For a woman to get pregnant, a man’s sperm must travel from the vagina through the cervix (narrow, lower part of the womb), into the uterus (womb) and up into one of the fallopian tubes. If sperm arrives in the tubes soon after the release of the egg from the ovary (ovulation), the sperm and and egg can meet in the tube, most commonly, on the side that ovulation took place, and then fertilization may occur.




In vitro fertilization (IVF) is a method of assisted reproduction that involves combining an egg with sperm in laboratory dish. If the egg is fertilized and begins cell division, the resulting embryo is transferred into the woman’s uterus where it will hopefully implant in the uterine lining and further develop. Today, IVF is used to treat many causes of infertility, such as endometriosis and male factor, or when a couple’s infertility is unexplained.




The basic steps in an IVF treatment cycle are ovarian stimulation, egg retrieval, fertilization, embryo culture, and embryo transfer. These are discussed in the following sections.


During ovarian stimulation, also known as ovulation induction, medication or “fertility drugs,” are used to stimulate multiple eggs to grow in the ovaries rather than the single egg that normally develops each month. Multiple eggs are stimulated because some eggs will not fertilize or develop normally after fertilization. Generally, 8 to 14 days of stimulation are required.

  • Egg Retrieval:

Egg retrieval is a minor surgical procedure that can be performed in the physician’s office or an outpatient center. An ultrasound probe is interested into the vagina to identify the follicles. The eggs are removed from the follicles through the needle connected to a suction device. Removal of multiple eggs can usually be completed in less than 30 minutes.

  • Fertilization and Embryo Culture:

After the eggs are retrieved, they are examined in the laboratory for maturity and quality. Mature eggs are placed in an IVFculture medium and transferred to an incubator to await fertilization by the sperm.

Fertilization may be accomplished by insemination, where motile sperm are placed together with the oocytes and incubated overnight or by intracytoplasmic sperm injection (ICSI),where a single sperm is directly injected into each mature egg.

Embryos may be transferred to the uterus at any time between one and six days after the egg retrieval.


  • Embryo Transfer:

The next step in the IVF process is the embryo transfer. The physician identifies the cervix using a vaginal speculum. One or more embryos suspended in a drop of culture medium are drawn into a transfer catheter (a long, thin sterile tube) with a syringe on one end. The physician gently guides the tip of the transfer catheter through the cervix and places the fluid contacting the embryos into the uterine cavity. The procedure is usually painless, although some women experience mild cramping.




Many factors should be considered when determining the appropriate endpoint in therapy. Members of the IVF team can help couples decide when to stop treatment and discuss other options if appropriate.