Prenatal Conception-Birth Physical Development In the 3rd week, the Central Nervous System and the heart take formation. By the 8th week, the unborn will have developed ears, eyes, limbs and teeth. Language Development At 24 weeks, the fetus responds to sounds. Cognitive Development The brain begins to form in week 12 and continues to grow and make connections At 28 weeks, the fetus begin to recognize voices, songs and stories. The fetus will begin to respond to these familiar sounds Atypical Development Fetus is not growing or gaining weight Fetus does not move or respond to sounds or other stimuli at 28 weeks. Strategies to Help Development Mother should be visiting her Doctor regularly, getting proper nutrition, exercise and taking prenatal vitamins for the healthy development of the fetus. Mother should also avoid any alcohol, drug or tobacco use.