Sweet baby Matthew Swetnam waited four long months to hear his mother's voice.

Matthew was born eight weeks early, weighing 2 pounds, 11 ounces. Following his premature birth, he stayed in the NICU for 47 days from complications of congenital cytomegalovirus (CMV).

Similar to the Zika virus, CMV causes severe birth defects and developmental disabilities. CMV caused his deafness and other birth defects explained Matthew's mother, Erin Swetnam, in her YouTube channel video description.

Four long months after birth, they fitted Matthew with hearing aids. The first time his hearing device turned on, his eyes bulged wide from the sudden flood of sounds.

"Is mama's voice not very pleasant?" Erin joked on camera in response to his crying.

A moment later, the crying ceased and an astonished smile spread across his face. The next heart-melting moments allowed a tear streaked mother to lock eyes and smiles with her hearing baby boy.

"In the future, he will most likely receive bilateral cochlear implants," Erin wrote in Matthew's first hearing video description.

Erin used her son's video as an instructive warning to women, pregnant or planning pregnancy, to get tested for CMV to avoid serious health problems.