Ch. 4 Prenatal Development and Birth

What are three major developments in the germinal period?

- rapid cell division and the beginning of cell differentiation. -About a week after conception, blastocyst, forms two distinct parts a shell that will become the placenta. -a nucleus that will become an embryo.

What are the potential consequences of drinking alcohol during pregnancy?

An embryo exposed to alcohol can develop fetal alcohol syndrome (FAS), which distorts the facial features (especially the eyes, ears, and upper lip). It leads to hyperactivity, poor concentration, impaired spatial reasoning, and slow learning.

Why are the developmentalists concerned that surgery is often part of birth?

C- sections are warranted in only about 15 percent of births. While they are generally safe, they are performed for convenience's sake. In the case of microsurgery required by some infants in distress, there is concern for the fragile life that is sustained needing long-term, costly care.

Why has the rate of cesarean sections increased?

Cesareans make scheduling a baby's delivery easier than the unpredictable vaginal birth, and the actual delivery is quicker than a vaginal birth. Cesareans also carry an added bonus for the hospital since they are quite expensive.

What are the differences among a doula, a midwife, and a doctor?

Doulas support laboring women through massage of pressure points, careful timing of contractions, provide encouragement, and do whatever else is helpful. Midwives have training in the birth process and are often as skilled as physicians in delivery. Doctors are licensed and paid more.

What are the differences among LBW, VLBW, and ELBW?

Low birthweight (LBW) is defined as birthweight that is less than 5 ½ pounds (2,500 grams). Babies who weigh less than 3 pounds, 5 ounces (1,500 grams) are classified as very low birthweight (VLBW); those who weigh less than 2 pounds, 3 ounces (1,000 grams) are classified as extremely low birthweight (ELBW).

What teratogens may harm the fetus's developing body structure?

Teratogens that affect the developing body structure include the following: medicinal drugs, such as lithium, tetracycline, retinoic acid, ACE inhibitors, and thalidomide; psychoactive drugs such as excessive alcohol use, tobacco, marijuana, heroin, cocaine and inhaled solvents; and social and behavioral factors such as very high stress, malnutrition, and excessive, exhausting exercise

How has the Apgar scale increased newborns' survival rate?

The Apgar scale alerts doctors to the condition of a newborn who needs medical attention.

What body parts develop during the embryonic period?

The embryonic period consists of the third through the eighth week after conception (day 14 to day 56). First, a thin line called the primitive streak appears down the middle of the embryo; it will become the neural tube 22 days after conception and eventually develop into the central nervous system (the brain and spinal column). The head appears in the fourth week, a minuscule blood vessel that will become the heart begins to pulsate. By the fifth week, buds that will become arms and legs emerge. The upper arms and then forearms, palms, and webbed fingers grow. Legs, knees, feet, and webbed toes, in that order, are apparent a few days later, each having the beginning of a skeletal structure. Then, 52 and 54 days after conception, the fingers and toes separate. The head develops first, in a cephalocaudal (literally head to tail) pattern, and the extremities form last, in a proximodistal (near to far) pattern.

What major milestone is reached about halfway through the fetal period?

The fetal period consists of the ninth week after conception up until birth. The sex organs of the fetus start to develop forming either a boy or girl. Organs also become more mature and the fetus reaches age of viability, when it may be able to survive outside the mother's uterus if specialized care is available.

What are three major reasons pregnancy continues months after the fetus could live outside the uterus?

The final three months improves the odds, not only of survival but also of life without disability. In the final three months of prenatal life, the lungs begin to expand and contract, and breathing muscles are exercised as the fetus swallows and spits out amniotic fluid. The valves of the heart go through a final maturation, as do the arteries and veins throughout the body. Among other things, this helps to prevent "brain bleeds," one of the hazards of preterm birth in which paperthin blood vessels in the skull collapse. The fetus usually gains at least 4 ½ pounds during these final three months. By full term, human brain growth is so extensive that the cortex (the brain's advanced outer layers) forms several folds in order to fit into the skull. Simply put, the neurological, respiratory, and cardiovascular systems mature dramatically

List four reasons a baby might be born LBW.

baby born preterm maternal malnutrition Small for Gestational age (SGA) underweight, under eating, underage, and smoking