{Reference Type}: Case Reports {Title}: In utero ultrasound diagnosis of bilateral cataract and hydrops in a mule pregnancy: Case report. {Author}: Renaudin C;Villanueva ES;Martin-Pelaez S;Huggins L;Davis K;Dujovne G;Choi E;Martins B;Dini P; {Journal}: J Equine Vet Sci {Volume}: 132 {Issue}: 0 {Year}: 2024 Jan 28 {Factor}: 1.386 {DOI}: 10.1016/j.jevs.2023.104973 {Abstract}: Once diagnosed pregnant with ultrasound at an early stage of gestation, mares are usually not examined before foaling. The objective of this case report was to highlight the importance of transrectal ultrasound screening examination and to report a unique case of fetal congenital cataracts associated with other feto-placental abnormalities in a mule pregnancy, its in utero ultrasound diagnosis and outcome. A 17-year-old Thoroughbred research mare carrying a mule fetus was examined by transrectal ultrasonography at 186 days of gestation for a routine pregnancy examination. Ultrasonography allowed in utero diagnosis of fetal congenital cataracts, hyperechogenic bowels, intrauterine growth restriction (IUGR), hydramnios and placental abnormalities. The mare was monitored bi-monthly to observe the progress of the pregnancy. At 258 days of gestation, the abnormal chorioallantois detached at the cervical star and at 272 days, fetal asystole was diagnosed. Abortion was induced and the fetus was delivered uneventfully. Post-mortem gross and histologic findings confirmed the prenatal ultrasonographic diagnosis. This case highlights the diagnostic value of a complete fetal ultrasound examination to detect equine fetal abnormalities.