PT 433 Prenatal Development

conception to birth

Prenatal development time period

266 days, 38 weeks, 9 months

Length of pregnancy in days, weeks, months

Germinal, embryonic, fetal

3 prenatal developmental periods

Trimesters

How is pregnancy sectioned?

conception, last menstrual period

Two ways "due dates" can be determined

38

If dues dates were determined from date of conception, how many weeks would you add?

40

If dues dates were determined from the first day of the woman's last menstrual period, how many weeks would you add?

Gestational age

the way in which a pregnancy can be dated based on the first day of the last menstrual cycle; also referred to as menstrual age

1 (39 weeks to 40 weeks and 6 days)

A baby is full term between ____ week(s) before or after the due date

7 days

How long does it take for a fertilized egg to travel the length of the fallopian tube?

stays the same

While in the fallopian tube, the cell size ______________

increases

While in the fallopian tube, the cell number ______________

7 days

Once in the uterize, the fertilized egg takes how long for full implantation?

Germinal period

First trimester begins with this period

conception, implantation

Where does the germinal stage begin and end?

14 days, 2 weeks

Length of geminal stage

germinal period

Includes rapid cell division, beginning of cell differentiation

1/2

____ of zygotes do not survive the germinal period

Embryonic period

Occurs from third week to the eighth week after conception

organogenesis

during the embryonic period, what process occurs?

ectoderm

the outer germ layer that develops into hair, skin, and nervous tissue

Mesoderm

middle germ layer; develops into muscles, bones, and much of the circulatory systems

endoderm

the inner germ layer that develops into the lining of the digestive and respiratory systems

4

At _____ weeks the embryo is about 2mm

7

At _____ weeks the embryo is about 1inch

3-4

Beginnings of the brain form at _______ to ________ weeks

Embryonic period

Period when the neural plate should form into the neural tube

spina bifida

a congenital defect that occurs during early pregnancy when the spinal canal fails to close completely around the spinal cord to protect it

folic acid

What can prevent spina bifida

Fetal Period

Period beginning 9 weeks after conception until birth

all 3

Which trimesters does the fetal period affect?

3 months

When can the baby's sex organ first become visible via ultrasound?

20 weeks

When can the baby's sex organ first become definitively confirmed?

20 wks

When can the baby's heartbeat be heard via stethascope?

Quickening

the first movement of the fetus in the uterus that can be felt by the mother

18-20 weeks

When does quickening occur?

Age of viability

the age at which a baby can survive in the event of a premature birth; survival outside of the uterus

20 wks conception, 22 weeks GA

What is the age of viability in terms of conception and gestational age?

CNS, respiratory system

What two things are sufficiently developed and activated when they reach the age of viability?

Proximal to distal

What direction does brain development occur?

Hindbrain

What part of the brain is developed first?

Midbrain

What part of the brain is developed second?

forebrain

What part of the brain is developed last?

25 y/o

When does the brain stop developing

Proliferation, 10-20 weeks

First stage of CNS development where brain cells increase in numbers, AND time period this occurs

Migration, 12-24 weeks

Second stage of CNS development where brain cells move locations to determine function, AND time period this occurs

Differentiation

Third stage of CNS development where brain cells become specialized

Synaptogenesis, 20 weeks-puberty

Fourth stage of CNS development where brain cells undergo synaptic plasticity, AND time period this occurs

synaptic plasticity

the ability of a synapse to change over time through use or disuse

Myelination, 24 weeks-10 years

Fifth stage of CNS development where brain cell axons become wrapped in fatty tissue to increase he transmission speed , AND time period this occurs

Fetal Period Final Trimester

Specific time period providing time for extensive growth and folding in the cortex

lungs, heart valves and arteries/veins

The Final Trimester of the Fetal Period involves the expansion and contraction of the ___________, as well as final maturation of the ____________

7.5

Average birth weight in lb

4.5

How many pounds does the baby gain in its last trimester?

Teratogens

Any disease, drug, or environmental agent that can harm a developing fetus

Thalidomide

A mild tranquilizer that, taken early in pregnancy, can produce a variety of malformations of the limbs, eyes, ears, and heart.

low birth weight, preterm birth

What harm can tobacco cause to a developing fetus?

True

Radiation from x-ray and cancer treatment may harm a developing fetus. True or False?

fetal alcohol syndrome, intellectual disability

What harm can alcohol cause to a developing fetus?

genotype

The effect of the teratogen depends upon the ______________ of the organism

critical period

The impact of teratogens largely depends on this time period:

dosage

The impact of teratogens depends on the:

fetal brain

signals the release of hormones to trigger the female's uterine muscles

9-14 hours

Average duration of labor for firstborn babies

50%

The duration of labor for one's second time is cut by what percent?

Stage 1, 12-24 hours

Stage of Labor where contractions occur, and time time before birth in which this occurs

4 inch

How large does the cervix enlarge during stage 1 of labor?

stage 2, 15 min-1 hr

Stage of Labor where fetus's head passes through cervix to vagina and baby emerges from the mother's body , and time time before birth in which this occurs

Stage 3, minutes after

Stage of Labor where placenta is expelled , and time time before birth in which this occurs

head down, face backward

Optimal position of baby for birth

brachial plexus injury, anoxia

What could occur as a result of a breech birth?

anoxia

lack of oxygen due to pinched umbilical cords or sedatives given

Cesarean section

If baby is in breech position, what kind of birth is recommended?

False

If mothers are given medication for pain relief during delivery, the baby will not be drugged. True or False?

Epidurals

These drugs lengthen labor and require instrumental assist

Age, emotion, nutrition

What maternal factors talked about in class can have an effect on their child's development?

age, exposure to toxins

What paternal factors talked about in class can have an effect on their child's development?

20-34

What age ranges have the lowest pregnancy mortality rates?