Alyssa's+Page+Teratogens+(Accutane+and+Alcohol)

=**Introduction**= A teratogen is any substance or drug that interferes with the development of a fetus that may lead to birth defects or developmental malformations. Some examples of teratogens include; certain drugs, infection, and ionizing radiation. =Normal Human Embryo Development= During normal human embryo development the embryo gets fertilized and implants onto the uterine wall to continue developing. After conception the zygote divides into a 16 cell morula then forms a cavity in the center and becomes a blastocyst. The zygote travels down the fallopian tube and attaches tot he uterine wall. Once attached to the uterine wall the blastocyst will continue developing into an embryo and will get its' nutrients, oxygen, and blood supply from the mother via the umbilical cord. There are many steps along the way of human embryo development and mutations or defects in any of these steps can result in a deformed baby or other malformations caused by teratogens. The development process can be broken into periods which will be described below. The embryonic period begins at fertilization and continues until the 10th week of gestation. The embryo travels down the fallopian tube after fertilization starting out as a single cell zygote and then dividing many times to form a ball of cells better known as a morula. The cells continue to divide and soon the morula turns into a blastocyst. The embryo does not grow in size when all of this dividing is occuring and it is inside the zona pellucida. The blastocyst will reach the uterus at around day five and the zona pellucida is then lysed. The lysing of the zona pellucida allows the cells of the blastocyst to attach to the lining of the uterus. After the blastocyst attaches soon the placenta will emerge and the blastocyst will remain implanted. It usually takes 8 to 10 days for the embryo to implant after ovulation. The next event is a flow of rapid growth and the embryo starts to form its' external features by a process called differentiation which will give rise to the many different cell types. It is this period of development that teratogens can have a huge impact on development and many times cause a miscarriage.

The fetal period starts at the end of the 10th week of gestation and the embryo is now refered to as a fetus. Most of the precursors for the organs are created and the fetus is not as likely to be harmed by enviromental teratogens but instead be damaged by toxic teratogens. The fetal period is made up of all of teh organs having their own development; the circulatory, digestive, endocrine, integumentary, lymphatic, muscular, nervous, urinary and reproductive, and respiratory systems ("Prenatal development-wikipedia, the," 15 N).

=Accutane= Accutane is a synthetic derivative of Vitamin A and was developed by Roche Pharmaceuticals and in 1982 was authorized by the FDA for the use of treating acne. Before it was released for use it had been found in studies of animals to cause serious defects and pregnant women were warned against taking the drug. The only sure way of preventing malformations of the fetus is to stop taking Accutane while pregnant or while trying to get pregnant.

Effects of Taking the Drug
If a pregnant woman becomes pregnant while taking Accutane there is a high risk of the fetus being malformed even if the woman took a small amount of the drug. The birth defects caused by taking Accutane include hydrocephalus (fluid on the brain), microcephaly (small head), mental retardation, eye and ear diseases, cleft lip and palate, and heart defects. Accutane also increases the risk of miscarriages, premature births, and death of the baby. These defects can occur in the first weeks of pregnancy right after conception and it only takes one dose of Accutane to cause severe defects.

Hydrocephalus
Treatments of hydrocephalus include the implantation of a shunt that will drain the cerebral spinal fluid from the brain to another part of the body. Another treatment option is called an endoscopic third ventriculostomy (ETV). This procedure is done by using an endoscope and puncturing a hole in the floor of the third ventricle which allows the cerebral spinal fluid to flow through the other cavities of the brain (Smith, 2008).

Cleft Lip or Palate
Treatment for a cleft lip or palate varies based on the type of defect the baby has. Surgery for a cleft lip repair can be done between 10 weeks and 3 months of age and a cleft palate repair can be done between 6 and 18 months of age. The surgical technique for a cleft lip is to close the separation in the lip. A surgeon makes incisions on both sides of the cleft and makes flaps of tissue and the stitches the flaps together. This surgery creates a more normal appearing and functioning upper lip. Cleft palate repair surgery includes the closure of the separation and rebuilding the hard and soft palates of the mouth. The surgeon makes incisions on either sides of the cleft like that in the cleft lip surgery and then stitch the incision back together. Other surgeries may be needed to help with the appearance of the baby. The surgeries improve the baby's appearance, ability to eat, breathe, and talk. Some children will need to go to speech therapy to help with their speech later in their development.

=Alcohol= Alcohol is considered a teratogen taht can be harmful to the fetus. Studies have shown that alcohol is the leading preventable cause of birth defects and childhood disability in the United States ("Fetal alcohol spectrum," ).

Affects of Drinking Alcohol while Pregnant
When a woman who is pregnant drinks the alcohol goes through the placenta and enters into the bloodstream of the fetus through the umbilical cord. The alcohol level of the fetus is higher than that of the mother and remains high longer because the fetus cannot breakdown the alcohol like an adult ("Fetal alcohol spectrum," ). It is not known the amount or when alcohol consumption damages the fetus. There is no known threshold value. It has been shown that as little as one drink per week can adversely relate to child behavior at ages 6 and 7. The higher the levels of alcohol consumption increases the amount of damage to the fetus. When someone binge drinks or has four or more drinks in two hours, it increases teh damage drastically. No drinking means no dmage to the fetus and that is the only known preventative step.

Fetal Alcohol Syndrome
Fetal alcohol syndrome occurs when the mother consumes alcohol during pregnancy. Studies have shown that if the father consumes alcohol before conception of the fetus it can affect both conception and the fetus after conception. Some studies show that sons of fathers who consumed alcohol before conception, have memory deficits, hyperactivity, and other neurological problems. The only proven prevention of FAS is for the mother to not drink while pregnant and for both the mother and father to not drink while trying to concieve.