Chapter 3 Genetics, Conception, Fetal Development, and Reproductive Technology

! Genetics " study of heredity

! Genomics " addresses all genes and their interrelationships in order to identify their combined influence on growth and 

development of the organism

o Providing better methods for preventing disease and abnormalities, diagnosing diseases, predicting health risks, 

personalizing treatment plans

! 30,000 genes in the human genome (organism’s complete set of DNA)

! 46 chromosomes; 22 homologous pairs of chromosomes and one pair of sex chromosomes

! genotype " person’s genetic makeup

! phenotype " how genes are outwardly expressed (eye color, hair color, height)

! recessive genetic disorders " sickle cell anemia, cystic fibrosis, thalassemia, Tay-Sachs disease

! carrier testing " identify individuals who carry one copy of a gene mutation that, when present in two copies causes a 

genetic disorder; used when there is a family history of genetic disorder

! preimplantation testing/preimplantation genetic diagnosis " used to detect genetic changes in embryos that are created 

using assisted reproductive techniques

! prenatal testing " early detection of genetic disorders

! risks for conceiving child with genetic disorder " maternal age older than 35, man/woman who has genetic disorder; 

family history of genetic disorder, history of previous pregnancy resulting in a genetic disorder or newborn 

abnormalities

! refer to support group whether they wish to terminate/continue with pregnancy

! sickle cell anemia

o most common of African ancestry

o sickle-cell hemoglobin forms rigid crystals that distort and disrupt RBCs; oxygen-carrying capacity of blood is 

diminished

! cystic fibrosis

o most common genetic disease of European ancestry

o production of thick mucus clogs in bronchial tree and pancreatic ducts

o most severe effects are chronic respiratory infections and pulmonary failure

! Tay-Sach disease

o Most common among Jewish ancestry

o Degeneration of neurons and nervous system results in death by the 2 years old

! PKU

o Lack of enzyme to metabolize the amino acid phenylalanine " leads to severe mental and physical retardation

o Effects may be prevented by use of a diet at beginning of birth that limits phenylalanine

! Huntington’s Disease

o Uncontrollable muscle contractions between 30-50 years followed by memory loss and personality

o No treatment that can delay mental deterioration

! Hemophilia (X-linked)

o Lack of factor 8 

o Can be controlled with factor 8 from donated blood

! Duchenne’s Musclular Dystrophy

o Replacement of muscle by adipose or scare tissue with progressive loss of muscle function; often fatal before age 

20 due to involvement of cardiac muscle

! teratogens " any drugs, viruses, infections, or other exposures that can cause embryonic/fetal developmental 

abnormality 

! degree or types of malformation vary on length of exposure, amount of exposure, and when it occurs during human 

development 

! developing human is most vulnerable to effects of teratogens within first 8 weeks of gestation (organogenesis)" can 

cause gross structural defects

! exposure after 13 weeks may cause fetal growth restriction or reduction of organ size

! toxoplasma is a protozoan parasite found in cat feces and uncooked/rare beef and lamb

o can cause fetal demise, mental retardation, blindness when fetus is exposed

o avoid contact with cat feces and eating rare beef or lamb if pregnant or attempting pregnancy

! rubella " increased risk for heart defects, deafness and/or blindness, mental retardation, fetal demise

! cytomegalovirus " increased risk for hydrocephaly, microcephaly, cerebral calcification, mental retardation, hearing loss

! herpes varicella/chicken pox " increased risk for hypoplasia of hands and feet, blindness/cataracts, mental retardation

! syphilis " increased risk for skin, bone and/or teeth defects, fetal demise

! cocaine " increased risk for heart, limbs, face, GI/GU tract defects, cerebral infarctions, placental abnormalities

Chapter 4 Physiological Aspects of Antepartum Care

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! G/P System

o Gravida: # times a woman has been pregnancy including current pregnancy

o Para: # of births after 20 weeks’ gestation whether live or stillbirths

o Abortions are not accounted for in this system

! GTPAL

o G: # times pregnancy

o T: # of term infants born after 37 weeks

o P: # of preterm infants between 20 and 37 weeks

o A: # of abortions either spontaneous or induced before 20 weeks

o L: # of living children

! Nulligravida: woman who has never been pregnant or given birth

! Primigravida: woman who is pregnant for the first time

! Multigravida: someone who is pregnant for at least the second time

! Prenatal period " entire time period during which a woman is pregnant through birth of baby

! Nurse places emphasis on health education and health promotion

! Family-centered maternity care is a model of obstetrical care based on a view of pregnancy and childbirth as a normal life 

event, a life transition that is not primarily medical but rather developmental

! Low-risk population should have approximately 14-16 prenatal visits per pregnancy

! First trimester

o Woman learns frequency of follow-up visits and what to expect from pregnancy visits as pregnancy progresses 

during initial visit

o Comprehensive health and risk assessment; currently pregnancy history; complete physical and pelvic examination; 

nutrition assessment; psychosocial assessment; assessment for intimate partner violence

o Fetal heart tones are auscultated with US Doppler, initially by 10 and 12 weeks

o At end of first trimester, fetus is 3 inches in length and weights 1-2 ounces, all organ systems are present

o Assessment of uterine growth after 10-12 weeks is measured by height of fundus with centimeter measuring tape; 

zero point of tape is placed on the symphysis pubis and tape is extended to top of fundus; MEASUREMENT 

SHOULD EQUAL # OF WEEKS PREGNANT

o Certain types of fish (king mackerel, shark, swordfish, tilefish) should be avoided due to high levels of 

methylmercury

! Second trimester

o Chart review; interval history; focused physical assessment; pelvic exam/sterile vaginal exam if indicated; confirm 

EDD

o Triple/quad screen (neural tube defect); US; screening for gestational diabetes; hemoglobin and hematocrit;

antibody screen if Rh-negative (Administration of RhoGAM if Rh-negative and anti-body screen negative)

# Administered prophylactically at 28 weeks to prevent isoimmunization from potential exposure to Rhpositive fetal blood during normal course of pregnancy 

# Adverse reaction " pain at IM site; fever

o Slight decrease in blood pressure toward end of second trimester

o Assess for quickening " when the woman feels baby move for first time

o Leopold’s maneuvers to identify position of fetus

o Slight lower body edema is normal due to decreased venous return

o At 20 weeks, fetus is 8 inches long and weights 1 pound

o Increase in calorie intake by 340 kcal/day

! Third trimester

o Chart review; interval history; nutrition follow-up; focused physical assessment; pelvic exam/sterile vaginal exam if 

indicated

o Group B Strept at 35-37 weeks; H&H if not done in second trimester; repeat GC, chlamydia, RPR, HIV HbSAg; 1-

hour glucose challenge test at 24-28 weeks

o Record fetal movement count " 10 distinct fetal movements within 2 hours is considered reassuring OR 4 

movements in 1 hour

o At term, fetus is 17-20 inches long, 6-8 pounds

o Increase in calorie intake by 452 kcal/day

Chapter 6 Antepartal Tests

! Chorionic villus sampling " aspiration of a small amount of placental tissue for chromosomal, metabolic, or DNA testing

o Between 10 and 12 weeks to detect fetal abnormalities caused by genetic disorders

o Tests for cystic fibrosis but not neural tube defects

o Supine position for transabdominal aspiration with US to guide placement

o Lithotomy for transvaginal aspiration with US to guide placement

o Small biopsy of chorionic (placental) tissue is removed

o Assess fetal and maternal well-being post-procedure; FHR is auscultated twice in 30 minute