Prenatal testing timeline

  • Genetic counseling

    -Would visit before pregnancy if you know you have an increased chance of having a child with a birth defect or genetic condition
    -Can visit during pregnancy if diagnosis has occurred to learn more
    -Run bloodwork to look at family genetics and determine risk
  • Ultrasound

    -First trimester ultrasound (6–9 weeks)
    Internal ultrasound
    Check for implantation location
    Size and position will be measured to determine gestational age.
    Not required
    -Second trimester ultrasound (18–22 weeks)
    Measure fetal anatomy and heart rates
    Might show developmental concerns that require additional testing
    Gender of baby
    -3D and 4D ultrasounds
    Not covered by insurance
    Show more realistic detail of baby
    Done between 24 and 32 weeks pregnancy
  • Glucose screening

    -Measures the level of glucose in mom’s blood, by requiring her to fast and drink a special sugar mixture and have blood drawn an hour later
    -Done between 24 and 28 weeks of pregnancy unless risk factors indicate it needs to be done earlier
    -High blood sugar level may be a sign of gestational diabetes
  • Prenatal cell-free DNA (cfDNA)

    -Noninvasive screening to check for certain chromosomal abnormalities
    Down syndrome
    Trisomy 18
    Trisomy 13
    Trisomy 21
    -DNA collected through maternal blood sample
    -At least 10 weeks pregnant
    -Not diagnostic; if test comes back positive, additional diagnostic testing required
    -Can have false positive test results and no abnormalities
    -Can tell gender with 99.7% accuracy
  • Maternal serum alpha-fetoprotein (MSAFP)

    -Examines levels of alpha-fetoprotein in mom’s blood
    -Done between 14 and 22 weeks pregnancy
    -Recommended for women
    Have family history of birth defects
    Women over 35 years old
    Women who used possible harmful medications or drugs during pregnancy
    Women who have diabetes
    -Test measures levels of alpha-fetoprotein and combines results with mom’s age and ethnicity to give probability of potential genetic disorder
  • Amniocentesis

    -Testing of amniotic fluid, which contains cells shed by fetus
    Genetic disorders
    Open neural tube defects
    Inherited gene defects
    Metabolic disorders
    Lung maturity
    -Done between 15–20 weeks of pregnancy
    The mother is over 35 years old
    Family history or previous child with genetic disorder
    Risk of open neural tube defects
    If a prenatal screening shows abnormal results
    Risk of sex-linked genetic disorder
    -Complications may include cramping, bleeding, infection, and miscarriage.
  • Group B strep

    -Common bacteria that live in the body
    -In women, found in vagina, which can cause problems if passed to baby during delivery
    -Done between 36 and 38 weeks pregnant
    -Swab sample taken from vagina and rectum
    -If positive, the mother is given an antibiotic through an IV once labor has started
  • Chorionic villus sampling

    -Testing of the chorionic villus
    Chromosomal conditions
    Genetic disorders
    -Done as early as 10 weeks of pregnancy but usually during 11–14 weeks pregnancy
    Consider if there were positive results from a prenatal screening test
    Prior chromosomal conditions in previous pregnancy
    Family history of specific genetic conditions (either parent)
    -Complications may include miscarriage, Rh sensitization, infection, and bleeding.