Prenatal Diagnosis of Canine and Feline Twins Using Ultrasound: A Retrospective Study

SIMPLE SUMMARY: This study focused on the ultrasound diagnosis of twins in canine and feline species. Prenatal diagnosis is becoming increasingly important even in small animals to assess foetal morphology and identify any eventual abnormalities. In canine and feline species, which are typically polytocous species, only monochorionic twins, i.e., sharing at least the same placenta, can be termed, using ultrasound, as twins. In this study, seven cases of monochorionic twins were reported with a prevalence of under 1%. The clinical relevance of such a diagnosis is to prevent complications during pregnancy and, especially, delivery. ABSTRACT: Prenatal diagnosis comprises a set of investigations, both instrumental and laboratory-based, which aim to monitor the health of the foetus during pregnancy, from the early stages of embryonic development to the moments preceding delivery. A growing interest is emerging for the preterm ultrasound morphological screening of embryos and foetuses, aimed at assessing the integrity and viability of the conceptus, as well as the early diagnosis of anomalies which can cause complications. This study is a retrospective study of the ultrasonographic findings of twins in the authors’ clinical activity from 2016 to 2022. Only seven cases of monochorionic twins were recorded, out of the whole number of evaluations performed on 3120 foetuses, with a prevalence of 0.6% and 0.2% in feline and canine foetuses. All the twins had their own amniotic sac and umbilical cord but presented a single placenta and a single allantoic sac. Unfortunately, the three feline cases were not more recognizable at term. In the four canine cases, three were of opposite sex and then necessarily dizygotic. Twins may have an impact on the success of a pregnancy due to the risk of dystocia, as observed in some of the reported cases. Prenatal ultrasound allows early recognition of twins in dogs and cats.