CHAPTER 1 E TEXT a new information medium that merges the traditional text with the vast resources on the Internet Developmentalists researchers and practitioners who study the development process development the gradual accumulation and integration of relatively permanent age related changes in biological and psychological systems through transactions with the environment Development is gradual cumulative relatively permanent and transactional Risk threatens to undermine development and sacrifice the child s potential opportunity supports development and promotes the realization of that potential resilience the tendency to overcome risk as vulnerability the tendency to fall prey to risk is CHAPTER 3 Conception Female Reproductive System Male Reproductive System menstrual cycle the timing of hormone secretions and the processes they regulate body temperature spikes the last 14 days of the cycle after ovulation infertile unable to conceive after one year of sexual relations without contraception or unable to carry the fetus to term 1 in 6 couples are infertile prenatal stage of development Approximately 266 days or 38 weeks elapse from the date of fertilization to the birth of the baby trimesters or three month periods the period of the zygote or germinal period the period of the embryo and the period of the fetus period of the zygote The first two weeks of the prenatal stage In this first two week period cells begin to divide at a very rapid rate and the cells begin to differentiate into distinct layers that will eventually form individual organ systems period of the embryo begins at the end of the second week and extends to the end of the eighth week following conception During this 6 weeks all of the major organ systems of the baby are structurally formed with the exception of the genitals period of the fetus 30 weeks long placenta the organ that provides for the exchange of nutrients and waste products between the mother and baby teratogens Agents that are known to enter into the biological system of the embryo and fetus and negatively influence development Greek teras means monster anencephaly the baby is born without a brain central nervous system damage is possible thalidomide In the early 1960s some 7 000 babies were born with severe physical deformities most notably small flipper like appendages in place of the arms or legs The birth defects were traced to the mothers use of an over the counter sedative called thalidomide Diethylstilbestrol DES a synthetic estrogen was routinely prescribed to prevent miscarriages in up to two million pregnant women In the mid 1960s scientists realized that DES was in fact ineffective in preventing miscarriage DES babies appeared normal at birth but at adolescence some girls developed a rare form of vaginal cancer Although the worst estimates are that one in 500 DES daughters has developed vaginal cancer approximately 59 show abnormalities of vaginal tissue and or the cervix Accutane the treatment for an extreme form of cystic acne Even small doses of the drug are extremely teratogenic therefore it has been prescribed with appropriate warnings against use by pregnant women Despite these precautions however many babies have been born with severe birth defects of the brain heart and face in instances where the woman either was unaware she was pregnant or borrowed the drug from friends and therefore did not know its potential effects CIGARETTES Approximately one out of four women who smoke cigarettes continue to smoke throughout their pregnancy Milunsky 1989 These mothers and their babies pay a considerable price for this indulgence Babies born of mothers who smoke weigh between 6 and 7 ounces less at birth than babies of nonsmoking mothers Nieberg 1985 That s if they live Smoking during pregnancy is also associated with a significant increase in the rate of miscarriages stillbirths and death of babies soon after birth Naeye 1978 The reason for these effects seems to be the reduced oxygen supply to the fetus Quigley et al 1979 Fetal oxygen deprivation is associated with abnormalities of both the brain Naeye 1978 and the heart The damage to the fetus is directly correlated with the number of cigarettes smoked per day it also seems associated with the period of pregnancy when the mother smokes Some evidence suggests that cutting down to four or five cigarettes daily by the fourth month of pregnancy can prevent the expected growth retardation fetal alcohol syndrome FAS FAS is characterized by mental retardation as well as a combination of deformities of the face brain heart genitals bones and joints and growth retardation The head may be abnormally small with inadequate development of the brain Alcohol ranks third after Down syndrome and Fragile X chromosome abnormality as a cause of mental retardation STREET DRUGS When a mother who is addicted to heroin or methadone a potent narcotic used in drug rehabilitation gives birth her baby too will be addicted to the drug and will soon experience withdrawal The withdrawal symptoms are severe including tremors vomiting and fever The newborn may die if not given the drug immediately The addiction can be eliminated by gradual reduction of the drug BACTERIA VIRUSES PARASITES Unfortunately the placental barrier is only slightly more resistant to the transfer of bacteria and viruses to the fetus than it is to the transfer of drugs Several of the most common diseases that have teratogenic effects on the fetus are described below Rubella or German measles is an infection that causes mild cold symptoms and a rash in adults If a mother contracts rubella during the first trimester of her pregnancy the fetus is likely to be affected Fetal rubella syndrome may result in spontaneous abortion or stillbirth if the fetus survives its problems may include mental retardation as well as deafness or malformation of the eyes ears and or heart depending on the period of pregnancy during which the disease is contracted The rate of malformation is approximately 50 for mothers infected during the first trimester with reduced likelihood of effects from second and third trimester illness Approximately 10 20 of infected infants die before age one Herpes simplex 2 HSV is a very common sexually transmitted disease that causes painful genital sores in adults HSV is transmissible only when sores are present If the mother has HSV the fetus is most likely to contract it at delivery through exposure to maternal secretions There is a 50
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