Genetics, Conception and Prenatal Development Lecture Notes PDF

Genetics, Conception and Prenatal Development Course: Developmental Psychology: Childhood and youth University of Europe for Applied Sciences Berlin Dr. Costanza De Simone November 6th 2024  WHAT WE’LL LEARN THIS WEEK 1. The Construction Plan for a Human Bein...

Genetics, Conception and Prenatal Development Course: Developmental Psychology: Childhood and youth University of Europe for Applied Sciences Berlin Dr. Costanza De Simone November 6th 2024  WHAT WE’LL LEARN THIS WEEK 1. The Construction Plan for a Human Being: Chromosomes, Genes, and Heredity 2. The Beginnings of Life 3. The Prenatal Environment: Factors Influencing Development 4. Prenatal Care and Prenatal Tests 5. Special Pregnancy Issues: Infertility and the Premature End of a Pregnancy 2 1. The Construction Plan for a Human Being: Chromosomes, Genes, and Heredity 3 The Basics of Heredity all living things are made of cells each cell in the human body has a nucleus that contains 23 pairs of chromosomes 46 chromosomes total Chromosome a threadlike structure found in the nucleus of most living cells contains the genetic information of an organism 4 Of the 23 chromosome pairs, 22 are autosomes autosomes DO NOT determine a person’s sex these 22 pairs are identical in males and females The 23rd pair consists of 2 sex chromosomes each of a pair of chromosomes that determine a person’s biological sex females have two X chromosomes males have one X chromosome and one Y chromosome 5 FIGURE 3.1 Computer illustration of male (left) and female (right) karyotypes. 6 Chromosomes are made of long strands of DNA DNA = deoxyribonucleic acid, a molecule that carries hereditary material each “step” of the spiral staircase is made of a pair of biochemical bases DNA strands can be divided into segments called genes 7 Genes a segment of a DNA strand in a chromosome, which carries genetic information contains information for creating proteins needed for many body functions humans have about 21,000 genes 8 Genome the entire set of an organism’s genes From person to person, genes differ just a little bit in how the base pairs are arranged these different variants of a single gene are called alleles these tiny variations in our genes are the reason for individual differences between people 9  Zygote the cell that is created when Gametes gamete cells (ovum and sperm) sex cells are joined an organism’s reproductive cells has 46 chromosomes in 23 pairs female gametes are called ova or egg cells male gametes are called sperm gametes only have 23 chromosomes each 10 FIGURE 3.3 Hereditary composition of the zygote. 11 Gene Expression expression of a gene depends on whether it is dominant or recessive Dominant Traits expressed even if there is only one gene for that trait and the second gene is for a competing trait Recessive Traits are expressed only if they are paired with a second gene for the recessive trait if paired with a gene of the dominant trait, the dominant trait will be expressed 12 Heterozygous having two different alleles of a gene for a particular trait Homozygous having identical alleles of a gene for a particular trait on both chromosomes Polygenic trait a trait that is controlled by two or more genes makes it difficult to predict the outcome of a trait in future offspring example: eye color 13 FIGURE 3.4 When both the mother and father are carriers of the gene that causes PKU, 14 Our traits are influenced by more than just our genes -the environment plays a significant role in shaping human traits Genotype the person’s genetic makeup Phenotype a person’s actual characteristics the result of the interaction of the person’s genes with the environment Although our bodies have genetic “instructions”, not all these characteristics will actually be expressed 15 Epigenetic modification a process that activates or deactivates genes by tightly or loosely winding up DNA our environment influences our genes such they are ”turned on” or “turned off” tightly wound DNA cannot be decoded and thus the genes in that part are “turned off” loosely wound DNA activates the genes by making them “readable” or “turned on” 16 Monozygotic (MZ) twins Dizygotic (DZ) twins “identical” twins fraternal twins have their origin in the same zygote develop when a woman releases two ova (eggs) during ovulation and during the first few days of both are fertilized pregnancy, the egg splits into two halves, which then develop into two individual children have roughly the same genome 17 FIGURE 3.5 These two images show a pair of chromosome 3 of monozygotic twins Robert and Richard. 18 19 Heritability extent to which genetic differences contribute to individual differences in traits Expressed as a numerical value ranging from 0 to 1 a value of 0 indicates that the differences in people in one trait are solely due to differences in their environment a value of 1 indicates that the differences in people in one trait are completely due to genetics 20 0 = environment 1 = genetics 21 Dr. Nancy Segal on Twins 22 Table 3.1 Heritability: The Influence of Genes on Traits and Disorders Intelligence Highly polygenic (Benyamin et al., 2014) Influence of genes increases significantly as a person gets older (Plomin & Deary, 2015). © chalermphon_tiam/ Stimulating activities like reading and Shutterstock.com athletics as well as diet and other factors play a role (Sternberg & Grigorenko, 2014). Personality Strong genetic basis in childhood With increasing age, environment © iStock.com/LUNAMARINA becomes more important (Bleidorn et al., 2014; Pesta et al., 2020). On average, 40% of individual differences in traits can be attributed to genetic factors and 60% to environmental influences (Vukasović & Bratko, 2015). Physical and psychological disorders Individuals inherit a predisposition for a number of disorders like autism, attention- deficit/hyperactivity disorder, or reading disorder (e.g., Cheroni et al., © Syda Productions/ 2020). Shutterstock.com A predisposition increases the probability that a disorder will be displayed; it does not indicate that a person will indeed get the disorder or how serious the disorder will be. 23 Chromosomal Disorders a person has either an incorrect number of chromosomes or chromosomes that are altered from what they should be Most disorders are not passed on from one generation to the next but are random events 24 Down syndrome (also called trisomy 21) the chromosomal disorder that occurs most often individuals have an extra copy of chromosome 21 about 1 in 700 babies is born with Down syndrome older women have a higher risk of conceiving an infant with Down syndrome 25 FIGURE 3.6 Number of babies born with Down syndrome, by age of mother. 26 Table 3.2 Chromosomal and Genetic Disorders Dominant/ Autosom Disorder Incidence Description Treatment recessive al/ X- linked Cystic fibrosis 1 in 2,000 births Mucus buildup in lungs and Physical therapy to Recessive Autosomal pancreas leads to breathing clear airways of difficulty and lung damage mucus; medication as well as impaired to treat infections digestion. Life expectancy and loosen mucus; is approx. 40 years. enzymes to aid digestion Duchenne 1 in 3,500 male Progressive weakening of None Recessive X-linked muscular births the muscles leads to dystrophy wheelchair dependence in early adolescence. Hemophilia 1 in 4,000 Abnormal blood clotting leads Infusions of hormones Recessive X-linked male to excessive bleeding from or clotting factors birthsa both external and internal (proteins involved in injuries. blood clotting) Huntington’s 3–7 in 100,000 Deterioration of nerve cells in None. Condition is Dominant Autosomal disease births the brain leads to loss of usually fatal within 10– muscle coordination and 20 years of the onset cognitive of symptoms. function. Symptoms first appear after age 30 (approx.). Phenylketonuria 1 in 10,000 birthsb Metabolic disorder in which Can be diagnosed at Recessive Autosomal (PKU) the body cannot produce birth; intellectual the disability can be enzyme needed to break prevented with a diet down the amino acid that limits foods phenylalanine. Subsequent containing buildups lead to intellectual phenylalanine. disability. Sickle-cell anemia 1 in 365 Blood disorder in which Blood transfusions to Recessive Autosomal African misshapen red blood cells increase number of American inhibit blood flow and oxygen healthy red blood cells; births supply throughout the body, bone marrow transplants; resulting in joint swelling antibiotics for infections; and pain, delayed growth, pain relievers and frequent infections 27 Table 3.2 (Continued) Dominant/ Autosom Disorder Incidence Description Treatment recessive al/ X- linked Tay-Sachs 1 in 3,600 Neurological disorder that None; usually fatal in Recessive Autosomal disease Jewish (of destroys nerve cells in early childhood European brain and spinal cord descent) births Neural tube Anencephaly: 1 in Anencephaly: Absence of a Anencephaly: None; Multiple defects: 1,000 major portion of the brain most children die genes Anencephaly pregnancies and skull before birth involved and spina and 1 in Spina bifida: Exposure of Spina bifida: Surgery to bifida 10,000 live parts of the spinal cord close the spinal canal births Spina bifida: 1 in 2,500 live births Turner syndrome 1 in 800 Incomplete or lack of Hormonal treatment X-linked female one X chromosome to stimulate growth births leads to and pubertyc short height, heart defects, and infertility Triple X syndrome 1 in 1,000 A third X chromosome Interventions and services X-linked female births typically leads to for cognitive and motor developmental delays delays Fragile X 1 in 4,000 males One X chromosome has a S y m p t o m - l e d X-linked syndrome 1 in 6,000 females deactivated gene that treatment; often leads to intellectual special education disabilities and behavior and speech therapy problems Klinefelter 1 in 500 males An extra X chromosome Hormone therapy X-linked syndrome leads to a more female to stimulate appearance and intellectual puberty; special disabilities education a U.S. National Library of Medicine. 2017. Hemophilia. https://ghr.nlm.nih.gov b R. A. Williams et al. 2008. Clin Biochem Rev 29: 31–41. c K. O. Klein et al. 2018. J Clin Endocrinol Metab 103: 1790–1803. 28 Sex-linked chromosomal disorders involve an altered, extra, or missing sex chromosome Turner syndrome females who lack an entire X chromosome or part of it usually shorter than other girls may be infertile as adults because their ovaries have not developed adequately 29 FIGURE 3.7 Color-enhanced micrograph of a karyotype showing Klinefelter’s syndrome, Triple X syndrome females with an extra copy of the X chromosome Klinefelter syndrome males with an extra copy of the X chromosome Fragile X syndrome males and females a gene located on the X chromosome and responsible for producing a particular protein is turned off 30 FIGURE 3.8 Children with fragile X syndrome typically have long and narrow faces, large ears, and extraordinarily flexible fingers. 31  One of the most well-known dominant genetic disorders is Dominant Genetic Disorders Huntington’s disease affects children even if only one nerve cells in the brain die parent carries the gene for the persists over generations because disorder symptoms occur later in life and many carriers have children before they experience any symptoms symptoms include: personality changes and mood swings walking difficulties impaired cognitive functioning 32 Recessive Genetic Disorders Cystic Fibrosis affects children only when they a progressive disorder affecting have inherited the gene for the 30,000 Americans disorder from both people thick mucus builds up in the lungs and pancreas, making breathing People who carry only one gene difficult and hindering food digestion for a recessive disorder do not exhibit any symptoms many individuals do not even know they are carriers of that particular gene 33 FIGURE 3.9 In people affected with sickle-cell anemia, misshapen red blood cells clog blood vessels and carry insufficient amounts of oxygen. 3.1 The Construction Plan for a Human Being: Chromosomes, Genes, and Heredity 20 Sickle-cell anemia a blood disorder in which red blood cells misshapen this leads to clogged blood vessels and impaired oxygen transport throughout the body 34 X-linked genetic disorders the affected gene is located on the X-chromosome of the 23rd pair These disorders affect men often than women women have a second X chromosome that can in some cases compensate for the damaged genes Duchenne muscular dystrophy Hemophilia 35 FIGURE 3.10 Genetic testing can be done at a variety of times. Carrier testing occurs before conception. 36 37 1. The Beginnings of Life 38 All human life begins at conception (or fertilization) fertilization occurs when a sperm cell and an egg cell unite During sexual intercourse the male partner ejaculates and his sperm enter the vagina the sperm make their way through the cervix into the uterus and onward into the fallopian tubes only a small fraction of all sperm make it to the ovum 39 Fertilization creates the basis for a new baby Prenatal development has begun and will end at birth Three stages of prenatal development the germinal stage (lasts for 2 weeks) the embryonic stage (lasts for 6 weeks) the fetal stage (last for approximately 31-33 weeks, ends with birth) 40 The egg and sperm cells both contain half a set of chromosomes At fertilization, the 2 gametes fuse to create one cell this cell is called a zygote the zygote contains a complete set of 46 chromosomes in 23 pairs from this zygote a new human will develop 41 Table 3.3 Prenatal Development Can Be Divided into Three Stages of Varying Length Sta ge Development Size/Weight 1/100th of an inch FI 9– Germinal stage: Conception–2 weeks Ovum and sperm form a zygote, which long (≈ a RS 12 Source © Omikron/Science has a complete set of 46 poppyseed) T we chromosomes TR ek Zygote starts to divide and implants IM s in the wall of the uterus ES 3– © Anton Starikov/Shutterstock.com TE 8 R we Embryonic stage: 3 weeks–8 weeks By 8 weeks: half an inch Cells begin to differentiate and long (≈ a raspberry) ek assume different functions s Neural tube forms from which brain 1– and spinal cord will develop 2 Major organs form © Dr M.A. Ansary/ © EM Arts/Shutterstock.com we Heart starts to Photo Library ek beat Science s First blood cells are produced Brain starts to develop First movements Fetal stage: beginning at 9 weeks By 12 weeks: 3 inches long, Development of ovaries or testes less than one ounce (≈ a plum) Science © DOPAMINE/ Can suck thumb, swallow, and urinate Photo Library © Tim UR/Shutterstock.com 42 Table 3.3 (Continued) SE 13 Rapid neuron production By 16 weeks: 7 inches long, 4 Neurons migrate to their final ounces (≈ an avocado) C – destination in brain O 26 Toenails and fingernails N we develop Bones harden © Nataliya Schmidt/ D ek Hormone production Shutterstock.com TR s begins Can have hiccups © Neil Bromhall/ IM By 24 weeks: 12 inches long, Photo Library Mother can first feel fetal ES movement Responds to sound more than a pound (≈ an Science eggplant) TE May be able to survive if born around 24 weeks R © Nataliya Schmidt/ Shutterstock.com TH 27 Develops sense of smell By 30 weeks: 16 inches, over 3 IR – Practices breathing pounds (≈ a movements Myelination of cabbage) D 40 brain cells Produces fat Library © MEDI-MATION/Science Photo TR we layers for insulation Reacts IM ek to sounds ES s Turns head down in uterus © Chattaphan TE Sakulthong/ Organ systems mature and Shutterstock.co R prepare for independent m functioning after birth Activity level decreases as birth nears due to space restrictions in uterus By birth: 18–21 inches, 6–9 pounds 43 Germinal Stage: The First Two Weeks the shortest stage in prenatal development within 24 hours of conception, the zygote starts to divide into 2 identical cells Through mitosis, the cells continue to divide and duplicate producing 4 cells then 8 cells then 16 cells and so on 44 While the cells are dividing, they move through the fallopian tubes toward the uterus After 3-4 days, the cell cluster arrives in the uterus It is now called a blastocyst it has changed its shape to contain not only the dividing cells but also a fluid-filled cavity in the center once in uterus, the blastocyst implants itself in the wall of the uterus implantation is usually complete by the 2nd week of pregnancy after implantation, cells begin to specialize during differentiation 45 FIGURE 3.12 Once in the uterus, the blastocyst implants itself in the wall of the uterus. 46 Embryo develops in the amniotic sac a protective pouch made of membranes and filled with amniotic fluid amniotic fluid regulates the temperature of the environment in which the embryo grows and buffers shocks 47 Embryonic Stage: Week 3 through Week 8 begins with implantation of the embryo most of the embryo’s organs form during this stage The embryo is particularly sensitive to influences that might disturb development or lead to malformations this period when body parts form (and are particularly susceptible to damage) is called a critical period 48 FIGURE 3.13 Children’s bodies develop (A) from the head toward the toes (cephalocaudal trend) as well as (B) from the trunk outward (proximodistal trend). Development of the embryo follows two trends: Cephalocaudal: head to toe Proximodistal: inside out 49 Within the first 3 weeks neural tube has formed the neural tube is a hollow structure from which the spinal cord and brain will develop developing heart begins to beat a home pregnancy test can detect the pregnancy due to high levels of pregnancy hormones present in the mother’s body 50 By the end of the 4th week Week 6 buds representing the beginnings cerebral cortex starts to develop of future arms and legs have embryo begins to move reflexively appeared By start of the 8th week One week later (week 5) fingers and toes as well as facial the liver has begun to produce features begin to develop blood cells brain has 2 hemispheres and eyes have started to develop accounts for about 40% of the embryo’s weight 51 52 Fetal Stage: Week 9 until birth lasts from the start of the 9th week until birth during this time, the developing organism is referred to as a fetus Month 3 of the 1st trimester the fetus grows and develops biologically gradually exhibits behaviors that are characteristic of humans after birth (for example: yawning, urinating, being startled at noises, sucking its thumb) fetuses begin showing individual differences the SRY gene on the Y chromosome triggers the development of testes neuron production begins and continues at a rapid rate 53 The 2nd Trimester As the fetus grows rapidly and gains weight it becomes increasingly active and can move its arms, hands, and feet as well as its head (and even get the hiccups!) By the 10th week the fetus has about 90% of the body parts an adult has 54 Between weeks 10 and 12 the fetus starts to suck its thumb and swallow amniotic fluid in the next few weeks, fingernails and toenails grow, bones harden and the fetus starts to produce hormones Around the 16th week the fetus weighs roughly around 4 ounces and is about 7 inches long the pregnant woman can begin to feel the movements of the fetus gender differences start to appear female fetuses move their jaw more often than male fetuses 55 By the 19th week an ultrasound can potentially reveal the sex of the fetus During the 6th month final month of the 2nd trimester the fetus starts to be able to hear and respond to sounds also starts to experience rapid eye movements (like the ones observed when people dream during sleep) 56 The 3rd trimester Once it reaches the 3rd trimester a fetus is considered viable which means that it has a chance at survival if it is born odds of survival are still low if the fetus is born in the 2nd trimester or early in the 3rd trimester The fetus: performs breathing like movements about 40% of the time has developed a sense of smell is increasingly aware of the mother (is getting used to her voice) 57 58 3 The Prenatal Environment: Factors Influencing Development 59 The Prenatal Environment Placenta a temporary organ that sustains the life of the fetus during pregnancy by delivering nutrients and oxygen from the mother while eliminating waste products may also harbor harmful substances that put the fetus at risk Teratogens a substance that can interfere with the health development of the fetus 60 Maternal Factors Influencing Prenatal Development: Dietary needs Age Disease Drugs taken during pregnancy Stress 61 FIGURE 3.14 Experiments with humans are limited for ethical reasons: It would be unethical to expose a pregnant mother to toxins or limit her daily diet for the sake of an experiment. Therefore, researchers often use rodents to study variables they could not possibly experimentally manipulate in humans. The mice in this photo are the same age, have the same genes, and while in the womb were exposed to the toxic substance BPA (bisphenol A), which is found in plastics used to make some food and beverage containers (Pinney et al., 2017). The key di erence? The mother of the mouse on the right was fed a diet supplemented with nutrients like folic acid and vitamin B12, which helped counteract the e ects of BPA exposure. The study illustrates how nutrients can counteract the toxins we encounter in the environment. 62 ff ff FIGURE 3.15 Most organs develop in the embryonic period. 63 Table 3.4 Effects of Teratogens on Pregnancy and Health of the Fetus INFECTION Agent Effect What you can do STIs—gonorrhea, Miscarriage Premature Treatment of mother chlamydia birth Severe eye infection If necessary, treatment of infant C-section to avoid infection during birth HPV (human Does not usually cause complications papillomavirus) during pregnancy and childbirth HIV (human 10–20% of infants get infected C-section to prevent transmission of virus immunodeficiency Drugs given to infant during first weeks virus) of life lower risk of infection (American Pregnancy Association, 2017) Syphilis Damage to organs, ears, eyes, and skin Rubella Organ defects Vaccination before pregnancy Deafness © Bochkarev Photography/Shutterstock.com Blindness Intellectual disabilities Low birthweight (Centers for Disease Control and Prevention, 2016) Influenza (flu) Preterm birth Vaccination before or during pregnancy Autism Antiviral drugs Schizophrenia (Antonson et al., 2017) Medication to lower fever 64 Table 3.4 (Continued) DRUGS Agent Effect What you can do Caffeine Low birthweight Limit caffeine intake (coffee, tea, Childhood obesity cola, energy drinks, chocolate) (Greenwood et al., 2014; Li et al., 2015) Alcohol Fetal alcohol spectrum Abstain from alcohol consumption disorder Miscarriage, stillbirth Nicotine Premature Stop smoking before or at least birth Low during pregnancy birthweight The nicotine in nicotine patches and e-cigarettes can be harmful Attention-deficit/hyperactivity as well disorder (Zhu et al., 2014) About 10% of pregnant women Respiratory disorders (England et participating in a 2011 survey al., 2015; Holbrook, 2016) reported that they smoked during the last trimester of their pregnancy (England et al., 2015; Holbrook, 2016) Cocaine Miscarriage Stop drug use before/during © Daniel Heighton/Shutterstock.com Lower pregnancy Treatment of medical birthweight symptoms Special education Smaller heads Roughly 750,000 expectant mothers in Behavior the United States use cocaine during problems their pregnancy Cognitive deficits (Behnke et al., 2013; Buckingham-Howes et al., 2013; Smith et al., 2015) Heroin Infant is born addicted to Hospitalization heroin Withdrawal symptoms: Treatment of withdrawal symptoms fever, Infants may get addicted to irritability, slow weight gain, methadone seizures, vomiting if used as substitute for heroin Short attention span Slow language development (Buckingham-Howes et al., 2013) Methamphetamine Premature Up to 5% of pregnant women use birth Low the drug during their pregnancy (Derauf et al., 2007) birthweight Cognitive problems (Derauf et al., 2007) 65 Table 3.4 (Continued) Marijuana Low birthweight Stop using marijuana months before Higher likelihood of a planned pregnancy because the hospitalization after birth active ingredient is stored in the mother’s fat Problems with attention, impulse control, and visual memory Do not use during pregnancy (Gunn et al., 2016; Smith et al., From 2002 to 2014, marijuana use 2016; Volkow et al., 2017) among pregnant women rose significantly from 2.4% to 3.9% (Brown et al., 2017) Accutane Brain and heart Use birth control while taking the drug (isotretinoi defects Intellectual Between 3 and 6 per 1,000 female n, acne users of isotretinoin become disabilities drug) pregnant while taking the drug (Henry et al., 2016) ENVIRONMENTAL HAZARDS Agent Effect What you can do BPA (bisphenol A) Increased cancer Can be found in plastic food risk Obesity containers and water bottles, store receipts, CDs and DVDs, as well as Heart disease other consumer products and Early onset of puberty electronics. Avoid these products, if Reproductive problems possible (Paulose et al., 2015; Prins et al., 2017; Stafford et al., 2014) Flame retardants Low birthweight Avoid foam products that contain Increased risk of premature flame retardants, like carpet delivery and stillbirth padding, upholstery, car seats, nursing pillows Reduced ability to pay attention Lowered IQ (Bohannon, 2014; Shaw et al., 2014) Heavy metals Miscarriage, increased Lead: in drinking water and old paint; (lead, arsenic, risk of premature birth use water filter and get rid of old paint © Voronin76/Shutterstock.com mercury) Lowered IQ safely Permanent brain Arsenic: in drinking water; use water damage Nervous filter Mercury: in seafood; avoid system damage species that Kidney damage are particularly high in mercury 66 Table 3.4 (Continued) MATERNAL FACTORS Agent Effect What you can do Maternal stress Suboptimal brain development Treatment of underlying causes like Increased risk of obesity Increased depression risk of asthma and Relaxation methods and autoimmune disorders (Entringer et meditation al., 2015) Counseling Increased risk of disorders like schizophrenia, attention-deficit/ hyperactivity disorder, and autism spectrum disorders (Bronson & Bale, 2016; MacKinnon et al., 2017) © George Rudy/Shutterstock.com 67  Paternal Factors Influencing Prenatal Development: Children of fathers aged 45 or older: have an increased risk of autism, ADHD, and psychiatric disorders such as bipolar disorder are more likely to have to repeat a grade or have lower educational outcomes Father’s exposure to teratogens may also have an impact on the child’s future health e.g., In the 1990s, reports surfaced that the children of workers in a nuclear plant in Sella eld, England, had a signi cantly higher rate of leukemia than did other children whose fathers did not work in the plant (Anderson et al., 2014).. 68 fi fi 4. Prenatal Care and Prenatal Tests 70  Visits focus on: Up until the 32nd week of pregnancy, prenatal visits for births the parent’s health expected to be unproblematic the fetus’s health occur about every 4-6 weeks education on a wide range of issues such as nutrition and exercise during pregnancy Between the 32nd and 37th week, visits occur about every 2 weeks After the 37th week, visits are usually weekly 71  Not all groups in the United Worldwide, only 58% of women States have equal access to actually have at least 4 prenatal prenatal care care visits In 2017, 5% of expectant White mothers received prenatal care beginning in the 3rd trimester or no prenatal care at all, compared to 8% of Hispanic mothers and 10% of African American mothers 72  Health Indicators Wetaskiwin Rest of Alberta Fertility rate (%) 74.8 53.1 Infant mortality rate (%) 6.6 6.2 Teen birth rate (% in women aged 65.6 18.9 15–19) Smoking during pregnancy (%) 50.5 18.0 Drinking during pregnancy (%) 8.0 4.0 Source: S. Di Lallo. 2014. NWH 18: 38-46, with permission from Elsevier. Data from various sources. 73 Table 3.5 Prenatal Testing Techniques Method How does it work? What is it used for? What are the risks? Ultrasound High-frequency sound waves Monitor fetal growth Non-invasive; no risk sonogram create a picture of the fetus in Detect structural Detection rate of the womb abnormalities Detect multiple abnormalities of up to 80% pregnancies Determine (American Academy of Pediatrics, 2017) gestational age Determine sex of fetus Shutterstock.com Business Images/ (not always conclusive!) © Monkey Triple Screen Test Blood test Screen for neural tube No risks except Performed between 15th defects, trisomy 18, and discomfort from blood and 20th pregnancy trisomy 21 drawing week Relatively high percentage of Recommended for false positive results (American Pregnancy women who are age Association, 2016c) © Elnur/Shutterstock.com 35 or older with a family history of birth defects with medical problems Screens for AFP (alpha-fetoprotein; protein produced by fetus) hCG (human chorionic gonadotropin; hormone produced in placenta) estriol (hormone produced in placenta and by fetus) 74 Table 3.5 (Continued) Amniocentes Insert needle through stomach Genetic and chromosomal Risk of miscarriage is into amniotic sac to withdraw disorders like Down syndrome, ranges around 1 in 300 fluid cystic fibrosis, and spina bifida (American Pregnancy The amniotic fluid contains stem Determination of sex Association, 2016a). cells from the fetus that can be of the fetus analyzed Paternity testing Usually performed between 15th and 20th week of pregnancy © iStock.com/zilli Often performed in women older than age 35, or when genetic abnormalities are suspected Chorionic Hairlike structures from placenta are Genetic and chromosomal Miscarriage risk about 1 villus removed vaginally or through stomach disorders like Down syndrome, in 100 procedures sampling wall and analyzed cystic fibrosis (no testing for (American (CVS) Usually performed between 10th neural tube defects possible) Pregnancy Association, Library © Saturn Stills/Science Photo and 13th week of pregnancy Determination of sex of the 2016b) fetus Paternity testing 75 Infertility about 10% of American couples have trouble conceiving a child Generally, a couple is considered infertile if they have not conceived within 12 months of unprotected sexual intercourse Many providers evaluate and treat couples after 6 months of unprotected intercourse when the woman is 35 years of age or older 76 77 5. Special Pregnancy Issues: Infertility and the Premature End of a Pregnancy 78 Infertility can derive from many sources, in about 25% of cases several causes simultaneously contribute to the couple’s infertility Infertility in Men one of the most common causes is low sperm count Infertility in Women most common cause is irregular ovulation or absence of ovulation other causes include: blocked fallopian tubes, diseases, or ova of suboptimal quality 79 Options for couples who cannot conceive: Artificial Insemination In Vitro Fertilization Donor In Vitro Fertilization Surrogate Mothers Adoption 80 Between 11% and 22% of pregnancies end in a spontaneous abortion (also called miscarriage) which is a pregnancy loss in the first 20 weeks often experienced as a delayed period often caused by genetic problems in the embryo or health conditions of the mother Risk of miscarriage increases with age 81 After 20 weeks, when the fetus dies in the womb it is called a stillbirth about 1% of pregnancies end in stillbirth Women who suffer from a still birth or miscarriage are at risk of post traumatic stress disorder as well as depression and anxiety The couple may also have a harder time grieving because many in people in their surrounding may not understand what it means to grieve a child that never lived outside of the womb 82 A pregnancy may also end in an abortion Abortion an intervention that terminates pregnancy in 2018, about 620,000 abortions were reported in the United States most women who have received abortions do not experience any negative psychological consequences but a number report that the abortion is traumatic and they have trouble coping with the stress 83 85 86