Fetal Assessment Flashcards
US purpose in first trimester?
-estimate gestation age (+5-7 days)
-assess vaginal bleeding source
-determine if multiple fetuses are present
-examine for indications of birth defects of the brain/spine
US purpose in 2nd trimester?
-estimate gestational age (accuracy +7-10 days)
-determine size, position of placenta, fetus and umbilical cords
-examine for indications of major birth defects (cardiovascular/neural tube)
US purpose in 3rd trimester?
-estimate gestational age (accuracy +21-30 days)
-assess fetal viability
-determine size and position of placenta, fetus, and umbilical cord
-estimate volume of amniotic fluid
what is CVS, why and how is it preformed?
-chorionic villus sampling - chromosomal, DNA and enzymatic analysis is done on the tissue
-preformed by inserting a catheter into the uterus to obtain placenta villi for testing
how is a preformed amniocentesis?
US guided 22 gauge spinal needle in the uterine cavity, first few drops of fluid are discarded, 15-20ml of amniotic fluid is withdrawn and placed in tube. US monitored the removal and then for any leakage. FHT are monitored.
When are amniocentesis preformed and why?
-15-20 weeks to evaluate for genetic disease
-30-35 weeks to determine fetal lung maturity
Risk for amniocentesis?
-streaming (leakage of fluid)
-if the mother is Rh-negative, she is given Rh immune globulin immediately
-miscarriage risk is 1 in 1600
-infection of the placenta (chorioamnionitis) is rare
what is chorioamnionitis?
infection of the placenta
List the 5 part of the BPP
Fetal Heart Rate, Fetal Respirations, Fetal Movement, Fetal Tone and Amniotic
BPP: explain how Fetal Heart Rate is measured
- measures FHR and accelerations (NST)
- REACTIVE: 2+ FHR accelerations of 15 BMP above baseline for 15+ secs in a 20-40 min period
- NONREACTIVE: 0-1 FHR accelerations in 40 mins
BPP: Explain how Fetal Respirations are measured including what is normal and abnormal
- assessed by US
- one or more episode of rhythmic breathing for 30 seconds or more in 30 min period
- less then 30 seconds of rhythmic breathing in 30 seconds
BPP: explain Fetal Movement, the normal and abnormal
-Assessed by US and toco
- normal: 3 or more separate movements in 30 mins
- abnormal: less then 2 movements in 30 mins
BPP: Explain Fetal Tone, normal and abnormal
-assessed via US
- 2 or more episodes of extensions and flexion of arm/leg (or opening/closing of a hand)
- no extension/flexion
BPP: explain Amniotic Fluid Volume, normal and abnormal
- assessed by US and amniotic fluid index
- normal: at least one single vertical pocket greater then 2 cm
- abnormal: largest single vertical pocket is less then 2 cm
How is a normal BPP scored?
10/10, 8/10 (no NST), or 8/10 (-2 points for movement, tone, or breathing but not amniotic fluid) = normal test result
Equivacal Result of BPP score explained
- ## 6/10 (-4 points for two of movement, tone or breathing, but +2 for amniotic fluid) = equivocal result = a significant possibility of developing fetal asphyxia cannot be excluded, test needs to be repeated or fetus needs to be delivered
Explain abnormal BPP result (2)
-6/10 or 8/10 with 0 points for amniotic fluid = abnormal result risk of fetal asphyxia within 1 week is high
-4-0/10 = abnormal result; risk of fetal asphyxia within one week is high, delivery is usually indicated
What is alpha-fetoprotein (AFT) and how is it measured?
When is this test most accurate?
-AFT is protein produced by the yolk sac for the 6 weeks of gestation and then by the fetal liver. Levels peak about 15 weeks. This test is primarily used to detect neural tube defects. This is done with an amniocentesis. This test is most accurate at weeks 15-16 weeks.
What is included in the triple screening?
-serum AFT level, serum HCG, and estriol
What is test are in a quad screening?
AFP, HCG, Estriol, and Inhibin A
Who should get the Quad Screening done?
It is offered to everyone but is especially to those with history of brith defects in family, over the age or 35 and use of teratogenic medications during pregnancy, DM with insulin use, exposure to high dose radiation, and hx of viral infection during pregnancy
Positive Neural Tube Defects results in Quad Screening?
AFP - HIGH
HCG - Normal
Estriol - Normal
Inhibin A - Normal
Positive Quad Screen for Trisomy 21 results?
AFP - Low
HCG - HIGH
Estriol - Low
Inhibin A - High
Positive Quad Screening for Trisomy 18?
AFP - Low
HCG - Low
Estriol - Low
Inhibin A - Low
Positive Quad Screen for multiple gestation?
AFP - HIGH
HCG - HIGH
Estriol - Normal
Inhibin A - Normal
FFT contraindications?
cervical dilations of 3 cm, suspected placental absorption or previa, vaginal bleeding, membrane rupture, gestational age less 22 weeks, gestational age greater then 35 weeks
how to take FFN?
speculum exam by rotating the swab across the vaginal for nix for 10 secs and then inserting the swab into the collection tube
what does FFN test for?
fetal extracellular glycoprotein that can be found in maternal cervical and vaginal secretions - if positive, may indicate preterm labor may start
What can cause false positives on FFN?
fetal or maternal infection, cervical manipulation before collection, sexual intercourse within 24 hours, lubricating gels and vaginal bleeding
What is PUBS?
Percutaneous umbilical cord blood sampling (or cordocentesis)
How to collect PUBS?
22 gauge need is inserted into the umbilical vein at or very near the place where it joins the placenta, US guided to placement
What does PUBS test for?
Used to assess RBCs and platelet status, genetic analysis with karyotyping, immunological, hematological, and metabolic studies, fetal acid base balance
complications from PUBS?
fetal injury or death, fetal bradycardia, amniotic fluid loss, vaginal bleeding, infections or bleeding into the cord or from the fetus into the mother’s circulation.
What is IUT?
intrauterine transfusion
indications for IUT?
-erthrocyte alloimmunization - red blood cell antigens resulting in anemia and leads to fetalis hydrops (large amount of fluid builds up in fetus, edema)
-platelet allloimmunization - mother is alloimmuized against fetal paternal platelet antigens. IUTs may be given to prevent cerebral hemorrhage but are required weekly and associated with significant morbidity
-fetal to maternal hemorrhage - may be indicated if the hemorrhage is ongoing
-infection - parvovirus B19 may result in RBC hypoplasia and severe anemia.
genetic disorders - alpha thalassemia major may be treated with IUT to correct the anemia and prevent fetal loss
What is FMH?
fetomaternal hemorrhage
Neonates blood volume range?
85-100ml/kg
What is kleihauer-betke (KB) tests what and why?
sample of the mother’s blood that is examined for the presence of fetal hemoglobin. The KB test estimates the amount of hemorrhage that taken place
Fetal scalp blood sampling can be use to test what and why?
check blood gases during labor when ROM and there is access to the scalp, can show signs of fetal distress along with EFM
when should a umbilical cord blood gases be drawn?
up to 60 mins post delivery, ACOG recommends drawing arterial and venous cord blood after C section due to fetal distress, abnormalities during FHR during labor, low APGAR, growth restrictions, maternal hypothyroidism, maternal fever and multiple fetuses. helps guide the treatment for compromised neonate
