Diagnostic test in high risk pregnancy/prenatal determination of fetal status

ULTRASONOGRAPHY

ULTRASONOGRAPHY

1. Description A non invasive diagnosis procedure utilizing high frequency sound waves to detect intrabody structures.

2. Purposea. In early pregnancy : to confirm pregnancyb. To detect the fetus’s:•Viability, growth•Number (multiple pregnancy)•Position, presentation•Abnormalities(structural)•Heart tones (FHT)

•Age of gestation by determining the biparietal diameter of the fetal head

o Most accurate at 12 to 24 weekso Biparietal diameter of 9.5 cm = mature fetus

•Detects placental location (placenta previa) or placental abnormality (H mole)•An important aid in high risk procedures like the amniocentesis 3. Preparation

a. Advise mother to drink one quart of water 2 hours before the procedure.

b. Instruct NOT TO VOID. In amniocentesis with ultrasound to offer visualization, the mother should void to prevent injuring the distended bladder with needle insertion.

c. Transmission gel is spread over maternal abdomen.

o Encourage verbalization of fears and concerns. Explain further that:

•Procedure is non invasive and safe for mother and fetus.•Confinement is not needed•No need for dye and here is no X ray irradiation.•Procedures take a short time (about 30 min) to accomplish.

d. Psychological support is given to the mother/father (couple):

o Explain the reasons for the procedure together with its benefits and the preparations.

o Explain that there is no known risk with infrequent and brief exposure to high frequency sound waves.

FETOSCOPYFetoscopy is a procedure to allow the visualization of the baby while it is still in the uterus with the aide of fetoscope, a thin flexible instrument. Fetoscopy is usually done around the 18th week of pregnancy because the placenta and the baby is well developed.

PURPOSES OF FETOSCOPY• To evaluate fetal birth defects, such as spina bifida• To collect blood samples from the umbilical cord• To collect skin tissue samples from the baby

PREPARATION• Do not eat or drink for 8 hours before the procedure.• The doctor will check the fetal heart rate.• You may be asked to take medicine like Demerol to prevent the baby from moving around a lot.• You are required to remove your clothes around your waist down – leaving your stomach exposed.• You need to lie down but your upper body will be slightly raised.

• Your stomach will be cleaned and a local anesthetic will be given to the area where the incision will be done.•Doctor will determine the position of the fetus and the placenta using ultrasound.• Your health care provider will determine the best place to make an incision and then examine the baby.• After the procedure, fetoscope is removed and the incision will be closed.• An ultrasound will be done again, to check the status of the baby.

RISKS INVOLVED• Miscarriage• Excessive bleeding, infection or excessive leakage of the amniotic fluid• Preterm rupture which can cause early delivery of the baby• Mixing the mother and the baby’s blood

COMPLICATIONS• Moderate or severe abdominal pain or cramping• Chills or fever• Dizziness• Fluid or blood leaking from the vagina or from the cut in the belly

AMNIOCENTESISAmniocentesis is a procedure whereby a sample of fluid is removed from the amniotic sac for analysis.

AMNIOCENTESIS•Entering amniotic sac to aspirate amniotic fluid for a variety of diagnostic exams to detect fetal well being.•Major riskso Trauma: fetus, placenta , umbilical cord and maternal surfaceo Infectiono Abortion o Pre term labor

Preparation•Secure an inform consent.•Prepare for ultrasonography: to locate placenta and to provide visualization to a blind procedure.o Ultrasound in amniocentesis: client needs to void. o Pelvic ultrasound only: client should not void

•Increase oral fluid: take 1 quart water 2 hours before.•Prepare needle: G20 -22; 3” -6”.•Prepare for administration of local anesthesia of abdomen.•Provide psychological support.

Amniotic fluid to be aspirated up to 30 ml at 15 – 18 weeks of gestation.

Aftercare •Monitor for 30-60 min•Observe for side-effects such as :o Vaginal dischargeo Increase uterine /fetal activityo Fever and chills

Purposes of amniotic fluid analysis•To determine the maturity of the lungs of the fetus Result – L/S ratio of 2:1 means mature lungs, done between the 32 to 36 AOG , evaluation of any abnormal AFP test done between the 15th and 20th weeks of pregnancy• For genetic testing, chromosome analysis and evaluation of abnormal AFP testAlpha- fetoprotein (AFP) levels: increasing- high levels may indicate the presence of neural defects such as spina bifida or tracheoesophageal atresia. Low AFP level may indicate the potential force down syndrome

oGenetic disorders: for chromosomal studies, testing like hemophilia, sickle cell anemiaoFetal distress: passage of meconium in cephalic presentation( not significant in breech presentation)

SPINA BIFIDAA birth defect (a congenital malformation) in which there is a bonydefect in the vertebral column so that part of the spinal cord, which isnormally protected within the vertebral column, is exposed. People withspina bifida can suffer from bladder and bowel incontinence, cognitive(learning) problems and limited mobility. Spina bifida is caused by the failure ofthe neural tube to close during embryonic development. The neural tube is theembryonal structure that gives rise to the brain and spinal cord. The risk ofspina bifida varies according to country, ethnic group and socioeconomicstatus. In the US as a whole, spina bifida occurs in about one in every 1-2,000births. The risk of spina bifida and other neural tube defects such asanencephaly can be decreased by women taking folic acid supplements beforethey conceive and during the first months of their pregnancy.

Esophageal atresia (EA) is a developmental defect of the upper gastrointestinal tract in which there is a loss of continuity between the upper and lower esophagus. EA can occur with or without tracheoesophageal fistula (TEF), an abnormal connection between the trachea and the esophagus.

X-RAY: LATERAL PELVIMETRY

Indication for radiography to determine pelvic size and shape: a.suspected cephalopelvic disproportion (CPD)b.history of injury/disease of the pelvic and spinec.previous difficult deliveryd.cases of maternal deformity or limp

CHORIONIC VILLI SAMPLY (CVS)

CHORIONIC VILLI SAMPLING

Chorionic Villi Sampling (CVS) is removal of a small piece of chorionic villi from the uterus to screen the baby for genetics defects. CVS needs abdominal ultrasound to determine the position of the uterus, the size of the gestational sac, and the position of the placenta within the uterus.

TWO METHODS OF CVS1. Transcervical procedure - performed by inserting a thin plastic

tube through the vagina and cervix to reach the placenta.2. Transabdominal procedure - performed by inserting a needle

through the abdomen and the uterus and into the placenta.

PURPOSEDetecting genetic disorders, used to study DNA, chromosomes and

certainsigns of disease in the developing baby. It is usually done 10-12

weeksAOG. Test results take about 2 weeks. It does not detect neural tubedefects or Rh incompatibility.

PREPARATION• Explaining the procedure, the risk and the alternative procedures• Genetic counselling• Consent• Prior to the procedure, drink fluids and refrain from voiding

POSSIBLE COMPLICATIONS• Bleeding• Infection• Miscarriage• Rupture of membrane

SIGNS OF COMPLICATIONS• Excessive bleeding• Excessive vaginal discharge• Fever

PERCUTANEOUS UMBILICAL SAMPLING (PUBS)

Also called CORDOCENTESIS, a diagnostic genetic test that examine blood from the umbilical cord to detect fetal abnormalities.

PUBS is usually done when diagnostic information can not be obtained through amniocentesis ,CVS and ultrasound. It is usually done at 18 weeks AOG. It does not help identify neural tube defects.

PURPOSE • Detects chromosone abnormalities (i.e. Down Syndrome) and blood disorder such as fetal hemolytic disease. • Helps to diagnose any of the following concerns: o Malformation of the fetuso Fetal infection (rubella)o Fetal anemia

RISKS• Blood loss from the puncture site• Infection• Drop in fetal heart rate• Premature rupture of membranes

SIGNS OF COMPLICATIONS• Fever • Chills• Leaking of amniotic fluid

NON STRESS TEST (NST)

NON STRESS TEST (NST)

Description•Observation of FHT related to fetal movement.•A test of fetal well being

Preparation •Position – semi fowler’s or left lateral position slightly turned to the left.•BP is checked first.•Explain:o Procedure takes 30 to 60 min to finish.o Mother needs to activate “mark button” with each fetal

movemento Does not need hospitalization – ambulatory basiso Requires external electronic monitoring of FHT with

ultrasound transducer and tocodynamometer to trace fetal activity and /or uterine activity.

Interpretation •Normal: reactive Increased FHT (acceleration) greater than 15 bpm above baseline – lasting 15 sec or more in a 10 to 20 min period with fetal movement

•Abnormal: Non reactiveo No FHR acceleration with fetal movemento Implication of resultso Normal: high risk pregnancy continueso Abnormal results: mother needs another test, may be

biophysical profile.

OXYTOCIN CHALLENGE TEST (OCT) or CONTRACTION STRESS TEST (CST)

PURPOSE•Observation of response of the fetus to induced uterine contractions•A test of feto-placental well-being

PREPARATION•Semi-Fowler’s or left lateral position•BP is checked priorly and q 15 minutes during the test•Explain:o Procedure takes 1 to 3 hours to finisho Mother receives oxytocin of increasing dosage “piggybacked” to the mainline and aimed to cause 3 uterine contractions in 10 minuteso May be done on outpatient basis•Requires external electronic FHT monitoring with ultrasound transducer and tocodynamometer to detect uterine activity.

INTERPRETATION•Normal : Negative – no late decelerations of FHR with each of three contractions during a 10-minute interval•Abnormal : Positive – with late decelerations of FHR with three contractions in 10 minutes

IMPLICATIONS OF RESULTS•Normal result – pregnancy continues; normal result of OCT may require weekly tests•Abnormal result – may indicate a need to terminate pregnancy

BIOPHYSICAL PROFILE (BPP)

1. A Scoring combining ultrasound assessment of:

a. Fetal breathing b. Fetal movement c. Fetal tone d. Reactivity of the heart rate e. Amniotic fluid volume BPP could be used to

predict fetal well-being in a high-risk pregnancy

2. Scores

• 8 – 10 : Normal, low risk for chronic asphyxia• 4 – 6 : Suspected chronic asphyxia• 0 – 2 : Strong suspicion of chronic asphyxia

Biophysical Variable

Normal (Score = 2) Abnormal (Score = 0)

Fetal breathing movements

Greater than or equal to 1 episode of 30 seconds or more of fetal breathing movement in 30 minutes

Absence of 30 seconds or longer of fetal breathing movement in 30 minutes

Gross fetal movement

3 or more discreet movements of the body or any limb in 30 minutes

2 or lesser discreet movement of body or a limb in 30 minutes

Fetal tone 1 or more episodes of extension and flexion of fetal limb(s) or trunk. Opening and closing of hand is considered normal tone

Either slow extension with return to partial flexion or movement of limb in full extension or absent fetal movement

Reactive fetal heart rate

2 or more episodes of accelerations of 15 bpm or more lasting for 15 seconds or longer in 20 minutes; associated with fetal movement

Less than 2 episodes of acceleration of fetal heart rate or acceleration of less than 15bpm in 20 minutes

Qualitative amniotic fluid volume

1 pocket or more of fluid measuring 1 cm or more in two perpendicular planes

Either no pockets or a pocket of 1 cm or lesser in two perpendicular planes