Understanding the Quadruple Marker Test
What It Is:
The Quadruple Marker Test, also known as the Quad Screen, is a prenatal screening test that measures the levels of four substances in a pregnant woman's blood:
Alpha-fetoprotein (AFP): A protein produced by the baby's liver.
Human chorionic gonadotropin (hCG): A hormone produced by the placenta.
Unconjugated estriol (uE3): A form of estrogen produced by the fetus and the placenta.
Inhibin A: A hormone released by the placenta.
Why It's Done:
Assessing Risk:
The test evaluates the risk of the baby having certain genetic disorders and birth defects, such as:
Down syndrome (Trisomy 21): A chromosomal disorder causing intellectual disability and developmental delays.
Trisomy 18 (Edwards syndrome): A chromosomal disorder that is often fatal and causes severe developmental delays.
Neural tube defects (NTDs): Birth defects affecting the brain and spinal cord, such as spina bifida.
Abdominal wall defects: Conditions where the baby's intestines or other abdominal organs stick through the belly button.
How the Test Works:
Procedure:
The Quadruple Marker Test is a simple blood test performed between the 15th and 20th weeks of pregnancy, with the most accurate results obtained between the 16th and 18th weeks.
A blood sample is taken from the pregnant woman's arm and sent to a laboratory for analysis.
The test poses no risk of miscarriage or other pregnancy complications.
Understanding the Results:
Normal Range:
The levels of the four substances are compared to normal ranges for the specific stage of pregnancy.
The results are combined with other factors, such as the woman's age, weight, ethnicity, and the baby's gestational age, to assess the risk of genetic disorders.
Abnormal Findings:
Abnormal levels of the substances may indicate an increased risk of genetic disorders or birth defects.
Further diagnostic tests, such as amniocentesis or chorionic villus sampling (CVS), may be recommended to confirm the diagnosis.
Why Your Doctor Might Order This Test:
Risk Factors:
The test is recommended for all pregnant women, especially those with risk factors such as:
Age of 35 or older when the baby is due.
Family history of birth defects.
Previous child with a birth defect.
Diagnosis of Type 1 diabetes prior to pregnancy.
Viral infection during pregnancy.
Exposure to high levels of radiation.
Usage of harmful medications or drugs during pregnancy.
Symptoms That Might Prompt This Test:
The Quadruple Marker Test is a routine screening test and is not typically prompted by specific symptoms. It is part of standard prenatal care to assess the risk of genetic disorders and birth defects.
Lifestyle and Management:
Depending on the results, your healthcare provider might recommend further tests, treatments, or lifestyle changes to manage the pregnancy effectively.
Regular monitoring and follow-up are essential for successful pregnancy management.