Postpartum uterus involution observed by real-time ultrasound scanning and vaginal cytology in Van cats

The objective was to investigate postpartum uterus involution by real-time ultrasonography and vaginal cytology in Van cats.

This study included 15 healthy Van cats belonging to the Van Cat Research Centre (Yuzuncu Yil University, Van, Turkey). Starting 24 h postpartum, ultrasonographic measurements were performed on the placental and interplacental uterine horn regions every day. Decreases in the diameters and uterine content were considered as criteria for uterine involution. Vaginal discharge samples were collected every day for 4 weeks postpartum. The smears were stained with Papanicolaou stain.

The average diameters of placental and interplacental regions (IPRs) in the uterine horns were 3.12 ± 0.29 cm and 2.36 ± 0.43 cm, respectively, at 24 h postpartum. Placental regions (PRs) shrank faster than IPRs. At 48 h postpartum, it became difficult to distinguish PRs from IPRs in the uterine horns. The uterine horns could be seen in the abdominal cavity up to 5.60 ± 0.99 days postpartum. The mean of the last assessable diameter of the uterine horns from days 4 to 7 in all cats was 0.49 ± 0.07 cm. The vaginal epithelial cells appeared to be under the effect of oestrogen for 4 weeks postpartum.

The morphological involution of the uterus completes, to a large extent, within the first 48 h postpartum in Van cats. A more detailed hormonal analysis would contribute greatly to the understanding of the physiological processes involved in this period. Although postpartum involution appeared complete by 5.60 ± 0.99 days after parturition in Van cats, histological verification of this finding is needed.