An H&C reader got in touch with concerns about his mare who is in foal.

“I have just found out that my eight-year-old mare is in foal for the first time. She is only 10 days gone but the ultrasound revealed that she is expecting twins. I was thrilled, but my vet has told me that we must reduce them to a single pregnancy. Is this really necessary?”

H&C turned to Ann Egan who breeds purebred Percheron horses from Northpoint Farm in Connecticut, USA, for advice.

"Twinning in horses occurs in about 10% of all equine pregnancies and 70% of those twin pregnancies are naturally reduced by day 40 of the pregnancy.

While many people think that having their mare deliver twins would be really great, and no doubt it would be, twin births are undesirable in horses. If a twin pregnancy is not reduced to a single pregnancy, the outcome is usually late term abortion for both foetuses. There are many consequences to late term abortion of twins including retained placenta, dystocia, delayed uterine involution, metritis, and death of one or both twins.

Embryo 'pinching'

As your mare’s twins have been caught early enough (i.e. before day 16), the embryo’s can be ‘pinched’ before they become fixed, although a more accurate description of what happens is that they are crushed.

One of our Percheron mares recently had triplets, and we were able to pinch two of the embryos just in time. Our vet pinched one embryo in the morning and then let the mare rest for a few hours. He then let the remaining embryos separate before pinching the second embryo after lunch.

There is always a risk when doing a reduction of twins (or triplets) that the mare will naturally abort due to the trauma of the reduction on the uterus. But we hope that our mare – and yours – continue with their pregnancy and deliver a happy and healthy single foal in 2013."