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Maternal Serum Screening

Your healthcare provider will be able to help you decide if you want to have maternal serum screening and which option is the best choice for you.

GenPath Offers the Following Maternal Serum Screening Options

  • Combined first screening: A first trimester screening test done between 11 weeks and 13 weeks, 6 days gestation. It includes bloodwork and an ultrasound measurement and assesses the chance of having a baby born with Down syndrome or trisomy18.
  • Integrated screening: A two-part screening test that assesses the chance of a having a baby born with Down syndrome, trisomy18, and open neural tube defects (ONTDs). The first stage includes bloodwork and an ultrasound performed between 11 weeks and 13 weeks, 6 days. The second stage includes additional bloodwork between 15 and 22 weeks. Results are released once both parts are completed.
  • Sequential screening: A two-part screening test that assesses the risk of a baby being born with Down syndrome, trisomy18, or open neural tube defects (ONTDs). The timing and components of each part are the same as integrated screening. However, initial results are released after the first trimester portion of the test. Final results are released after the bloodwork from the second portion is incorporated.
  • Serum integrated screening: Also a two-part screening test that assesses the risk of a baby being born with Down syndrome, trisomy18, or open neural tube defects (ONTDs). However, it does not include the ultrasound portion. Bloodwork is done between 11 weeks and 13 weeks, 6 days gestation, and additional bloodwork is done between 15 and 22 weeks. Results are released once both parts are completed.
  • Quad screening: A second trimester screening test done through bloodwork collected between 15 weeks and 22 weeks, 6 days gestation. It assesses the risk of a baby being born with Down syndrome, trisomy18, or open neural tube defects (ONTDs).
  • Alpha-fetoprotein (AFP) screening: Assesses the risk of a baby being born with an open neural tube defect by measuring only the alpha-fetoprotein level in maternal blood. It can be performed between 15 weeks and 22 weeks, 6 days of gestation.

Conditions Screened for by Maternal Serum Screening

What is Trisomy 21?

Trisomy 21 (Down syndrome) is a chromosome abnormality caused by having three copies of chromosome 21 instead of the typical two copies.1 About one in every 700 babies is born with Down syndrome.2 Down syndrome causes mild to moderate intellectual disability and, in some cases, heart defects, digestive abnormalities, and other birth defects. While a woman of any age can have a child with Down syndrome, the risk of this happening increases with age.2 For this reason, age is one of the factors used in determining a woman’s chance of having a baby with a chromosome abnormality.

What is Trisomy 18?3

Trisomy 18 (Edwards syndrome) is a chromosome abnormality caused by having three copies of chromosome 18 instead of the typical two copies. This causes severe intellectual disability and life-threatening birth defects. A significant number of affected pregnancies end in stillbirth in the second and third trimesters. Trisomy 18 occurs in about one of every 2,500 pregnancies and one in 6,000 live births.

What are Open Neural Tube Defects (ONTDs)?4

Open neural tube defects (ONTDs) are problems with the way the brain, spinal cord, or spine, forms while a baby is developing. These problems occur in about one of every 1,500 babies each year. Spina bifida is the most common type of ONTD, which can cause varying degrees of paralysis, lack of bowel and bladder control, club feet, fluid build-up in the head (hydrocephaly), and sometimes intellectual disability. Anencephaly is a more severe type of ONTD where part of the baby’s brain and skull do not form. Babies with anencephaly are often stillborn or live for only a short period of time after birth.

References

  1. Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html. Accessed May 23, 2019.
  2. Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/birthdefects/downsyndrome/data.html. Accessed May 23, 2019.
  3. Trisomy 18 Foundation. https://www.trisomy18.org/what-is-trisomy-18/. Accessed May 23, 2019.
  4. University of Rochester Medical Center. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=160&contentid=90. Accessed May 23, 2019.