In vitro fertilization (IVF), sometimes called "test tube baby," is a process that was first successful in England in 1978. Initially IVF was used to treat only infertility caused by blocked fallopian tubes. Today, IVF has evolved to being an effective treatment for all causes of infertility for which simpler treatments have not been successful or are not an option. IVF has also become much more successful. In fact, many clinics are now attaining IVF success rates of 50 percent or more for women under 35 years old.
The IVF procedure
In natural conception, an egg is released from the ovary into the fallopian tube in the middle of a menstrual cycle. The egg is fertilized in the fallopian tube. The fertilized egg then begins to divide in the fallopian tube, thus becoming an early embryo. After being in the fallopian tube for several days the embryo enters the uterus where it will implant.
IVF can be thought of as a bypass of the fallopian tubes. The IVF process involves stimulating the ovaries with "fertility shots" to mature multiple eggs. Development of the eggs is monitored with blood tests and vaginal ultrasound examinations. Once the eggs are "mature," they are removed from the ovary with a very minor surgical procedure and mild anesthesia. After the eggs are retrieved, they are put into a petri dish and exposed to the partner's sperm. The eggs are examined the following morning to see if they have been successfully fertilized by the sperm. The fertilized eggs are left in the petri dish for several days during which time they begin to divide and become early embryos (as occurs in the fallopian tubes during natural conception). The embryos are then placed in the woman's uterus with a small catheter through the cervix that is generally no more uncomfortable than a Pap test. If there are extra embryos that are viable, they may be cryopreserved (frozen) for future use.
IVF laboratory procedures
The full spectrum of IVF laboratory procedures are performed at Cleveland Clinic, including:
- Fertilization with intracytoplasmic sperm injection (ICSI).
ICSI is when insufficient sperm are available, sperm parameters are compromised, or when previous fertilization methods have failed. Through ICSI, even the most severe cases of male infertility – very low numbers of sperm or even no sperm in the ejaculate – can be successfully treated with IVF. In these cases, sperm often can be obtained from the testes or epididymis by a minor outpatient procedure.
- Assisted hatching.
In order for an embryo to implant in the uterus it must break through the zona pellucida, a thin "shell" surrounding the embryo. The process of the embryo breaking through the zona pellucida is called "hatching." Hatching can be aided by making a tiny opening in the zona pellucida just prior to transferring the embryo to the uterus. In Cleveland Clinic's IVF program, assisted hatching is routinely performed on all embryos before they are transferred to the uterus.
- Embryo freezing.
Surplus embryos not transferred to the patient's uterus may be able to be frozen ("cryopreserved") for future use by the couple. In Cleveland Clinic's IVF program, cryopreservation of embryos is carried out either on the third day after egg retrieval when the embryo is between 6 and 8 cells in size or on the fifth or sixth day after egg retrieval (the "blastocyst" stage). Embryos that have potential to become successful pregnancies in the future are cryopreserved.
- Preimplantation genetic diagnosis (PGD).
In 2002, Cleveland Clinic's IVF program was the first in the region to launch a PGD program. PGD involves removing a single cell from a developing embryo at the eight-cell stage. The cell is then analyzed for chromosomal and / or specific genetic disorders. For patients with sex-linked diseases or single gene disorders such as cystic fibrosis, genetic screening of embryos is a powerful technique. In these patients, IVF coupled with embryo screening can greatly reduce the risk of offspring being affected by the disease.
- Oocyte / ovarian tissue cryopreservation.
Cleveland Clinic's IVF laboratory is becoming increasingly active in the area of freezing eggs and ovarian tissue There have been very few births resulting form ovarian tissue cryopreservation and it is clearly very experimental. Egg freezing has become much more successful in the past few years but it also is still considered to be experimental. After appropriate informed consent egg freezing is currently being offered to:
- Women with cancer who are about to undergo chemotherapy that can cause their ovaries to be unable to make eggs in the future
- Women who are undergoing In Vitro Fertilization who do not feel comfortable freezing all or any embryos
- Women in their 30's who want to delay child bearing
- 24-CHR screen.
Cleveland Clinic is offering a new technique for screening patient embryos and selecting those most likely to result in a pregnancy. This powerful new technique know as Trophectoderm Biopsy allows the removal of multiple cells at the blastocyst stage. Embryos can be examined for inherited genetic disorders as well as chromosomal abnormalities. Patients with recurrent losses or at risk for chromosomal abnormalities can have their embryos analyzed using the new Genesis-24 screen. By testing a patient’s embryos for chromosomal abnormalities and selecting only normal embryos for transfer, the patient's opportunity for a pregnancy with a healthy baby is increased. The Genesis-24 technique is quite powerful and allows transfer of embryos in the same IVF cycle.