At what gestational week is a fetus's hearing ability well-developed?

The ability of a fetus to hear sounds is significantly developed by about the 28th week of gestation. By this time, the structures of the ear have matured enough to process auditory stimuli. Sound waves begin to penetrate the amniotic fluid, allowing the fetus to detect noises, which may include maternal voice and external sounds. This auditory development is crucial for the fetus as it lays the foundation for later language acquisition and social bonding.

Prior to this period, although some basic auditory reflexes may be observed as early as the 24th week, the hearing capability is not yet fully matured. Therefore, while earlier gestation weeks reference the beginnings of hearing, it is at the 28th week that the auditory system is sufficiently developed for the fetus to respond meaningfully to sound.