Fragment removal is a related technique
designed to promote development in embryos adversely affected by fragmentation.
The fragments are pieces of cytoplasm contained within the zona pellucida, the
membrane surrounding the developing cells. Although the exact causes of embryo fragmentation have not been proven at this time, they may be linked directly to
the eggs and sperm that created the embryo. Embryo fragmentation also may be a
by-product of the IVF process, caused by conditions related to the culture
medium in which fertilization and embryo development occur. It also is possible
that embryo fragmentation, found in some 80% of embryos created during IVF, is part of
normal embryo development.
In any event, research indicates that significant fragmentation can interfere
with implantation and pregnancy and is related to infertility. However, assisted hatching and fragment removal
together may restore an embryo’s normal development potential.
The Fragment Removal Procedure
Fragment
removal is an extension of the assisted
hatching technique. After the hole is made in the zona, the same needle is
used to aspirate all or most of the fragments within the embryo. Fragment
removal is performed on the third day of development, prior to replacement of
embryos in the uterus.
The figures below depict fragmented embryos before (left panels) and after
(right panels) assisted hatching and fragment removal.
