Retrospective study of dystocia in mares at a referral hospital.

The research is a retrospective study examining the efficacy of a coordinated dystocia management protocol (CDMP) in reducing the time to resolution of dystocia, a difficult or abnormal birth labor, in mares. The study also evaluates the survival rates of both the mares and the foals under this protocol.

Methodology

• The study was conducted at a university hospital referral center and included cases presenting from 1991 to 2004. These cases were split into two groups – Group 1, which included cases from before the institution of the CDMP, and Group 2, which included cases managed under CDMP.
• The cases were further categorized based on whether the mares were part of an emergency dystocia referral population (referred as EM cases) or were already in the hospital due to high-risk pregnancy concerns (referred as HRP cases), and subsequently experienced dystocia at parturition.

Results

• In referred emergency cases, the time from hospital presentation to the resolution of dystocia significantly decreased by 32 minutes following the use of CDMP.
• The survival rate of mares at discharge was 86%. Among the foals of EM cases, only 10% in Group 1 and 13% in Group 2 survived to discharge. However, for EM foals delivered alive, the survival rate to discharge increased to 30% and 43% in Groups 1 and 2 respectively.
• The study also found a significant correlation between the duration of Stage II of labor and survival rates – longer durations negatively impacted foal survival rates. The median duration of Stage II for EM foals delivered alive was 71 minutes, as opposed to 282 minutes for those not alive at delivery. Similarly, the median duration of Stage II was significantly less for EM foals surviving to discharge – 44 minutes versus 249 minutes for those not surviving to discharge.
• The survival rate of HRP dystocia foals to discharge was recorded at 79%.

Conclusions

• The implementation of CDMP improved timing from presentation to resolution in emergency dystocia cases, but did not significantly alter the total duration of Stage II or the foal outcome.
• The study urges the very early referral of mares with dystocia to referral centers featuring dystocia management protocols. It was observed that increasing the duration of Stage II labor negatively affects the fetal outcome, suggesting the necessity of early intervention for improved chances of survival.