Doppler evaluation of maternal vessels in normal gestation and threatened abortion in canines

Abstract

Background: Ultrasonographic monitoring of the pregnant bitch is an established routine in many veterinary clinics. In order to better assess foetal health and avoid pregnancy losses, Doppler ultrasonographic evaluation of the pregnant uterus is the need of the day. Investigations on the dynamics of maternal and foetal blood flow using Doppler ultrasound have been conducted in multiple species recently and it is invisaged that it would be a reliable diagnostic tool in future in monitoring pregnancy. The present study was designed to compare Doppler parameters systolic peak velocity (SPV), end diastolic velocity (EDV), pulsatility index (PI) and resistivity index (RI) of the uteroplacental (UPA) and umbilical arteries (UA) measured during 40 to 50 and 51 to 60 days in normal gestation and threatened abortion in canines. Results: In total 40 pregnant bitches with known history of breeding; irrespective of age and parity belonging to different breeds were classified into normal gestation (NG) and threatened abortion (TA). Bitches with the history of greenish black discharge or expulsion of one foetus were included in the abortion group and bitches with no such symptoms were included in the normal gestation group. End diastolic velocity of uteroplacental vessels decreased while PI and RI increased significantly with decrease in body weight in threatened abortion cases during 40 to 50 and 51 to 60 days of gestation in canines. Systolic peak velocity and EDV of umbilical arteries increased while PI decreased significantly with decrease in body weight during 40 to 50 days of gestation in canine threatened abortions. Conclusions: Doppler evaluation of uteroplacental and umbilical arteries is recommended as a diagnostic tool to monitor high risk pregnancy during 40 to 50 and 51 to 60 days of gestation in canines.

Ultrasonography for the evaluation of pregnancy in the female canine

“…The absence of Uma diastolic flow along with elevation in RI and PI indicate high blood flow resistance and may indicate intrauterine growth restriction which can affect foetal well‐being (Figure 8) (Miranda & Domingues, 2010). Abnormal placentation and trophoblast invasion may result in abnormal Ua and Uma waveforms (PSV increases but EDV stops increasing when RI starts to increase) and increased RI and PI result (Blanco et al, 2008; Blanco et al, 2009; Blanco et al, 2011; Gaikwad et al, 2020; Miranda & Domingues, 2010). Foetal renal RI also increases in abnormal pregnancies indicating decreased perfusion to the foetal kidneys, while foetal internal carotid blood flow increases (brain sparing effect) (Blanco et al, 2011).…”

Evaluation of Functional Structures in the Ovaries Pre and Post Ovulation by Doppler Ultrasonography in Bitches

“…In veterinary ultrasonography, information about all arteries and veins in the body can be obtained with the Doppler blood flow method (6)(7)(8).…”