Chapter Three Flashcards
The most vulnerable time for teratogens is when?
teratogens (substances or agents that can cause malformations or functional abnormalities in a developing embryo or fetus) is generally considered to be during the embryonic period, which spans from the third week to the eighth week after conception. This is the critical period when organogenesis (formation of organs) occurs, and exposure to teratogens during this time can have significant and lasting effects on the developing fetus.
What is the Apgar test?
The Apgar test is not designed to assess infant intelligence. The Apgar test is a quick assessment tool used to evaluate the physical condition of a newborn immediately after birth. It was developed by Dr. Virginia Apgar and is named after her.
The Apgar test evaluates five criteria:
Appearance (skin color)
Pulse (heart rate)
Grimace response (reflexes)
Activity (muscle tone)
Respiration (breathing rate and effort)
Each criterion is scored on a scale of 0 to 2, and the scores are summed to give a total Apgar score, which can range from 0 to 10. The test provides a quick snapshot of the newborn’s overall well-being and helps healthcare professionals determine if any immediate medical interventions are needed. It does not assess cognitive abilities or intelligence.
What is trophoblast
The trophoblast is the outer layer of cells in the blastocyst, which is the early stage of development in a fertilized egg before it implants into the uterus
what is blastocyst
Blastocyst: The morula continues to divide, and a fluid-filled cavity develops within it. This results in the formation of a blastocyst, which has an outer layer of cells called the trophoblast and an inner cell mass.
What is Cephalocaudal development
Cephalocaudal development refers to the pattern of growth and development that occurs from the head (cephalic region) to the tail or feet (caudal region). In cephalocaudal development, growth typically occurs in a sequential and directional manner, with the head developing first, followed by the lower parts of the body.
What is proximodistal development
Proximodistal development refers to the pattern of growth and development that occurs from the center or core of the body (proximal) outward toward the extremities (distal). In proximodistal development, control and coordination of the central parts of the body develop before those of the peripheral parts.
Germinal Period
Period of prenatal development that takes place in the first two weeks after conception.
Includes the creation of the fertilized egg (zygote), followed by cell division and 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 for the embryo
Embryonic period
a period of prenatal development that occurs 2-8 weeks after conception. The rate of cell differentiation intensifies, support systems for the cells from, and organs appear
amnion
prenatal life support system that is a bag or envelope containing a clear fluid in which the developing embryo floats
umbilical cord
A life-support system that contains two arteries and one vein and connects the baby to the placenta
placenta
a life-support system that consists of a disk-shaped group of tissues in which small blood vessels from the mother and offspring intertwine
organogenesis
Organ formation that takes place during the first two months of prenatal development
The fetal period
lasting about 7 months. in the prenatal period between two months after conception and birth in typical pregnancies
teratogen
is any agent that can potentially cause a birth defect or negatively alter cognitive and behavioural outcomes. (tera means monster). So many teratogens exist that practically every fetus is exposed to at least some teratogens. It’s difficult to know which teratogen causes which problems
Teratology
The field of study that investigates the causes of birth defects is called teratology. 3 things effect the severity.
1) dose - the greater the dose of an agent, such as a drug, the greater the effect
2) Genetic susceptibility - e.g how a mother metabolizes a certain drug influences the degree to which the drug effects are transmitted
3) Time of exposure - teratogen exposure does more damage when it occurs at some points in development than at others. In general the embryonic period is more vulnerable than the fetal period
Prescription drugs
prescription drugs that can function as teratogens include antibiotics, some antidepressants, certain hormones, accutane.
Non prescription drugs - diet pills, high dosages of aspirin
Psychoactive drugs
caffeine - seems okay during pregnancy
alcohol - heavy drinking can lead to fetal alcohol spectrum disorder
nicotine - prenatal development, birth, postnatal development - preterm birth, low birth weight, fetal and neonatal death and respiratory problems and SIDS are more common among the offspring of women who smoked
cocaine - lower birth weight, length and head circumference, lower arousal , higher excitability, lower reflexes, attention and behaviour problems
Incompatible Blood Types
Incompatibility between the mother and father’s blood types poses another risk to prenatal development.
If a surface marker called the Rh-Factor, is present in an individual’s red blood cells they are Rh-positive, if the Rh-marker is not present, they are Rh-negative.
If a pregnant woman is Rh-negative and her partner is Rh-positive, the fetus may be Rh-positive. If the fetus is Rh-positive and the mother is Rh-negative, the mother’s immune system may produce antibodies that will attack the fetus. - this can result in miscarriage, stillbirth, anemia , jaundice, heart defects, brain damage or death soon after birth.
The first baby is generally not at risk , but with each pregnancy the risk increases. A vaccine rhoGAM may be given to the mother within 3 days of the child’s birth to prevent her body from making antibodies that will attack any future Rh-positive fetuses in subsequent pregnancies.
Environmental Hazards
examples - radiation, toxic wastes, chemical pollutants
Maternal dieseases
E.g. rubella (german measles) can cause prenatal defects.
Syphilis is damaging later in prenatal development includes eye lesions which can cause blindness.
Genital herpes can contract when through the birth canal.
AIDS - infect baby during gestation across placenta 2)during delivery 3) post partum through breastfeeding
Maternal Diet
folic acid a complex b vitamin lowered preterm labour risk , lower behaviour problems in toddlers, lower risk of spina bifida
Maternal age
mortality rate of infants born to adolescent mothers is double that of infants born to mothers in their twenties.
older maternal age is linked to risk of down syndrome
Paternal Factors
Men’s exposure to lead, radiation, pesticides, petrochemicals may cause abnormalities in sperm that lead to miscarriage or diseases such as cancer.
Stages of Birth
The birth process occurs in three stages. The first stage is the longest of the three.
Second stage when baby’s head starts to move through the cervix and the birth canal lasts until the baby is out of the mothers body.
Afterbirth is the third stage, the placenta, umbilical cord and other membranes are detached and expelled.
Medication for birth
analgesia: relieves pain
Anesthesia: block sensation in an area of the body or to block consciousness.
oxytocin/pitocin: induce labour
Apgar Scale
widely used to assess the health of newborns at 1 and 5 minutes after birth.
Evaluates heart rate, respiratory effort, muscle tone, body colour, reflex irritability.
Score 7-10 - babies health is good.
5 - may be developmental difficulties
3 or below - signals emergency and baby might not survive.
Brazelton Neonatal Behaviour Assessment (NBAS)
24-36 hours after birth. A sensitive index of neurological competence up to one month after birth .
Assesses the neurological development, reflexes, and reactions to people and objects.
16 reflexes such as sneezing, blinking, rooting are assessed.
Neonatal Intensive Care unit network of Neurobehavioural scale (NNNS)
assessment of neurobiological and stress responses, regulatory capacities.
NBAS assess normal healthy full term babies, NNNS is used for evaluating preterm infants.
Preterm and Small for Date infants
low birth weight, preterm delivery, small for date … three related conditions .
Consequences of preterm birth and low birth weight - higher rates of illness and developmental problems than infants of normal birth weight.
Kangaroo care
Can stabilize infants heartbeat, temperature and breathing
low birth weight
infant that weighs less than 5.5 pounds at birth
preterm
born before 37 weeks gestation
small for date
birthweights below normal
postpartum period
about 6 weeks
