The main purpose of this paper is to demonstrate the capability of fetal phonocardiographic measurements to indicate some congenital heart defects. It deals with the results of investigations carried out during the last four years involving 820 pregnant women. During the investigations fetal cardiac murmurs presenting typical waveforms and incidences of acoustic signals were recorded. Causes of these murmurs are suggested based on comparison with the well-known waveforms of infants and children. A sophisticated signal processing method for murmur discovery is presented, that is also useful for automatic perinatal screening after the 28th week of gestation. By these means low-risk population may also be fully tested for cardiac malfunctions.