Ultrasonographic findings associated with normal pregnancy and fetal well-being in the bottlenose dolphin (Tursiops truncatus)

Reproductive success is vital in sustaining free-ranging bottlenose dolphin (Tursiops truncatus) populations and is a critical component of managed care. Ultrasonography has proven to be invaluable in wild dolphin health assessments and in marine mammal preventative medicine. It is also a non-invasive standard of care in assessing the fetomaternal unit in humans and animals, including dolphins and horses. The purpose of this prospective longitudinal study was to develop a protocol for fetomaternal ultrasonographic monitoring in Tursiops truncatus and to report normal measurements and descriptive findings correlated with a positive outcome. From 2010-2017, serial ultrasonographic evaluations of 12 healthy dolphins in managed care were performed over the course of 16 pregnancies. A total of 203 ultrasound exams were conducted, including parameters such as fetal biparietal diameter (BPD), thoracic width in dorsal and transverse planes, thoracic height in a sagittal plane, aortic diameter, blubber thickness, uteroplacental thickness, and lung: liver mean pixel intensity.