Host surrogacy (also knows as gestational surrogacy)
The eggs are from the commissioning mother and the sperm are from the commissioning father. They are fertilised by IVF treatment and the resulting embryos are placed inside the womb of the surrogate host. The resulting baby is not genetically related to the surrogate host. In this arrangement, the commissioning couple literally rent the womb of the surrogate host.
The sperm from the commissioning father is usually frozen for six months (he has screening for HIV, HTLV, hepatitis B and hepatitis C at the time of freezing the sperm and again at the end of six month period). The commissioning mother undergoes ovarian stimulation for IVF and her eggs are collected and fertilised with the frozen-thawed sperm of her husband. The resulting embryos are used fresh for transfer into the host and the surplus embryos are frozen. The host can have embryos transferred in a natural cycle or a hormonally prepared cycle.
Straight surrogacy (also known as partial or natural surrogacy)
Here the surrogate not only carries the baby but also acts as an egg donor. The resulting baby is genetically her baby.
In this situation, the treatment required is usually intra-uterine insemination which is simpler compared to IVF. Intra-uterine insemination can be performed on a natural cycle or a drug controlled cycle (please see info). Occasionally IVF may be required in straight surrogacy also, if IUI attempts are not successful. Then the surrogate undergoes the whole IVF treatment.
There is a third scenario, where the commissioning mother’s eggs are not available or suitable for the treatment, but the commissioning couple does not wish to use the surrogate’s eggs. They can use eggs from another woman who will act as an egg donor. The egg donor can be known or anonymous to the commissioning couple.
This arrangement involves three parties:
- The commissioning couple who want the baby
- The surrogate host who carries the baby
- The egg donor who provides the eggs
Some commissioning couples feel that this arrangement may make it easier for the surrogate to hand over the baby at the end if the baby is not genetically related to her. In some cases, the surrogate may share this feeling too.