Because sounds from the outside world have to travel through the mother's abdominal tissue and through the amniotic fluid that surrounds the fetus, the voices fetuses hear, starting around the fourth month of gestation, are muted and muffled.
Karena suara dari dunia luar harus menembus jaringan abdominal sang ibu dan melalui cairan ketuban yang mengelilingi janin, maka suara yang didengarkan bayi mulai sejak sekitar bulan keempat kehamilan redup dan redam.