In Vitro Fertilization ( IVF) is the process of fertilization by manually combining an egg and sperm in a laboratory dish. When the IVF procedure is successful, the embryo transfer process will used to physically place the embryo in the uterus.

The in vitro fertilization(IVF) procedure:
There are basically five steps in the IVF and embryo transfer process as the following:

Step 1: Ovulation induction.
Fertility medications are prescribed to control the timing of the egg ripening and to increase the chance of collecting multiple eggs during one of the woman's cycles. Egg development is monitored using ultrasound to examine the ovaries and urine or blood test samples to check hormone levels.
Step 2:
The eggs are removed from the ovaries which uses ultrasound imaging to guide a hollow needle through the pelvic cavity, which is called follicular aspiration. Sedation and local anesthesia are provided to remove any discomfort that you might experience. Some women may experience cramping on the day of retrieval, which usually subsides the following day; however, a feeling of fullness or pressure may last for several weeks following the procedure.
Step 3:
Sperm, usually obtained by ejaculation, is prepared for combining with the eggs.
Step 4: Insemination
The sperm and eggs are placed in incubators in the laboratory which enables fertilization to occur. In some cases where fertilization is suspected to be low, intracytoplasmic sperm injection (ICSI) may be used in this step.
The eggs are monitored to confirm that fertilization and cell division are taking place. Once this occurs, the fertilized eggs are considered embryos.
Step 5:
The embryos are usually transferred into the woman's uterus anywhere from one to six days later, but most commonly it occurs between two to three days following egg retrieval.
At this point, the fertilized egg has divided to become a two-to-four cell embryo. The transfer process involves a speculum which is inserted into the vagina to expose the cervix. A predetermined number of embryos are suspended in fluid and gently placed through a catheter into the womb. This process is often guided by ultrasound. The procedure is usually painless, but some women experience mild cramping.

These steps are followed by rest and watching for early pregnancy symptoms. A blood test and ultrasound will be used to determine if implantation and pregnancy has occurred.

Success rate of  in vitro fertilization:
The success rate of IVF depends on a number of factors including patient characteristics and treatment approaches.

• 30 to 35% for women under age 35
• 25% for women ages 35 to 37
• 15 to 20% for women ages 38 to 406 to 10% for women ages over 40

The risks of  in vitro fertilization:
The risks of in vitro fertilization depend upon each specific step of the procedure.
"Ovarian Hyper stimulation Syndrome"-ovary stimulation carries the risk of hyperstimulation- where the ovaries become swollen and painful. This condition is usually rare, mild, and include the following affects: nausea, vomiting, lack of appetite, or a feeling of being bloated.
More severe symptoms which occur in 1% of cases, include the following:

• Severe abdominal pain
• Severe nausea or vomiting
• Decreased urinary frequency
• Dark-colored urine
• Shortness of breath
• Weight gain within three to five days

Additionally, there is a slight risk of bleeding, infection, and damage to the bowel, bladder, or a blood vessel. Less than one patient in 1,000 will require surgery to repair damage caused during the egg retrieval process.
The chance of a multiples pregnancy is increased in all assisted reproductive procedures. There are additional risks and concerns related to multiples during pregnancy such as increased risk of premature delivery.
Assisted reproductive technology (ART) involves a significant physical, financial, and emotional commitment on the part of the couple. Psychological stress and emotional problems are common, and even more so if IVF is unsuccessful.

The number of  embryos should be created or transferred:
It has been said in the medical literature that transferring no more than four embryos per IVF cycle will yield optimal results. Transferring more than four is believed to result in excess numbers of multiple pregnancies, which increases the possibility of other complications.
Transferring four embryos versus one or two increases the probability that pregnancy will occur, but it is important to realize that all four embryos could implant. Some people have concerns regarding what happens to leftover embryos, so this would be something that the couple would discuss with their physician.