Why women lower the tone post-pregnancy

NEW mothers naturally adopt a deeper voice after giving birth in order to assert their authority.

Scientists at the University of Sussex carried out a long-term study of women before, during and after their first pregnancy and found their voices lowered in pitch more than a semitone, the equivalent of one key on the piano.

They believe the drop, which appeared to revert to the original pitch after 12 months, may be a subconscious response to becoming a mother for the first time and the need to express authority. Alternatively, the change may be the result of the significant hormonal changes that take place after birth.

The team embarked upon the research, which is published in the journal Evolution and Human Behaviour, after questioning why female singers are frequently advised not to perform in the months after having a baby.

The study sample included 20 mothers, as well as 20 age-matched controls who had never given birth, whose voice recordings were obtained from ar- chives. The researchers analysed speech before, during and after pregnancy.

Dr Kasia Pisanski, who led the research, said: “We found that women’s voices become lower-pitched and more monotonous after giving birth.

“Research has already shown that people with low-pitched voices are typically judged to be more dominant, so it could be that women are modulating their own voices to sound more authoritative, faced with the new challenges of parenting.”