2Biological Beginnings: Conception Ova are released from the ovaries and travel down the fallopian tubes, where conception occurs. Development begins at conception.Males produce an average of 300 million sperm per day. Only reach the ovum.Sperm can live for 6 days and ova for one.
3The Three Periods of Pregnancy Germinal (Period of the Zygote)First two weeks, ends with implantationEmbryonic Period2-8 weeks, organogenesisFetal Period9 weeks – birth (all trimesters)
4Period of the Zygote (Germinal) 4th day – blastocyst, hollow, fluid filled ball (60-70 cells)Inside, embryonic disk will become new organismOutside, troboblast, protective covering
5Period of the Zygote (Germinal) Within about 1 week of conception, cell differentiation beginsImplants (attaches to the uterine wall) on the 10th to 14th day
6Period of the Zygote (Germinal) Troboblast will form the amnion (fluid sac which regulates temperature and forms a cushion)Will also form the chorion, from which fingerlike villi or blood vessels emerge and the placenta forms as they burrow into the uterine lining.
7Embryonic Period – 3rd week after conception Umbilical cord connects the growing organism to the placentaIt has one vein and two arteriesThe mother’s and embryo’s blood will not mix directly (red blood cells, bacteria, hormones, maternal waste are filtered)
8Embryonic Period – 3rd week after conception Embryonic disk forms:Ectoderm – skin and nervous systemMesoderm – muscles, skeleton, circulatory systemEndoderm – digestive system, lungs, urinary tract, glands
9Embryonic Period (2-8 weeks) - Organogenesis Neural tube develops first, will become brain and spinal cordNext, heart begins to pump bloodThe basic structure of all the organ systems growsEyes, ears, nose, jaw, neck, arms legs, fingers & toes formAt the end of this period, it weighs less than one ounce, about one inch long.
10Period of the Fetus – Growth and Finishing Phase – 3rd Month The fetus can kick, bend its arms, form a fist, curl its toes, open its mouth, suck its thumb, smile & swallowBy 12th week external genitals well formed, also fingernails, toenails, tooth buds, eyelidsHeartbeat can be heard with a special stethoscopeEnd of 3 months, 3 inches, 3 ounces
11Period of the Fetus – Growth and Finishing Phase Called a fetus from the 8th week until birthFetus means fully-formed human being because all organ systems are now in placeDuring the 3rd month (12-16 weeks) it will have coordinated movements, be able to roll over in the amniotic fluidHair, eyelashes, eyebrows will grow
12Period of the Fetus – Growth and Finishing Phase – 2nd Trimester Mother can feel movementsCan hear heartbeat with ordinary stethoscopeNeurogenesis proceeds rapidly (250,000 neurons per minute)At 20-weeks can be stimulated/irritated by sound; will shield eyes during fetoscopy
13Period of the Fetus – Growth and Finishing Phase-Age of Viability Age at which the fetus can survive outside the mother (38-40 weeks is full term)5% survive at 22 weeks50% survive at 26 weeks (6 months)95% survive at 28 weeks
14Problems with Preemies Depends upon gestational age at birthBreathingHyaline membrane diseaseRegulating blood oxygen levelsApneaTemperature regulationFeedingParenting – 40% faster weight gain & brain development with touchKangaroo care
15Fetal Period – 3rd Trimester Begins sleep-wake patternResponsiveness, can feel pain after 24 weeksReact to soundsPrefer mother’s voiceAdds fat (5 pounds)Receives antibodiesAssumes birth position (head down)
16Teratogens (Monsters) Any environmental agent that causes prenatal damage (leading to birth defects)Types – drugs, diseases, radiation, environmental pollutantsFactors – dose, resilience (heredity), number of teratogens, gestational age at exposure (embryonic period worst)
17Teratogens - Drugs Examples Thalidomide – 7000 infants affected Limbs, heart, ears, kidneys, genitalsDES (diethylstilbestrol) – reproductive problems in adult children (cancer; abnormalities in reproductive organs)
18Teratogens - DrugsDon’t take anything without consulting your obstetricianExamplesAspirin – may be associated with LBW, infant death, lower IQ, poor motor developmentCaffeine – LBW, miscarriage, irritable infants
19Teratogens – Illegal Drugs CocaineHeroin/methodonePrematurity, LBW, breathing difficulties, physical defects, infant death, stressed and drug addictedMarijuanaSmaller head size, disturbed sleep, inattention in infancy
20Teratogens - tobaccoNicotine constricts blood vessels and lessens blood flow to the uterus, causes the placenta to grow abnormally, reduces the transfer of nutrients, raises the carbon monoxide concentration in the blood stream which may damage the central nervous systemSmoking during pregnancy is associated with LBW and increased frequency of prematurity, impaired breathing during sleep, infant death and childhood cancer.
21Teratogens - AlcoholFetal Alcohol Syndrome (FAS/FAE) is the leading preventable cause of mental retardation.Other symptoms include impaired motor coordination, attention, memory & language; slow physical growth & overactivity.Facial abnormalities include widely spaced eyes, short eyelid openings, thin upper lip, small head, small upturned nose.
22Teratogens - AlcoholLesson – Women should avoid alcohol during pregnancy.Alcohol inteferes with brain development – causing abnormalities in structure and function.Oxygen needed for cell growth is taken from the fetus to metabolize alcohol.
23Environmental Teratogens Radiation (Hiroshima, Nagasaki, Chernobyl)Miscarriages, babies with underdeveloped brains, physical deformities, slow growthMercury – 1950s Minamata, Japan – resulting brain damage in childrenLead – prematurity, LBW, brain damage, physical defectsPCBs (insulators for electrical equipment) – lower intelligence
25Other Maternal Factors NutritionEmotional stressMaternal age & previous births
26Prenatal Health Care18% of women in the U.S. wait until the second trimester, and 4% until the end to get careMany of these are unmarried, adolescent, or poverty stricken.Reasons include lack of insurance, ambivalent feelings, high risk behaviors, and lack of transportation.
27Approaches to Childbirth How much medical care/availability?Should it be natural or prepared?How about the epidural?How about a midwife (or a doula)?
28The Birth ProcessDilation and effacement (of the cervix)(Labor)At transition a clear channel from the uterus to the vagina is formed (birth canal)Birth of the baby (Delivery) minutesDelivery of the placenta (afterbirth) (5-10 minutes)
29Birth Complications and Medical Interventions AnoxiaBreech positionCerebral palsyFetal monitorsMedication (90-95% of births)Analgesics, anestheticsCesarean delivery (30% of births)
30Low Birthweight Infants (LBW) (Low)Birthweight is the best available predictor of infant survival & healthy development.Low Birthweight Babies weigh less than 5.5 pounds.1 of 14 American infantsMore problems with inattention, overactivity, language delays, low IQ scores, and motor deficits
31Low Birthweight Infants (LBW) Preterm babies – born early (35 or fewer weeks) may be weight appropriateSmall-for-date babies have more serious problems.
32Apgar (1 & 5 minutes after birth) 5 characteristicsHeart rate, respiratory effort, reflex irritability, muscle tone, color)0,1,or 2 points on eachTotal score7+, good physical condition4-6, baby requires assistance3-, infant in serious danger, requires emergency attention
33The Newborn - Arousal Sleep 18-20 hours per day 50% is REM sleep SIDS (Sudden Infant Death Syndrome)