When serious defects occur during the embryonic period they often?

When serious defects occur during the embryonic period, they often: are reversible with fetal surgery. result in spontaneous abortion.

The embryonic period is the time when serious defects are most likely to occur because the foundations for all body parts are being laid down. During the fetal period, tera- togenic damage is usually minor. However, organs such as the brain, ears, eyes, teeth, and genitals can still be strongly affected.

One may also ask, which body system is most affected throughout the embryonic and fetal period by teratogens? There are some organ systems that are sensitive to teratogens throughout the entire pregnancy, such as the central nervous system. The central nervous system is the baby’s brain and spine. One teratogen that affects the central nervous system is alcohol.

Keeping this in view, what stage are teratogens most harmful?

Most teratogens are harmful only during a critical window of development (e.g., thalidomide is teratogenic only between days 28 and 50 of pregnancy).

What is the most critical period of fetal development?

In general, major defects of the body and internal organs are more likely to occur between 3 to 12 embryo / fetal weeks. This is the same as 5 to 14 gestational weeks (weeks since the first day of your last period). This is also referred to as the first trimester.

During which period of development is the greatest sensitivity to teratogens?

The embryo is most susceptible to teratogenic agents during periods of rapid differentiation. The stage of development of the embryo determines suscep- tibility to teratogens. The most critical period in the development of an embryo or in the growth of a particular organ is during the time of most rapid cell division.

Which body system develops first and fastest in the embryo?

Your itty-bitty embryo is making big developmental moves even before that pregnancy test comes back positive. Here’s how the fetal nervous system develops. The fetal nervous system — i.e., your baby’s brain and spinal cord — is one of the very first systems to develop.

How does maternal stress affect prenatal development?

Maternal stress has been associated with poor birth outcomes including preterm birth, infant mortality and low birthweight. Stress results in increases in cortisol, norepinephrine and inflammation which affect the fetal environment and have implications for maternal and infant health.

What are 4 teratogens?

Teratogens are classified into four types: physical agents, metabolic conditions, infection, and finally, drugs and chemicals. The word teratogen originates from the Greek word for monster, teratos.

What is the most dangerous teratogen for a fetus?

Known Teratogens angiotensin converting enzyme (ACE) inhibitors, such as Zestril and Prinivil. alcohol. aminopterin. androgens, such as methyltestosterone (Android) busulfan (Myleran) carbamazepine (Tegretol) chlorobiphenyls. cocaine.

Is aspirin a teratogen?

Aspirin has not been formally assigned to pregnancy category by the FDA. Aspirin use in pregnancy has been associated with alterations in both maternal and fetal hemostasis. In addition, high doses have been associated with increased perinatal mortality, intrauterine growth retardation, and teratogenic effects.

Which stage of pregnancy is most susceptible to teratogens?

The fetus is most susceptible in the 3rd–8th weeks of pregnancy during organogenesis in the embryonic period; after 8 weeks, growth and function are affected. The earlier the exposure to the teratogenic agent in utero, the more severe the defects are in the embryo/fetus.

Is smoking a teratogen?

Types of Teratogens Perhaps the two most important teratogens today are alcohol and smoking. They are among the leading preventable causes of birth defects and developmental disabilities. Infectious Agents: Rubella, cytomegalovirus, varicella, herpes simplex, toxoplasma, syphilis, etc.

Why do teratogens cause birth defects?

Teratogens are substances or other factors that can cause congenital abnormalities, which are also called birth defects. Examples of teratogens include certain chemicals, medications, and infections or other diseases in the mother.

Is caffeine a teratogen?

The teratogenic effect of caffeine has been clearly demonstrated in rodents. The sensitivity of different animals species is variable. In humans, caffeine does not present any teratogenic risk. The increased risk of the most common congenital malformations entailed by moderate consumption of caffeine is very slight.

What are examples of teratogens?

Other examples of teratogens found in the environment and in extraordinary circumstances can include metals, chemicals, radiation, and even heat. Examples of these teratogens can include mercury, potassium iodide, nuclear fallout radiation, and even high-temperature hot tubs!

Is stress a teratogen?

Maternal psychological stress has essentially been conceptualized as a teratogen, that is, an agent that can generate deleterious perinatal and/or developmental outcomes.

Why is the embryonic stage critical?

This is the embryonic period of prenatal development. This stage lasts from implantation until about 8 weeks from the time of conception (or the 10th week of pregnancy). This is the most important time of prenatal development because the embryo is developing the foundations for a healthy baby.

What factors influence a teratogen?

Several factors influence the amount of damage a teratogen can have, including dose or level of exposure, heredity, age of the teratogen, and any other negative influences (for example, several teratogens or a teratogen combined with poor health).