Comparison of Blood Flow in the Arteriae Uterinae in Ovarian Stimulation Cycles

This study will measure the blood flow in the aa. uterinae in women, undergoing firstly ovarian stimulation for In-Vitro Fertilization (IVF) / Intracytoplasmic sperm injection (ICSI), in Hormonal Replacement cycles (HRT) and Natural cycles (NC) for Frozen Embryo Transfer (FET).

To evaluate the influence of ovarian stimulation on the blood flow in the arteriae uterinae as well as whether there is an influence of the type of endometrial preparation for FET with either hormonal replacement therapy or natural cycle on the blood flow of the arteria uterina left / right.