PRENATAL DEVELOPMENT AND BIRTHHow did you develop before birth?

Prenatal development

4D Ultrasound

2D Ultrasound

When can you confirm pregnancy?• Can not be confirmed by blood or urine tests until the

zygote implants in the uterus (about 10 days after conception).

What are the stages in prenatal development?

• Germinal - 1st 2 weeks• Embryo – Week 3 to 8 (2 months)• Fetus – Week 9 to birth

When is the germinal period?• First 2 weeks

• Conception• Zygote• Implantation

Conception

Zygote

How does an embryo develop?• Week 3 – 8 (2 months)• First - “Primitive streak” develops =

neural tube = brain & spinal column• 4th. Week

• Head takes shape• Early heart begins to pulsate

• 5th. Week• Arm & leg buds develop• Webbed fingers and toes develop

• 8th. Week• 1 inch long• Has all basic body parts and organs (except

sex organs)

Primitive streak

4 Weeks

8 Weeks

Do you remember?• What needs to happen for pregnancy to be confirmed?

• About how long after conception does this occur?

• What are the three major stages in prenatal development?• How long is the germinal period?

• What ends this period?

• How long is the embryo when it becomes a fetus?• At how many weeks does this happen?

When is it a fetus? (9 weeks – Birth)• 9th. Week

• Male gene triggers development of male organs• If not, female organs develop

• Fourth, fifth, sixth months• Heartbeat becomes stronger• Digestive and excretory systems develop• New neurons & synapses develop

• Up to one 500,000 brain cells per minute are created

• Age of viability• Can possibly survive outside the mother (with

intensive medical care)• 22 weeks

9th. Week

22 weeks

Fetus (9 weeks - birth)• Final three months• Lungs begin to expand and contract (fetal respiration)

• Breathe using amniotic fluid as a substitute for air

• Fetus• Grows and moves more• Startles and kicks at a loud noise• Becomes used to mother’s heartbeat and voice

• Teddy bear with Mother’s heart sounds story

• Responds if mother is fearful or anxious

Labor & birth• Labor

• 12 hrs. – first child• Stages of labor

• 1st. = Cervical dilation• 2nd. = Crowning

• Only about 1/3 of zygotes implant successfully, and additional pregnancies are lost due to miscarriage and other factors. (Note: This varies slightly from the lecture, but does not effect the exam.)

Cervical dilation chart

10 Cm.

Crowning

What is the Apgar Scale?• Activity

• Muscle tone

• Pulse• Heart

• Grimace• Reflex irritability

• Appearance• Skin color

• Respiration• Breathing

• Done twice – 1 & 5 minutes after birth to determine if immediate medical care is needed

• Score = 0,1,2 for each item• Total of 7 or above is desired

Do you remember?• When does it become a fetus?• When is the age of viability?• What are the five items the Apgar test looks for?

What are some problems and solutions?

What are teratogens? (Items increasing prenatal abnormalities)• Types

• Substances (drugs, pollution)• Conditions (Stress or malnutrition)

• Teratogens = Physical defects• Cleft palate• Thalidomide babies (deformed limbs)

• Behavioral teratogens = Behavioral defects• Hyperactivity• Antisocial• Learning-disabled• Autism

Cleft palate

Thalidomide baby

What triggers harmful teratogens?• Timing

• Some only cause damage during critical periods• When organ or body part is most vulnerable

• Before pregnancy• Avoid drugs (e.g. smoking & alcohol)

• Fetal alcohol syndrome

• Better diet• Immunizations

• Problem – Half of births are unplanned

• Threshold effect• Some are harmless until they “cross the threshold” and become harmful• Alcohol, tobacco, and marijuana do more harm in combination

• This lowers the threshold for each

• Genes – May increase birth defects• My story

What are the causes & effects of low birth weight?

• Causes• Born preterm• Born small for gestational age (SGA)

• Maternal or fetal illness• Drug use

• Every psychoactive drug• Tobacco (Most prevalent cause)• Malnutrition

• Effects• Infant death• Thinking (cognitive) problems• Seeing and hearing problems• In adulthood - higher rates of:

• Obesity• Heart disease• Diabetes

What do newborn reflexes do?• Reflex = involuntary response to a stimulus• Reflexes that aid survival

• Breathing – Maintains oxygen• Shivering – Maintains temperature• Sucking – Manages feeding

• Rooting – Searching for a nipple

• Reflexes that show the state of brain and body functions• Babinski reflex – Toes fan upward when feet are stroked• Stepping reflex • Swimming reflex• Palmer grasping reflex• Moro reflex - Being startled

Do you remember?• What are behavioral teratogens?

• What is an example?

• What is SGA?• What is the most prevalent cause of it?

• What are the reflexes that aid survival?• What five reflexes show that the brain and body are

functioning correctly?