Comparison of Cell-Free Fetal DNA Plasma Content Used to Sex Determination Between Three Trimesters of Pregnancy in Torkaman Pregnant Mare.

The research focused on comparing the amount of cell-free fetal DNA (cffDNA) in the plasma across three trimesters of pregnancy in Torkaman horses, and assessing its efficiency in determining the sex of the fetus.

Objective and Methodology

• The primary goal of the study was to compare the presence of cell-free fetal DNA (cffDNA) in the maternal plasma during the three trimesters of pregnancy in Torkaman breed mares.
• The researchers collected peripheral blood samples from 32 pregnant mares at various stages in their pregnancies.
• The samples were secured in tubes containing a compound known as ethylenediaminetetraacetic acid, which preserves the DNA for later evaluation.
• The cffDNA was then extracted from 3mL of the maternal plasma for further testing and analysis.

Testing and Analysis

• The researchers employed a conventional polymerase chain reaction (PCR) test targeting the sex-determining region Y (SRY) gene that is present in the Y chromosome.
• Of the 32 mares tested, 24 were carrying male fetuses (those with an SRY gene) and 8 were carrying female fetuses (those without an SRY gene).

Findings

• The accuracy of the test varied across the trimesters; having 48.75%, 68.75%, and 75% accuracy for the first, second, and third trimesters, respectively.
• The sensitivity of the test also increased with each trimester, starting at 25% in the first trimester, increasing to 58.32% in the second trimester, and finally achieving 66.66% in the third trimester.
• It’s crucial to note that the specificity of the test was 100% across all trimesters. Meaning, the test was 100% accurate in determining if a fetus was female (no SRY gene present).

Conclusion

• While the study found that the SRY gene detection using cffDNA analysis in maternal plasma was more accurate in the third trimester of pregnancy, it was still an effective tool to determine the sex of the fetus in all trimesters, given its 100% specificity rate.