Week 2 - Conception Heredity & Prenatal Dev; Birth & the Newborn Student Slides PDF

Conception, Heredity, and Prenatal Development; Birth and the Newborn PSY 323 – Professor Agbayani Announcements: Slight change in office hours! Still on Wednesdays in my office Crean 132F – now from 2pm-3pm. Last time: Intro to Child Development theories: p...

Conception, Heredity, and Prenatal Development; Birth and the Newborn PSY 323 – Professor Agbayani Announcements: Slight change in office hours! Still on Wednesdays in my office Crean 132F – now from 2pm-3pm. Last time: Intro to Child Development theories: psychoanalytic, cognitive, and social learning Today: Describe processes associated with conception and prenatal development Describe processes associated with childbirth and the care of neonates (newborns) Before we start: how many of us have taken physio psych (or similar?) Genes & Chromosomes  Genes & Chromosomes Genes: Basic units of genetic information, composed of specific sequences of DNA molecules Arranged in specific locations, in a specific order, along 46 chromosomes (23 pairs) The exception is sex chromosomes, which aren’t always in homologous pairs (XX versus XY; XXY; X0) Genetics basics – mixing and matching Dominant Trait ○ The trait that is expressed when two competing traits are present Recessive Trait ○ A trait within an organism that is present genetically, but is not expressed Genetics basics – mixing and matching Genotype ○ The combination of genetic material present in an organism ○ All genes Phenotype ○ An observable trait; the trait that actually is seen ○ Physical appearance Transmission of Genetic Information Homozygous ○ Inheriting similar genes from parents for a given trait ○ Necessary to express recessive traits Heterozygous ○ Inheriting different forms of a gene from parents for a given trait Transmission of Genetic Information – PKU example Phenylketonuria (PKU): A metabolic disorder in which the individual cannot metabolize phenylalanine, an amino acid found in our diet. Can result in developmental deficits; easily detected and treated with a special diet Transmission of Genetic Information – PKU example Transmission of Genetic Information – PKU example The way genes affect our development is complicated! We have more than 20,000 genes In almost all cases, single genes are not responsible for a single outcome Our development/outcomes are polygenic Changes in your environment will increase or decrease expression of a gene - epigenetics Epigenetics Changes in gene expression without modifying DNA e.g., changes in brain development resulting from parents’ drug or alcohol use during gestation A gene may be active in one person and not another, or within different cells in one individual. Can Your Environment Affect Your DNA? | Epigenetics Explained Think/pair/share with a partner or group (~10 minutes, then time for group discussion): How can our understanding of epigenetics translate to supporting children’s success? Think about topics like equity for health care, educational, other programs/resources for both children and parents. There are many ways to support infant health before birth (before even taking genetics into account)  Access to health insurance Can influence use & timing of prenatal care Adequate prenatal care is associated with healthier birth outcomes, such as a longer period of gestation, healthier birthweight  Access to health insurance Many individuals in the U.S., particularly those with lower incomes, lack access to health insurance Adverse conditions in the perinatal period are typically more prevalent for people of color, resulting largely from long-standing discrimination within health systems (Hoyert & Miniño, 2020; Martin et al., 2019)  Prenatal Testing First trimester screening (FTS), nuchal translucency (NT) and noninvasive prenatal testing (NIPT) provide information on a developing baby FTS is a blood test evaluates substances in the blood (analytes) ○ Used with NT, a sonogram that looks at the back of the fetal neck  Prenatal Testing NIPT is another option for a blood test, coupled with a first trimester ultrasound Data can help assess if a fetus has a genetic anomaly: ○ Down syndrome/Trisomy 21 ○ Trisomy 13 ○ Trisomy 18 Moving on from genes – Our earliest development Gametes: Sex cells (sperm and egg) from biological parents that form a new cell at conception Gametes have 23 chromosomes versus 46 (they only make one copy of each pair when they undergo meiosis) Zygote: New cell formed by the process of fertilization – 46 chromosomes Moving on from genes – Our earliest development From here, we undergo 3 major stages or periods of development: 1. The period of the zygote (or the germinal period) 2. The period of the embryo 3. The period of the fetus Period of the zygote: fertilization to 2 weeks First—and shortest—stage of the prenatal period Zygote divides and grows in complexity… Travels to the uterus Implants in uterine wall Placenta forms  Period of the embryo: 2 to 8 weeks Significant growth occurs in the major organs and body systems Embryo has three distinct layers: 1. Ectoderm—forms skin, hair, teeth, sense organs, brain and spinal cord 2. Endoderm—produces digestive system, liver, pancreas, and respiratory system 3. Mesoderm—becomes the muscles, bones, blood, and circulatory system  Period of the embryo: 2 to 8 weeks An embryo: Is ~1 inch long Appears to have gills and a tail-like structure Has rudimentary eyes, nose, lips, and teeth Has stubby bulges that form arms and legs Undergoes rapid head and brain growth—50% of its length and 100,000 neurons a minute Nervous system starts functioning around the 5th week, producing weak brain waves  Period of the embryo: 2 to 8 weeks How Development Proceeds: Cephalocaudal development: Pattern of human growth proceeds from the head downward Proximodistal development: Human growth occurs first in central areas and then extends outward Teratogens are most harmful during this period  Teratogens The effects of substances on prenatal development resulting in negative outcomes (e.g., low birth weight, underdevelopment, etc.) Outcomes are affected by dose, cumulative effects, and sensitive period (times of rapid physiological or behavioral development) 4 categories of teratogens  Teratogens 1. Physical teratogens: E.g., saunas, hot tubs, or infections that raise body temperature to 102 degrees Fahrenheit or higher. Associated with neural tube defects, spontaneous abortions, and various cardiovascular abnormalities.  Teratogens 2. Metabolic conditions affecting pregnancy: Metabolic conditions affect the process of converting energy from food, affecting the development and function of the body. These include: malnutrition, diabetes, and thyroid disorders.  Teratogens 3. Infections: Rubella virus, herpes simplex virus, and syphilis can cause congenital abnormalities  Teratogens 4. Drugs and chemicals: Radiation, heavy metals (including lead), insecticides and herbicides, prescription and over the counter drugs, illicit and recreational drugs, alcohol, cigarettes, nicotine, caffeine, and even some vitamins.  Teratogens Generally speaking: Effects of teratogens vary with time – Period of the zygote: Relatively impervious – Period of the embryo: Most deleterious – Period of the fetus: Minor damage Hard to pinpoint primary cause of damage – Effects different for different individuals – Cumulative effects are common – Race and socio‐economic status (SES) are influential factors  Period of the fetus: 8 weeks to birth Fetus undergoes rapid change Increases in length about 20 times Proportions change 2 months: 50% of length is the head 5 months: 3/8 of length is the head Birth: ¼ of length is the head  Period of the fetus: 8 weeks to birth Fetus substantially increases in weight 4 months: weighs ~4 ounces – can feel them move 7 months: weighs ~3 pounds Birth: weighs just over 7 pounds Organs become differentiated, begin to function Fetus can hear and feel vibrations of sound Birthing parents also go through many changes: (+attendance) Time for a break!  Let’s talk birth settings! Where are babies born? Who is typically present?  The birthing team In the US, commonly takes place in a Labor & Delivery (L&D) unit in a hospital ○ An OB-GYN (obstetrician-gynecologist) is usually present, along with L&D nurses and other professionals Some hospitals/home birth settings have midwives present: credentialed health care professionals who provide prenatal, delivery, and postpartum care (some are nurses) Doulas: nonclinical professionals who support parents emotionally and physically during the perinatal period, including birth and postpartum What’s a Doula? Labor occurs in 3 stages Stage 1 Contractions, dilation, and thinning of the cervix Latent stage: Infrequent contractions, not especially painful Active stage: More intense and frequent contractions; infant transitions into the birth canal Stage 2 & 3 Delivery of the infant (Stage 2) Delivery of the placenta (Stage 3)  The placenta – what is it? An organ that develops with the baby to provide nutrients and oxygen throughout term – attached to the uterus Care teams may delay clamping & cutting the umbilical cord after delivery to increase flow of nutrient-rich blood from the cord & placenta to the baby. ○ Increases the baby's iron levels, reduces the risk of anemia The placenta is typically delivered in ~30 minutes  The placenta – what is it? Mild, less painful contractions that are close together help move the placenta into the birth canal Labor & delivery team will examine the placenta to make sure it's intact & remaining fragments must be removed from the uterus to prevent bleeding and infection In the United States, typically the care team will dispose of the placenta (as biohazard waste) – but many cultures practice burying the placenta to honor its role in baby’s development & improve outcomes for the birthing parent Traditional birthing practices – “The ‘Iewe (placenta) Incident” Position at birth is important Vertex position: Ideal; head first, face down Back birth: Less than ideal; head first, face up Position at birth is important Breech position: Less than ideal; feet first Transverse position: sideways, impossible for vaginal delivery; Cesarean section necessary  Pain Relief Non-medicinal: Breathing techniques, such as Lamaze Changing positions, walking  Pain Relief Medicinal: Analgesia: Reduces pain only, not sensations such as pressure Anesthesia: Blocks nerve receptors that carry pain information (spinal blocks and epidurals) Use of pain medications does not make labor “less natural” nor does it increase the likelihood of a Cesarean birth. There are no long-term effects on baby/child development. Infant Extraction Techniques Decreased use over time, still used in some cases: Forceps: Grasp infant around head, guide delivery from canal Vacuum: Suction applied to scalp In frequent (+ increasing!) use: Cesarean deliveries: Surgical delivery of infant through abdominal incision Cesarian birth, Wellstar OBGYN clinic in GA – footage mostly from behind surgical curtain (no footage of incisions) Preterm births Premature infants are born at or before 37 weeks (full- term) ~13.4 million babies were born preterm in 2020 (World Health Organization, 2023) ○ More than 1 in 10 babies Increased risk for breathing & feeding difficulties, vision & hearing issues, developmental delays (e.g., speech, motor) Preterm births Issues related to prematurity are the leading cause of death in children under the age of 5 years Feasible and cost-effective care options to combat negative outcomes: warmth, breastfeeding support, basic care for infections and breathing difficulties Even with supportive care, preterm birth increases likelihood of low birthweight Birth weight Full‐term infant weighs about 7½ pounds at birth Low birth weight: Less than 5½ pounds Very low birth weight: Less than 3¼ pounds Small for gestational age: Weigh less than expected for gestational age The role of resilience: better outcomes may be associated with responsive care from adults & the presence of positive personality traits (e.g., friendliness, sociability) Baby is born – now what? We assess neonate/newborn’s functioning: APGAR scale Sign 0 Points 1 Point 2 Points Appearance (skin Blue-gray, pale all Normal, except Normal over color) over for extremities entire body Pulse Absent Below 100 bpm Above 100 bpm Grimace (reflex No response Grimace Sneezes, coughs, irritability) pulls away Activity (muscle Absent Arms and legs Active movement tone) flexed Respiration Absent Slow, irregular Good, crying SOURCE: Apgar (1953). Baby is born – now what? Assessed 1 and 5 minutes after birth Sign 0 Points 1 Point 2 Points Appearance (skin Blue-gray, pale all Normal, except Normal over color) over for extremities entire body Pulse Absent Below 100 bpm Above 100 bpm Grimace (reflex No response Grimace Sneezes, coughs, irritability) pulls away Activity (muscle Absent Arms and legs Active movement tone) flexed Respiration Absent Slow, irregular Good, crying SOURCE: Apgar (1953). Baby is born – now what? 7+: No concern; 3 or less: Critical condition Sign 0 Points 1 Point 2 Points Appearance (skin Blue-gray, pale all Normal, except Normal over color) over for extremities entire body Pulse Absent Below 100 bpm Above 100 bpm Grimace (reflex No response Grimace Sneezes, coughs, irritability) pulls away Activity (muscle Absent Arms and legs Active movement tone) flexed Respiration Absent Slow, irregular Good, crying SOURCE: Apgar (1953). Baby is born – now what? Few infants score a perfect 10, most in normal range at 5mins Sign 0 Points 1 Point 2 Points Appearance (skin Blue-gray, pale all Normal, except Normal over color) over for extremities entire body Pulse Absent Below 100 bpm Above 100 bpm Grimace (reflex No response Grimace Sneezes, coughs, irritability) pulls away Activity (muscle Absent Arms and legs Active movement tone) flexed Respiration Absent Slow, irregular Good, crying SOURCE: Apgar (1953). Overall physical appearance of the newborn Vernix—thick, greasy substance that smooths the passage through the birth canal Lanugo—fine, dark fuzz May have puffy eyelids May have blood or other fluids (leftover amniotic fluid) After baby is cleaned, they’re usually returned to the birthing parent for skin-to-skin contact Physical competence of the newborn Neonates have to take over all the functions of the placenta/umbilical cord As digestive system begins to function, newborns initially produce meconium (first stool) Newborns show several reflexes—unlearned, organized, involuntary responses that occur automatically in the presence of certain stimuli: Sucking, swallowing, and rooting reflexes Coughing, sneezing, and blinking Sensory capabilities Vision ○ Visual acuity is not fully developed ○ Pay close attention to scenes highest in information ○ Can discriminate levels of brightness ○ May have a sense of size constancy ○ Can distinguish different colors and have color preferences Blue and green objects Sensory capabilities Hearing ○ Capable of hearing, but auditory acuity is not fully developed ○ React to certain kinds of noises ○ Exhibit familiarity with certain sounds Touch ○ Most well developed sense at birth ○ Respond to stimuli and are aware of puffs of air Sensory capabilities Smell and taste ○ Well developed ○ Pucker lips when a sour taste is placed on them ○ Respond with suitable facial expressions to other tastes  Reflex Approximate Age Description Possible Someof reflexes: Disappearance Function Rooting 3 weeks Turn head toward things that touch cheek Food intake Stepping 2 months Movement of legs when held upright with Preparation for feet touching floor independent locomotion Moro 6 months Startle reflex—arms are thrust outward Protection from and appear to grasp onto something falling Babinski 8-12 months Toes fan out in response to a stroke on the Unknown outside of foot Tonic neck 4 months When lying on the back with the head to Unknown – maybe one side, arm and leg on that side are coordination of extended while flexing the limbs on the upper and lower opposite side body Sucking 4 months;voluntary Suck at things that touch lips Food intake afterward Newborn/Infant Reflexes Assessment