This diagnostic test looks at chromosomal abnormalities and fetal infections. It is also used for sex determination by looking at a small amount of amniotic fluid.
Amniocentesis
This blood test checks a mom's blood for a substance made in the liver of a fetus. It helps to see whether the baby may have such problems as spina bifida and anencephaly.
Alpha-fetoprotein (AFP)
This is a prenatal test that is used to detect birth defects, genetic diseases, and other problems during pregnancy. It takes a small sample of cells taken from the placenta where it attaches to the wall of the uterus.
Chorionic villus sampling (CVS)
This is a scan that uses ultrasound to assess the developing baby's risk of having down syndrome and some other chromosomal abnormalities, as well as major congenital heart problems.
Done at 11-13 weeks gestation
Nuchal Translucency
What are the 4 components of the Antepartum Fetal Surveillance?
1. Non stress test (NST)
2. Biophysical Profile (BPP)
3. Amniotic Fluid Index (AFI)
4. Contraction Stress test (CST)
This is part of the AFS. It is based on that the premise of the heart rate of the fetus will temporarily accelerate with fetal movement and loss of reactivity associated with fetal sleep (or CNS depression, including fetal acidosis)
What is it and how is it performed? How is it assessed?
Nonstress test (NST): with the patient in the lateral tilt position, the FHR is monitored.
In FHR accelerations the peak is at least 15 bpm above the baseline and lasts 15 seconds.
In the NST test, what is a reactive vs. nonreactive NST?
reactive: has > or = FHR accelerations within a 20 minute period, with or without fetal movement
nonreactive: lacks sufficient fetal heart rate accelerations over a 40 minute period
Fill in: the NST (nonstress test) of the normal preterm fetus is frequently nonreactive:
24-28 gest week: up to _a_ % are nonreactive
28-32 gest. week: up to __b__ % are non reactive
a. 50
b. 15
This is part of the AFS (antepartum fetal surveillance) which consists of NST (non stress test) combbined with four observations through ultrasonography.
Biophysical profile (BPP)
What are the components of the Biophysical profile test (BPP)? How are they scored?
1. Fetal breathing movement
2. Fetal movement (> or = 3 discrete body or limb movements within 30 seconds)
3. Fetal tonus (flexion, opening or closing of hands)
4. Amniotic fluid volume (a single vertical pocket of amniotic fluid exceeding 2cm is considered evidence of adequate)
5. NST (may be omitted if all four ultrasound components are normal)
each of the five are assigned a score of 2 (normal) or 0 (absent), summing up to 8-10 as normmal.
Which trimester is the BPP test done?
a. 1st trimester
b. 2nd trimester
c. 3rd trimester
b and c
This part of the AFS is based on the response of the fetal heart rate to uterine contractions. It relies on the premise that fetal oxygenation will be transiently worsened by contractions.
How is it assessed?
Contraction stress test (CST)
It is interpreted according to the presence or absence of late fetal heart rate deceleration.
What does the AFI measure?
It is part of the AFS and it measures the quantitative estimate of amniotic luid. It is an indicator of fetal well-being.
How is the AFI measured? What are normal levels?
What levels would be considered low and high?
AFI in cm is the amount of flud seen on ultrasonography of a pregnant uterus.
Normal: 8-18
Low: <5-6
High: >20-24
What AFI level is considered oligohydramnios?
C.
What AFI level is considered polyhydramnios?
C.
Which trimester is the AFI measured? amniotic fluid index)
a. 1st trimester
b. 2nd trimester
c. 3rd trimester
b and c
What are 4 major categories that cause low amniotic fluid?
Leaking or rupture of membranes
Placental problems (not providing enough blood and nutrients
Birth defects (kidney or urinary issues, causing little urine production)
Maternal complications (HTN, diabetes, dehydration, preeclampsia, and chroonic hypoxia)
During prenatal care, how soon should an ultrasound (transvaginal) be done?
C.
What is the purpose of performing a transvaginal ultrasound in the 1st trimester?
Confirm pregnancy and fetal #
Gestationall date
Confirms viability
Evaluates anatomy
Cervical length (PTL or predicted value of length)
Adjunct to other testing
Which trimester do you want to perform these prenatal diagnostic tests:
How is the amniocentesis test done and what does it measure?
Taking a small sample of the amniotic fluid, which contains cells from the fetus.
An ultrasound is used to find the position of the fetus, then a fine needle is inserted into the abdomen, guided by the ultrasound, and into the amniotic sac.
It checks for chomosomal abnormalities, like downs
fetal infections
sex determination
This test is done at 16-18 weeks and is part of the triple marker screening. It checks for neural tube defects (spina bifida) and chromosomal anomalies (downs)
MSAFP: Maternal serum Alpha-fetoprotein
What are the 3 components of the triple marker screen test?
AFP - checks for birth defects (downs and spina bifida)
HGC levels
Estriol - an estrogen that comes from both fetus and placenta
What do low and high levels of HGC mean?
High: can indicate a molar pregnancy or multiple pregnancy
Low: potential problems, including miscarriage or ectopic pregnancy
When is the CVS (Chorionic villus sampling) done during pregnancy and what does it test for?
1st trimester (10-13 weeks): tests for chromosomal abnormalities such as down syndrome
What is the Lecithin / Sphingomyelin Ratio (LS) of the amniotic fluid? What does it test for?
The two substances are surfactants made by the lungs to let them work properly. The lungs release them into the amniotic fluid in the last 3 months of pregnancy which can be measured.
When does a mother need to do the LS test?
If mother is expected to deliver before 39 weeks or the healthcare provider doesn't know exactly how many weeks pregnant she is. the provider probably won't order this test if your baby may be born at less than 32 week. At that point, his or her lungs will be immature regardless of test results.
What is Hemolytic Disease?
When IgG molecules from the mother passes through the placenta into the fetus. They are antigens which attack the tRBC in the fetal circulation.
How is Hemolytic diagnosed and treated?
Diagnosis: blood test shows if the mother is Rh- and the baby is Rh+. This will cause very severe anemia in the baby.
Prevention: Mothers are offered Rho(D) immune globulin at 28 weeks during pregnancy, 34 weeks, and 48 hours after deliver.
What is Rho(D) used to treat?
When mother is Rh- and baby is Rh+
What is the fetal fibronectin (fFN) and what does it maeasure?
This "leaks" into the vagina if a preterm delivery is likely to occur. fFN is a protein that hold the baby in place of the womb.
A screening test is done and when the ffN test is +, it is an inconclusive test.
From weeks 22-35, there should be very little amount
What do FHR accelerations mean?
when heart rate of fetus goes up
If FHR = 130, what the suspected BPM and duration? How many of these accelerations should we see in a 20 min period?
45 bpm for 15 secs
and 2 of these in a 20 min period
T or F: During the NST of FHR, if the fetus is <32 weeks, we should suspect them to be 10x10
What should they be >32 weeks?
True
15x15
This diagnostic test captures both still and video images. It allows to detect movement such as fetal heartbeat, breathing, and body movement. As well as greater detail of the fetal body.
Ultrasound
What is the purpose of a transvaginal ultrasound in the first trimester? (7)
Determine location (if intrauterine or not) of fetus
Detecting for multifetal gestation
Estimating gestational age
Confirming fetal viability
Identifying need for follow-up testing
ID fetal abnormality, such as chromosome defects
"As an adjunct for transcervical or transabdominal chorionic villus sampling
List purposes of ultrasound during the 2nd and 3rd trimester (6)
Eval of anatomy
Estimate gestational age and growth progress
Assess fetal growth progress
Eval of amniotic fluid
Determine location of placenta and umbilical cord
Fetal presentation
Guiding needle placement for procedures
What is the function of the color doppler? Nondirectional color dopplers?
It is useful for determining the relationships between body structures.
NCDs uses a single color to ID structures, as in assessing the number of vessels in the umbilical cord.
This info can be used to determine if the heart structure is normal.
Color dopplers can determine blood flow and pulsations within umbilical cord vessels.
T or F: AFP can be measured from either maternal circulation or from the amniotic fluid
True: AFP (alpha-fetoprotein) found in maternal serum is called MSAFP, and called AFAFP if found in amniotic fluid.
(AFP is the main protein in fetal plasma: abnormal amounts are associated with fetal anomalies)
What do low levels of MSAFP (maternal serum alpha-fetoprotein) indicate? What is the most common cause of elevated AFP
Low levels is associated with chromosomal anomalies, such as trisomy 21 (down syndrome)
Elevated levels common cause is failure of the embryonic neural tube or anterior body wall to close properly, allowing high concentrations of AFP to seep into amniotic fluid, and then enter the maternal serum.
How can an inaccurate gestational age affect MSAFP readings?
Without an accurate estimation of gestational age, it can result in apparent abnormal levels, causing greater anxiety and expense if follow-up tests are indicated (AFP levels will increase as gestational age increases)
What weeks in pregnancy is optimal to perform an MSAFP screening?
16-18 weeks
Along with MSAFP, what two other markers have been added to evaluate to screen for chromosomal abnormalities, including trisomy 18 and 21?
hCG and unconjugated estriol
Using the multiple-marker screening for trisomy 18 and 21, state whether these levels will be high or low if the test is positive.
hCG
MSAFP
Estriol
If the test is positive, what additional testing should be offered?
hCG: high
MSAFP: low
Estriol: low
Additional tests: amniocentesis (withdrawal of amniotic fluid) or additional ultrasound to look for physical characteristics.
With multiple-marker screening for Trisomy 18 and 21, what are the four markers?
1. hCG
2. Estriol
3. MSAFP
4. inhibin A
This marker improves the accuracy of multiple-marker screening for identifying trisomy 21 in women younger than 35 years old.
B.
What is the purpose of chorionic villus sampling (CVS)? At what weeks is it usually performed?
What is the difference between and MSAFP?
Purpose: uses transcervical or transabdominal sampling to obtain villi to dx fetal chromosome or metabolic abnormalities
It is normally done between 10 and 13 weeks
While both CVS and MSAFP are both used to detect for fetal chromosome abnormalities, CVS cannot be used to dx anomilies for which amniotic fluid is essential.
T of F: CVS can be performed earlier than an amniocentesis
True: it offers an alternative to for testing for women who find later procedures unacceptable.
This is ideal for women who may want to choose abortion if the results are found to be abnormal.
What are risks associated with CVS?
2.5% pregnancy loss rate
Rate of limb reduction defects for CVS performed before 10 weeks
Occasional uterine infection (cervical or vaginal infection is a contraindication for the transvaginal approach)
Rh cross contamination from mother to fetus
When can an amniocentesis be performed and what are its purpose during those times?
Second-trimester (15-20 weeks): for fetal genetic abnormalities. It examines for fetal cells present in the amniotic fluid to ID chromosomal or biochemical abnormalities.
It is also used to evaluate the fetal condition when the women is sensitized to Rh+ blood
And to test the AFAFP for cases when MSAFP is abnormal
Third-Trimester: may be used to determine fetal lung maturity or to evaluate fetal hemolytic disease (blood disorder)
What is reduction amniocentesis?
It is a variation in which excess amniotic fluid is removed and discarded when hydramnios occurs.
The lecithin / sphingomyelin (L/S) ratio is the best knjown test for estimating what? How is it read?
Fetal lung maturity: the L/S ratio are lipoproteins that make up surfactant.
Until the 30th week of gestation, the ratio is equal, but lecithin will then continue to increase. An L/s ratio greater than 2:1 generally indicates that surfactant is adequate.
*Surfactant keeps alveoli open by reducing surface tension on their inner walls.
Along with L/S to test for fetal lung maturity, what other markers are also tested? (hint: these are present in the amniotic fluid)
PG (phosphatidylglycerol) and PI (phosphatidylinositol) which are phospholipids that boost the properties of Lecithin
Other tests: TDx fluorescence polarization immonoassay to determine surfactant content in amniotic fluid
Foam stability index (FSI) often called "shake test" used to determine fetal lung maturity
What is PUBS test for?
Major indications include dx and intrauterine management of Rh dz, infections, or for diagnosing disorders that require fetal blood for testing.
List the three methods of antepartum fetal surveillance
1. Nonstress test (NST)
2. Contraction stress test (CST)
3. Biophysical profile (BPP)
The purpose of this antepartum fetal surveillance is to identify whether an increase in the FHR occurs when the fetus moves, indicating:
- adequate oxygenation
- a healthy neural pathway from the fetal CNS to the fetal heart
- and the ability of the fetal heart to respond to stimuli
A. NST (Nonstress test)
List characteristics of a reactive (reassuring) NST
At least two FHR accelerations (with or without fetal movement) occuring within any 20minute period
Peaking at least 15 BPM above the base line and lasting 15 seconds from baseline to baseline
The purpose of this test is if there is a concern of fetal oxygenation, and is done by either oxytocin infused contractions or nipple stimulation. What advantages does this test offer over the others?
C. Contraction stress test
Advantages: the test allows follow up for a nonreactive NST result or BPP.
- If findings are negative, CST offers more than 99% reassurance, which is likely to support life for at least 1 more week.
This test assess a total of five parameters of fetal well-being.
C. BPP (Biophysical Profile)
The five parameters include: (1) the NST, (2) fetal breathing movements, (3) gross fetal movements (large trunk movements), (4) fetal tone (small body movements), (5) amniotic fluid volume.
When a fetus starts going into hypoxemia, FHR will start to fall, then gross body movements and muscle tone will slow and cease, amniotic fluid production will also cease as the fetal kidneys and lungs become affected.
What factors can affect the readings of a tocotransducer, which is useful for observing the frequency and duration of contractions
Fetal size: a small fetus does not allow the uterus to push firmly against the abdominal wall
Abdominal fat thickness
Maternal position
Location of transducer: uterine activity is best detected where it is strongest, and where the fetus lies close to the uterine wall. (this location is usually over the upper uterus)
What kind of ultrasound is done in the first trimester and what are you looking for?
Transvaginal:
confirm pregnancy & fetal #
gestational dating: how old baby is
confirms viability
evaluates anatomy
cervical length (PTL)
When do you try to locate placenta placing?
1st trimester
2nd trimester
3rd trimester
2nd and third
Depending where it is, it could determine if c-sec needed (Placenta Previa)
What do you test for in the 2nd/3rd semester?
Placenta location
AFI
BPP
Guide for amniocentesis
Assess fetal growth
Evaluate anatomy
Doppler studies
At what weeks do is ideal for a former ultrasound to assess fetal growth and inner anatomy
16-20 weeks
At what weeks do you perform fetal fibernectin test and for what indications.
List some s/s for indication
20-35 weeks: presents with s/s of preterm labor
cramping, back pain, fullness
How many fetal movements within 12 hours (per book)?
at least 10 fetal movements in 12 hours
What numbers are you looking for in a NST?
FHR: 110-160
Greater than or equal to 2 spontaneous accelerations (15 bpm increase for 15 seconds) for every 20 minutes
Best done in the morning or after a meal
When looking at a CST, how long should each contraction last (pitocin induced)
3 contractions at least 40 seconds long, occurring in 10 minute period
What does an equivocal CST mean?
Some intermittent late decels or significant variable decels
Not as bad as a positive CST, but still not good
List scoring in the BPP you're looking for:
NST
Breathing movement
Body movement
Muscle tone
AFI
NST: 2 or more HR increases of 15 bpm or more seen with mvoement
Breathing movement: 1 or more breathing movements last at least 30 seoncds
Body movement: 3 or more movements of the arms, legs or body
Muscle tone: arms and legs are usually flexed and head rests on the chests; 1 or more extensions and return to flexion are seen
AFI: at least one pocket of amniotic fluid of at least 2cm
What can an absent FHR indicate?
Lack of circulation or perfusion because the HR isn't changing enough because of either movement, hormonal changes in the fetus, etc.
What are the most common causes of decelerations? Which one of them can be considered a good kind of deceleration?
Head compression (early decels)
Cord compression (variables)
Uteroplacental insufficiency (late decels)
Early decels = good d/t when baby is going down the pelvis during labor, and head is compressed during contractions.
Which of these decels will look like a U or V:
Early decels
Variables
Late Decels
Variable: d/t cord compression (cord wrapped around baby, neck, or baby is leaning against it)
How many BPM variations will you see around baseline for moderate variability?
6-25 bpm variation
If you see >25 bpm variation, what can type of variability is this?
Marked variability
Fill in: for accelerations, you will see Acme of __a__ bpm above baseline with duration of > __b__ secs but < __c__mins
a. 15
b. 15
c. 2
What are some simple interventions when seeing late decels?
Give IV fluids, O2 (8-10), change position
What is the first intervention you should do when seeing a variable deceleration?
Change position of mom
Next: give O2 (8-10lpm) and/or stop pitocin if needed, contact MD
Match:
This pain can be experienced in the first stage of labor with diffuse abdominal cramping/uterine contractions
a. Visceral pain
b. Somatic pain
a.
Match: this pain can be experienced during the second stage of labor with sharper more continuous pain felt in the perineum
a. visceral pain
b. somatic pain
b.
List 3 opioids analgesics given with use of IV with labor (systemic drugs)
1. Fentanyl
2. Nubain
3. Stadol
4. Demerol
(rapid onset and can be titrated given hourly while in active labor)
At what cm is a good time to give pain medications during labor?
4cm: doing before can prolong that stage
How many doses of fentanyl can you give during labor?
3 doses of increasing strengths
What parts of the body will a Intrathecal epidural block affect?
Belly button and below will be numb
Spinal block is indicated for what?
C-sec
What are common s/e of epidurals?
Low bp
fever
Urinary retention
Postpartum URINARY INconteinence
shivering, n/v, itching
bachache after birth
Blood patching in the spinal epidural space is done to resolve what symptom?
Headaches when changing positions
What are contraindications for epidurals?
Coagulopathies
Spinal problems
Syphilis
What are indications for local infiltration / Pudendal block?
For episiotomy and laceration repair
When will general anesthesia be used for labor?
Systemic pain control with loss of consciousness for surgery
Typically emergencies: fetal distress
**does effect fetus**
A reactive NST in a term fetus is one where the fetal HR...
increases by 15 beats per minute for 15 seconds twice in 20 minutes
AFP test performed between the 15th and 18yh weeks indicate what potential problem?
decreased AFP suggest down syndrome
What is the purpose of the Nuchal Translucency screening?
It uses ultrasound to measure the thickness of the fluid buildup at the back of the baby's neck. It checks this area for thickness, which indicates early sign of Down, trisomy 18, or heart problems.
