Presentation on theme: "PRENATAL DEVELOPMENT, BIRTH, AND NEWBORNS’ READINESS FOR LIFE"— Presentation transcript:
1PRENATAL DEVELOPMENT, BIRTH, AND NEWBORNS’ READINESS FOR LIFE
2Prenatal DevelopmentDevelopment that occurs between the moment of conception and the beginning of the birth processDevelopment occurs in the mother’s uterus and the degree of safety depends on:(1) Mother’s age(2) Health(3) Food quality(4) Drug Intake(5) Chemical/Environ. ExposureHuman growth occurs more rapidly during the prenatal period than any other period of human development
3FROM CONCEPTION TO BIRTH Development begins in the fallopian tube when a sperm penetrates the wall of an ovum…This union forms a zygoteGestational Period (266 days)From conception (zygote) to readiness for birth (fetus of some 200 billion cells)
4PERIODS OF PRENATAL DEVELOPMENT Germinal (zygote) PeriodLasting from conception until the developing organism becomes firmly attached to the wall of the uterusEmbryo PeriodLasting from the 3rd through the 8th prenatal week. During which the major organs and anatomical structures take shapeFetus PeriodLasting from the 9th prenatal week until birth. During this period, all major organ systems begin to function and the fetus grows rapidly
5The Germinal Period (2 weeks) While traveling down the fallopian tubes towards the uterus, cell division occurs thru mitosis.Continued cell division (60 to 80 cells) eventually forms a blastocyst. Generally occurs within 4 days of conception.As a result of continued cell differentiationThe inner layer of the blastocyst (embryonic disk) becomes the embryoThe outer layer of cells develops into tissues that protect and nourish the embryo
6IMPLANTATIONThe Blastocyst approaches the uterus (6 to 10 days) and attaches itself to the wall of the uterus thru small burr like tendrils which tap into the mother’s blood supply.Only about half of all fertilized ova are firmly implanted.Half of those that firmly implant are genetically abnormal, fail to develop, or implant in an area that is not conducive. Resulting in miscarriages.3 out of 4 zygotes fail to survive the initial stage of prenatal development.
7DEVELOPMENT OF SUPPORT SYSTEMS Once implanted, the blastocyst’s outer layer rapidly forms 4 major support structures that protect and nourish the organismAmnion—a watertight membrane that surrounds the developing embryo, serving to regulate its temperature and to cushion it against injuriesChorion—surrounds the amnion and eventually becomes the lining of the placentaPlacenta—an organ formed from the lining of the uterus and the chorion, that provides for respiration and nourishment of the unborn child and the elimination of its metabolic wasteUmbilical cord—a soft tube containing blood vessels that connects the embryo to the placenta
8THE PERIOD OF THE EMBRYO 2 wks to 2 months The embryonic disk differentiates into 3 cell layers:Ectoderm—outer layer which becomes the nervous system, skin, hairMesoderm—middle layer which becomes muscle, bones, circulatory systemEndoderm—inner layer which becomes digestive, lungs, urinary tract, vital organs (pancreas, liver)
9EMBRYO CONTINUED In the 3rd week after conception A portion of the ectoderm folds into a neural tube (brain and spinal cord)By the end of the 4th weekThe heart has formed and has begun to beat.Eyes, ears, nose, and mouth are also beginning to form.Buds which will eventually become arms and legs begin to form30 days after conception the embryo is only about ¼ of an inch. But 10,000 times larger than that of the zygote
10EMBRYO CONTINUED During the 2nd month The embryo starts to appear human. Circulatory system is independent. Liver and spleen producing blood from the yolk sac.A primitive tail appears which eventually becomes enclosed by protective tissue. Forming back bone or coccyxBetween the 5th and 7th weekEyes have corneas and lenses, ears are well formed, skeletal system developed. Limbs and muscular system developing.Development is occurring in a proximodistal and cephaloclaudal mannerDuring 7th and 8th weekSexual development begins to appear (indifferent gonads/genital ridges).Male, gene on Y chromosome triggers chemical reaction to produce male testicles.If female, gonads will receive no instruction and will produce ovaries
11THE PERIOD OF THE FETUS (2-9 months) All of the structures which will be present when the baby is born are formed at the end of 2 months.Body systems become interconnected. Nervous and Muscular system allow for kicking, twisting of bodyDigestive and Excretory allow for swallowing, digest nutrients, urinationSexual differentiation increasing rapidly.Male testes secrete testosterone—hormone responsible for the development of penis and scrotum. In the absence of testosterone, female genitals are developed.By end of 3rd month, sex can be determined by ultrasound. The reproductive systems already contain immature ova and sperm cells.All of these developments in a mere 3 months (1st trimester) and when the fetus is only 3 inches long and weighs less than an ounce
12THE SECOND TRIMESTERMotor activities become refined actions such as thumb sucking or kicking strong enough to be felt by the motherHeartbeat can be detected using a stethoscope and the hardening skeleton can be detected with ultrasoundNails harden, skin thickens, eyebrows, eyelashes, and scalp hair appearsThe fetus is now covered by a white cheesy substance called vernix (protects skin from chapping) and a fine layer of body hair called lanugo (helps vernix stick to the skin)By the end of 2nd trimester, fetus visual and auditory senses become functional
13THE THIRD TRIMESTERAll organs mature rapidly/ preparing the fetus for birth7 months from conceptionFetuses reach the age of viability (a point by which survival outside of the mother’s uterus may be possible)Signs of viability.Organized and consistent heart rate activityGross motor activitySleepiness/waking activity (Determined thru fetal monitoring techniques).However, children born prematurely still require oxygen assistance because of immature air sacs in the lungs called pulmonary alveoli
143rd Trimester Continued By the end of 7 monthsFetus weighs nearly 4 pounds and 16 inches long.A month later, the fetus has grown an extra pound or two and grown a inch or two longer due to fat accumulation (regulation of body temp).By the middle of the 9th month, fetal activity slows and sleep increasesFetus is now so large that the most comfortable position is head down at the base of the uterus/ limbs curled in a fetal position
15ENVIRONMENTAL INFLUENCES ON PRENATAL DEVELOPMENT TeratogensExternal agents such as viruses, drugs, chemicals, and radiation that can harm a developing embryo or fetus by causing physical deformities, severely restricting growth, blindness, brain damage, and even deathAbout 95% of newborn babies are perfectly normal and that many of those born with defects have mild, temporary, or reversible problems
16Key Points About Teratogens The effects of teratogens are worst on a body part during the period when that structure is forming or growing most rapidlyNot all embryos or fetuses are equally affected by a teratogen (genes and prenatal care play a vital role)Similar defects can be caused by different teratogensA variety of defects can result from a single teratogenThe longer the exposure to or higher the dose of a teratogen, the greater the severity of harmEmbryos/fetuses can be affected by fathers and mothers exposure to teratogensThe long-term effects of a teratogen often depend on the quality of the postnatal environment
17Sensitive PeriodsA period during which an organism is highly susceptible to certain environmental influences.Teratogens may still have impact but greater exposure may be required.Most organs and body parts are forming during the period of the embryo (3 to 8 wks).Therefore, exposure during this period may have serious consequences.This is also the time when a woman may not even know that she is pregnant that the embryo is most vulnerable to teratogens.
18Maternal DiseasesSome diseases are small enough to cross the placental barrier and affect developing embryo (immature immune system)Rubella (German measles)—mothers who contract this early in pregnancy delivered babies who were blind, deafness, cardiac abnormalities, and mental retardation (most serious during 1st tri but impactful during 2nd.Toxoplasmosis—caused by a parasite found in animals. Generally causes severe eye and brain damage. Even abortion.Sexually Transmitted Diseases—most common teratogens and generally more hazardous.Syphillis—can cause eye, ear, bone, heart, brain damageGenital Herpes—kill about 1/3 affected newborns, cause blindness, brain damage, neurological disordersAIDS—worldwide, nearly 4 million women of childbearing age carry this virus and can transmit it to their young. ZDV an antiviral drug used to treat aids improve longevity of life however, those affected by aids will eventually die due to complication
19Continued The Thalidomide Tragedy Drug used in the 1960s to reduce the occurrence of morning sickness.Pretests with rats revealed no harmful effectsThousands of women who used this drug in the 1st trimester produced severe deformities: eyes, ears, noses, and hearts.Many developed PhocomeliaA structural abnormality in which all or parts of limbs were missing and the feet and hands may be attached directly to the torso (similar to flippers)
20Fetal Alcohol Syndrome Causes microcephaly (small head)Malformations to heart, limbs, joints, and faceFAS babies display excessive irritability, hyperactivity, seizures, and tremors. Generally, smaller and lighter than most babies.Physical and cognitive growth lags
21ContinuedLithiumProduces heart defects when taken during 1st trimesterSex hormones found in contraceptives—heart defects and mild deformationsDiethylstilbestrol (DES)Used mid 1940’s to 1965—synthetic hormone formally prescribed to prevent miscarriages, found to produce cervical cancer in female offsprings and genital tract abnormalities in males
22CIGARETTE SMOKINGCigarette smoking found to cause spontaneous abortion.Low birth weightIncreased in respiratory infectionsPoorer cognitive performance
23KEY QUESTIONSShould we pass laws surrounding alcohol consumption and pregnancy?
24ILLICIT DRUGS Marijuana Found to have few physical defects. Babies display tremors, sleep disturbances, lack of interest in the environment in early lifeHeroinFew physical defects, increased risk for miscarriages, premature deliveries, SIDS1st month is difficult for these babies but start to normalizeCocaineIncreased risk for physical defects.Problems with blood restriction/pressure.Miscarriages/premature births
25MATERNAL CHARACTERISTICS Mothers generally advised to gain 25/30 pounds. Doctors now focus on a healthy (high protein and calorie) and nutritious dietSevere malnutrition stunts growth. Also, additional effects depends on the trimesterMalnourished babies show cognitive defects/behavioral problems later in childhood. Imbalance of brain cellsContinue malnutrition after birth leads to irritability which affect the parent/child attachment and reduce the amount of facilitated play and supportive interaction that could foster healthy social and emotional developmentSmall amounts of zinc and magnesium have been found to improve placenta & reduce difficult pregnanciesFolic acid found to prevent down syndrome, spinal bifida, anencephaly, and other defects of the neural tube (most women consume less than half the recommended daily amount needed)Massive campaigns to produce awareness but controversial due to the assumption that more is better
26MOTHERS EMOTIONAL WELL-BEING Prolonged stress can have a detrimental impact on fetal development.Stress produces chemical responses that is released in the blood and pass the placental barrier. Consequently, causing premature delivery, low birth, stunted growthStress may also weaken the mother’s immune system, consequently, increase the risk of impactful diseasesStress appears to be most impactful when the mother has poor coping skills. Other concerning factors:Ambivalent/negative about their marriage or pregnancyNo social support systems
27Mother’s AgeThe safest time to bear a child appears to be around age 16 to age 35 (SIDS, LBW, Down Syndrome)Younger teens are at risk because they are likely impoverished, high levels of stress, and have little access to supervised prenatal careTeen moms are generally not at risk when they receive adequate prenatal careOlder moms risk spontaneous abortion, genetic dysfunctionsAdequate prenatal care is the key among all moms irrespective of age
28Child birth is a 3 stage process THE BIRTH PROCESSChild birth is a 3 stage process1st stage—the period of the birth process lasting from the first regular uterine contractions until the cervix is fully dilated2nd stage—the period during which the fetus moves through the birth canal and emerges from the mother’s body3rd stage—expulsion of the placenta
29The Baby’s ExperienceBabies are born under stress but their own stress hormones enable them to withstand the stressors of the birthing process.Generally babies born blush in color due to oxygen deprivation. They also pass thru a narrow cervix and birth canal (resulting flattened noses, misshapen foreheads, and mild bumps and bruisesGenerally about 20 inches long and weights about 7 to 7.5 pounds
30APGAR TESTAn assessment for the newborn’s heart rate, respiration, color, muscle tone, and reflexes that is used to gage perinatal stress and to determine whether a neonate requires immediate medical assistance.Score range 0-10 with 7 being normal. Generally done at birth and 5 minutes later to determine improvement.
31Neonatal Behavioral Assessment Scale A test that assesses a neonate’s neurological integrity and responsiveness to environmental stimuliTypically administered few days after birth. Measures the strength of 20 inborn reflexes, changes in infant’s state, and reactions to comforting and other social stimuliLow scores due to slow responses may be indication of brain damageIf reflexes are good but sluggish or irritable when responding to social stimuli—indication that they may need more playful stimulation
32The Social Environment Surrounding Birth Only 20 years ago, most hospitals barred fathers from delivery rooms and quickly removed babies once they were bornToday, 99% of children are born in hospitals.
33Parent’s ExperienceSome research that the first 6 to 12 hours are a sensitive period for emotional bonding between parents and the newbornPostpartum DepressionHormone changes in the mother sometimes cause depression. Elevated and extended depression leads to the diagnosis. Occurs in 10% on new momsNew fathers display engrossment. Intense fascination.
34Birth Complications3 birthing complications that can affect development:Anoxia (oxy deprivation)Low birth weightPremature deliveryANOXIA (occurs in 1% of cases)Breech babies at risk due to tangling of umbilical cordDetachment of umbilical cordBirth sedatives cross placentaGenetic incompatibility between Rh positive fetus and Rh negative motherDelayed motor and mental development (3 to 7yrs)
35Low Birth WeightDue to such factors as drug usage and malnourishment. Tends to be higher among low-income women from ethnic minority groups due to elevated levels of stress and poor education about prenatal careIncreased risk of SIDS, generally due to respiratory distress syndrome (irregular breathing patterns)
36Premature Births Preterm babies Small-for-date babies Babies born more than 3 weeks before due dateSmall-for-date babiesInfants whose birth weight is far below normal, even when born close to their normal due dates