Comparison of cell-free fetal DNA plasma content used to sex determination between 3 trimesters of pregnancy in Torkaman pregnant mare

Abstract This investigation aimed to compare of cell-free fetal DNA (cffDNA) plasma presence in 3 trimesters of pregnancy in Torkaman pregnant mare. Peripheral blood samples of 32 pregnant mares in 3 trimesters of pregnancy were collected into tubes containing EDTA, at a three-time point. Circulating cell-free fetal DNA was extracted from 3 mL of maternal plasma. Using outer and inner primers, a conventional PCR was performed for the SRY gene present on the Y chromosome. Of the total 32 Torkaman pregnant mares, 24 were carrying male, and 8 were carrying female fetuses. In total, the accuracy of the test was 48.75%, 68.75 %, and 75% in the 1st, 2nd, and 3rd trimester of pregnancy, respectively. The sensitivities were 25%, 58.32%, and 66.66%, respectively, whereas their specificities were 100% in all trimesters. To conclude, the SRY gene can permit the detection of equine fetal sex with good accuracy through cffDNA analysis in maternal plasma just in 3rd trimester of pregnancy, although specificity in all duration of pregnancy was 100%.