Ultrasonographic findings associated with pregnancy or fetal well-being in the bottlenose dolphins (Tursiops truncatus) during health assessments conducted in Barataria Bay, Louisiana from 2011-08-03 to 2018-07-19

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 report measurements and descriptive findings from pregnancies in wild northern Gulf of Mexico dolphins. Ultrasonographic evaluations were performed on 43 pregnant dolphins during health assessments conducted in Barataria Bay, Louisiana from 2011-2018. Outcomes of these 43 pregnancies included 9 successful, 28 failed and 6 unknown with 35 exams collected during the first trimester, 7 from the second trimester, and only 1 exam from the third trimester. Ultrasound analysis was comprised of up to 70 parameters per exam including potential biophysical predictors of failure such as changes in corpus luteum size, changes in uteroplacental thickness, placental abruption, decreased fetal lung/liver ratio, and umbilical cord abnormalities.