Medical Procedures
Ovulation Induction
Hormones are given to stimulate egg production, while preventing ovulation until the desired time. Doctors monitor estrogen levels over several days and by day five, vaginal ultrasound is used to monitor the growth, size and number of developing ovarian follicles.
Egg Retrieval
Vaginal ultrasound guided aspiration is used to harvest the egg(s). Intravenous pain medication is used to make the woman comfortable during this relatively minor procedure. Timing is crucial. If the egg harvest is done too early, the eggs won’t fertilize; if it is done too late the eggs may have been released spontaneously or may be too mature.
Fertilization of the Eggs and Embryo Culture
Once the egg(s) have been harvested, anywhere from 50,000 to one million sperm are mixed with the eggs and allowed to incubate for 14-18 hours. The fertilized eggs (embryos) are then transferred to a new growth medium. The embryologist will look for embryos that have two pronuclei, indicating normal fertilization has occurred. Approximately 40 hours later, the embryos are examined and assessed to determine how they are developing. If the embryos are developing normally, the surrogate mother will visit the clinic to have the embryos transferred into her uterus.
Preparation of the Endometrium
In order to time the embryo transfer properly, the surrogate mother must have the uterine cavity, called the endometrial, prepared to allow implantation. Several medications are administered to achieve this goal. Birth control pills are taken at the beginning of the menstrual cycle. Hormones are injected on a daily basis to stimulate the pituitary gland to regulate ovarian function. After 8-12 days, a menstrual period occurs.
Once the embryos have been created the surrogate will begin to prepare her body for the IVF transfer. Estrogen is essential for building and thickening the lining of the uterus (endometrium). A thick, healthy endometrium is vital for an embryo to implant successfully. Progesterone further prepares the endometrium for embryo implantation and maintains its stability during early pregnancy. These medications can be administered via intramuscular injections, pills or patches. The clinic will monitor for appropriate levels through vaginal ultrasounds and blood tests.
Embryo Transfer
Before transfer, embryos will usually be at the two to eight cell stage. Some clinics are now letting embryos grow for 5 days to the blastocyst stage.
The embryos and a small amount of the liquid medium in which they have been growing are drawn up into a soft rubber catheter, which is inserted into the vagina, through the cervix and into the uterus. The embryos are flushed gently out of the catheter. Ultrasound may be used to help the doctor place the embryos in the uterus. Progesterone will be given daily to maximize the chances of getting a good uterine lining for implantation to occur.
A blood test is performed 5-10 days after the embryo transfer to confirm a pregnancy. If pregnancy occurs, estrogen and progesterone medication is continued until approximately twelve weeks of pregnancy. During the entire treatment cycle, the surrogate mother is monitored by a doctor to make sure medication levels and effects are appropriate.