Genetics & Prenatal Assessment Flashcards
What does a Biophysical risk factor mean ?
originates within the mother or fetus
- endometriosis
- ectopic pregnancy
- sickle cell anemia
- low/high BMI
- genetics, nutrition, illness
- chronic illnesses, HTN, poorly controlled diabetes
What does a Psychosocial risk factor mean ?
maternal behaviors/adverse lifestyle
- smoker
- alcohol and drug use
- interpersonal violence
- emotional distress
- social support
- relationships
What does a Sociodemographic risk factor mean ?
mother/family characteristics
- age (teen or over age 35)
- access to care (ability to pay for adequate foods, health check-ups)
- income
- parity
- ethnicity (some genetic disorders are more common in certain ethnicities)
What does Environmental risk factors mean ?
exposure to hazards
- occupational hazard (work in factory where exposed to chemicals, cashier who stands all day)
- infection
- drugs
- pollutants
At how many weeks do we start to count fetal kicks ?
begins at 28 wks gestation
What is a fetal kick count ?
simple yet variable method to evaluate the condition of the fetus
- non invasive
- baby who kicks is well oxygenated and has a good nervous system
- count # of movements in 1 hour
- 10 movements per hour is normal
When should we be concerned about fetal kick counts ?
if they have fewer than 10 movements in 2 hours
- needs further investigation and need to call provider
What is a Non-Stress Test (NST) ?
where accelerations and moderate variability will occur in response to fetal movement
- indicates normoxic fetus with a functioning CNS
When is a Non-Stress test performed ?
performed after 28 weeks
What is a Reactive (expected value) result of a Non-Stress test (NST) ?
2 accelerations within 20 mins
- 28 wks to 32: acceleration of 10 bpm from baseline lasting 10 secs with each fetal movement
- >32 week: increase in 15 bpm from baseline every 15 secs with fetal movement
What is a Non-Reactive NST mean ?
did not meet criteria within 40 mins
- needs further testing
What is a Biophysical Profile (BPP) ?
real-time assessment of fetus using ultrasound
- non-invasive
- 30 to 120 mins
When is a Biophysical Profile (BPP) performed ?
after 28 weeks after non-reactive NST or routine testing with risk factors
What are the 5 categories scored in for a Biophysical Profile ?
- breathing movements
- movements
- tone
- amniotic fluid
- NST
What is a Contraction Stress Test (CST) ?
determining fetal heart rate response to contractions (stressor) to see respiratory functioning during stress
- invasive and time consuming
- oxytocin stimulated
When is a contraction stress test (CST) performed ?
after 34 weeks
What are some contraindications for a contraction stress test ?
if pt shouldn’t be delivering baby vaginally because of:
- placenta previa (placenta is against the cervix and can cause increased risk of bleeding)
- previous classical c-section
- high risk for preterm labor (multiple gestation)
- PPROM (preterm premature rupture of membranes)
What are we looking for in a contraction stress test ?
the fetal heart rate (FHR) for decelerations (late or variable) with 3 contractions within 10 minutes
What does a negative, positive, or equivocal contraction stress test result mean ?
- Negative: no decels with contractions
- Positive: late decels with 50% or more contractions
- Equivocal: decels are intermittent
How does an ultrasound work ?
sound waves are sent through the amniotic fluid and bounce back to reflect a picture
- abdominal or transvaginal (good for early pregnancy)
What do we look for in a first trimester ultrasound ?
- confirm pregnancy and viability (heart beat at 8 wks)
- determine uterine abnormalities
What do we look for in a second trimester ultrasound ?
- confirm due date
- anatomy scan (map out the measurements to see where baby falls)
- detect anomalies
- measure growth
- determine placental location
At how many weeks gestation is the anatomy fetus scan ?
at 20 wks
- look for placenta placement too
What do we look for in the third trimester ultrasound ?
- measure fetal growth
- assess placental functioning
- determine fetal presenting part
- determine placental location
- perform doppler flow studies
What are genes ?
the basic physical units of inheritance that specify traits
- genetic testing is a part of the newborn assessment
How many chromosomes do we have ?
23 pairs
- 22 autosomes
- +1 sex chromosome
What are some examples of a chromosomal, singe-gene and complex disorder ?
- Chromosomal: trisomy 13, 18, and 21 (21 is down syndrome and 13 & 18 have many disease incompatible with life)
- Single-gene: sickle cell anemia, cystic fibrosis, Huntington’s
- Complex: neural tube detect (spinal bifida), diabetes, cancer
What chromosome causes Down syndrome ?
triosomy 21
- extra chromosome at #21
- risk increases with those pregnancies above the age of 35
- life expectancy is 47 yrs old
What are some common associated health conditions for someone with down syndrome ?
- congenital heart defects
- hearing loss
- obstructive sleep apnea
- ear infections
- eye disease/need for glasses
What are some physical characteristics (phenotype) of someone with Down syndrome ?
- almond shaped eyes with upward slant
- small or low-set ears
- flat nasal bridge
- palmar crease
- hypotonia: don’t want to flex as much (limp baby)
- tongue protrusion
What is a Dominant Autosomal Inheritance Disorder ?
- Huntington’s, Marfan syndrome
- only requires 1 abnormal gene to have disorder
- if parent passes down the disease, offspring has 50% chance of inheritance
What is a Recessive Autosomal Inheritance Disorder ?
- sickle cell anemia, cystic fibrosis, tay-sachs disease
- both genes must be abnormal to have disorder
- one affected gene means they are a carrier (only exists in recessive disorders)
- if both parents are carriers, offspring has 25% chance of inheritance
What is Cell Free DNA (cfDNA) ?
a screening tool to test for certain disorders/syndrome’s
- maternal plasma contains small fragments of fetal cfDNA
- doesn’t diagnose
- less sensitive in obese pt’s
When can we perform cell free DNA screenings ?
10-12 wks gestation
- for trisomy 13, 18, and 21
- if positive then need further testing
- not good option for twins because don’t know which fetus it affects
What is Fetal Nuchal Translucency ?
where you measure the fluid in the nape of the neck via ultrasound
- an early indicator of down syndrome, trisomy 18 or heart problems
- a SCREENING tool
How many mm of nuchal fluid is considered abnormal ?
> 3 mm nuchal fluid
- if abnormal consider other testing like CVS, amniocentesis
What is a Quad screen ?
maternal blood test to screen for neural tube defects (NTD) and down syndrome (Ds)
- 4 components
- AFP (alpha-fetoprotein) alone is recommended for all pregnant pt’s
What are the 4 components in a Quad screen ?
- Alpha-Fetoprotein (AFP): produced by fetal liver and GI system
- Human Chorionic Gonadotropin (hCG): pregnancy hormone
- Inhibin A
- Estriol: estrogen derivative
When is a quad screen done ?
at 16-18 wks gestation
When is a Chorionic Villus Sampling (CVS) done ?
10-13 wks gestation
What is a chorionic villus sampling (CVS) ?
DIAGNOSTIC test to determine fetal genetic abnormalities
- removal of small tissue specimen from fetal portion of placenta
- invasive with risks
- transvaginal or abdominal with ultrasound guidance
What are some risks of CVS ?
- miscarriage
- fetal limb anomaly
- Rh incompatibility
- hemorrhage
- infection
What are some indications (reasons) CVS (chorionic villus sampling) may be done ?
- previously affected child or family history of a genetic disease, chromosomal abnormality, or metabolic disorder
- maternal age >35 by due date
- risk of sex-linked genetic disease
- previous ultrasound with questionable or abnormal findings
- abnormal cfDNA
What are the 2 diagnostic tests in genetics ?
- Chorionic Villus Sampling (CVS)
- Amniocentesis
What is Amniocentesis ?
DIAGNOSTIC test to determine genetic concerns, and fetal lung maturity
- needle inserted through maternal abdominal wall to collect amniotic fluid for analysis (essentially fetal urine full of fetal cells)
- ultrasound guided
When is Amniocentesis done ?
14-18 wks for genetics
- or in 3rd trimester to determine lung maturity (surfactant needed at expand alveoli at birth)
What are some potential risks of a Amniocentesis ?
- miscarriage
- infection
- damage to organs
- Rh sensitization
- preterm labor
- leakage of amniotic fluid
What are some RN considerations for genetics and prenatal education ?
- identify families at risk
- give info, resources and education
- testing available and information it will provide
- post-op assessment and education
- administer, assist, and/or interpret findings
- administer and interpret NST and CST
- Assist with CVS and Amniocentesis
- develop plan of care for families affected by genetic conditions
- provide emotional support
What are “soft markers” ?
indicators to a potential genetic disorder/syndrome
- not diagnostic
