A study of ultrasonographic characteristics of the cervix of bitches during anoestrus, oestrus, and pregnancy

Abstract

The main objective of the present study was to investigate the ultrasonographic characteristics of the cervix of bitches during anoestrus, oestrus, and pregnancy by using two-dimensional transabdominal ultrasonography. Ultrasonographic examinations were performed on 40 bitches using an ultrasound scanner (MyLab30vet, Esaote, Genoa, Italy) with a linear-array transducer (Esaote LA-522, Esaote, Genoa, Italy). According to the results, the cervix was a mild to moderate hyperechoic cylindrical structure lined by hyperechoic serosal margin in anoestrous bitches. The mean diameter of the cervix in anoestrus was 0.93 ± 0.37 cm (range, 0.59 - 1.81 cm), while the cervical canal could not be clearly demarcated by ultrasonography. However, in bitches in oestrus, the mean diameter of the cervix was 1.32 ± 0.11 cm (range, 1.2 - 1.45 cm). The cervical canal was visible as a hypoechoic irregular passage with the mean diameter of 1.5 ± 0.7 mm (range, 1.2 - 2.7 mm). In pregnant bitches, the mean diameter of the cervix was 1.57 ± 0.47 cm (range, 0.82 - 2.18 cm). The cervical canal of pregnant bitches was occluded with the cervical mucus plug which was heterogeneous echogenicity. The diameter of the cervix of pregnant bitches was significantly higher than that of bitches in anoestrus (P=0.001). Further, it was found that the diameter of the cervix increased when the pregnancy advanced. In conclusion, this study evaluated the morphological characteristics of the cervix in bitches during anoestrus, oestrus, and pregnancy. The findings of this study can be used as useful information to evaluate the cervix of bitches in clinical reproductive practice.