Presentation on theme: "Chapter 4: Prenatal development, birth, and newborns’ readiness for life. Dr. Pelaez."— Presentation transcript:
1 Chapter 4: Prenatal development, birth, and newborns’ readiness for life. Dr. Pelaez
2 From conception to birth Prenatal development is divided into 3 major phases:Germinal periodEmbryonic periodFetal period
3 Germinal Period From conception to implantation (about 14 days). Zygote moves toward uterus through fallopian tubeImplantation occursSupport system develops (4 structures)Implantation: blastocyst forms tendrils which attach to the uterine wallSupport System includes amnion (water like membrane to regulate temperature and cushion), chorion, placenta, umbilical cord.
4 Embryonic period Lasts from week 3 to week 8. Neural tube development begins.Heart begins to beatGrows about 1/30 inches per day.External body structures form (ears, limbs, eyes)Neural tube: spinal cord develops from ectoderm and becomes the CNS.ectoderm develops into nervous system, skin & hairMesoderm develops into muscle, bone & circulatory systemEndoderm develops into digestive system, lungs, and other vital organs
5 Fetal period Lasts from week 9 to term. By end of month 3, sex can be detected on ultrasoundNeural and muscular systems continue to developBy second trimester (month 5-6), covered by vernix & lanugo (substance that protects fetal skin & fine hair which helps vernix to stick to body).Third trimester (weeks 25-38) involve rapid growth and maturity of all organ systems.Age of viability: a point between the 22-28th weeks in which survival outside the uterus may be possible.
6 TeratogensExternal agents such as viruses, drugs, and radiation that can be harmful to developing embryo or fetus.Sensitive periodsLong-term effects depend on the quality of postnatal environmentSensitive periods: each organ has a time when it is highly susceptible to teratogenic agents.Example: 69h week of development is a sensitive period for external genital development.
7 Maternal diseasesDiseases capable of passing through placenta and damage embryo/fetusRubella % of babies exposed will have birth defects.STD’s (AIDS, herpes, syphilis).ToxoplasmosisInfluenzaMalariaTuberculosis
8 DrugsDrugs taken by mother can have harmful effects on children: (low birth weight, heart defects, brain & neurological defects, and death).ThalidomideDiethylstilbestrol (DES)AlcoholCigarettesIllegal, prescription, and over the counter drugsThalidomide: used in the 1960’s to help mothers who experienced nausea.DES: drug prescribed in 1940’s-50’s. Later risk for abnormalities in reproductive organs, including cervical cancerDrugs: marijuana, heroin, cocaine, amphetamines, sex hormones, vitamins, aspirin, tranquilizers.
9 Environmental hazards Environmental hazards that may cause low birth weight, miscarriages, or genetic defects to embryo/fetus:RadiationLeadZincMercuryOther harsh chemicals
10 Maternal characteristics Maternal behavior can affect the outcome of her pregnancyMother’s dietMother’s emotional well-beingMother’s ageFolic acid should be consumed to prevent CNS defectsMothers should gain between pounds, ideally.Prolonged & severe stress tends to have effects such as irritability, low weight, and irregular sleeping and feeding habits on babies.Ideal age to bear children is between
11 Birth ProcessPerinatal environment: environment surrounding birth; includes influences such as drugs given to the mother, delivery practices, and the social environment.3 stage process:1. first stage of labor: uterine contractions. Lasts about 3-8 hours.2. second stage of labor: fetus moves through birth canal & emerges from mother’s body.3. third stage of labor: expulsion of the placentaFirst stage: contractions are at 10-1 minutes intervals.Second stage: baby delivery
13 Social environment at birth First hours are a sensitive period of emotional bonding.Postpartum depression may inhibit emotional bonding.Early father-infant interactions may make fathers feel more a part of the family.If experiencing post partum depression, seek professional help. Otherwise, infant attachment may be insecure.
14 Assessing the baby’s condition Apgar test: assess newborn heart rate, color, respiration, muscle tone, and reflexes.Neonatal Behavioral Scale (NBAS): assess neonate’s neurological integrity and responsiveness to environmental stimuli.NBAS administered a few days after birthAssess 20 reflexes.Low scores may indicate brain damage or other neurological problemsNBAS: ideally,heart rate :over 100bpm.Respiratory effort: good, baby is cryingMuscle tone: strong & Active motionColor: completely pinkReflex: vigorous cries, coughs, sneezes
15 Birth complications Anoxia Premature delivery Low birth weight Oxygen deprivationBreech positionRh factorPremature deliveryPreterm: born 3 weeks or more before term.Small for date babiesLow birth weightSmall for date: slow growthUnder 5 lbsMay experience respiratory distress syndromeRh factor: blood protein that when present in fetus, but not mother, can cause antibodies to be produced which may attack the red blood cells in subsequent fetuses who have the protein in their blood.Respiratory distress syndrome: irregular breathing due to insufficient surfactin.Medications can cross placenta and make the baby lethargic or inattentive
16 Readiness for life Healthy newborns display a number of reflexes. Survival reflexes: breathing, sucking & swallowingPrimitive reflexes (disappear during first year of life): babinksi reflex, swimming, stepping reflexBabinksi: fanning/curling toes when foot is stroked
17 Readiness for life continued Infant states.Regular sleep: 8-9 hours/dayIrregular sleep: 8-9 hours/dayDrowsiness: ½-3 hours/dayAlert inactivity: 2-3 hours/dayAlert activity: 1-3 hours/dayCrying: 1-3 hours/dayInfants spend have of their sleeping hours in REM sleep.SIDS: leading cause of death of infants within first year of life