IMPORTANCE OF PLACEMENT OF EMBRYOS IN THE UTERINE HORN

[ETschool]

Steel reported that embryos graded # 1 (859) resulted in equal pregnancy rates when they were placed in either lower, middle or upper one third of the horn (73%, 73%, and 74%) respectively next to the CL on the ovary, providing the embryo was deposited past the palpable division of the horns.

However, there were significant differences in pregnancy rates for embryos graded 2 or 3 when they were placed in different parts of the horn. As expected when the embryo was delivered in the upper one third of the horn a pregnancy rate of 66% ( 209 embryos ) was achieved, but for # 2 embryos 59% (151 embryos ) pregnancy rate when placed in the middle one third of the horn and only 49% (41 embryos ) when placed in the lower one third of the horn.

Embryos graded #3 continued this trend. Placed in the upper one third of the horn 41% pregnancy rate was achieved (91 embryos ), in the middle one third of the horn 35% pregnancy rate (55 embryos) and embryos delivered to the lower one third of the horn only 26% became pregnancies (23).

These results are subjective of course relying on the grading skills of the technician and the quality of the transfers. In other words some technicians will be more skillful than others but these excellent records point out obvious differences which many of us suspected.
So the take home message is careful, accurate palpation taking particular note of the tone of the uterus, and depositing the embryo in as little time as possible, high in the horn without damaging the cells of the uterine wall and causing hemorrhage in as little time as possible.

Dr. Peter Elsden
http://www.ETschool.com

To View Related Articles Visit Our Website: http://www.etschool.com/embryoTransferBlog.asp

 

[R V]

Dr. Elsden,
Please clarify these regions in relation to the bifurcation of the uterine horns. Does upper mean closest to the bifurcation or most anterior?
Thanks!
Ron

 

[ETschool]

Upper refers to closest to the ovary end.

 

[R V]

Dr. Elsden,

Thanks for the clarification! I was worried that I needed to change where I placed the embryo. Isn't there some data in heifers where placement is not as important as in cows?

Ron

 

[ETschool]

I am not aware of data referring to differences in heifer and cow embryo placements,however it could be true as the heifer uterus is much smaller so the embryo trophoblast cells excreting interferon ( which stops the production of prostaglandin ) has a relatively larger field of response compared to the cow,s uterus. Another factor to consider is the much lower tone in the heifer uterus which enables the operator to place the embryo higher in the horn. An interesting question !