Prenatal Testing

1. Reasons for Testing (Motive)

  1. Enhance life to provide life-saving information and treatment
  2. Enhance death to eliminate children affected by physical deformity, wrong sex, or maternal preference

2. The Truth about Prenatal Testing (the search for the perfect baby)

  1. It cannot prevent birth defects and doesn’t diagnose all of them
  2. It encourages prenatal discrimination (Bible references: Exodus 4:11; Luke 14:13,14)
  3. Can harm the experience of pregnancy (decreases ability of mom to bond with the growing baby. It becomes a tentative pregnancy.)
  4. Not 100% accurate (false’s and false’s)

3. The Most Common Prenatal Tests

  1. Alphafetoprotein (AFP) or Maternal Serum AFP (MSAFP)
  2. Ultrasonography
  3. Amniocentesis
  4. Chorionic Villus Sampling (CVS)
  5. Fetoscopy
  6. Percutaneous Umbilical Blood Sampling (PUBS)
  7. Transabdominal Fetal Echocardiography

4. Methods and Risks of Each Test


    1. AFP or MSAFP
      1. Sample of mother’s blood for level of AFP
      2. AFP: protein produced by the baby’s liver to help maintain fluid balance. It is excreted into the amniotic fluid some of which seeps into maternal circulation
      3. Abnormally elevated levels indicate possible neural tube defect (spina bifida), twins, abdominal wall defect, or anencephaly. Abnormally low levels may indicate Down Syndrome or other chromosome abnormality. Usually, maternal estriol and HCG levels are also checked at the same time and all results are viewed and compared to identify possible problems.
      4. Abnormal levels mean further testing must be done. (AFP results alone do not result in a diagnosis.)
      5. Risk: none
      6. Test performed at 15-16 weeks after last menstrual period. Results available in about a week.


    1. Ultrasonography
      1. Sound waves take a picture of the baby (echoes from the sound waves are converted into an image of the baby on a TV screen)
      2. Reasons for doing an ultrasound:
        1. Determine gestational age
        2. Identify ectopic pregnancy
        3. Identify multiple pregnancy
        4. Evaluate fetal growth
        5. Determine possible miscarriage
        6. Help perform other diagnostic tests
        7. Help diagnose birth defects (spina bifida, anencephaly)
        8. Determine fetal well being late in pregnancy in a diabetic or hypertensive mother
        9. Help select delivery method (abnormal fetal position, size, or placement of placenta.)
      3. Risks: none identified
      4. Immediate results (unless you have to wait for the doctor to analyze)
      5. May result in safer delivery or allow prenatal treatment


    1. Amniocentesis
      1. The procedure:
        1. Ultrasound first determines fetal and placental location
      2. Thin needle inserted thru abdomen and into uterus (can be done under ultrasound guidance.)
        1. Amniotic fluid withdrawn
        2. Fluid sent for chromosomal analysis
        3. Results available between 8 21 days
      3. Offered when there is increased risk of chromosomal defects, or based on AFP studies.
      4. Increased risk determined by:
        1. Older maternal age (over 35)
        2. Previous child or pregnancy with birth defect
        3. Positive family hx of birth defects
        4. Suspected neural tube defects (usually can be dx’d c ultrasound)
      5. Performed 14 18 weeks after last menstrual period
      6. May be done in third trimester to determine fetal lung maturity, dx uterine infections, or determine fetal anemia in Rh disease.
      7. Offers no guarantee of a healthy baby (can’t identify all abnormalities.)
      8. Can result in diagnoses that allow prenatal medical treatment
      9. Risks: miscarriage (1 in 200) and infection


    1. Chorionic Villus Sampling (CVS) (chorion: name of placenta in early pregnancy)
      1. Also called placental bx or placentocentesis. Originally done by the Chinese to determine sex and ensure male births.
      2. Performed transabdominally or transcervical. If abdominally, a needle inserted thru abdominal wall into the uterus. If transcervical, a catheter is inserted into the vagina and thru the cervix. Samples of villi are taken for analysis.
      3. Chorionic villi: wisps of tissue that attach fetal sac to wall of uterus
      4. Offered for older maternal age or previous hx of birth defects (not spina bifida as this can be well diagnosed by ultrasound)
      5. Risks: miscarriage and infection (higher risk ratio than amnio) Also high risk of misleading results. (Maternal tissue can be taken with the sample, as can placental tissue this can result in a false reading. If maternal sample is taken, then the mother’s chromosomes are analyzed, not the child’s. If placental tissue is taken, may have a result called “placental mosaicism” which is a reading of abnormal placental cells while the fetus itself is normal.)
      6. Early dx of some defects may lead to prenatal treatment (or doctor may encourage abortion.)


    1. Fetoscopy (virtually replaced by ultrasound)
      1. Fiberoptic tube inserted transabdominally into uterus to observe baby directly. Fetal blood withdrawn from vessels at base of umbilical cord.
      2. Can visually detect facial clefts, limb abnormalities, and skin conditions.
      3. Fetal blood analyzed to identify hemophilia, sickle cell anemia and other blood conditions.
      4. Risks: miscarriage (2 10%) and infection
      5. Limited amount of blood can be obtained
      6. Most safely performed at 18 21 weeks


    1. Percutaneous Umbilical Blood Sampling (PUBS) also called cordocentesis or fetal blood sampling.
      1. Procedure same as for fetoscopy, only blood obtained from umbilical vein of cord, or from blood vessel in the baby’s body, or the fetal heart. (The umbilical cord normally has 2 arteries and one vein. Occasionally, the cord will have one artery and one vein, this is known as “SUA” or single umbilical artery. In 20% of cases, another malformation will be present along with SUA, frequently in the heart. In a few cases, poor fetal growth has been associated with SUA. If SUA is detected by ultrasound, a Color Doppler Ultrasound may be ordered to resolve this issue. If confirmed, they may do a fetal echocardiography.)
      2. Fetal blood obtained for chromosome analysis or to identify Rh or anemia
      3. Identification of fetal anemia may allow for transfusions inutero using this same procedure.
      4. Performed anytime after 16 weeks
      5. Complications: persistent bleeding from the cord, and fetal death


    1. Transabdominal Fetal Echocardiography
      1. Ultrasound of fetal heart to determine structure and function
      2. Performed either transabdominally or transvaginally
      3. Can dx cardiac abnormalities at early gestational age
      4. Risks: none


  1. Fetal Biopsy (rare. Can be done to dx severe skin disorders)

5. A Christian Approach to Prenatal Testing

  1. Identify why test is being requested (is it life affirming, or life denying?)
  2. Any test can be refused. Decisions about tests which are right for the person cannot be made by the doctor. They must be made on personal religious and moral beliefs. Full discussion with the MD is mandatory. If he disagrees, find a prolife MD. Earlier and earlier prenatal tests are being developed. The reason for this in the medical literature is to allow for earlier abortions before the mother has time to bond with her infant.)
  3. Life affirming reasons for tests:
    1. Can guide prenatal care
    2. Can lead to prenatal treatment decreasing risk to child and or mother
    3. Permits parents to prepare emotionally if there are problems
    4. Allows for planning safest time, location, and method of delivery.
    5. Allows for appropriate specialists to be available at birth

6. Bible Verses to Consider

  1. Exodus 23:7
  2. Proverbs 6:1617
  3. Exodus 4:11
  4. Luke 14:1314
  5. John 9: 13


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