When does a baby have normal brain waves?

Answer 1

Generally speaking, the first measurable brain waves can be captured on an electroencephalogram (EEG) around the 12th week of pregnancy.

Prior to that, the central nervous system of an embryo begins to develop in a sequence from "tail" to head. The brain tissue and the creation of a spinal cord are some of the early structures that begin the development process of the nervous system, but it will be longer before they are fully functioning.

In the fifth week after conception the first synapses begin forming in an embryo's spinal cord. Conception is traditionally defined as when the egg and sperm unite to form a new human being, initially called a zygote, however several years ago the American Association of Obstetrics and Gynecology decided to change the definition to a week later when the embryo implants in the uterus. To add to the confusion, obstetricians typically date pregnancy from about 3 weeks earlier at the time of the last menstrual period. Thus, it is very important to know what definitions are being used when studying prenatal (before birth) human development. Synapses are what connections of nerves are called. By the seventh week after the embryo begins development, these early neural connections permit the first movements of an embryo. The woman will not feel these movements but researchers can detect the movement through ultrasound imaging. These first movements do not involve fine motor movement but are trunk movements caused by the muscle and central nervous system development.

Other movements will follow--of the limbs (around eight weeks) and fingers (ten weeks), as well as some reflex movements such as hiccuping, stretching, yawning, sucking, swallowing, grasping, and thumb-sucking. By the end of the first trimester (first 3 months), a fetus's movement repertoire is remarkably rich, even though most pregnant women still feel none of it. Many women sense or feel the first fetal movements in the 5th and 6th months of the pregnancy; some may feel something as early as eighteen weeks of pregnancy.

Terminology:

A zygote is the first step in development of an embryo. The zygote formed from the union of 2 haploid cells (sperm and egg) to form one diploid cell. It is the first stage of the embryo. As the embryo is transported don the Fallopian tube to the uterus, further development occurs. At about one week, the blastocyst (name for that stage of embryonic development) implants in the uterine wall. 8 weeks after fertilization, when all organ systems have formed, the embryo is called a fetus up until birth, and then for the first 28 days after birth the medical term is neonate. These are the proper medical terms, but in English the term "baby" or "child" is used from the day the zygote is formed until a year - or several years - after birth. "Infant" can also be used for the first year after birth.

Answer 2

The baby has normal brain waves between 6 and 8 weeks into the pregnancy.