The Impact of Maternal Voice on the Fetus: A Systematic Review

Background: Studies have shown pre-natal memory underlining the ability of newborns to discriminate maternal vs. other voices and to recognize linguistic stimuli presented prenatally by the mother. The fetus reacts to maternal voice at the end of gestation but it is important to clarify the indicators and conditions of these responses.
Objective: To understand the state of the art concerning: 1) indicators of fetal reactions to maternal voice vs. other voices; 2) conditions of maternal voice required to obtain fetal response, 3) neonatal recognition of maternal voice and of linguistic material presented prenatally and 4) obstetric and behavioral maternal conditions compromising fetal ability to discriminate between maternal and other female voices.
Method: Systematic review using EBSCO, WEBSCIENCE and MEDLINE. Eligibility: studies with maternal voice delivered before birth as stimulus and with fetal or neonatal behavior as responses.
Results: Fetal responses to maternal voice are observed through fetal cardiac, motor (fetal yawning decrease, mouth opening, fetal body movements) and brain responses (activation of the lower bank of the left temporal lobe). Newborns’ head orientation and non-nutritive sucking are shown as being neonatal indicators.
Conclusion: Gestational age, baseline measures (fetal state, acoustic conditions and pre-stimulus time) and obstetrical conditions may enable or compromise fetal discrimination between maternal and other voices. The role of maternal voice for prenatal human bonding needs to be discussed according to different maternity conditions such as surrogate mothers. A new paradigm is suggested;
the focus of research should be on maternal-fetal interaction under the presence of maternal voice