What is a Genetic Sonogram?
A Genetic Sonogram is a detailed ultrasound performed between 18 and 22 weeks of pregnancy. It assesses fetal anatomy and markers that may indicate risk for chromosomal abnormalities such as Down syndrome, Trisomy 18, and Trisomy 13. Unlike diagnostic tests, it provides risk estimation and helps guide further testing.
Why is it done?
- Advanced screening for chromosomal anomalies when non-invasive prenatal testing (NIPT) is inconclusive or unavailable
- Abnormal first trimester screening results
- Family history of genetic disorders
- Advanced maternal age (35 years or older)
- Suspicious findings on routine mid-trimester ultrasound
When should I get it?
The ideal time for a Genetic Sonogram is between 18 and 22 weeks + 6 days of gestation, when fetal structures are developed enough for detailed evaluation.
How is the scan performed?
- You lie on an examination table with your abdomen exposed
- A water-based gel is applied, and a transducer is moved over your abdomen to obtain images
- The sonographer examines standardized anatomical landmarks and measures soft markers such as nuchal fold, echogenic bowel, and femur length ratio
- The report summarizes normal findings and any soft markers or structural anomalies
What does it show?
- Detailed evaluation of brain, heart, spine, face, abdomen, and limbs
- Assessment of soft markers: nuchal fold thickness, echogenic intracardiac focus, echogenic bowel, renal pyelectasis, and femur length tomography
- Identification of structural anomalies or markers associated with genetic syndromes
Benefits and Limitations
Benefits:
- Non-invasive and safe with no radiation exposure
- Early detection of soft markers that indicate increased genetic risk
- Helps inform decision-making regarding invasive testing
Limitations:
- Not diagnostic; soft markers are not conclusive
- May yield false positives or negatives
- Operator-dependent and image quality affected by fetal position and maternal factors
Frequently Asked Questions (FAQs)
Is the Genetic Sonogram safe?
Yes. It uses ultrasound and is safe for both mother and fetus.
How long does the scan take?
Usually 30–45 minutes.
Do I need any preparation?
No special preparation is needed; wear comfortable clothing.
Will I need invasive testing?
If soft markers or anomalies are found, follow-up with diagnostic tests like amniocentesis may be recommended.
When will I receive the report?
Preliminary findings are discussed immediately; detailed report available in 1–2 days.