Psychologists from the Sussex university (Great Britain) have found out that the woman's voice after the birth of the first child becomes below and more monotonously.
20 mothers and control group of 20 childless women of similar age have participated in a research. For the analysis of vocal changes home archives of participants in ten years have been analysed. It has allowed to track what were voices of women to and during pregnancy and as they have changed after the child's birth. 634 rollers lasting 277 minutes have been in total estimated. As researchers note, only a talk between adults as during communication with the child parents can change intonation was estimated.
On average the voice of young mother "sat down" more than on 5%, these are about 15 Hz or 1,3 half tones. The upper bound of range decreased on 2,2 half tones (or by 44 Hz). Researchers have also paid attention that after the delivery voices of women became more monotonous. As a rule, changes were noticeable within a year. After a voice came back to norm.
According to authors of a research, vocal changes can be connected with hormonal and also with fatigue or the new status. As psychologists note, people with deep voices more often are perceived as more competent and mature. Perhaps, unconsciously women change own voice to seem more authoritative.