Changes in plasma progesterone concentrations from days 17 to 42 of gestation in mares maintaining or losing pregnancy.

This research examines the changes in plasma progesterone levels in pregnant horses, specifically from days 17 to 42 of gestation. The study finds that a drop in plasma progesterone rarely leads to a loss of pregnancy during this period.

Overview of the Study

• Plasma progesterone concentrations were examined in 179 pregnant mares in a period from day 17 to 42 of gestation.
• During this time, 10% of the mares, i.e., 17 in total, lost their pregnancies, and out of these, 11 lost it before Day 25.
• The research aimed to establish whether a decline in progesterone could be the cause of these pregnancy losses.

Key Findings

• The timing of the pregnancy loss was accurately determined in 15 out of 17 mares.
• The findings revealed that only in one mare, a decline in the progesterone level preceded the loss of pregnancy.
• Therefore, the researchers concluded that a drop in plasma progesterone is rarely the cause of pregnancy loss between Days 17 and 42.

Implication of the Study

• This study carries significant implications for understanding horse reproduction and gestation biology.
• It quashes the widely held belief that a decrease in plasma progesterone could lead to a loss of pregnancy in mares within the timeframe of days 17 to 42 of gestation.
• The results could help in developing more effective strategies and interventions to prevent pregnancy loss in horses.