[DEV] CH3 Prenatal Development

The Course of Prenatal Development

• begins with fertilization and ends with birth

• 266 and 280 days

a. germinal period

b. embryonic period

c. fetal period

germinal period

• first 2 weeks after conception

• Includes creation of the fertilized egg: zygote

[GP] differentiation

•  specialization of cells to perform various tasks: starts to take place by one week after conception 

[GP] blastocyst

•  inner mass of cells that develop into embryo

[GP] trophoblast

outer layer of cells that later provides nutrition and support for the embryo

[GP] implantation

• attachment of zygote to uterine wall 

embryonic period

• 2 to 8 weeks after conception 

• rate of cell differentiation intensifies

• blastocyst attaches to uterine wall

• Neural tube eventually becomes spinal cord forms

layers of the cell

• endoderm: inner layer of cells -> digestive and respiratory systems 

  • Internal body parts

• Mesoderm; middle layer -> circulatory systems, bones, muscles, excretory system and reproductive system 

  • Surround internal areas

• Ectoderm; outermost layer -> nervous system, brain, sensory receptors, and skin

  • Surface parts

[EP] amnion

•  sac that contains clear fluid in which developing embryo floats 

[EP] amniotic fluid

• environment that is temperature and humidity controlled 

[EP] umbilical cord

• 2 arteries and one vein and connects baby to placenta

[EP] placenta

• disk-shaped group of tissues in which small blood vessels from the mother and the offspring intertwine but do not join 

• Placenta of drugs that can be harmful to fetus 

[EP] organogenesis

• process of organ formation during first 2 months 

  • Organs especially vulnerable to environmental changes 

fetal period

• 7 months 

• between two months after conception and birth in typical pregnancies

• Growth and development continue their dramatic course during this time 

• Fetus is more active, showing a preference for a particular position in the womb 

• Last 2 months of development: fatty tissues develop and the functioning of organ systems

when does viability begin?

end of 2nd trimester

brain development

• Birth: 20 to 100 billion neurons which handle information processing at the cellular level in the brain 

• Postnatal life are characterized by gradual increases in connectivity and functioning of neurons 

a. neural tube

b. neurogenesis

c. neuronal migration

d. neural connectivity

neural tube

• begins forming as a long, hollow tube located on the embryo’s back

• Develops out of the ectoderm 

• Tube closes at the top and bottom ends at about 27 days after conception 

• Failure of the neural tube to close are anencephaly and spina bifida

  • Spina bifida; results in varying degrees of paralysis of lower limbs

  • Adequate amounts of the B vitamin folic acid

neurogenesis

• Massive proliferation of new immature neurons begins to take place at about the 5th prenatal week and continues throughout the reminder of prenatal period

• A process that continues through the remainder of the prenatal period but is largely complete by the end of 5th month after conception

neuronal migration

• Cells moving outward from their point of origin to their appropriate locations and creating the different levels, structures, and regions of the brain

neural connectivity

• Connections between neurons begin to occur, a process that continues postnatally

teratogen

• any agent that can potentially cause a birth defect or negatively alter cognitive and behavioral outcomes 

• May take a long time for the effects of teratogen to show up

teratology

• Investigates the causes of birth defects

dose

the greater, the greater the effect

genetic susceptibility

•  type or severity of abnormalities caused by teratogen is linked to the genotype of the pregnant woman and the genotype of the embryo or fetus

• Male fetuses are far more likely to be affected by teratogens than female

time of exposure

• Does more damage when it occurs at some points in development than others 

• Germinal period may even prevent implantation

• Embryonic period is more vulnerable

prescription drugs

•  function as teratogens; antibiotics, antidepressants, isotretinoin 

nonprescription drugs

•  diet pills, high dosages of aspirin 

types of psychoactive drugs

• Act on the nervous system to alter states of consciousness, modify perceptions, and change moods

1. caffeine

2. alcohol

3. nicotine

4. marijuana

5. heroine

6. cocaine

caffeine

• Maternal caffeine intake = lower birth weight and babies being born small for gestational age

alcohol

• Fetal alcohol spectrum disorders (FASD); cluster of abnormalities and problems that appear in the offspring of mothers who drink alcohol heavily during pregnancy 

• Abnormalities; facial deformities and defects of limbs and heart

• Limitations; even just 1 or 2 servings of beer or wine can have a negative effect

nicotine

• Cigarette smoking by pregnant women can also adversely influence prenatal development, birth, and postnatal development

• Effects; preterm births, low birth weights, fetal deaths, respiratory problems, sudden infant death syndrome

• Risk factor for development of attention deficit hyperactivity disorder in offspring 

• Concern; e-cigs

cocaine

• Reaches quickly crosses the placenta to reach the fetus 

• effect: reduced birth weight, length, and head circumference 

  • Neurological, medical, and cognitive deficit

marijuana

• Negative outcomes for offspring 

• Lower intelligence in children 

• Alters brain functioning in the fetus

heroin

• Infants whose mothers are addicted to heron show several behavioral difficulties at birth 

• Effects; withdrawal symptoms

incompatible blood types

• Incompatibility between mother and father blood types poses a risk 

• Mother’s immune system may produce antibodies that will attack fetus 

  • Effect; miscarriage, stillbirth, etc.

• Rh incompatibility; blood transfusions before or right after birth

• Environmental pollutants and toxic wastes also pose a danger 

  • Carbon monoxide, mercury, lead, fertilizers

maternal diseases

• Can produce defects by crossing placental barrier or can cause damage during birth

1. rubella

2. syphillis

3. genital herpes

4. AIDS

5. diabetes

rubella (german measles)

• cardiac defects, pulmonary problems 

syphillis

damaging in prenatal dev

• Effects: Stillbirth, eye and skin lesions, bone damage, congenital syphilis

genital herpes

• delivered through birth canal of a mother with genital herpes

AIDS-HIV

• human immunodeficiency virus (HIV) destroys body’s immune system

  • During gestation across placenta

  • During delivery through contact with maternal blood or fluids 

  • Postpartum (birth) via breastfeeding 

  • Symptoms: infected & symptomatic, asymptomatic, not infected

other parental factors

1. maternal diet and nutrition

2. maternal age

3. emotional states and stages

4. paternal factors

maternal diet and nutrition

• Developing embryo or fetus depends completely on its mother for nutrition = comes from mother’s blood

• Determined by mother’s total caloric intake, proteins, vitamins, and minerals 

• Maternal obesity -> increased rates of hypertension, diabetes, respiratory complications, infections, and depression in mother

  • Increase in stillbirth and NICU

• Important nutrient: folic acid, B-complex vitamin 

  • Neural tube defects/spina bifida

maternal age

>35

• Mortality rate is higher x2

• Adverse pregnancy outcomes; down syndrome

emotional states and stages

• negative mood states = mother will engage in unhealthy behaviors 

• High levels of stress increased risk for having child with ADHD, language delay 

• Maternal depression; adverse effect on birth outcomes and children’s development

  • Antidepressants; autism

paternal factors

• Men’s exposure to lead, radiation may cause abnormalities in sperm -> miscarriage or cancer

• Father’s smoking also can cause problems for offspring 

  • Impaired male fertility, increased DNA damage, aneuploidy, and mutations

• Increasing paternal age decreases success rate in IVF and risk of preterm birth 

• Relationship with mother

prenatal care

• Prenatal programs; comprehensive educational, social, and nutritional services 

• Exercise can benefit mother’s health and has positive neonatal outcomes or that there are no differences in outcomes 

• Positive benefits for offspring 

• CenteringPregnancy: US program

  • Relationship-centered and provinces complete prenatal care in a group setting 

  • Empowering women to play an active role in experiencing a positive pregnancy

stages of birth

1. uterine contractions:

•  15-20 minutes apart at the start and last up to 1 min

• Contractions come closer together, appearing 2-5 minutes 

• Contractions dilate cervix to 10cm 

2. Second birth stage; babys head starts to move through cervix and canal

3. Afterbirth; placenta, umbilical cord, and other membranes are detached

midwives

•  profession that provides healthcare to women during pregnancy, birth. And postpartum period 

• Give women information about reproductive health and annual gynecological examinations

• No adverse effects 

doulas

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

• Independent providers hired by the expectant parents 

methods of childbirth

1. medication

2. natural and prepared childbirth

3. cesarean delivery

medication

1. analgesia; pain reliever

2. anesthesia;  used in late first-stage labor and during delivery to block sensation in an area of the body or to block consciousness

   1. epidural block: regional anesthesia that numbs the woman’s body from waist down 

3. oxytocin: hormone that promotes uterine contractions and decrease duration of first stage of labor

natural childbirth

• method that aims to reduce the mother’s pain by decreasing her fear by providing information about childbirth

bradley method

•  involves husbands as coaches, relaxation for easier birth, and prenatal nutrition and exercise 

prepared childbirth / Lamaze method

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

cesarean delivery

• Baby is removed from the mother’s uterus through an incision made in her abdomen 

• Failure to progress through labor and distress 

• Breech position; baby’s butt first to emerge from vagina instead of head

Apgar Scale

•  assess the health of newborns one and five minutes after birth

  • Evaluates an infant’s heart rate, respiratory effort, muscle tone, body color, and reflex irritability

  • Good at assessing the newborn’s ability to cope with the stress of delivery and the demands of a new environment

Brazelton Neonatal Behavioral Assessment Scale (NBAS);

• within 24-36 hours after  birth 

  • Sensitive index of neurological competence up to one months after brith for typical infants and as a measure in many studies of infant development 

  • Assess the newborn’s neurological development, reflexes, and reactions to people and objects

Neonatal Intensive Care Unit Network Neurobehavioral Scale (NNNS)

• Newborn’s behavior, neurological and stress responses, and regulatory capacities

low birth weight infants

less than 5 pounds 8 ounces at birth

• very low birth weight: 3 pounds 4 ounces

• extremely low: less than 2 pounds 3 ounces

preterm infants

• three weeks or more before pregnancy 

• 35 or fewer weeks

• Extremely preterm infants; less than 28 weeks

• Very preterm infants; less than 33 weeks 

small for date infants

• birth weight is below normal when the length of the pregnancy is considered

kangaroo care

• skin-to-skin contact in which the baby, wearing only a diaper, is held upright against the parent’s bare chest

  • 2-3 hours per day 

• Coordinating heartbeat and breathing, temperature

• Effective in improving body weight and reducing length of hospital stay for low birth weight infants

postpartum period

• period after childbirth or delivery that lasts for about 6 weeks or until the mother’s body has completed its adjustment

physical adjustments

• concern; loss of sleep that primary caregiver experiences

• Great deal of energy and feel exhausted 

• Fatigue can undermine mother;s sense of wellbeing and confidence in her ability to cope with baby 

• hormone productions

emotional and psychological adjustments

• depression

• fathers also undergo adjustment during postpartum

• fathers support can play a role

postpartum blues

2-3 days after birth = depression, anxious, and upset

Postpartum depression;

• major depressive episode that typically occurs about 4 weeks after delivery 

  • Strong feelings of sadness, anxiety, or despair that for at least 2 weeks they struggle with daily tasks

  • Psychotherapy helps

bonding

• The formation of a connection, especially a physical bond between parents and the newborn in the period shortly after birth

• Need to form an emotional attachment as a foundation for optimal development = DEPENDS

• Hospitals have rooming-in arrangement; baby remains in mother’s room most of the time during its hospital stay