According to the National Institutes of Health, the focus of research studying the effect that maternal emotional states have on fetal development has been on fetal reaction to a stressful stimulus. Increasing awareness of fetal development may be one factor which has sparked interest in prenatal enrichment among expectant parents. A prenatal enrichment approach includes stimulating the baby in utero through singing, reading and talking, all of which are believed to enhance a baby's intellectual development. Reading to a baby in the womb may have a positive effect on fetal development, even if not the one intended by advocates of prenatal enrichment.
Reduction of Maternal Stress and Anxiety
An online journal article of the American Academy of Pediatrics suggests that prenatal stress and anxiety is predictive of certain illnesses and the use of antibiotics after birth. This underscores conventional wisdom that pregnant women should make time for rest and activities that promote peace and relaxation. The developing fetus whose mother enjoys reading aloud during pregnancy likely benefits more from her sense of calm and well-being than from the actual words themselves.
Practicing Bonding Behavior
When a woman reads aloud to her baby in utero, she may relate to him or her more actively and directly while doing so. A positive state of mind during pregnancy may benefit the developing baby. It is common for women to report feeling bonded with their babies during pregnancy. Talking to the baby, whether through reading or speaking aloud, helps to create a sense of the baby as he or she will be after birth. Reading to the baby in utero may help a woman to practice bonding behaviors.
A 2008 study from Johns Hopkins University and published on the National Institutes of Health site reports that a fetus responds with beneficial signs in its heart rhythm when a mother experiences induced relaxation. It is unknown how, if at all, a baby in utero benefits from attempts to enrich her through reading, talking and singing. It is believed that a baby does learn to recognize his mother's voice prenatally. Babies are often observed to track the sound of their mothers' voices shortly after birth.