Prolonged Gestation Associated with Fetal Death
Fetal death may be followed by abortion, fetal maceration, or fetal mummification. In cases of abortion and fetal maceration, the hormonal support of pregnancy is lost. The animal normally shows signs that pregnancy has terminated. An aborted fetus may be found, the dam may show an abnormal vaginal discharge, and she may return to estrus. Fetal bones may be trapped in the uterus and compromise future breeding.
In cases of fetal mummification, fetal death is often not immediately apparent. In such cases, the corpus luteum persists in the ovary, and there is no vaginal discharge and no signs of estrus. The abnormal pregnancy in such animals continues indefinitely. Affected animals are normally identified when owners notice that external signs of late pregnancy, including abdominal enlargement, are less obvious than in other members of a group. Clinical examination reveals that the fetus is dead, although the dam is pregnant. Rectal examination reveals an irregularly shaped, contracted uterus with a fetal mass but no fetal fluid within it. There is no fremitus in the uterine artery. Ultrasonographic examination of accessible parts of the uterus per rectum confirms the diagnosis. The abnormal pregnancy can be terminated by a single IM injection of prostaglandin F2α. The fetus is expelled from the uterus and can be manually removed from the vagina 48 hr later.
In sheep, fetal mummification can be diagnosed by abdominal palpation supported by a transabdominal ultrasonographic scan. Affected animals are normally culled on economic grounds. Treatment can be attempted (see above).