Transabdominal ultrasonographic determination of pregnancy and fetal viability in mares

Abstract

The study was designed to evaluate the efficiency of transabdominal ultrasonographic approach for pregnancy diagnosis and monitoring the viability of fetus in mares as an alternative approach to the transrectal ultrasonography to minimize the opportunity of misdiagnosis and prevent the deleterious effect of transrectal invasive. Forty-five mares were scanned by transrectal and transabdominal ultrasonography. Results showed that 26 mares were pregnant and 19 mares were non-pregnant. The accuracy, sensitivity, specificity, the positive and negative predictive values of both approaches were 100%. Transabdominal approach required less time in comparison to transrectal ultrasonography to reach the final decision for non-pregnant mares 5.26±0.27 vs. 8.11±0.31 min, mares at second trimester 4.36±0.49 vs. 5.57±0.29 min and third trimester 4.12±0.51 vs. 5.86±0.26 min, respectively. Both methods recorded no significant correlation between the scanning time and the gestational age. The positive predictive values for determining fetal viability were 26.9% for transrectal and 80.8% for transabdominal ultrasonography. A significant variance was reported between the positive predictive values obtained by transrectal and transabdominal ultrasonography. In conclusion, the transabdominal is an effective, practical, and often essential approach of ultrasonographic for determination of pregnancy and fetal viability in mares, especially at the second and third trimesters of pregnancy. We recommended transabdominal ultrasonographic scanner as the first examination for mares presented for pregnancy diagnosis, if this approach does not accurately diagnose, the mares can be scanned transrectaly. So, we can minimize the stress and hazard of the transrectal examination.