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. In fact, IVF success rates of 50 percent or more can be seen in women under 35 years old.
In vitro fertilization (IVF), sometimes called "test tube baby," is a process that was first successful in England in 1978. IVF is the only treatment option for couples with nonreparable tubal disease or severe male factor infertility but may be utilized all other causes of infertility, including unexplained infertility, when conventional treatment has not been successful. During the IVF process, the ovaries are stimulated with injectable fertility medications to mature multiple eggs. Once monitoring with ultrasound and blood tests indicate that the eggs are ready, they are collected nonsurgically with an ultrasound-guided needle under deep sedation. The in vitro fertilization procedure takes about 20 minutes and is painless. Fertilization is accomplished by exposing the eggs to sperm in a culture dish, or by directly injecting a single sperm into each mature egg (intracytoplasmic sperm injection - ICSI). After fertilization, embryo development is monitored over the next 3-5 days at which time usually 2 to 3 embryos are placed into the uterus with a small catheter through the cervix. Excess embryos may be frozen for future use.
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 non-surgically using a vaginal ultrasound-guided needle with the patient under deep sedation. 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 the Cleveland Clinic, including:
- Fertilization with intracytoplasmic sperm injection (ICSI). ICSI is used 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 the Cleveland Clinic 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 the Cleveland Clinic 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). Only embryos of good quality are cryopreserved since they have the best potential to become successful pregnancies in the future.
- Co-culture. Following fertilization, the embryo and the endometrium (lining of the uterus) are advancing each day getting ready for the implantation process. The embryo has to keep up with the developing endometrium in order to implant and create a viable pregnancy. Embryos from some patients need extra help growing in the culture dish. For these patients, embryos are grown on a layer of special cells, to further mimic the normal environment in the fallopian tube. The growth factors secreted by these cells can help embryos continue to divide and activate their genetic material, hopefully enhancing the embryos' chance of successfully implanting in the uterus. This treatment option technique has been used quite successfully at the Cleveland Clinic IVF laboratory for improving clinical outcomes in patients with repeated IVF failures, or poor quality embryos.
- Preimplantation genetic diagnosis (PGD). In 2002, the Cleveland Clinic IVF program launched its PGD program and is one of the only clinics in the region offering this technology. PGD involves removing a single cell from a developing embryo at the eight-cell stage. The cell is then analyzed and embryos with normal chromosome content are selected for transfer to the woman's uterus. For patients with sex-linked diseases or single gene disorders, genetic screening at the preimplantation embryo stage 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. The Cleveland Clinic IVF laboratory is becoming increasingly active in the area of freezing eggs and ovarian tissue. Work in this area is still very preliminary and the potential for successful pregnancies resulting from frozen eggs and/or ovarian tissue is very small at this time. As the success rate increases in the future, these procedures will offer some very exciting opportunities including:
- Freezing of eggs for women in their 30s who want to delay child bearing.
- Freezing of eggs or ovarian tissue for women undergoing chemotherapy or radiation in order to preserve their childbearing capabilities. This is being done for selected patients currently.
- Freezing of extra eggs obtained during IVF cycles. Many couples feel more comfortable with frozen eggs than with frozen embryos. This procedure is currently being offered to selected couples who are going through the IVF procedure but do not want all of the eggs fertilized.
