The Uterus as an Influencing Factor for Late Embryo/Early Fetal Loss—A Clinical Update

Abstract

Here we revise circumstances of non-infectious causes in which the uterus may be associated with pregnancy loss during the late embryo/early fetal period (following a positive pregnancy diagnosis in lactating dairy cows). As the uterine size increases with parity and pregnant heifers with no detrimental effects of a previous parturition, a primigravid uterus is proposed as a reference for identifying risk factors that negatively influence pregnancy in lactating cows. Cows suffering placenta retention or with a large uterus at insemination were selected as topics for this revision. Retained placenta, that occurs around parturition, has a long-lasting influence on subsequent pregnancy loss. Although retained placenta is a particularly predisposing factor for uterine infection, farm conditions along with cow factors of non-infectious cause and their interactions have been identified as main factors favoring this disorder. A large uterus (cervix and uterine horns lying outside the pelvic cavity) with no detectable abnormalities has been associated with low fertility and with a greater incidence of pregnancy loss. A large reproductive tract may well derive from an inadequate uterine involution. Therefore, peripartum management and strategies to reduce the incidence of uterine disorders should reduce their associated financial losses in the herds.

Cow and management factors and their association with estimates of uterine size and position at the time of insemination of dairy cattle

“…It is influenced by the negative energy balance, abnormal calving and age (Lin et al, 2020). Thus, logically, primiparous animals postpartum will have a smaller uterus with both uterine horns within the pelvic cavity (Szelényi et al, 2022). In the present study, the use of sexed semen may have been a factor promoting a smaller uterus as most heifers delivered females.…”

Predictive biochemical and oxidative markers for dairy cows with and without retained fetal placenta

“…RFM frequently develops from abortions that happen during the second part of pregnancy, whether they are random or contagious. When compared to normal parturitions, hydrops, uterine torsion, twinning, and dystocia generally increase the incidence of RFM(Beagley et al, 2010;Szelényi et al, 2022). It is also made worse by heat stress and peripartum hypocalcemia.…”