Accuracy of fetal gender determination in maternal plasma at 5 and 6 weeks of pregnancy

Prenat Diagn. 2006 Dec;26(13):1219-23. doi: 10.1002/pd.1592.


Objective: To assess the viability of the early diagnosis of fetal gender in maternal plasma before 7 weeks of pregnancy by real-time polymerase chain reaction (real-time PCR), starting at 5 weeks of pregnancy.

Method: Peripheral blood was collected from pregnant women, starting at 5 weeks of gestation. After centrifugation, plasma was separated for fetal DNA extraction. DNA was analyzed by quantitative real-time PCR for two genomic regions, one on the Y chromosome (DYS-14) and the other shared by both sexes (ss-globin), by the TaqMan Minor Groove Binder (MGB) probe assay. The results of the examinations were compared to fetal gender determined after delivery.

Results: A total of 79 examinations of fetal DNA in maternal plasma were performed for 52 pregnant women. Accuracy according to gestational age was 92.6% (25 of 27 cases) at 5 weeks, and 95.6% (22 of 23 cases) at 6 weeks. These results also demonstrate that fetal DNA is present at low concentrations in maternal plasma at 5 weeks (8.5 genome equivalents (GE)/mL) and 6 weeks (34.1 GE/mL) of pregnancy.

Conclusion: Quantitative real-time PCR and TaqMan MGB probes specific for the detection of fetal gender in maternal plasma starting at 5 weeks of gestation have good sensitivity and excellent specificity.

Publication types

  • Evaluation Study

MeSH terms

  • Chromosomes, Human, Y
  • DNA / blood*
  • DNA / genetics
  • Female
  • Fetus / embryology*
  • Gestational Age
  • Humans
  • Male
  • Maternal-Fetal Exchange
  • Pregnancy
  • Pregnancy Trimester, First / blood*
  • Pregnancy Trimester, First / genetics
  • Pregnancy-Specific beta 1-Glycoproteins / genetics
  • Reproducibility of Results
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sensitivity and Specificity
  • Sex Determination Analysis / methods*


  • Pregnancy-Specific beta 1-Glycoproteins
  • DNA