Sonography guided procedures and additional testing

High risk pregnancy

Pt had previous child with defect, disorder, syndrome, preexisting condition that may affect the pregnancy

Abnormal quad screen

Suspected or diagnosed abnormality

Multiple gestation

Advanced maternal age

IUGR

Maternal diabetes

Amniocentesis optimum age for sample karyotyping

15-16 weeks

Amniocentesis is performed on 3rd trimester fetuses to assess…

Lung maturity

Amniocentesis Indications

AMA, increased AFP, prior history of birth defects, maternal metabolic disorders, carrier of genetic defect, characterize sonographic abnormalities

Results in 7-14 days

Role of sonographer for amniocentesis

Assess GA, viability, number of gestations and placental location

Detect large fluid pockets

Document fetal heart before and after

Multiple gestations may require the injection of _______________ into amniotic sac after each sample to prevent sampling fluid from the same sac twice during an amniocentesis

Indigo carmine

Amniocentesis is used to assess

AFO

Rh disease

Open spinal defects (increased ACHE levels)

Lung maturity

DNA testing

Karyotyping

Fetal anemia and erythroblastosis fetalis

Chorionic villus sampling is performed between what weeks

10-12

CVS primary advantage

ONLY Offers earlier karyotyping option than amnion

24-48hrs for results

CVS performed TA or ___

TV

In CVS, sample taken of ___________ (chorion frondosum)

Trophoblastic tissue

CVS lateralization phenomenon

4D imaging is helpful during chorionic villus sampling and cordocentesis

Needle placement is crucial in these procedures and using the 4D imaging improves sampling accuracy

Refers to a needle position demonstrated on US that is not the true needle location

Karyotyping only for…

Genetic defects/syndromes

CVS does NOT detect ___ levels and is NOT used to screen for neural tube defects

AFP

Coelocentesis

Sample of coelomic fluid around the amniotic sac

Performed as early as 6 weeks

US guided sample taken with a needle inserted through the vaginal canal

Used to assess fetal karyotyping

Percutaneous Umbilical Blood sampling

Blood sample obtained from placental insertion site of the cord

Performed after 17 weeks gestation

Rapid results available <72hrs

Allows for direct testing of the fetal blood for karyotyping and Rh factor testing

Percutaneous Umbilical Blood sampling is also known as

Cordocentesis

Percutaneous Umbilical Blood Sampling can also assess for

Hemophilia, anemia, clotting disorders and immunodeficiencies

Percutaneous Umbilical Blood sampling is used to perform a

Fetal blood transfusion

Percutaneous Umbilical Blood sampling post procedure scan performed _____ minutes after completion to document fetal viability

30-60

Detailed anatomic evaluation is critical in determining the appropriateness of fetal __________ intervention

Surgical

A fetus with an isolated fetal abnormality is the best candidate for __________

Intervention

A fetus with multiple malformations or those with aneuploidy or a syndrome are usually excluded from …

Intervention

Conditions considered for intervention:

TTTS, selective fetal growth restriction, 10th percentile for GA, myelomeningocele, congenital diaphragmatic hernia, congenital cystic adenomatoid malformation, pleural effusion, critical aortic stenosis, lower urinary tract obstruction, sacrococcygeal teratoma, amniotic band syndrome, chorioangioma

Triple screen test

Blood drawn from the mother

Measures levels of AFP, hCG and Estriol

Predicts multiple pregnancy, molar pregnancy, Trisomy 21, 18 and NTD

Quad Screen Test

Blood drawn from the mother

Adds inhibin-A to triple screen

Evaluates a fetus for aneuploidy

The most common cause of abnormal results is inaccurate estimation of

Gestational age

AFP

Produced by the fetus

Unit is multiples of the median

>2.5 multiples of median is considered elevated

High levels are associated with NTD and multiple gestation pregnancy

Low levels are associated with Trisomy 21 and 18

hCG

Produced by the placenta

Increased with Trisomy 21 and decreased with Trisomy 18

Estriol

Synthesized in the placenta using a hormone produced by the fetal adrenal gland

Used to evaluated placental function and detect chromosome abnormalities

Low levels are normal in non-gravid females and the level increases with pregnancy

Abnormality low levels in pregnancy are associated with Trisomy 18 and 21

Inhibin A

Protein produced by the corpus luteal cyst (early) and the placenta (after CL cyst involutes)

Elevated levels associated with Trisomy 21

Pregnancy associated plasma protein - A (PAPP-A)

Another protein level that can be evaluated for fetal well-being

Produced by the placenta

Decreased levels with Trisomy 21, 18 and Turners

Increased AFP levels

Inaccurate dating of pregnancy (MOST COMMON), spina bifida, anencephaly, congenital skin defects, abdominal wall defects, GI defects, cloacal exstrophy, cystic hygroma, sacrococcygeal teratoma, fetal urinary obstruction, PCKD, osteogenesis imperfecta, low birth weight, oligohydramnios, multiple gestation, chorioangioma

Decreased AFP levels

Inaccurate dates, trisomies, hydatidiform mole, fetal demise/missed abortion

Cell-free DNA testing

The maternal plasma contains fetal DNA than can be evaluated for chromosomal anomaly

Reserved for high-risk women

Tests for aneuploidy and other chromosomal defects

Lung maturation testing

Performed to find out if fetal lungs are mature enough to deliver the fetus early

Predicts potential for fetal respiratory distress (FRD)

L/S ratio <2:1 ratio indicates high priority of FRD

Most accurate method of lung maturation testing

Phosphatidyglycerol levels are present in the amniotic fluid after 35 weeks

Foam stability index

Foam stability index

Amniotic fluid sample used to evaluate lung maturity by shaking with ethanol

Fluorescent in-situ hybridization (FISH)

Uses amniotic fluid sample

Cytogenic procedure

Dye used to tag chromosome markers

Used to detect and localize the presence or absence of specific DNA sequences on chromosome

Provides rapid results (24-48hrs)

Antepartum fetal assessment

Used to assess the risk of fetal death in complicated pregnancies

Techniques include NST, contraction stress test, BPP, modified BPP, fetal kick counts, umbilical doppler

NST

2 or more fetal heart rate changes of at least 15 bpm for 15 seconds that are related to changes in fetal movement; evaluated for 30 mins

NST is performed due to

High risk pregnancy, maternal health condition like diabetes, post-dates pregnancy

NST requires documentation of __ episodes of HR acceleration >15 bpm for __ seconds

2; 15

Contraction stress test

Oxytocin is administered vie IV into mother to induce uterine contraction

Fetal heart rate monitored during the procedure

Cardiotocography (CTG) is the technique of recording the fetal heartbeat and the uterine contractions

Normal = Fetal HR increases during contraction

Abnormal = fetal heart rate decreased during contraction

Evaluation of fetal movement

Decreased fetal movement indicates an increased risk of stillbirth

Quickening - When fetal movement is first detected by mother (19-20 weeks)

Fetal kick counts - Mother lies on her side and counts fetal movements (10 kicks within 2 hours = normal)

Glucose screening

Blood test

Used to assess the mother for gestational diabetes

Performed when the fetus is 24-28 weeks

The delta OD450 test evaluated the amount of _________ in the amniotic fluid to assess the fetus for ________

Bilirubin; anemia

Which of the following levels is increased with Trisomy 21?

AFP

hCG

Testosterone

Estriol

hCG

Estriol is produced in the ___________, while inhibin-A is produced in the _______

Placenta; ovaries

Which of the following values is used to asses fetal lung maturity and risk of respiratory distress?

Lecithin/salphingomyelin ratio

Phosphatidylglycerol

Foam Stability

All of the above

All of the above

A modified BPP involves what two components of testing

NST and AFI levels

Quickening

When fetal movement is first detected by the mother