Problems in Late Pregnancy

The last ultrasound examination for pregnancy is usually performed at about 35 to 50 days of gestation. Once it has been confirmed that a single fetus is developing normally at this stage of pregnancy, the incidence of subsequent fetal loss (abortion) is approximately 8%. Although this is only a small percentage of total pregnancy losses, any of the conditions mentioned can affect not only the viability of the fetus, but also the pregnancy rate during the following breeding season. Precise information on the influence of the health of the mare on fetal well-being remains unclear. This is despite the recent clinical advances in the application of transabdominal ultrasonography, fetal echocardiography and even amniocentesis to determination and monitoring of fetal health. Detection of any problems during late pregnancy are very important in routine clinical practice. Whilst the fetus can be adversely affected by any systemic disease (colic, endotoxaemia, scouring) this paper will consider the commonest specific diseases and complications of late pregnancy in the mare. It is vital that those concerned with the management of the late-pregnant mare are able to recognise any warning signs shown by the dam that may either be responsible for or be an indication that such complications exist.

Haemorrhage from the external genitalia
Haemorrhage seen as blood from the vulval lips can occur either from vaginal varicosities or vulval trauma. In severe cases, diathermy may be necessary to cauterise the bleeding vessels. It is important to appreciate that blood at the vulval lips is more likely to be a sign of vaginal varicose veins than impending abortion. Impending abortion due to placental detachment or placentitis is rarely associated with haemorrhage. Blood can originate from the urinary tract due to cystitis or urolithiasis and urinary tract disease needs to be excluded as the source of the bleeding.

Haemorrhage from the uterus
Rarely, fatal haemorrhage can occur from rupture of the uterine arteries during pregnancy. The haemorrhage may occur following trauma during exercise or transport, uterine torsion or uterine rupture. However, most cases of haemorrhage occur during parturition.  [...]