Doppler ultrasonography of the umbilical artery during normal caprine pregnancy

This investigaion was designed to study the haemodynamic changes in the umbilical artery during normal caprine pregnancy using Doppler ultrasonography. Ten nanny goats were synchronized using 2 intramuscular injections of PGF2a 12 days apart, only six were pregnant. The pregnant goats were examined, between 25 – 125 days of pregnancy, every 5 to 10 days using a combination of two – dimensional real – time ultra – sonography, color Doppler and ppulsed wave Doppler ultrasongraphy. Transrectal scanning was done using a 7 MHz vector transducer between days 25 – 50 of gestation. Thereafter, transabdominal scanning was performed using a 5 MHz linear transducer. After locating the umbilical cord by real – time ultrasonography, the umbilical artery was defined by color Doppler ultrasonography. Pulsatility index (PI), resistance index (RI) and systolic to diastolic (S / D ) ratio in the umbilical artery were measured by using pulsed wave Dopper ultrasonography. The angle of the ultrasound beam to the umbilical artery was 45*. RI and S / D ratio had a significant linear correlation with the gestational age. In conclusion, the resistance to blood flow within the umbilical artery decreases with advancement of caprine pregnancy to match the fetoplacental development.