Understanding Different Types of Surrogacy
Egg donors will often not know what happens to their eggs following their donation. While an intended mother will occasionally carry the donor egg in her own uterus, in many cases a donor’s eggs will eventually be transferred into the uterus of a surrogate.
With surrogacy, a woman carries a child to term and then relinquishes the baby to the intended parent(s) upon delivery. There are two main types of surrogacy: traditional and gestational. Here’s a look at how the two types differ.
Traditional surrogates will also act as egg donors. The surrogate mother is impregnated with semen from the intended father or sperm donor and uses her own eggs. In this case, the surrogate mother will be genetically related to the child. An egg donor’s genetic material is not needed for this type of surrogacy.
Cases requiring the use of a donor egg are referred to as gestational surrogacies. This method is both more popular and effective. While in some cases the intended mother may be able to use her own eggs in this form of surrogacy, many cases do require an egg from a donor. The surrogate mother is not genetically related to the child in this form of surrogacy.
There are three stages to gestational surrogacy:
Egg donation—either the intended mother or the egg donor undergoes an egg retrieval procedure.
Fertilization—the egg is fertilized with semen in the laboratory to create an embryo.
Transfer—the fertilized egg, or embryo, is implanted into the surrogate mother’s womb. This is often referred to as an embryo transfer, or just transfer.
A fertilized egg may be transferred to the surrogate either when it is freshly fertilized, or after it has been taken from cryogenic storage and thawed. In order to prepare for a fresh embryo transfer, the intended mother or egg donor and the surrogate must take hormone pills at the same time to synchronize their cycles.
The success rate of IVF depends on a number of factors such as the age and health of the woman providing the eggs.