1. Prenatal Development and Birth
Part I
Chapter Four
Prenatal Development and Birth
From Zygote to Newborn
Risk Reduction
The Birth Process
Prepared by Madeleine Lacefield Tattoon, M.A.

2. Prenatal Development and Birth
The majority of newborns are male (52%), and more are Chinese (30%)… yet every baby is unique… every area of development is directly relevant to the 150 million babies born in the world every year… there are generalities and variation… but expect to be awed by the miracle of birth.

3. From Zygote to Newborn
Prenatal development is divided into three main periods
germinal Period (0-2 weeks)
embryonic Period (3-8 weeks)
fetal Period (9 weeks-birth)

4. From Zygote to Newborn blastocyst placenta Implantation
Germinal: The First 14 Days
Conception occurs in fallopian tubes
Cell differentiation and multiplication
42% of conceptions successfully implant in uterus
blastocyst
when cells take on distinct characteristics and gravitate toward particular positions, the entire cell mass (still very fragile and tiny)
placenta
the organ that surrounds the developing embryo and fetus, sustaining life via the umbilical cord…attached to the wall of the uterus
Implantation
the process, beginning about 10 days after conception, which the developing organism burrows into the placenta that lines the uterus, where it can be nourished and protected as it continues to develop.

5. From Zygote to Newborn embryonic period (3-8 weeks)
Embryo: from the third through the eighth week
embryonic period (3-8 weeks)
major organs develop
at eight weeks, organism is less than 2˝ long

6. From Zygote to Newborn Fetus: From the Ninth Week Until Birth
Fetal Period (9 weeks-birth)
Sex organs develop
Brain development is significant
Age of viability occurs around 22 weeks
fetus
a developing organism from the ninth week after conception until birth

7. From Zygote to Newborn The Third Month
the fetus has all its body parts
weighs approximately 3 ounces, about 3 inches long
growth is rapid
fetus is too small survive outside of the womb

8. From Zygote to Newborn The Middle Three Months: Preparing to Survive
in the fourth, fifth and sixth months the heartbeat becomes stronger
the cardiovascular system more active
the brain increases about six times in size
age of viability
twenty-two weeks after conception a fetus can survive outside the mother’s uterus if specialized medical care is available

9. From Zygote to Newborn
The Final Three Months: From Viability to Full Term
Viability
life outside the womb is possible
born in the seventh month requires intensive hospital care and life-support systems
difference between preterm and newborn is the maturation of neurological, respiratory, cardiovascular systems

10. Risk Reduction
toxins, illnesses and experiences can harm a developing person before birth
teratology
a science of risk analysis, the study of birth defects
teratogens
Agents and conditions that can harm the prenatal brain, impairing the future child’s intellectual and emotional functioning
behavioral teratogens

11. Risk Reduction Determining Risk risk analysis
the science of weighting the potential effects of a particular event, substance, or experience to determine the likelihood of harm
Timing of Exposure
critical period
In prenatal development, the time when a particular organ or other body part of the embryo or fetus is most susceptible to damage by teratogens

12. Risk Reduction Amount of Exposure Threshold effect Interaction effect
a situation in which a certain teratogen is relatively harmless in small doses but becomes harmful once exposure reaches a certain level (the threshold)
Interaction effect
the result of a combination of teratogens. Sometimes risk is greatly magnified when an embryo or fetus is exposed to more than one teratogen at the same time

13. Risk Reduction
Protective Measures
Benefits of Prenatal Care

14. The Birth Process The Newborn’s First Minutes Apgar scale
a quick assessment of a newborn’s body functioning.
color
heart rate
reflexes
muscle tone
respiratory effort

15. The Birth Process Variations medical Intervention birth complications
cesarean section
fetus is removed through incisions in the mother’s abdomen and uterus
birth complications
includes anything in the newborn, the mother, or the birth process itself that requires special medical attention
anoxia
a lack of oxygen that, if prolonged during birth, can cause brain damage or death to the baby

16. The Birth Process Low Birthweight (LBW)
the average weight of a newborn is 7½ lbs.
LBW is considered less than 5½ lbs.
preterm is less than 35 weeks
lifestyle choices
e.g., cigarette smoking accounts for 25% of LBW births worldwide!
maternal malnutrition
multiple births
prescription drugs
unknown causes

17. The Birth Process Social Support Postpartum Depression
Mother, Father, and a Good Start
Help from fathers
parental alliance – cooperation between a mother and a father based on their mutual communication to their children… the parents agree to support each other in their shared parental roles
Postpartum Depression
8-15% of women experience postpartum depression, a sense of inadequacy and sadness after birth.
includes irritability, sleep and eating disruptions, sadness, feeling overwhelmed and inadequate as a mom, no interest or overly worried about baby.