Typical Prenatal Development

• begins with fertilization and ends with birth
• takes between 266 to 280 days (38 to 40 weeks)
• divided into three periods:
  1. germinal
  2. embryonic
  3. fetal

The Germinal Period

• takes place in the first two weeks after conception
• includes the creation of the fertilized egg (called a zygote), cell division, and the attachment of the zygote to the uterine wall

Blastocyst

• the inner layer of cells that develops during the germinal period
• these cells later develop into the embryo

Trophoblast

• the outer layer of cells that develops in the germinal period
• these cells provide nutrition and support the embryo

Implantation

• the attachment of the zygote to the uterine wall
• takes place 11 to 15 days after conception

The Embryonic Period

• the period of prenatal development that occurs from two to eight weeks after conception
• begins as the blastocyst attached to the uterine wall
• the rate of cell differentiation intensifies
• support system for cells form
• organs appear
• three layers of cells:
  • endoderm
  • mesoderm
  • ectoderm

Embryo

• mass of cells

Endoderm

• inner layer of cells
• will develop into the digestive and respiratory systems

Mesodem

• middle layer of cells
• will develop into the circulatory system, bones, muscles, excretory and reproductive system

Ectoderm

• outermost layer of cells
• will become the nervous system and brain, sensory receptors and skin parts

Amnion

• the life support system
• bag-like
• contains a clear fluid (amniotic fluid) in which the developing embryo floats

Amniotic Fluid

• provides an environment that is temperature and humidity controlled
• shook proof

Umbilical Cord

• a life support system
• contains 2 arteries and one vein
• connects the baby to the placenta

Placenta

• life support system
• consists of disk-shaped group of tissues in which small vessels from the mother and offspring interwine

Organogenesis

• organ formation
• takes place during the first two months of prenatal development
• organs are especially vulnerable during this time
• third week after conception = neural tube that eventually becomes spinal cord forms
• about 21 days: eyes begin to appear
• 24 days: the cells of the heart begin to differentiate

Fetal Period

• lasts about seven months
• prenatal period between 2 months after conception to birth

The Brain & Prenatal Development

• neurons handle information processing at the cellular level in the brain
• babies have approx 100 billion neurons by the time they are born
• the third trimester of prenatal development and the first 2 years of postnatal life are characterized by connectivity and functioning of neurons

Neurons

• nerve cells, which handle information processing at the cellular level in the brain

Nervous System & Prenatal Development

• the nervous system begins forming as a long, hollow tube located in the embryos back
• forms about 18 to 24 days after conception

Anencephaly

• the highest regions of the brain fail to develop
• or when head end of the neural tube fails to close
• baby dies in the womb, during childbirth or shortly after birth

Spina Bifida

• results in varying degrees of paralysis of the lower limbs
• usually needs assistive devices: such as crutches, braces, or wheelchairs
• risk factors: maternal diabetes and obesity
• preventive measures: mother take adequate amounts of vitamin B folic acid

Neurogenesis

• the generation of new neurons

Neuronal Migration

• involves cells moving from their point of origin to their appropriate location
• occurs at approx. 6 to 24 weeks
• Once a cell has migrated to its target destination, it must mature and develop a more complex structure

Teratogen

• any agent that can potentially cause a birth defect or negatively affect cognitive and behavioral outcomes
• Ex:
  • food
  • drugs
  • chemical toxins

Teratogen Influence

• Dose
  • the greater the dose of an agent the greater the effect
• Gene Susceptibility
  • the type or severity of abnormalities caused by a teratogen is linked to both the genotype of the pregnant mother and fetus/embryo
• Time of Exposure
  • exposure to teratogens does more damage when it occurs at some points int development that at others

Critical Period

• a fixed time period very early in development during which certain experiences or events can have a long-lasting effecting on development

Teratology

• field of study that investigates the causes of birth defects

Fetal Alcohol Spectrum Disorder

• a cluster of abnormalities that appear in the offspring of mothers who drink alcohol heavily during pregnancy
• Abnormalities
  • facial deformities
  • defective limbs, face, and heart
  • learning problems

Normal Gestational Weight Gain

• 11 to 20 pounds

Prenatal Care

• involves a defined schedule of visits for medical care
• includes:
  • screening for manageable conditions & treatable diseases (that can affect the baby or mother)
  • comprehensive educational, social, and nutritional services
  • exercise regularly
    • helps prevent constipation
    • conditions the body
    • reduces excessive weight gain
    • positive mental state

Stages of Birth

1. (first stage)
   • uterine contractions are 15 to 20 minutes apart and last up to a minute
   • these contractions cause the woman's cervix to stretch and open
   • at the end of the first birth stage, contractions dilate the cervix to an opening of about 10 cm (4 in)...so baby can move from the uterus to the birth canal
   • lasts an average of 6 to 12 hours
2. (second stage)
   • begins when the baby's head starts to move through the cervix and the birth canal
   • typically lasts 45 mins to 1 hr
3. (third stage)
   • afterbirth
     • the placenta, umbilical cord, and other membranes are detached and expelled
     • lasts only a few minutes

Childbirth Setting & Attendants

• in the US 99% of births take place in hospitals
• Midwife
  • a person qualified to deliver babies and to care for women before, during, and after childbirth
• Doula
  • a caregiver who provides continuous physical, emotional, and educational support for the mother before, during, and after childbirth

Midwife

• a person qualified to deliver babies and to care for women before, during, and after childbirth

Doula

• a caregiver who provides continuous physical, emotional, and educational support for the mother before, during, and after childbirth

Methods of Childbirth

• Medication
• Natural and Prepared Childbirth
• Cesarean Delivery

Medication (methods of childbirth)

• Analgesia
  • used to relieve pain
• Anesthesia
  • used in late first stage of labor
  • blocks sensation in an area of the body
  • or block consciousness
  • epidural block
    
    • regional anesthesia that numbs the woman's body from the waist down
• Oxytocin
  
  • a synthetic hormone
  • used to stimulate contractions
  • pitocin (example)

Natural Childbirth

• method that aims to reduce the mother's pain by decreasing her fear
• done through education about childbirth
• teaching breathing methods and relaxation techniques during delivery

Prepared Childbirth

• special breathing technique to control pushing in the final stages of labor
• detailed anatomy and physiology course

Cesarean Delivery

• surgical procedure in which the baby is removed from the mother's uterus through an incision made in her abdomen

Breech Position

• the baby's position in the uterus causes the buttocks to be the first part to emerge from the vagina

Apgar Scale

• scale used assess the health of newborns at one and five minutes after birth
• evaluates an infants heart rate, respiratory effort, muscle tone, body color, and reflex irritability
• total score of 7 - 10 indicates that the newborn is in good condition

Brazelton Neonatal Behavioral Assessment Scale (NBAS)

• a measure that is used in the first month of life to assess the newborn's neurological development, reflexes, and reactions to people and objects

Low Birth Weight Infants

• weigh less than 5½

Preterm Infants

• infants born before the completion of 37 weeks of gestation

Small for Date Infants

• infants whose birth weights are below normal when the length of pregnancy is considered

Nurturing Low-Weight and Preterm Infants

1. kangaroo care
2. massage therapy

Kangaroo Care

• involves skin to skin contact between baby and mother
• 2 to 3 hours per day
• helps to stabilize the preterm infant's heartbeat, temperature, and breathing

Postpartum Period

• the period after childbirth when the mother adjusts both physically and psychologically, to the process of childbirth

Physical (postpartum adjustments)

• fatigue
• hormonal changes

Emotional & Psychological (postpartum adjustments)

• Postpartum Depression
  • major depression episode
  • typically occurs about 4 wks after delivery
  • strong feelings of sadness, anxiety, or despair