What is a Screening Test During Pregnancy?
Screening tests during pregnancy are tests performed to determine whether the baby has a genetic or chromosomal anomaly.
Genetic errors originating from the egg or sperm may lead to chromosomal disorders in the embryo. This condition may cause serious diseases such as;
- Down syndrome (Trisomy 21)
- Edwards syndrome (Trisomy 18)
- Patau syndrome (Trisomy 13)
Screening tests do not provide a definitive diagnosis, they only measure the risk of anomalies.
If the results indicate a high risk, advanced tests (for example, amniocentesis or NIPT) may be recommended by your doctor.
What Tests Are Performed During Pregnancy?
The most common screening tests performed during pregnancy include:
- Double Screening Test (Combined Test) – Performed between 11–14 weeks.
- Triple Screening Test – Performed between 16–18 weeks.
- Quadruple Screening Test – Performed between 15–22 weeks.
These tests are carried out using a blood sample taken from the expectant mother and ultrasound measurements.
They are applied in the same way in IVF pregnancies.
What is the Double Screening Test During Pregnancy?
Double Screening Test is the first screening test recommended for all pregnant women.
The aim is to determine the risk of the baby having Down syndrome or other chromosomal anomalies.
How is it performed?
- It is applied between the 11th and 13th weeks of pregnancy.
- With ultrasonography, the baby’s nuchal thickness (NT measurement) and nasal bone are evaluated.
- In the blood taken from the expectant mother, β-HCG and PAPP-A hormone levels are measured.
- The results are compared with maternal age and gestational week to calculate the risk ratio.
⚠️ The double test can be performed on a full or empty stomach. No special preparation is required for the test.
Result evaluation:
- Low risk → Follow-up is sufficient.
- High risk → If necessary, amniocentesis or NIPT test may be performed.
What is the Triple Screening Test During Pregnancy?
Triple Screening Test evaluates the risk for chromosomal disorders such as Down syndrome and Trisomy 18.
Timing:
It is performed between the 16th and 18th weeks of pregnancy.
How is it performed?
- Three biochemical parameters are measured in the blood sample taken from the mother:
- HCG (Human Chorionic Gonadotropin)
- AFP (Alpha-Fetoprotein)
- E3 (Estriol)
- The results are compared with maternal age and gestational week to determine the risk.
This test also does not provide a diagnosis; it only determines risk.
If the result indicates high risk, confirmation is made with advanced examinations.
In recent years, the quadruple test has started to replace the triple test because it provides more comprehensive information.
What is the Quadruple Screening Test During Pregnancy?
Quadruple Screening Test is an improved and more reliable version of the triple test.
It evaluates the risk of both Down syndrome and Trisomy 18 as well as other congenital defects.
When is it performed?
It is performed between the 15th and 22nd weeks of pregnancy, ideally between the 16th and 18th weeks.
How is it performed?
The following 4 values are examined in the blood sample taken from the mother:
- HCG
- AFP
- E3 (Estriol)
- Inhibin-A
Interpretation:
- Approximately 75% of Down syndrome cases in women under 35,
- and 85–90% in women over 35 can be detected with this test.
The quadruple test is recommended for expectant mothers who miss the time window for the double test.
How Reliable Are Screening Tests?
Screening tests allow genetic risks to be detected at a rate of approximately 80–90%.
However, test results only indicate probability; they are not definitive diagnostic tests.
The following advanced tests may be performed for a definitive diagnosis:
- Amniocentesis
- Chorionic Villus Biopsy (CVS)
- Non-invasive Prenatal Test (NIPT)
If pregnancy is achieved through IVF treatment, healthy embryos can be selected before embryo transfer with advanced genetic analysis methods such as NGS (Next Generation Sequencing).
When Are Screening Tests Performed During Pregnancy?
| Test Name | Week of Application | Purpose |
|---|---|---|
| Double Test | Week 11–14 | Down syndrome risk analysis |
| Triple Test | Week 16–18 | Trisomy 18 and Down syndrome risk |
| Quadruple Test | Week 15–22 | Comprehensive genetic screening |
Are Screening Tests Mandatory?
Screening tests are not legally mandatory, but they are recommended for all pregnant women.
They provide important information about the baby’s developmental process and possible genetic risks.
The results of each test should be evaluated individually by the doctor.
Pregnancy Follow-Up with FertiJin IVF and Women’s Health Center
FertiJin Women’s Health and IVF Center,
throughout your pregnancy process provides double, triple, and quadruple screening tests,
detailed ultrasound, glucose loading test, and NST applications
to closely monitor both the mother’s and the baby’s health.
📍 Istanbul / Şişli