The gestational surrogacy procedure is similar to in vitro fertilization.  After the female partner's ovaries have been stimulated, the eggs are aspirated, inseminated with sperm from the male partner, incubated and one or more of the resulting embryos are subsequently transferred into the surrogate's uterus.
 
Please note this is an example of a gestational surrogacy treatment sequence. Actual treatment is individualized.

All medications are given as pills, skin patches, vaginal capsules or tiny, shallow injections just under the skin and or as intramuscular injection.
Gestational surrogacy consists of the following steps:

1.    Egg Stimulation of the Female Partner

During the 7 to 12 day ovarian stimulation, two to four ultrasound examinations and blood Estrogen determinations are used to follow the development of the eggs.  When the eggs are ready for retrieval, the egg donor/ intended mother will take another subcutaneous injection of hCG (human chorionic gonadotropin) hormone.  This hormone completes the maturation process of the eggs.

The ultrasound image below shows fully stimulated ovaries. Each of the grape-like follicles (0.5 to 1 inch in diameter) contains a microscopic egg.

2.    Egg Retrieval

Thirty-six hours after the hCG injection, a non-surgical oocyte retrieval is done at the clinic. This is typically a 5 to 10 minute procedure.

Using ultrasound guidance, a thin aspirating needle is passed through the top of the vagina into the follicles. Only the tip of the aspirating needle enters the pelvic area. Since the ovaries are located just above the top of the vagina, the tip of the needle is passed into the follicles without penetrating the uterus, cervix or the Fallopian tubes.

3.    Fertilization

The male partner collects a semen sample by masturbation at the clinic and the highest quality sperm are added to the eggs 6 hours after the egg retrieval.  If your infertility history suggests the possibility of a male factor significant enough to keep the eggs from being fertilized using regular laboratory methods, then you may be scheduled for the ICSI procedure. ICSI, or Intracytoplasmic Sperm Injection, is a micromanipulation technique in which a single sperm is inserted directly into an egg.

The next day, the embryologists will examine the eggs for signs of fertilization.  A normally fertilized egg will show two pronuclei representing the genetic material from the egg and sperm (image at left).

The following day, embryos reach 4 cells, the day after, 8 cells they would reach a three day transfer or by day 5 after egg retrieval, they should reach the blastocyst stage.

4.    Embryo Transfer

One to five days after the egg retrieval, the resulting embryo(s) are transferred into the surrogate's uterus by passing a thin embryo transfer catheter through the cervix to the top of the uterus.

Extra embryos that are not transferred at this time can be cryopreserved and stored in liquid nitrogen.

5.    Establishment of Pregnancy

A blood pregnancy test is scheduled approximately two weeks after the embryo transfer.  A fetal heartbeat ultrasound is done two weeks after a positive pregnancy test.
Estrogen and progesterone supplementation of the pregnancy continues for 6 to 8 weeks.  By that time, the placenta produces enough of its own Estrogen and progesterone so that the supplementation can stop.

This ultrasound picture shows a six week pregnancy.   The pregnancy sac is approximately an inch in diameter. The baby inside the sac is about 0.5 inch long, yet it is possible to already distinguish the head and the "tail" portion of the baby's body.