Outcomes of pregnant broodmares treated for colic at a tertiary care facility.
Authors: Douglas Hope F, Stefanovski Darko, Southwood Louise L
Journal: Veterinary surgery : VS
Summary
# Colic in Pregnant Mares: Survival and Pregnancy Outcomes at Tertiary Care Pregnant broodmares presenting with colic represent a clinical challenge where treatment decisions must balance maternal and fetal welfare, yet outcomes data remain limited. This retrospective cohort study examined 104 pregnant mare admissions for colic between 2010 and 2016, tracking survival rates, recurrent colic episodes, and pregnancy outcomes using Cox and logistic regression modelling. Survival was achieved in 70.2% of cases, though this was substantially compromised by admission hyperlactatemia (hazard ratio 3.24) and elevated packed cell volume (hazard ratio 2.89), both markers of systemic compromise; recurrent colic occurred in 47.1% of surviving mares, with Thoroughbreds showing significantly higher risk (odds ratio 5.09). Negative pregnancy outcomes occurred in 21.5% of pregnancies that continued to term, with in-hospital diarrhoea (odds ratio 379.3) and systemic inflammatory response syndrome (odds ratio 31.2) being the strongest predictors, whereas progestin administration (altrenogest) was protective. These findings indicate that severity markers at presentation—particularly lactate, haematocrit, inflammatory status, and gastrointestinal involvement—offer practical prognostic value for counselling owners on combined maternal and fetal risks, whilst progestin supplementation warrants consideration as part of a pregnancy-preservation protocol in severe colic cases.
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Practical Takeaways
- •Pregnant mares presenting with colic carry significant mortality and morbidity risk; elevated lactate and packed cell volume at admission are strong warning signs that warrant aggressive intervention and close monitoring
- •Nearly half of discharged pregnant colic patients develop recurrent colic—close post-discharge monitoring is essential, particularly for Thoroughbreds; consider preventive management protocols
- •Development of diarrhea or SIRS during hospitalization carries very high risk for pregnancy loss—early recognition and intervention (including altrenogest therapy if indicated) may improve outcomes
Key Findings
- •Survival rate of pregnant mares treated for colic was 70.2% (73/104 admissions); admission hyperlactatemia and high packed cell volume significantly reduced survival (HR 3.24 and 2.89 respectively)
- •Recurrent colic occurred in 47.1% of discharged broodmares (33/70), with Thoroughbred breed showing 5× higher risk than other breeds
- •Negative pregnancy outcome occurred in 21.5% of cases (14/65); diarrhea during hospitalization was the strongest predictor (OR 379.3) along with SIRS development (OR 31.2)
- •Altrenogest administration during treatment was protective against negative pregnancy outcome (OR 0.029), reducing risk by 97%