In vitro fertilization (IVF)
In vitro fertilization (IVF) was first successfully performed in 1978 in England, and since that time has become a first line treatment for many infertility conditions. IVF differs from natural fertilization because the union of the egg and sperm (fertilization) occurs in a Petri dish rather than in the body, at the end of the fallopian tube. The term “in vitro” literally means “outside of the body”.
IVF success rates have improved dramatically since its conception. At Northwell Health Fertility, our IVF success rates significantly exceed national averages. A successful IVF cycle requires that several steps be completed, which are outlined below.
Step 1: Follicular stimulation
IVF requires numerous eggs compared to a natural cycle, which only requires one. This is because some of the eggs used in an IVF cycle will be damaged during the ART procedures and others will not fertilize and develop. To produce the number of eggs needed for IVF, and to appropriately time egg release, IVF patients are started on fertility drugs. FSH is administered by injection and directly stimulates the ovaries to recruit and develop numerous follicles, each of which contains an egg. Drugs like Ganirelex, Cetrotide and Lupron are critical to a successful cycle as they block natural ovulation. Otherwise, ovulation may occur prior to egg retrieval resulting in a lost IVF cycle. While on these drugs, ovulation must be induced by the drugs hCG or Lupron or a combination of the two.
Step 2: Follicular monitoring
The progress of the IVF cycle is monitored by ultrasound scans of the ovary. As the follicles develop, the number and size can be measured using transvaginal ultrasound. As healthy follicles develop in an IVF cycle, they produce increasing levels of estrogen, which is monitored by blood tests. Estrogen levels are used to help determine the appropriate dosage of FSH and to avoid potential side effects, such as ovarian hyperstimulation syndrome.
Once the follicles developed during the IVF cycle are judged to be mature, an injection of hCG (or dual trigger with Lupron) is given to initiate the final phase of egg development. Sufficient development and an adequate number of eggs must be present in order to proceed to retrieval.
Step 3: Oocyte retrieval/insemination
IVF oocyte retrieval is performed using intravenous sedation. A needle is inserted under ultrasound guidance through the vagina into the follicle on the ovary. The follicles containing the eggs are punctured and aspirated. If the procedure is successful, one or more of the eggs will be obtained. Sperm are usually obtained the same day by masturbation. The eggs are inseminated with the processed sperm, and fertilization is allowed to take place. Note that allowing the embryos to grow in an environment established by culturing other cells from the woman sometimes improves the quality of the embryos (co-culture).
Step 4: Embryo transfer
In some IVF cycles, prior to transfer, some or all of the embryos may undergo assisted hatching to increase implantation rates. Once the embryos mature, a number (determined by the fertility specialist, embryologist, and patient) of them are inserted through the cervix into the uterus by means of a small catheter. The embryo transfer is usually painless and no sedation is required. Most IVF patients will be given drugs, such as progesterone, after the embryo transfer to insure endometrial development. Excess embryos may be frozen for possible transfer in a future cryopreserved IVF cycle.
Intracytoplasmic sperm injection (ICSI)
During , the fertilization process can be facilitated by using intracytoplasmic sperm injection (ICSI), which is often used in cases of male infertility. ICSI came into wide use in the 1990’s and is now a first line treatment. Using ICSI, a single sperm is inserted directly into each egg; this is done by a skilled embryologist and does not cause damage to the egg. The sperm can be obtained from an ejaculate or aspirated directly from the reproductive organs (sperm may be withdrawn directly from the testicles, called TESA, or other parts of the male reproductive tract, called MESA). This means that men who have few or no sperm in their ejaculate can often still produce genetically related children. With ICSI, fertilization and implantation rates are typically high.
ICSI may be used in the following cases:
- Moderate to severe cases (low sperm count, motility or morphology)
- Cases in which sperm can only be obtained by surgical procedures
- Cases in which there had been poor fertilization in a previous cycle
- Cases of unexplained infertility
- Cases where the ICSI will increase the pregnancy rate