# Concentrations of Progesterone (P4), Anti-Müllerian Hormone (AMH), and Haptoglobin (Hp) in Pregnant and Non-Pregnant Ewes and Their Association with Fetal Mortality, Maternal Weight, and Twinning Rate

## TL;DR

This study examines progesterone, AMH, and haptoglobin levels in pregnant and non-pregnant sheep to assess fetal viability, pregnancy progression, and how these markers relate to body weight and season.

## Contribution

The study identifies progesterone as a key marker for pregnancy detection and fetal death, while AMH and haptoglobin provide complementary insights into fetal viability and maternal physiology.

## Key findings

- Progesterone (P4) levels effectively distinguish between pregnant and non-pregnant ewes and detect fetal death.
- Anti-Müllerian Hormone (AMH) levels are higher in viable pregnancies up to day 30, suggesting early fetal viability assessment.
- Haptoglobin (Hp) and AMH levels decrease toward the end of pregnancy and correlate with maternal body weight and seasonal changes.

## Abstract

In sheep, the application of the Progesterone (P4) test enables not only the distinction between pregnant (P+) and non-pregnant (P−) animals but also the detection of fetal deaths (FD). P4 levels are a significant parameter for identifying fetal death as well as distinguishing between single and twin pregnancies. Higher Anti-Müllerian Hormone (AMH) levels observed up to day 30 of pregnancy compared to FD cases may serve as an early indicator of fetal viability. Marked decreases in AMH and haptoglobin (Hp) levels toward the end of pregnancy are important for monitoring the later stages of gestation. Furthermore, both AMH and Hp levels vary according to seasonal periods and maternal body weight (BW) changes. P4 levels were also found to be associated with BW. Collectively, these findings suggest that biochemical markers such as P4, AMH, and Hp play a critical role in monitoring pregnancy progression, fetal development, and physiological responses to seasonal and body weight changes in sheep.

The study groups (n = 39) included ewes with ongoing pregnancy (P+; n = 19), with fetal death (FD; n = 12), and that were not pregnant (P−; n = 8). Blood samples were taken on days 10, 20, 30, 40, 60, 80, and 150 post-mating. Ultrasonography (USG) controls started on day 30. The P4 concentrations differed significantly between P+ and P− on all days (p < 0.001). Regarding AMH concentrations, a significant difference was observed between P+ and P− on day 30. P4 increased significantly from day 60 to 80 and remained elevated until day 150 in P+, while remaining basal in P−. In FD and P− groups, P4 reached its lowest concentrations. A rapid decrease in P4 was observed in P− from day 20 onwards. A statistically significant difference in P4 was also noted between P+ and FD. Additionally, P4 concentrations differed between singleton and twin pregnancies, especially on days 20 and 40. Statistically significant differences in AMH were found between P+ and FD on days 10, 20, and 30. In P+ sheep, P4, AMH, and Hp concentrations varied by season. A significant relationship was found between AMH and Hp concentrations and body weight. In conclusion, P4 stands out as the primary marker for distinguishing pregnancy status and detecting embryonic loss, while AMH provides complementary support, particularly in identifying fetal death. Seasonal changes were reflected across P4, AMH, and Hp concentrations, with AMH and Hp also showing significant associations with BW.