR of patients presenting an unusual phenotype in response to FSH treatment, in order to detect a potential mutation involved in the receptor functionality.

The results of this study could allow us to increase our knowledge on the hFSHR physiology and functionality, in order to adjust treatment to the genetic profile of patients.

Inclusion Criteria:

• patients above 18 years,
• entering an IVF cycle
• informed consent
• NHS operative

Exclusion Criteria:

• No

Patients involved in an assisted reproduction programm, once engaged in a stimulation protocol