Ultrasound parameters of early pregnancy and Doppler indices of blood vessels in the placenta and umbilical cord throughout the pregnancy period in sheep
Date
2022
Authors
Brzozowska, Angelika
Stankiewicz, Tomasz
Błaszczyk, Barbara
Chundekkad, Pavitra
Udała, Jan
Wojtasiak, Natalia
Journal Title
Journal ISSN
Volume Title
Publisher
BMC Veterinary Research
Abstract
Background: Ultrasonography is one of the most important techniques that enable the detection and monitoring of
pregnancy. One such study using this technique is the assessment of the hemodynamics of fetal and umbilical blood
vessels.
However, there is little data on blood flow in the placentomes, which is the basic structural unit of the sheep’s placenta.
Therefore, the aim of this study was to determine the Doppler parameters in the arterial vessels of the caruncles,
cotyledons and the umbilical cord as well as measuring venous flow rates during the entire gestation period of
the sheep. Additionally, the usefulness of various other ultrasound parameters in the early diagnosis of pregnancy in
sheep was analyzed.
Results: Most of the Doppler parameters in umbilical, cotyledonary and caruncular arteries were significantly correlated
with the day of pregnancy (p < 0.01). In the early stages of pregnancy, the peak systolic velocity (PSV), regardless
of the location of the artery, was significantly lower than that in the later stages of pregnancy (p < 0.01). PSV was also
found to be significantly higher in the umbilical artery than in the cotyledonary and caruncular arteries (p < 0.01).
Until the 50th day of pregnancy, the end diastolic velocity (EDV) was not found in the umbilical and cotyledonary
arteries. EDV was significantly higher in the caruncular arteries than in the cotyledonary and umbilical arteries
(p < 0.01). The resistance index (RI) and pulsatility index (PI) in the early stages of pregnancy were found to be significantly
higher than that in the later stages of pregnancy (p < 0.01). The RI and PI were significantly lower in the
caruncular arteries than in the arteries of the cotyledons and umbilical cord (p < 0.01). In the umbilical vein, all Doppler
parameters were observed to be significantly higher than those in the placentomal veins (p < 0.01 or p < 0.05). Using
transrectal ultrasound, pregnancy was detected between 20 and 28 days after mating. The ovaries were observed to
have corpora lutea, the diameter of which was fairly consistent from the 17th to the 56th day of pregnancy. Conclusions: It has been demonstrated that both the location of the arterial vessel in the placental-umbilical
circulation and the gestational age have a significant impact on hemodynamic parameters. The results also provide
new insights about the blood flow in caruncular and cotyledonary arteries, which could contribute to a more holistic
understanding of hemodynamic changes in the placentas of sheep. Analyzing haemodynamic parameters in the
umbilical and placental veins are preliminary studies in sheep, but it could inspire further research in this field. Furthermore,
the research conducted confirms the practicality and convenience of transrectal ultrasonography in the early
diagnosis of pregnancy in sheep and also indicates that the identification and imaging of the corpus luteum using
B-mode ultrasonography can be a very early and simple method of confirming effective mating in sheep.
Description
Keywords
Placenta, Umbilical cord, Arteries, Veins, Corpus luteum, Doppler ultrasound, Pregnancy, Sheep
Citation
Brzozowska, A., Stankiewicz, T., Błaszczyk, B., Chundekkad, P., Udała, J., & Wojtasiak, N. (2022). “Ultrasound parameters of early pregnancy and Doppler indices of blood vessels in the placenta and umbilical cord throughout the pregnancy period in sheep.” BMC Veterinary Research, 18(326). https://doi.org/10.1186/s12917-022-03424-z