1,2 Studies also suggest a relationship between tobacco and miscarriage. 2nd stage of the prenatal development. The first stage is the germinal stage. Prenatal development takes about 38 weeks to complete and goes through these three developmental stages. (4th week) Head, face (eyes, nose, ears, and mouth), and neck develop. The environment can have an important influence on development, and this also includes the prenatal period. 29 2 Learning Objectives Prenatal Development 2.5 What behaviors have scientists observed in fetuses? Women who smoke have more difficulty becoming pregnant and have a higher risk of never becoming pregnant. 2.6a What techniques are used to as- sess and treat problems in prena- Gestational Age 8 weeks (1.8 months). Infancy is a Plateau in Development. The three primary stages of prenatal development are the germinal stage, the embryonic stage, and the fetal … These variable outcomes of prenatal cocaine exposure on physical growth and development are in part the result of important covariates such as amount of drug use and timing throughout pregnancy. The average embryo at 8 weeks is 0.6 inches (1.6 cm) long and weighs less than 1/2 ounce (15 grams) .. In fact, there is often a slight regression, such as loss of weight and a tendency to be less strong and healthy than at birth. Heartbeat begins (blood vessel to heart->pulse). The first two weeks of development are concerned with simple cell multiplication. By the fourth week there is the development of the anterior brain and the arms and legs also begin to form buds out of the body’s trunk. This tiny mass of cells then adheres to the inside wall of the uterus. Time: 2-8 weeks. Fortunately, the effects of many of these hazards can be greatly lessened or even avoided entirely. The germinal stage occurs during the first two weeks of a baby's development. By week 12, the embryo is the size of a large egg, about 3 ½ inches long and the placenta is well developed. (5th week) Buds for limbs form and grow. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Start studying three stages of prenatal development. The growth that happens during the nine months of prenatal development is nothing short of astonishing, but this period is also a time of potential vulnerability. During this time, the zygote moves from the Fallopian tube toward the uterus and rapidly divides. Problems in Prenatal Development 2.6 What are the effects of the major dominant, recessive, and sex-linked diseases? (3rd week after conception) Brain development (neural tube forms along neural plate to brain vesicles to parts of brain). Prenatal development: The process of growth and development within the womb, in which a single-cell zygote (the cell formed by the combination of a sperm and an egg) becomes an embryo, a fetus, and then a baby. The embryo is about the size of a bean. The rapid growth and development which took place during the prenatal period suddenly come to a stop with birth. During this time, a single-celled zygote develops in a series of stages into a full-term baby. The fingers and toes are developing. By the eight week, visible male characteristics start to form in the male embryos. Embryonic Age 6 weeks . The average length of time for prenatal development to complete is 38 weeks from the date of conception. 2,4 Smoking during pregnancy can cause tissue damage in the unborn baby, particularly in the lung and brain, and some studies suggests a link between maternal smoking and cleft lip.