In-Vitro Fertilization or IVF is a six step process. After controlled ovarian hyperstimulation, eggs are obtained from the ovaries by inserting an aspiration needle through the back of the vagina while under light anesthesia. The eggs are cleaned and husband or donor washed sperm is then added to the droplet containing the egg for fertilization. Micromanipulation of the egg and sperm, such as ICSI would be preformed at this stage, if indicated. The fertilized egg is called a zygote, zygotes develop into embryos. The embryos are incubated in the lab for three to five days. Prior to the embryo transfer the assisted hatching procedure is preformed to encourage implantation.
Step 1: Ovarian Stimulation – Injectable hormone medications such Gonal F are given with a thin, small needle just underneath the skin for several days to stimulate the ovaries to produce multiple follicles. The development of these follicles is monitored by frequent vaginal ultrasounds and blood tests. Once the follicles have matured to the appropriate size, an injection of another hormone medication such as Ovidrel is given, which works like luteinizing hormone (LH) to release the egg. It is usually given the day after the last dose of Follistim and given at a specific time as instructed by the nurse. It is extremely important to adhere to the time the nurse states. The in-vitro fertilization (IVF) scheduled time is dependent to the proper dosing time of the Ovidrel.
Step 2: Semen Collection/Processing – Shortly before the egg retrieval, a semen sample will be collected and processed to isolate the strongest most active sperm. These sperm will be placed with each aspirated egg. We strongly encourage patients to consider freezing a semen specimen several weeks in advance of the egg retrieval date for several reasons. Coordinating work and surgery schedules can prove difficult and illness can occur unexpectedly. Also, the expectation of producing a sample on demand the day of the egg retrieval can be stressful.
Step 3: Egg Retrieval – Under light sedation given by a licensed Anesthesiologist, in a special air filtration egg retrieval suite, the doctor aspirates each mature follicle with a needle guided by ultrasound. This is usually done through the back of the vaginal wall but on rare occasions can be done through the abdomen. The aspirated eggs are then passed on to the Embryologist to identify and fertilize.
This is the stage where additional micromanipulation can occur if needed such as ICSI.
ICSI involves an embryologist injecting a single sperm directly into a mature egg under a microscope. This procedure is done to increase probability of fertilization when there is a male factor problem such as low sperm count, poor motility/morphology, or when the sperm aspiration techniques TESA/MESA are used to obtain a sperm specimen. ICSI is also recommended if fertilization did not occur in previous IVF attempts.
Step 4: Fertilization Evaluation – 14 to 18 hours after the sperm and egg are placed together; they are evaluated by the Embryologist to confirm fertilization. If fertilization occurs, the zygotes (fertilized eggs) are cultured in preparation for embryo transfer. Continued observation will occur over the next few days by the Embryologist, who will determine the quality of the embryo. The quality of the embryo will determine when the embryo transfer will take place and the number of embryos to transfer. Depending on the number of fertilized eggs, some may be frozen for use in a later cycle.
Step 5: Assisted Hatching (AH) – This technique is used to improve the probability of the embryo’s implantation. Assisted Hatching involves the Embryologist opening a small hole in the outer membrane known as the zona pellucida of the embryo. This opening improves the ability of the embryo to leave its “shell” and implant into the uterine lining. Patients that may benefit from Assisted Hatching (AH) include those with previous In Vitro Fertilization (IVF) failure, poor embryo growth rate, moderate to excessive cytoplasmic fragmentation and women with advanced maternal age.
Step 6: Embryo Transfer – This brief, painless procedure involves the doctor placing a catheter that has been loaded with a selected number of embryos by the Embryologist, through the cervix and into the uterus to deposit the embryos. When possible Blastocyst transfers are done, which occur around day five of embryonic growth. Blastocyst transfers allow a more mature embryo to be transferred, allowing the Embryologist to select fewer embryos for transfer, achieving a high pregnancy rate with a lower risk of multiple gestations above twins. Occasionally, cleavage stage, day three of embryonic growth transfer are done at they recommendation of the Embryologist based on the quality of the embryo.