Chapter 4: Prenatal Development and Birth
The Developing Person Through Childhood and Adolescence (Berger, 13th
Edition)
I. Prenatal Development
A. Three Stages of Prenatal Development
1. Germinal Period (First Two Weeks After Conception)
○ Begins with fertilization (zygote formation).
○ Cell division (mitosis) occurs rapidly.
○ Blastocyst: A hollow ball of cells that forms around the 4th day.
○ Implantation: Around 10 days after conception, the blastocyst attaches to the
uterine wall.
○ Placenta Formation: Cells differentiate into the placenta and embryo.
2. Embryonic Period (Weeks 3–8)
○ Major Body Structures Begin to Form: Brain, spine, eyes, ears, nose, mouth,
and limbs.
○ Cephalocaudal Development: Growth occurs from head to tail.
○ Proximodistal Development: Growth progresses from the center of the body
outward.
○ Neural Tube Formation: Develops into the brain and spinal cord.
○ Heart Begins to Beat by Week 4.
3. Fetal Period (Week 9 to Birth)
○ Growth and Refinement: Body systems develop, and the fetus increases in
size.
○ Brain Maturation: Synapses form, neurons connect, reflexes appear.
○ Age of Viability (22–24 Weeks): The earliest point at which a preterm baby can
survive outside the womb with medical assistance.
○ Final Trimester: Lungs mature, and the fetus gains fat for temperature
regulation.
II. Teratogens and Prenatal Risks
A. What Are Teratogens?
● Harmful agents that can cause birth defects or developmental complications.
● Examples: Drugs, alcohol, tobacco, infections, radiation, pollution, malnutrition.
The Developing Person Through Childhood and Adolescence (Berger, 13th
Edition)
I. Prenatal Development
A. Three Stages of Prenatal Development
1. Germinal Period (First Two Weeks After Conception)
○ Begins with fertilization (zygote formation).
○ Cell division (mitosis) occurs rapidly.
○ Blastocyst: A hollow ball of cells that forms around the 4th day.
○ Implantation: Around 10 days after conception, the blastocyst attaches to the
uterine wall.
○ Placenta Formation: Cells differentiate into the placenta and embryo.
2. Embryonic Period (Weeks 3–8)
○ Major Body Structures Begin to Form: Brain, spine, eyes, ears, nose, mouth,
and limbs.
○ Cephalocaudal Development: Growth occurs from head to tail.
○ Proximodistal Development: Growth progresses from the center of the body
outward.
○ Neural Tube Formation: Develops into the brain and spinal cord.
○ Heart Begins to Beat by Week 4.
3. Fetal Period (Week 9 to Birth)
○ Growth and Refinement: Body systems develop, and the fetus increases in
size.
○ Brain Maturation: Synapses form, neurons connect, reflexes appear.
○ Age of Viability (22–24 Weeks): The earliest point at which a preterm baby can
survive outside the womb with medical assistance.
○ Final Trimester: Lungs mature, and the fetus gains fat for temperature
regulation.
II. Teratogens and Prenatal Risks
A. What Are Teratogens?
● Harmful agents that can cause birth defects or developmental complications.
● Examples: Drugs, alcohol, tobacco, infections, radiation, pollution, malnutrition.
