With nearly 3' 800 births in 2004, the maternity of the HUG is largest of Switzerland. Establishment of reference for the hospitals and private clinics of the area, it deals with risk pregnancies, premature births and all other maternal or perinatal complications. Obstetrics made enormous progress these twenty last years, progress giving birth in the 2000's to a speciality: fetal medicine. Did obstetrical art acquire a more scientific aspect because it's now based on clinical studies rather than only on the experiment, for diagnosis tests and interventions.