Answer:
At first, a fetus cannot distinguish between different voices.
A fetus begins responding to sound at between 22 and 24 weeks but can only hear low frequencies, such as a dog barking or a lawn mower.
As the auditory system and the brain continue to develop, this range increases. By late pregnancy, the fetus can hear voices and distinguish between
so at 22 weeks they're in the middle of the second trimester and can hear sounds but in the 3rd trimester can distinguish between voices