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PRENATAL DEVELOPMENT AND BIRTH How did you develop before birth? Prenatal development 2D Ultrasound 4D 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? Conception • First 2 weeks • Conception • Zygote • Implantation Zygote How does an embryo develop? Primitive streak • 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) 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 • 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 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 Cervical dilation chart • Labor • 12 hrs. – first child • Stages of labor 10 Cm. • 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.) 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) Cleft palate • Behavioral teratogens = Behavioral defects • Hyperactivity • Antisocial • Learning-disabled Thalidomide baby • Autism 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?