If you are considering in-vitro fertilization, it is important to understand what to expect. Below, we will review the steps of in-vitro fertilization.
Steps of In-Vitro Fertilization
When a Treatment Cycle Begins
The beginning of an IVF treatment cycle coincides with the beginning of the woman’s menstrual cycle. The patient will call the office on the first day of full menstrual bleeding. On the second or third day, the patient will go to the office to have a baseline blood test and an ultrasound. If a group is beginning at that time, the patient may begin taking fertility medications immediately. If a group is not starting at that time, the patient will take birth control pills until the next group begins.
The patient will receive a number of fertility injections to encourage the maturation of egg follicles while preventing ovulation. Each of the steps of in-vitro fertilization is associated with the use of different medications. Most patients will follow a schedule similar to the following:
- Follicle-stimulation hormone (FSH) – Injections of an FSH medication, such as Follistim, continue for 4-5 nights. On the fifth or sixth day, the woman will have another blood test and an ultrasound to determine the next steps.
- GnRH antagonist – A medication that acts as a GnRH antagonist, such as Cetrotide, is added on the fifth or sixth day to prevent the woman from ovulating too early.
- Human chorionic gonadotropin (hCG) – On the seventh or eighth day, the dose of FSH is reduced, and hCG is added.
- Trigger injection – This step occurs as early as the seventh day, or as long as the fifteenth day; on average, women are ready for the trigger injection at 9 or 10 days. For fresh embryo transfer, the woman will receive a high dose of FSH followed by a high dose of hCG.
- Antibiotics – After the trigger injection, the woman will take antibiotics for two days to reduce the risk of infection following the egg retrieval.
The eggs are retrieved two days after the trigger injection is given. The eggs are retrieved using a minimally invasive procedure, which is performed in an outpatient surgery center. To retrieve the eggs, the doctor uses an ultrasound to guide his actions. A thin, long needle is inserted, passing through the vagina to reach the ovaries. Once the needle is inside the egg follicle; fluid is aspirated. This step is repeated until all of the follicles have been aspirated.
After the egg retrieval, the woman will start taking progesterone to boost the chances that the embryo will implant once transferred. Progesterone is usually taken vaginally, but it can also be given intramuscularly. Progesterone continues after the embryo transfer.
Fertilization and Embryo Maturation
The fluid that has been retrieved is then taken to the laboratory. The embryologist places the fluid under the microscope to determine how many eggs were successfully retrieved. Then, the embryologist identifies which eggs are mature and healthy looking – on average, about 60% of eggs meet these criteria.
The selected eggs are each injected with sperm. The fertilized eggs are incubated overnight. The next day, the embryologist will examine the fertilized eggs to determine whether fertilization successfully occurred and whether the embryos appear normal. About 70% of injected eggs will be normally fertilized on average.
The successfully fertilized eggs are placed back in the incubator to mature for several days, until they reach the blastocyst stage of embryonic development, with about 100 cells. 3 and 5 days after the sperm was injected, the embryologist will examine the embryos to make sure that they are developing normally. Only embryos that appear viable are selected for transfer.
Embryo transfer is the final of the steps of in-vitro fertilization. Fresh embryo transfer usually occurs five days after the eggs are retrieved. Pregnancy only occurs if the embryo implants in the uterine lining. A blood test to confirm pregnancy can be performed 8 days after the embryo transfer.