The method comprising: immobilizing with a fastener element (120) the relative motion of a part of the body (110) of a pregnant patient pointing, with a laser device (130), to that part of the body (110) immobilized, measuring a first arterial pulse wave on the basis of an optical feedback interferometry technique identifying from the measured first arterial pulse wave at least an anomaly (300) analyzing the identified anomaly (300) and further extracting depending on the result of said analysis, from a set of information representative of the first arterial pulse wave measured, a second arterial pulse wave associated to the first arterial pulse wave by using a set of signal processing algorithms, wherein the second arterial pulse wave corresponds to the arterial pulse wave of a fetus.
