The pregnancy protecting effect of progesterone against human chorionic gonadotrophin challenge in mares.

This study investigated the potential of progesterone in preventing pregnancy failure in mares when exposed to human chorionic gonadotropin (HCG). The study suggests promising results with broader dosing and administration investigations required for confirmation.

Research context and objectives

• This research was conducted on 14 pregnant Welsh Mountain Pony mares with the aim of establishing the potential for progesterone to prevent pregnancy failure upon administration of human chorionic gonadotropin (HCG).
• HCG is known for its abortifacient property and the researchers aimed to counteract this effect using progesterone treatments.
• Insufficient luteal activity during early pregnancy in mares is often associated with pregnancy failure, and this research aims to manage this issue.

Research methodology

• 13 out of 14 pregnant mares were treated with progesterone through either injection or implant, always prior to the 38th day of pregnancy.
• HCG was administered in 3 doses on alternate days, with each dose amounting to 2000 imc/day.
• The 14th mare was given HCG towards the end of the experiment as a control to demonstrate HCG’s abortifacient properties.

Research findings and conclusions

• Following the experiment, 3 mares aborted and 1 of these became anovulatory.
• Though the study showed promise that progesterone may help maintain pregnancy in mares against HCG, the results remain inconclusive due to a small sample size and the occurrence of abortions.
• Further studies are needed to ascertain the most effective dose of progesterone and the best method of administration for mares.

Next steps

• One of the primary goals for future research will be to increase the sample size to gain more accurate data and a better understanding of how progesterone may protect against HCG-induced pregnancy failure.
• Additional studies should focus on optimal dosing and administration methods, and the relationship between timing of administration and pregnancy outcomes.
• The role of progesterone and HCG in equine pregnancies is a novel research area and this study encourages further investigation to broaden our understanding.