The In Vitro Process
The saying "nothing worth having comes easy" could refer to the process of trying to conceive via IVF. An IVF cycle takes four to six weeks to complete and usually costs about $12,000 [source: Baby Center]. Some women may have to endure multiple cycles before getting pregnant. In fact, in the United States, women under the age of 35 have only a 30 to 35 percent chance of having a baby after an IVF cycle, with the chance dropping to 20 to 25 percent in women between 35 and 40. Women over 40 have a 6 to 10 percent chance of a live birth per cycle of treatment [source: CDC].
There are five steps in the IVF treatment cycle.
- Ovarian stimulation. This step involves the use of ovulation, or fertility, drugs. These hormones, taken over a period of eight to 14 days, stimulate a woman's ovaries to produce several eggs per menstrual cycle instead of one. Successful IVF usually requires the fertilization of multiple eggs -- some may not fertilize or develop normally after fertilization. During this process, the physician will use ultrasounds or blood testing to determine when the eggs are ready for retrieval.
- Egg retrieval. Once the eggs are deemed ready for retrieval, the doctor performs a transvaginal ultrasound aspiration. This is a simple surgical procedure that uses a small amount of anesthesia, such as a mild sedative. Once the ultrasound locates the mature follicles in the ovary, the doctor inserts a needle into the follicles and removes the eggs with suction. If the ultrasound can't find or access the ovaries, doctors might have to perform laparoscopic surgery. This technique -- in which doctors cut a small incision in the abdomen and locate the ovaries with a tiny fiber-optic lens -- is still simple and short, but it requires stronger anesthesia.
- Insemination. After retrieval, doctors examine the eggs and decide which of them hold the most potential for a successful pregnancy. They place these eggs in an IVF culture medium to await insemination. Meanwhile, they separate the father's sperm from his semen. The most motile sperm (the "best swimmers") are then added to the eggs in the incubator.
- Fertilization and embryo culture. Usually within a matter of hours, a sperm cell penetrates an egg and fertilizes it. The following day, doctors visually confirm fertilization if they can see two pronuclei. These pronuclei are the basis of the embryo formation -- they will unite to form the nucleus of the zygote, which divides to become an embryo. A two- to four-cell embryo appears approximately two days after fertilization. On the third day, a six- to 10-cell embryo is seen. Five days after fertilization, the embryo can be called a blastocyst, which means it has formed a fluid cavity that results in the formation of fetal tissues and placenta. However, many embryos are not observed for this long. They can be placed in the uterus as early as one day and as late as six days after fertilization. In most cases, they're observed for two to three days to determine if the development is normal.
- Embryo transfer. About two to three days after fertilization, the resulting embryo or embryos are transferred to the woman's uterus. Doctors suspend them in a drop of fluid and draw it into a transfer catheter -- a long, thin, flexible tube that has a syringe on one end. They then guide the catheter into the vagina, past the cervix and into the uterus. The patient is encouraged to remain in a resting position for an hour or two to prevent any stress on the body. If the embryo or embryos do attach to the uterine wall, a positive pregnancy test will result.
Of course, something with this many steps is bound to have risks. We'll discuss the most common risks of IVF in the next section.