The IVF Process
More couples every year are treated with IVF, which has proven to be a safe and effective option for the treatment of many forms of infertility. It is an especially important option for many women in their late thirties and early forties
, or for women who have health conditions affecting the fallopian tubes, such as a blocked tube or a history of ectopic (tubal) pregnancy. IVF is usually the best treatment for couples when the man has a low sperm count
, or in couples who have not had success with other treatments including hormonal therapy and artificial insemination.
Step 1: Initiation of the IVF Cycle
During the first phase of an IVF cycle
, patients are typically treated with medications that may include oral contraceptives or estrogen to coordinate the start of the treatment cycle. Depending on a patient’s history and health, additional medications are sometimes administered to prepare a woman for ovarian stimulation.
Step 2: Ovulation Induction
Women normally produce a single mature follicle containing an egg during each menstrual cycle. This process is regulated by a naturally occurring hormone called follicle-stimulating hormone (FSH). During the ovulation induction phase of the IVF cycle, the woman is treated with an injectible form of FSH that is identical to naturally produced FSH. The FSH stimulates her ovaries to produce multiple follicles containing eggs to grow and mature. Multiple follicle development is advantageous because a significant percentage of the eggs a woman produces are abnormal. The percentage of abnormal eggs increases with age. At this stage of treatment, other hormones (GnRH analogs) are used to prevent the ovary from releasing an egg too soon. Doctors monitor this process with ultrasound and blood work over the course of treatment, usually lasting seven to ten days.
Step 3: Oocyte Retrieval
Once the follicles containing the eggs have reached an appropriate size, a hormone called hCG is used to mature the eggs. Thirty-six hours after the hCG injection, the eggs are removed from the ovaries in a minor surgical procedure. Anesthesia is administered to ensure patient comfort during this process. Guided by an ultrasound probe inserted into the vagina, doctors direct a needle into the follicles of the ovary to retrieve the eggs. The procedure takes anywhere from 15 to 30 minutes. Most women are able to return home an hour or so after the retrieval. On the next day, the woman starts injections of progesterone to prepare the uterus for implantation of the embryo.
Step 4: Oocyte Fertilization and Embryo Development
Once removed from the follicles, the eggs are examined by an embryologist and prepared and placed in an incubator. The eggs are then inseminated. The next day, the eggs are checked to see if they have been fertilized. The fertilized eggs, now called embryos, are then placed in a special medium to promote their growth before they are transferred to the uterus.
Embryos are typically allowed to grow in the laboratory for three days before being transferred into the woman’s uterus. In couples where it is difficult to select the best embryo for transfer after three days, their embryos will often be allowed to grow another two to three days, developing to what is known as the “blastocyst stage.”
A blastocyst is an embryo that has developed to the stage where it has two different cell types and a central fluid-filled cavity. This important advance in culture conditions allows for better selection of embryos because many abnormal embryos are not able to mature to the blastocyst stage. With better selection of embryos, we are able to reduce the risk of multiple births by transferring fewer embryos.
Step 5: Embryo Transfer
Embryos that have been cultured in the laboratory are now placed into a woman’s uterus using a catheter, which is inserted through the cervix. Doctors use ultrasound to help guide the catheter to ensure appropriate placement.
After the embryo transfer, the woman will continue her progesterone injections until about 14 days after egg retrieval, when a pregnancy test is done. If a pregnancy is confirmed, the woman will receive additional progesterone injections for about three to four weeks until her placenta begins to produce enough progesterone to support the pregnancy on its own.