First Description of Fetal Cystic Hygroma Associated With Early Equine Pregnancy Loss.
Authors: Martinez Zuviria Santiago, Ciurkiewicz Malgorzata, Wohlsein Peter, Madariaga Gonzalo, Zuccolilli Gustavo
Journal: Journal of equine veterinary science
Summary
# Fetal Cystic Hygroma as a Previously Unrecognised Cause of Equine Early Pregnancy Loss Cystic hygroma—a congenital lymphatic malformation arising from failure of the primitive lymphatic sac to establish drainage into the jugular venous system—has never before been documented in equine fetuses, despite being recognised in other species. During a five-year prospective study of 5,730 pregnancy examinations across 43 breeding and embryo transfer facilities, researchers identified 12 mares carrying affected fetuses via transrectal ultrasound between days 52 and 75 of gestation, with six cases confirmed through histopathological and karyotypic analysis. The malformation results in progressive lymphatic stasis originating in the neck and extending systemically, consistently causing pregnancy loss around day 65 of gestation. This first documented description establishes cystic hygroma as a significant embyronic anomaly that should now be included in differential diagnoses when investigating early pregnancy failure, particularly when characteristic fluid accumulations in the fetal neck region are identified during routine ultrasound screening. For practitioners managing breeding programmes and embryo transfer operations, heightened awareness of the ultrasonographic appearance of this condition during early pregnancy monitoring may enable earlier identification and removal of affected pregnancies, thereby improving overall reproductive efficiency on affected farms.
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Practical Takeaways
- •Veterinarians performing early pregnancy ultrasound examinations (days 52-75) should be aware that cystic hygroma appears as an ultrasound-detectable fluid-filled malformation in the fetal neck region and is associated with pregnancy loss
- •Transrectal ultrasound can reliably detect this congenital anomaly before pregnancy loss occurs, allowing early intervention and breeding decisions
- •Mare owners and breeding programs should understand this is a newly recognized cause of early embryonic loss that cannot be prevented but can be identified through routine pregnancy monitoring
Key Findings
- •Cystic hygroma was diagnosed via transrectal ultrasound in 12 pregnant mares between days 52-75 of gestation
- •This is the first description of cystic hygroma in equine fetuses as a cause of pregnancy loss around day 65 of gestation
- •Histopathological and macroscopic analysis confirmed the diagnosis in 6 collected fetuses
- •The condition results from failure of the primitive lymphatic sac to connect with the venous system at the jugular vein