The equine umbilical cord in clinically healthy pregnancies.
Authors: Lawson Jessica M, Verheyen Kristien, Smith Ken C, Bryan Jill S, Foote Alastair K, de Mestre Amanda M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Umbilical Cord Length Reference Values in Healthy Equine Pregnancies Excessive umbilical cord length has been implicated in equine pregnancy loss, yet clinicians lack standardised reference values to distinguish normal variation from pathological excess. Lawson and colleagues analysed umbilical cord specimens from 34 healthy term pregnancies and 32 clinically normal pregnancies from mares dying during gestation, measuring total cord length alongside its allantoic and amniotic components, then correlating these measurements with gestational age, fetal development (weight and crown-rump length), and maternal/paternal factors across Thoroughbred populations. Median total umbilical cord length at term was 53.5 cm, with amniotic and allantoic portions measuring 29.5 cm and 25.0 cm respectively; notably, amniotic cord length demonstrated moderate correlation with gestational age and increased exponentially until approximately Day 200, after which growth plateaued. Neither maternal age and parity nor paternal age nor fetal sex showed significant associations with cord length, though the study's reliance on limited post-mortem samples means results should be interpreted as approximate growth patterns rather than definitive thresholds. These findings establish clinically applicable reference ranges and growth trajectories that should help practitioners identify genuinely abnormal cord lengths and potentially stratify pregnancy risk more accurately, though further validation in live pregnancies using ultrasound would strengthen their clinical utility.
Read the full abstract on PubMed
Practical Takeaways
- •Veterinarians now have evidence-based reference values for normal umbilical cord length in term Thoroughbred pregnancies, enabling better identification of excessively long cords associated with pregnancy loss
- •The relationship between gestational age and umbilical cord length growth plateauing around Day 200 provides a clinical landmark for monitoring fetal development
- •These normative data support earlier detection of umbilical cord abnormalities through ultrasound assessment, potentially allowing intervention before pregnancy loss occurs
Key Findings
- •Median total umbilical cord length in healthy term pregnancies was 53.5 cm (IQR 16), with amniotic and allantoic components measuring 29.5 cm (IQR 7) and 25.0 cm (IQR 8) respectively
- •Gestational age and amniotic umbilical cord length showed moderate correlation (rho=0.53, p=0.04) with exponential increase followed by plateauing around Day 200
- •Linear relationship established between gestational age and crown rump length (predicted CRL = -17.60 + 0.38 × gestational age, p<0.001)
- •Reference values provided for umbilical cord length and fetal size measurements in healthy Thoroughbred pregnancies to aid in identifying abnormalities