In this article:
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What is Aneuploidy Screening Test?
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Types of Aneuploidy Screening Test
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Interpreting Aneuploidy Screening Test Results
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When Should One Consider Aneuploidy Screening Test?
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Conclusion
Early pregnancy comes with lots of excitement and
expectations. One such expectation is that the baby grows healthy and the
pregnancy progresses smoothly. However, sometimes, due to genetic conditions,
pregnancy complications, or chromosomal abnormalities, concerns arise. At this
stage prenatal care, particularly aneuploidy screening test in Lucknow, plays a
major role. Aneuploidy screening helps to detect potential chromosomal
abnormalities early on, allowing parents, and the Obstetrician, and Fetal Medicine Specialist in Lucknow to make
informed decisions and prepare for any challenges that may arise during the
pregnancy.
What is the Aneuploidy
Screening Test?
Aneuploidy refers to the occurrence of one or more extra
chromosomes or missing chromosomes in a cell. In general, our human body
consists of 46 chromosomes, arranged in 23 pairs. Aneuploidy occurs when this
number is deviated. Aneuploidy screening test helps detect these conditions
early in the pregnancy. This abnormality in chromosomes greatly impacts a
child’s development and health. It often leads to conditions like Down syndrome
(Trisomy 21), Edwards syndrome (Trisomy 18), or Patau syndrome (Trisomy 13).
Types of Aneuploidy Screening Test
This screening can be carried out in different stages of
pregnancy using various methods. These methods serve as an indication or
likelihood of an abnormality. All the methods incorporated have their
limitations, pros, and accuracy.
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First-Trimester
Screening
First-trimester screening is a
prenatal test that involves ultrasounds and blood tests to detect fetal
aneuploidies. This screening has a 95% detection rate with a 3% false positive
rate. Some screening that comes under this trimester is:
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Nuchal
Translucency (NT) Ultrasound:
This ultrasound measures the amount of fluid behind the
baby’s neck. With the amount received, the chances of having a chromosomal or
genetic variant are determined. The high amount of fluid indicates a higher
risk of aneuploidy, particularly Down syndrome while a small amount is
considered normal.
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Blood Tests:
Blood tests measure specific proteins and hormones in the
mother's blood, such as HCG (human chorionic gonadotropin) and PAPP-A
(pregnancy-associated plasma protein A). Abnormal levels can suggest a higher
risk of chromosomal abnormalities.
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Non-Invasive
Prenatal Testing (NIPT)
NIPT is a highly accurate screening method that analyzes
small fragments of fetal DNA circulating in the mother's blood. It is usually
performed around 10 weeks of pregnancy and can detect common fetal aneuploidies
like Trisomy 21, 18, and 13 with over 99% accuracy. NIPT has a lower
false-positive rate compared to other screening methods.
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Second-Trimester
Screening- Quadruple Marker Test (Quad Screen):
This blood test is typically done between the 15th and 20th
weeks of pregnancy. It measures four substances in the mother's blood:
alpha-fetoprotein (AFP), HCG, estriol, and inhibin-A. This test can detect an
increased or low risk of aneuploidy or neural tube defects.
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Combined Screening
A combination of first-trimester screening and NIP or
second-trimester screening to increase the accuracy of risk assessment.
Combined screening provides a way more comprehensive evaluation of the risk of
chromosomal abnormalities.
Interpreting Aneuploidy Screening
Test Results
It’s important to note that screening tests are not
diagnostic tests but rather they do assess the risk of chromosomal abnormality.
Screening test indicates two different results:
Low-Risk
Results
A low-risk result suggests that the likelihood of a
chromosomal abnormality is low, but it does not eliminate the possibility.
High-Risk
Results
A high-risk result indicates a higher chance of aneuploidy,
in which the health care provider may offer further diagnostic testing to fully
detect the aneuploidy.
When Should One Consider Aneuploidy
Screening Test?
Aneuploidy Screening is offered to all pregnant women, as a
part of their routine checkups and prenatal care. However, in certain
situations, this test is recommended with greater emphasis:
1.
Maternal Age: Women who are 35 years or older at
the time of delivery are at a higher risk of chromosomal abnormalities, making
aneuploidy screening important.
2.
Family History: If there is a family history of
chromosomal abnormalities or genetic disorders, this screening can help assess
the risk for the current pregnancy.
3.
Previous Pregnancy with Chromosomal
Abnormalities: Women who have had a previous pregnancy affected by a
chromosomal abnormality may choose to undergo aneuploidy screening in
subsequent pregnancies.
4.
Abnormal Ultrasound Findings: If an ultrasound shows
abnormalities that could indicate a chromosomal issue, aneuploidy screening can
help further evaluate the risk.
5.
Increased Risk Identified by
First-Trimester Screening: If early screening tests indicate an increased risk of
chromosomal abnormalities, further aneuploidy screening or diagnostic testing
may be recommended.
Aneuploidy screening is generally performed during the first
or second trimester of pregnancy, allowing for early detection and better
decision-making. Discussing with your fetal specialist can help determine the
best time for screening based on individual risk factors and preferences.
Conclusion
Aneuploidy screening test in Lucknow is a great medical invention
in the field of prenatal care, that offers an early insight into the health of
a fetus. Although the results of screenings are just the likelihood but do
provide an early indication to the parents as well as the doctor to make
informed and wise decisions.
If you are expecting or planning a pregnancy, discuss
aneuploidy screening with the leading fetal medicine specialist Dr. Mansi Gupta. Book an appointment now to explore and understand more options and ensure a healthy
pregnancy and baby.