Management of Twins

Management of Twins

Be careful about Wrong diagnoses by:
-Incomplete scanning of the uterus, which allows a twin to be missed -failure to recognise twins in the same horn. This is more common at 18-22 days before both embryos become visible, i.e. about day 25 - endometrial cysts - these can easily be confused with pre-21 day pregnancies; regular repeated scanning is the only way to make the distinction accurately. It is preferable to have 'mapped' the shape, size and position of cysts before pregnancy diagnosis is required

It is now an unusual event for twin pregnancies to be detected after 35 days. If this does occur, treatment options are limited and attempts to terminate the pregnancy and induce a fertile oestrous are likely to be unsuccessful. If no action is taken, approximately 10% of mares will give birth to a normal foal. Almost all of these are unicornuate twins. However, given the possible disruption to the following breeding season.

It may be advisable to consider termination of the pregnancy if both twins appear viable at day 60 by ultrasound examination. Techniques are being explored whereby one foetus is selectively reduced by needle puncture and drainage of the allantoic fluid. A needle is guided by ultrasound either through the vagina or through the ventral abdominal wall. This technique has had limited success so far and must be performed by 45-50 days of gestation.

Ultrasound examination; Ultrasound gives a much more accurate diagnosis of twins than palpation, as the contents of the uterus are visualised. However, ultrasound is not 100% accurate. At ultrasound examination the number of corpora lutea should be counted. This is not possible with rectal palpation but is possible with ultrasound. Mares with two corpora lutea should be treated with suspicion and scheduled for re-examination.

Twin pregnancies may be identified as early as 13-14 days. Most veterinarians now like to examine mares between day 13-15 to diagnose pregnancy, detect twin conceptuses and deal with twins. This is because placental limits are defined early in gestation and achieving a foetal death after this stage provides only a small chance of producing a normal single foal at full term.