In-vitro fertilization, also known as "Test Tube Baby," an assisted reproductive technique where the wife's egg and the husband's sperm are mixed together in laboratory to produce fertilization. If fertilization occurs, the resulting embryos are transferred into the uterus, where they may implant.

In-vitro fertilization is the treatment of choice for couples experiencing several types of infertility, for example endometriosis, male factor, immunological factors, or idiopathic infertility, in addition to the traditional tubal factor, when the patient's tubes are obstructed, damaged or absent.

Several exams and tests are required by the specialist to know whether in-vitro fertilization is the best recommendation for your case.

The expression ovarian stimulation applies to the use of medication that stimulates the ovaries to produce several mature eggs in one month.

There are two main reasons why these medications are used:

1. The natural ovulation mechanisms release only one mature egg during each ovulatory cycle. Usually, from 60% to 70% of the eggs are fertilized "in vitro," thus the probability that an egg is not fertilized varies from 30% to 40%. The larger the number of egg, the higher will be the chances for fertilization and development.

2. Pregnancy rates are higher when more than one embryo are transferred back into the uterus.

In a natural cycle, the follicle (a small cyst filled with liquid, containing the egg) growth and ovulation are controlled by hormones stimulation on the ovaries. If we want to have control over these natural mechanisms, we need a medication to cut off this natural ovarian control. As a consequence, we can stimulate the ovaries directly and obtain a larger number of oocytes. Ultrasound and hormonal tests are required for follicular growth control, adjusting the doses of medication. The frequency of these tests varies from case to case.

When the oocytes are mature, a new medication is used for final oocyte maturation. This medication is a single injection that must be taken at the correct time defined by the doctor.

Ovarian stimulation medications have been used for more than 30 years. However, all medications have side effects. You should discuss these effects with your doctor. The most common side effects are minor abdominal pain, reaction and swelling on the area of the injection.

It is important to note that each patient has a different response to these medications. The responses can also be different from one to the other.

Oocyte retrieval is the process of removing the oocytes from their follicles. Due to the ovarian stimulation, each ovary should have several follicles ready for retrieval.

On the day of the oocyte retrieval the couple must go to the clinic. The oocytes are suctioned with the patient under general anesthesia. Ultrasound is used to guide the process. It is the same ultrasound equipment used for follicle growth monitoring.

The doctor evaluates the ovaries with the ultrasound. Then, a needle is inserted through a probe (part of the ultrasound equipment that is inserted into the vagina). The suction of each follicle is performed with this needle. The liquid is suctioned and forwarded immediately to the embryologist, who will look for the oocyte. The complete procedure can take up to 30 minutes.

The sperm must be collected soon after the collection of the oocytes. The sperm can be collected by masturbation, or by direct retrieval from the testicles or epididymis (small organs located at the testicles).

Approximately one hour after the oocytes have been collected, the patient is allowed to return home. She will be advised on the medication to take.

All oocytes obtained are examined by the embryologist in the laboratory. They are classified and analyzed for their maturity, since this is important to define the moment when they will be mixed with the spermatozoa. The sperm is prepared to be mixed with the oocytes. Fertilization will occur starting from this moment, and its confirmation can be observed on the following day. Twenty-four hours later, the developing embryos are observed (2 to 4 cells). The embryos can be transferred within 72 hours after the retrieval (when they have 8 cells), or on the 5th or 6th day after the retrieval, on a stage called blastocyst. The transference at blastocyst stage offers better pregnancy chances, and lower probability for multiple pregnancies, since a smaller number of blastocysts can be transferred.

Embryo transfer, as the name implies, is the procedure for transferring embryos into the uterus.

It is a simple procedure, requiring no more than 5 minutes. No preparation or anesthesia is necessary. The patient is put on gynecologic position and a catheter will be inserted into the uterus, through the cervix. The embryos are deposited on the bottom of the uterus. The patient must rest for 60 minutes after the procedure.

The number of embryos transferred will depend on the day of transfer, and on their own quality. Therefore, it must be individualized for each case.

As the patient leaves the clinic, she will receive orientation on precautions, medications, and she will have a date assigned for her return for the pregnancy test.

After all embryos have been transferred, the implantation (fixation in the uterus) may or may not occur. When implantation occurs, it takes place from 2 to 5 days after the transfer. The patient will be using a medication to prepare the endometrium (the inside line of the uterus) to help the implantation.

If at least one embryo is fixed, you are pregnant.

Approximately 14 days after the transfer of the embryos, a pregnancy test is performed. If it tests positive, you will be asked to repeat the test, and an ultrasound will be schedulled.

If the ultrasound test detects pregnancy inside the uterus, with heartbeat of your baby, you will be referred back to your doctor for prenatal medical care.