A radiographic study of the fetus in late pregnancy and during foaling.

This research focused on studying the position, posture, and presentation of the fetus in mares during late pregnancy and birth, using serial radiography. The researchers also investigated the changes before and after inducing parturition, along with its implications for potential birth disorders.

Overview of the Research

• The article describes an investigation into the positions, gestures, and display of the fetus in mares during the advanced stages of pregnancy and labor. The study sample consisted of 18 crossbred Pony mares who were at the end of their gestation periods and during the first and second phases of labor. The experiments were primarily conducted via serial radiography, a first in such research topics.
• Another aspect of the study included evaluating changes in three mares, both before and after the induction of parturition, the process of birth, which was chemically triggered by a synthetic prostaglandin called fluprostenol. Prostaglandins play a crucial role in beginning labor and are used in medical fields to induce labor or abortion.

Fetal Movements and Positioning

• During the late gestation period and right up to the beginning of labor, scientists discovered that the fetus maintains a ventral position, a position in which the fetus faced the belly of the mare. The forelimbs and poll were either fully or partially flexed during this phase. The movement of the fetus was confined to the flexion and extension of the neck and forelimbs.
• During birth, the fetal head and limbs progressively straightened. Simultaneously, the forelimbs, head, and neck rotated to achieve a dorsal position with cranial extension, i.e., the fetus was now facing the spine of the mare.
• After this point, the forelimbs and muzzle navigated into the cervical canal, thus facilitating a quick delivery. The trunk and hindlimbs of the fetus also took a dorsal position during the second phase of labor.

Implications

• The scientists comprehensively examined the mechanics of these fetal movements and analyzed their relation to dystocia, a term used to describe difficult or abnormal labor due to issues in the birthing process. The choice of this topic stems from the need to better understand the causes of difficult labors in mares and potentially discover ways to prevent and treat them.