Effect of Acetylsalicylic Acid on Uterine Blood Flow, Gestation Length, Foal Birth Weight and Placental Weight in Pregnant Thoroughbred Mares – A Clinical Pilot Study.

This research article investigates the impacts of acetylsalicylic acid (commonly known as Aspirin) on different aspects such as blood flow in the uterus, the length of gestation, the weight of the foal and placenta in pregnant Thoroughbred mares. The study concludes that administering Aspirin twice daily during the latter part of the pregnancy increases the blood flow in the uterus.

Methodology and Participants

• The study was a double-blind, placebo-controlled research where neither the participants nor the experimenters knew who was receiving a particular treatment. This was to prevent biases during the study.
• The study involved 16 Thoroughbred mares of varying age and parity, meaning number of times a mare had given birth previously.
• These mares were assigned to three different groups – One control group (C) which received lactose as placebo, and two test groups which received Aspirin (ASA1 and ASA2). One Aspirin group received it once daily (ASA1), while the other received it twice daily later in pregnancy (ASA2).

Examination process

• Mares were examined by ultrasonography on multiple, predefined days. These were Day 14, Day 28, Day 60, and then every 21 days from Day 120 until the time of parturition (the process of giving birth).
• Various measurements related to blood flow were taken from both the uterine arteries. These included the cross-sectional area, time average maximum velocity (TAMV), and pulsatility index.

Findings

• All participating mares had a normal pregnancy and gave birth to live foals, indicating that the administration of Aspirin does not negatively interfere with the pregnancy.
• In the ASA2 group, where Aspirin was administered twice daily, a significant increase in the time average maximum velocity (TAMV) in the ipsilateral (same side) artery was observed.
• A trend of increased total blood flow volume was observed in the ASA2 group, although this was not statistically significant (P = 0.07).

Conclusions

• The results of the study suggest that administering Aspirin twice daily in pregnant mares leads to an increase in the uterine blood flow in the latter stage (from Day 305 to 346) of the pregnancy.
• Further studies might be needed to fully understand the implications of these findings for both the mare and the foal’s health, considering the trend towards increased blood flow volume observed in the research.