Transvaginal ultrasound-guided aspiration technique to reduce the twin pregnancy in the mare

Abstract

Transvaginal ultrasound guided aspiration (TUA) is a transvaginal ultrasound-guided reduction (TUGR) technique which was developed to reduce twin pregnancy in the mare after vesicle fixation. The usual protocol in the management of twin pregnancy in mares is to ‘squeeze’ or manually reduce one of the twin vesicles before fixation. However, in some circumstances twin pregnancy is not diagnosed or misdiagnosed during the early pregnancy checks and not picked up on until after vesicle fixation. In other instances, mares are not presented to the veterinarian until later in gestation and twins are not diagnosed until after the vesicles have fixed. Post fixation manual reduction of twin vesicles carries a higher risk of causing damage to both twin vesicles. It is associated with lower rates of success than when the technique is performed before vesicle fixation. TUGA technique is a possible alternative for the management of postfixation twins in the mare. This thesis aims to outline the origin of twin pregnancy and how twin vesicles develop as gestation progresses. The advantages and disadvantages of transvaginal ultrasound-guided aspiration will be discussed along with independent factors that influence the success rates achieved while using this technique.