Throughout prenatal development, there are times of greater susceptibility known as critical periods. For example, an embryo is most vulnerable to teratogens in the first eight weeks after conception.
What is the most vulnerable prenatal stage?
As in the case of the germinal period, often the mother does not yet know that she is pregnant. It is during this stage that the major structures of the body are taking form making the embryonic period the time when the organism is most vulnerable to the greatest amount of damage if exposed to harmful substances.
During which stage is the unborn child most vulnerable to outside influences?
Your developing baby is most vulnerable to injury during the embryo stage when organs are developing. Indeed, infections and drugs can cause the greatest damage when exposure occurs two to 10 weeks after conception.
In which stage of prenatal development is the unborn child most vulnerable to teratogens?
During the development of a baby, there are certain organs forming at certain times. If a teratogen has the potential to interfere with the closure of the neural tube, for example, the exposure to the teratogen must occur in the first 3.5 to 4.5 weeks of the pregnancy, since this is when the neural tube is closing.
Is prenatal development affected by environmental factors?
During prenatal development, environmental factors can significantly affect the development of the child. Most everything the mother ingests, including food, liquid, and even medication, travels through the placenta to the fetus; anything the mother is exposed to in the environment affects the fetus.
During which stage is an unborn baby most vulnerable to prenatal environmental influences and most at risk for miscarriage or spontaneous abortion?
The fetus is most vulnerable during the first 12 weeks. During this period of time, all of the major organs and body systems are forming and can be damaged if the fetus is exposed to drugs, infectious agents, radiation, certain medications, tobacco and toxic substances.
What are the 3 stages of prenatal development?
This union marks the beginning of the prenatal period, which in humans encompasses three distinct stages: (1) the pre-embryonic stage, the first two weeks of development, which is a period of cell division and initial differentiation (cell maturation), (2) the embryonic period, or period of organogenesis, which lasts …
What are the four stages of prenatal development?
Stages of Prenatal Development
- Germinal Stage.
- Embryonic Stage.
- Fetal Stage.
What is the first 12 weeks of pregnancy called?
The first trimester is the time in between fertilization of the egg by the sperm (conception) and week 12 of a pregnancy. A woman’s body goes through many changes during the first 12 weeks of a pregnancy.
During which stage of prenatal development does breathing movement begin?
Fetal breathing movements begin around week 20 or 21, and occur when contractions of the respiratory muscles cause the fetus to inhale and exhale amniotic fluid. These movements continue until birth and may help to tone the muscles in preparation for breathing after birth and are a sign of good health.
When is the embryonic stage?
After conception, your baby begins a period of dramatic change known as the embryonic stage. This stage runs from the 5th through the 10th week of pregnancy. During this stage, the baby is called an embryo.
What are the environmental factors that affect the unborn child?
Environmental factors which have been implicated in adverse pregnancy outcome include smoking, video display terminals, anesthetic gases, antineoplastic drugs and exposure to lead, selenium and inorganic mercury.
What are the environmental factors that affect child development?
Environmental factors that influence growth and development in humans include childhood housing arrangements, family income, educational opportunities, interpersonal relationships and employment-related factors, according to Best Start, Ontario’s Maternal Newborn and Early Child Development Resource Centre.
What are four environmental hazards that can affect a fetus?
These chemicals include commonly known hazards such as lead, mercury, and environmental tobacco smoke, as well as some pesticides, solvents, products containing chlorine, and other chemicals referred to as “persistent organic pollutants.” The fetus is particularly vulnerable to environmental chemicals that can disrupt …