Pregnancy Tests

Identifies risk factors and helps detect congenital anomalies (EX: genetic testing, cell-free DNA testing, etc.)

Prenatal screening

Confirms disease or condition → most precise test for a given condition (EX: chronic villus sampling (CVS), amniocentesis, etc.)

Diagnostic testing

in which trimester is a transvaginal ultrasound commonly used?

A) first trimester

B) second trimester

C) third trimester

A

An invasive procedure used in early pregnancy (first trimester) to confirm a pregnancy.

• Can detect ectopic pregnancies, measure cervical length, placental location.

Transvaginal ultrasound

What are the types of ultrasound images?

• Doppler

• Transvaginal

• Transabdominal

What can the transvaginal ultrasound detect? (SATA)

A) fetal anatomy

B) ectopic pregnancy

C) cervical length measurements

D) clearer images of placental location

E) fetal movement

BCE

In which trimester is a transabdominal ultrasound more commonly used?

A) first trimester

B) second trimester

C) third trimester

B

What can a transabdominal ultrasound be used to assess for? (SATA)

A) fetal anatomy & growth

B) fetal movement

C) ectopic pregnancy

D) potential structural abnormalities

E) fetal viability confirmation

ADE

Second trimester ultrasonography is used to assess for

• Congenital malformations

• Confirm fetal viability

• Assess serial fetal growth.

For which ultrasound is a patient required to have a full bladder?

A) 2D ultrasound

B) doppler ultrasound

C) transvaginal ultrasound

D) transabdominal ultrasound

D

Patient teaching for transabdominal ultrasound

Patients are advised to drink (4 cups) of water prior to the ultrasound to fill the bladder, lift and stabilize the uterus, displace the bowel, and act as an echolucent to better reflect sound waves to obtain a better image of the fetus (water carries sound better).

A full bladder is NOT required for a transvaginal ultrasound. True or false?

True

Name that ultrasound image: standard procedure, provides a flat image in black, white, and shades of gray

2D

Name that ultrasound image: shows multiple images at once and can provide more accurate identifications, almost as clear as a photograph

3D

Name that ultrasound image: capable of streaming live video images to detect fetal movement

4D

What category of ultrasounds obtains a general survey?

a. limited

b. standard (basic)

c. specialized

d. 3D

B

Purpose of a standard ultrasound at 20 weeks?

General survey/anatomy scan

Which category of ultrasounds addresses a specific problem or concern?

A) standard (basic)

B) specialized

C) limited

D) 4D

C

What is the purpose of a preimplantation genetic test?

Prenatal genetic diagnoses look for specific genetic conditions that may be inherited from one or both parents. (EX: sickle cell anemia & Tay-Sachs disease)

What screenings are a part of first trimester screenings? (SATA)

A) nuchal translucency measurement (NT)

B) Alpha-fetoprotein (AFP)

C) human chorionic gonadotropin (hCG)

D) cell-free fetal DNA (cfDNA)

E) chorionic villus sampling (CVS)

ACDE

which trisomies do a Nuchal Translucency (NT) Measurement screening test for?

A) 13, 21, and 18

B) 20 and 21

C) 17 and 9

D) 21 and 5

A

What is the purpose of cell-free fetal DNA testing (cfDNA)?

cfDNA looks for genetic markers of babies; used to screen for aneuploidies (abnormal number of chromosomes) → done at the 10th week of pregnancy!

When is cfDNA testing done?

10th week

HPV vs HSV

HPV = cervical cancer → PAP smear

HSV = herpes → vagina → give Valtrex (valacyclovir) to prevent outbreaks and harm to fetus → no vaginal birth

When to do kick counts?

20 weeks

Screening = diagnostic. True or false?

False

No abortions after ____ weeks of pregnancy in Texas

6

Confirms disease or condition

Diagnostic testing

Types of diagnostic tests

• Chorionic villus sampling (CVS)

• Amniocentesis (not as safe)

• Preimplantation diagnosis (PGD)

Who should be offered prenatal screening and diagnosis?

• All women who desire to be tested regardless of maternal age, family history, or genetic history

• All prenatal tests are voluntary; each woman has a choice

• Women should be counseled about benefits to make informed decisions

• For

• High-frequency sound waves obtain real-time images of maternal structures, placenta, amniotic fluid, and fetus

• Sound waves penetrate to the level of the structure being evaluated

• Ultrasound may be paused to take fetal measurements or

When to recommend genetic counseling to patients

• Patients w/ multiple recurring miscarriages

• Known carrier of a disease process that can be easily transmitted

• Ultrasound transducer is maneuvered back and forth across the maternal abdomen

• Allows visualization of multiple structures

• See fetus/gestation sack at 8-10 weeks

Transabdominal ultrasound

• Requires specially shaped transducer; probe goes just inside the vagina (can see when baby is much smaller at 5-6 weeks)

• Commonly used first trimester

• May be used later for cervical length measurements and determine placental location

Transvaginal ultrasound

Ultrasound used for general survey/anatomy scan (usually at 20 weeks)

Standard (basic) ultrasound

Ultrasound used to address a specific problem or concern

• Example: confirming presence of fetal four chamber heart

• May look for FHR, amniotic fluid, fetal movement

Limited ultrasound

Ultrasound that is detailed or targeted; specific

• Example: looking for structural abnormalities

Specialized ultrasound

Nonmedical OB ultrasound uses

Nonmedical use is discouraged due to unapproved providers and use of medical device.

• Gender identification

• Research

• Diagnostic purposes

Patient teaching for ultrasound

Ultrasound for early pregnancy or transabdominal → full bladder

Purpose of first trimester ultrasonography

Procedure: transvaginal

• Confirm pregnancy

• Verify the location of pregnancy (pregnancy implanted in tubes = high risk for mom)

• Identify multiple gestations

• Determine gestational age

• Identify markers

• Determine locations of the uterus, cervix, placenta

Second and third trimester ultrasonography

Procedure: transabdominal

• Confirm fetal viability

• Evaluate fetal anatomy

• Determine GA

• Assess serial fetal growth

• Compare growth of fetuses in multifetal gestations

• Evaluate four or 5 markers BPP

• Locate the placenta when placenta previa is suspected

• Determine fetal presentation

• Only available for IVF

• Analyzes one or more cells from an embryo between day 3 and 7 after fertilization

• Looks for specific genetic conditions that may be inherited from one or both parents

  • Sickle-cell anemia

  • Tay-Sachs disease

• Results received within 1-2 days

• Not as reliable as CVS or amniocentesis

Preimplantation genetic screening

Prenatal screening tests (FTS)

• Nuchal translucency (NT) → trisomy 21 (down syndrome) & 18 (incompatible with life)

• hCG → probable sign

• Cell-free DNA → gender (10 weeks of pregnancy)

Second trimester multiple-marker screening

• Report risks for trisomy 21 and 18; open NTDs

  • anencephaly and spina bifida

• Serum analytes for prenatal screenings (between 15 weeks and 22 6/7)

• hCG, AFP, inhibin-A uE3, hyperglycosylated hCG

• Triple quad and penta screening

Combined first and second trimester screening tests

• Combined tests allow for higher detection rates

• Integrated, sequential, or contingent

• May include measurements of serum analytes, NT, or both

Serum analytes for second trimester multiple-marker screening

hCG, AFP, inhibin-A uE3, hyperglycosylated hCG

• Used to diagnose fetal chromosomal, metabolic, or DNA abnormalities

• Used if something looks strange in ultrasound

• Usually performed 10-13 weeks

• Counseling about procedure

• Genetic counseling

• Transcervical and abdominal approach

CVS

Risks of CVS

• Rate of pregnancy loss less than 1% if performed by specially trained physician

• Reports of limb reduction defects when performed at less than 10 weeks

• Culture failure in growing chromosomes, subchorionic hematomas, infection, and spontaneous rupture of membranes.

Nursing responsibilities for CVS

• Educate clients about post-procedure complications

• Needle goes in and numb injection site

  • Spotting

  • Bleeding

  • Cramping

  • Rest and what to avoid

  • Written instructions of what and when to report if complications

• Invasive procedure that has been the foundation of prenatal diagnosis for many years

• Aspiration of amniotic fluid from the uterus

• Performed for a variety of indications and at different gestational ages

Amniocentesis

• Test used to identify chromosomal, metabolic, or genetic abnormalities

• To determine fetal lung maturity

• To diagnose fetal infections and amniotic fluid volume disorders such as hydramnios and oligohydramnios

Amniocentesis

In this procedure

• Ultrasonography is used to identify the largest pockets of amniotic that can safely be sampled and the abd is prepared aseptically

• Spinal needle inserted into the packet of fluid; 1-2 mL of fluid discarded

• Approximately 20 mL of fluid are removed for examination

Amniocentesis

When is amniocentesis done?

Between 15-20 weeks

Disadvantages of amniocentesis

• Final test results not available for 10-14 days

• Takes place in second trimester when pregnancy more apparent and fetal movement has been perceived by the mother

Amniocentesis t determine fetal lung maturity

• Pulmonary system is one of the last systems to mature structurally and physiologically

• Surfactant plays a key role in fetal lung maturation

• Evaluating fetal lung maturity (FLM) may be indicated to reduce neonatal complications

• Amniocentesis can also be performed.

Antepartum fetal testing methods

• Fetal movement counting (FMC)

• Nonstress test (NST)

• Contraction stress test (CST)

• Biophysical profile (BPP)

• Doppler flow ultrasound

Who’s at risk for defects and may need antepartum fetal testing?

• HTN, AMA, weight → can alter the maternal-fetal oxygen pathway

• Antepartum fetal testing my identify fetal hypoxia early enough so that treatment can begin before fetal oxygenation reaches a critical level

Antepartum fetal surveillance is typically initiated at ___ to ___ weeks for high risk pregnancies; earlier testing may be indicated based on risk factors.

24; 32

Antepartum testing is conducted

Weekly or biweekly

• Maternal perception of fetal movement = indicates life; absence of movement signaled death

• As the fetus becomes more hypoxic, fetal activity is reduced to conserve O2

• “Count to Ten” method/kick counts: 10 distinct movements in 1-2 hours is desired result

Fetal move counting (kick counts)

Desired result for fetal movement counting/kick counts or “Count to Ten” method

10 distinct movements in 1-2 hours is desired result

Do not get 10 kicks in 1 or 2 hours, even after position changes or drinking water → go to hospital.

Decreased fetal movement

Progression of antepartum fetal testing:

1)

2)

3)

4)

1) Kick counts

2) NST

3) CST

4) BPP

• Primary means of fetal of surveillance in pregnancies at risk for uteroplacental insufficiency

• Observes FHR response to fetal movement

NST

This antepartum fetal testing procedure involves:

• Comfortable position, such as semi-Fowlers, with a lateral tilt.

• Fetus position is determined using Leopold’s maneuvers

• Ultrasound transducer and tocotransducer applied and secured to woman’s abd.

NST

Good result from NST

2 accelerations in 20 minutes (acceleration = contractions; positive is good)

Considerations for NST

• Maternal ingestion of meds or substances

• May require vibroacoustic stimulation

NST interpretation

• Reactive: Two or more accelerations within a 20 min period

• Nonreactive: Fewer than two accelerations in a 40 min period

• This antepartum fetal testing records response of FHR to stress induced by uterine contractions

• May be done if NST findings are nonreactive

CST & Oxytocin Challenge

This antepartum fetal testing procedure involves:

• EFM

• Oxytocin/nipple stimulation

• Looks for decelerations of FHR/contraction

• 3 contractions in 10 mins = BAD

CST

This antepartum fetal testing procedure involves:

• FHR reactivity is interpreted from an NST

• Other 4 parameters are measured by real-time ultrasonography

CST with no late decelerations

Negative CST (GOOD)

CST with late decelerations are present with a minimum of 50% of contractions

Positive/reactive CST (BAD)

CST with intermittent late decelerations or significant variable decelerations

Equivocal-suspicious CST

CST with FHR decelerations in presence of contractions more frequent than every 2 mins or lasting longer than 90 sec

Equivocal CST

CST with fewer than 3 contractions in 10 minutes or a tracing that cannot be interpreted

Unsatisfactory CST

Negative CSTs are consistently associated wtih

Fetal well-being and may be repeated in one week

Positive CSTs are linked to

Increased incidence of:

• Fetal growth restriction

• Late decelerations during labor

• Meconium stained fluid

• 5 min Apgar scores

• Stillbirths

What will nurse do if there is a positive CST?

The health care team will discuss management options with the patient in the event of a positive CST.

Antepartum fetal testing that assesses for. Done after positive CST

• FHR

• Fetal movement

• Fetal tone

• Fetal breathing movement

• Amniotic fluid amount

BPP

BPP score

2 points for every criteria (out of 10) over 30 min

• FHR (does baby pass NST; 2 accels in 20 min)

• Fetal movement (is baby moving)

• Fetal tone (does baby have tone inflection)

• Fetal breathing movement (is it practicing breathing)

• Amniotic fluid amount (good amount of fluid)

• Fetal doppler flow ultrasound

BPP interpretation

• Characteristics are evaluated simultaneously over a 30 min period

• Performed by sonographers, advanced practice nurses, or physicians

• Nurses may perform if they have received specialized training and successfully completed competency verification

Good/okay BPP score

8-10 (meet 4/5 or 5/5 of criteria) → normal fetal oxygenation

Score of 6 in BPP

Is equivocal if amniotic fluid amount is normal; suspicious if abnormal amniotic fluid amount

Score of 0-4 on BPP

Usually associated with acidemia or perinatal asphyxia

• Combines NST with ultrasound measurement of amniotic fluids (AFI)

• NSTs are either reactive or nonreactive

• Amniotic fluid is assessed by measuring largest pocket of fluid in 4 maternal abdominal quadrants

• 4 measurements are totaled to obtain amniotic fluid index (AFI)

MBPP

Measurement of 2 cm or less in AFI BPP or MBPP indicates

Oligohydramnios

Measurement of 18-20 cm or more in AFI BPP or MBPP indicates

Excess volume or hydramnios

• Antepartum fetal testing that assesses condition of the placenta, including hemodynamic components of vascular resistance in high risk pregnancies with fetal growth restriction

• Particularly, it assesses flow of blood in umbilical artery from fetus to placenta; normally deoxygenated blood flows from fetus to placenta, but abnormally high resistance can push deoxygenated blood back to fetus → reverse end diastolic flow

• Detects fetal anemia when Rh alloimmunization is suspected

• Measures cardiac cycle differences between peak systolic and end diastolic blood flow velocity

• Deliver baby immediately

Fetal doppler flow ultrasound

Antepartum fetal testing that detects fetal anemia when Rh alloimmunization is suspected

Fetal doppler flow ultrasound

Which diagnostic test evaluates effect of fetal movement on FHR?

A) CST

B) Sonography

C) BPP

D) NST

D