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Fetal DNA detection in maternal plasma throughout gestation
Silvia Galbiati1, Maddalena Smid, Dania Gambini
1Unit of Genomics for Diagnosis of Human Pathologies, IRCCS H. San Raffaele, Via Olgettina 58, 20132 Milan, Italy.
Human Genetics
|May 21, 2005
Summary
Fetal DNA in maternal plasma is detectable from six weeks of gestation, offering a reliable, non-invasive source for prenatal diagnosis and pregnancy monitoring. This method shows high accuracy in fetal gender determination across all trimesters.
Area of Science:
- Molecular Biology
- Genetics
- Obstetrics
Background:
- Maternal plasma contains cell-free fetal DNA (cfDNA), a potential source for non-invasive genetic analysis.
- Understanding cfDNA concentration and detection across gestation is vital for developing reliable prenatal diagnostics.
Purpose of the Study:
- To assess fetal DNA detectability and concentration range in maternal plasma throughout pregnancy.
- To determine the optimal gestational window for obtaining maternal blood for non-invasive prenatal diagnosis.
- To evaluate the accuracy and predictive values of using fetal DNA for prenatal genetic testing.
Main Methods:
- Real-time PCR targeting the SRY gene was used for fetal DNA quantification in male-bearing pregnancies.
- A cohort of 1,837 pregnant women was analyzed.
- Fetal gender determination accuracy was assessed in a subset of 464 women across different trimesters.
Main Results:
- Fetal DNA was detectable from the sixth week of gestation and throughout all subsequent weeks.
- No false-positive results were observed in women with prior embryo loss or male infants.
- Fetal gender determination accuracy was high: 99.4% (first trimester), 97.8% (second trimester), and 100% (third trimester).
Conclusions:
- Maternal plasma fetal DNA is a reliable and adequate genetic source for non-invasive prenatal diagnosis.
- This approach supports early pregnancy genetic testing and monitoring of pregnancy complications.