Prenatal Development and Birth

Question 1

Period of the zygote

Answer 1

Begins at fertilization and ends when the ovum implants itself in the uterus - 2 week process

Question 2

Prenatal Developmental Stages

Answer 2

• -Period of the Embryo - 3rd to 8th week

- -Period of the Fetus - end of 2nd month until the birth of the baby (weeks 9 - 38)

Question 3

Period of the Embryo details

Answer 3

Important organs:

• -Placenta: link between mother and fetus, allows waste materials to be removed
• -Umbilical chord: attached to the placenta at one end and to the child on the other end, about 20 inches in length
• -By the end of the embryonic stage, the embryo is 1.5 - 2 inches in length and weighs .66 ounce; all the organs are present; after 8 weeks, the details are added

Question 4

Period of the Fetus details

Answer 4

Proximodistal - near to far
Cephalocaudal - Head to tail
Head and internal organs develop first; limbs and digits last

Question 5

What is a Teratogen?

Answer 5

External factors causing malformations or physical defects in a fetus

Question 6

Examples of Teratogens

Answer 6

• -Drugs: prescription (barbiturates, pain pills); non-prescription (aspirin)
• -Chemicals: mercury, hydrocarbons used as herbicides/insecticides, lead
• -Nicotive
• -Caffeine–high consumption may be harmful
• -Alcohol–mother who is heavy or moderate drinker can cause serious defects in children, such as Fetal Alcohol Syndrome and Fetal Alcohol Effcts
• -Narcotics (heroin, morphine), LSC, THC, cocaine

Question 7

Fetal Alcohol Syndrome & Fetal Alcohol Effects

Answer 7

• -Can cause facial malformations
• -Retarded physical growth
• -Impaired language development
• -Attention deficits
• -Learning impairment
• -Mental retardation
• -FAS is the leading cause of mental retardation in the US

Question 8

Diseases/Infections that can affect fetus

Answer 8

• -German Measles (Rubella)
• -Diabetes
• -Herpes
• -Aids (risk of transmission from mother to fetus is 35-60%, transmitted through the placenta or the virus being present in the lining of the birth canal.)

Question 9

How Teratogens influence Prenatal Development

Answer 9

• -Heredity makes some developing infants more susceptible than others to teratogens
• -The timing of exposure to a teratogen is very important
• -The impact of teratogens depends on the dose. The greater the exposure, the greater the risk.
• -It is difficult to determine the harm associated with individual teratogens since infants are frequently exposed to multiple teratogens.

Question 10

Fetal Stages

Answer 10

• -Born before 20 weeks,weighing less than 500 grams = abortion
• -Born between 20 and 28th week, weighing 1-2 pounds = immature birth (some now survive)
• -Born between 29th and 36th week, weighing 2 - 5 1/2 pounds = premature birth (many of these now survive)
• -Fetus born between 37th and 42nd week, weighing 5.5 lbs+ = mature birth
• -Late delivery = post mature birth

Question 11

Stages of Labor

Answer 11

Stage 1: Longest - may be 12-24 hours (1st birth), contractions of low intensity, cervix begins to dilate
Stage 2: Delivery - starts with baby’s head at opening of cervix, ends with birth of baby
Stage 3: Afterbirth - placenta & other membranes are expelled
–These stages are bypassed with Cesarean delivery, 30.3% of all births in 2005
–Rates have increased 46% since 1996

Question 12

Neonatal rating - the APGAR scale

Answer 12

–Done at 1, 5 & 10 minutes after birth
–Measures heart rate, respiratory Effort, Muscle tone, Color, Reflex irritability
–Maximum score is 10
–Average score is 7
–Special care needed at 4 or below
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