In-Vitro Fertilization – IVF
IVF is a sequential process by which eggs are retrieved from the ovaries, fertilized with sperm in the laboratory and cultured into cleaved embryos and then transferred into the uterus.
Step-by-Step Process of In-vitro fertilization(IVF):
Stage 1 – Controlled Ovarian Hyperstimulation
Stage 2 – Egg(Oocytes) Retrieval
Stage 3 – Fertilization/Incubation
Stage 4 – Embryo Transfer – ET
Stage 1 – Controlled Ovarian Hyperstimulation
To program the cycle, the patient starts with oral contraceptive pills followed by Lupron injections subcutaneously until and during ovarian stimulation following onset of next menstrual cycle. Lupron induces a condition called pituitary desensitization. Desensitized pituitary glands minimizes the chance of premature LH surge. Such a surge results in a canceled procedure because the follicles can not be retrieved.
Rather than having a single egg developed each month and in order to maximize chances for a successful IVF cycle, a fertility doctor will stimulate ovaries to produce as many ovarian follicles as possible using hormonal medications. Follicle Stimulating Hormone (FSH) is a hormone necessary for multiple follicles development and it is in a form of injection. Usually, daily injection of FSH (Gonadotropin) starts on cycle day 3 to cycle day 9. Along with the injection, ultrasound and estradiol (E2) level will be performed to monitor ovarian response to FSH. Ultrasound scan will be utilized to observe the size and number of follicles, and can determine follicle maturity. Developing follicles secrete increasing amounts of estradiol (E2). Blood estradiol levels are used along with the ultrasound scans to determine the optimal timing for the administration of Human Chorionic Gonadotropin (HCG) which acts as an ovulation inducer and is the final step leading to egg retrieval.
Stage 2 Egg Retrieval
The oocyte retrieval is performed under conscious sedation by an anesthesiologist. After a 30 to 50 minute procedure, the patient will be discharged post recovery from anesthesia. The oocyte retrieval usually takes place 34 to 36 hours following the administration of HCG. Egg retrieval procedure is performed by vaginal ultrasound using a long, small diameter needle inserted in a guide on the ultrasonic probe. The needle is connected to a suction pump and the fluid from any accessible follicle within the ovary is aspirated. The fluid is then examined by an embryologist under the microscope for presence of eggs. The process is repeated until all the mature follicles have been aspirated. After egg recovery, the eggs are transferred to a sterile Petri-dish to await fertilization.
Stage 3 Fertilization
To facilitate fertilization, sperm washing is performed to obtain the strongest and most active sperm from the ejaculate. Sperm are placed together with eggs in a dish and incubated at an environmentally constant temperature and appropriate levels of humidity and carbon dioxide level. Approximately 72 hours post oocyte retrieval, if the eggs have successfully been fertilized and are cleaving normally, they will be transferred into the uterus.
When indicated, i.e. poor quality/quantity sperm and/or egg, special micomanipulation procedure called Intracytoplasmic Sperm Injection (ICSI) is needed to increase chances of fertilization. This laboratory procedure involves the injection of a single sperm into the egg, bypassing the need to have sperm penetrate the egg.
Stage 4 – Embryo Transfer – ET
Not all inseminated eggs will go on to fertilization. The number of eggs achieving fertilization depends on many factors including egg quality, sperm quality and the binding process. Not all embryos will be transferred to the patient. The number of embryos transferred depend on the maternal age as well as the quality of the embryos. The doctor will suggest the optimal number of embryos to be transferred. If there are any remaining embryos, they can be cryopreserved and stored indefinitely. Frozen embryos can be thawed and used for future transfer.
Embryo transfer procedure is performed without anesthesia. The embryos are placed in a special soft plastic catheter and transferred into the uterus. Similar to artificial insemination, the physician will pass the catheter through the cervix into the uterine cavity. The patient will rest for two hours and will then be discharged. Pregnancy test is usually done in about 12 to 14 days after embryo transfer. During this time daily injection or vaginal creme of supplemental progesterone is also required.
Advantages and Indications of In Vitro Fertilization – IVF
- The ability to know if the male’s sperm has actually fertilized the eggs.
- Tubal bypass procedure, because the embryos are placed directly in the uterus, the women does not need to have functioning fallopian tubes.
- Women with Endometriosis, Pelvic Adhesion Disease, Tubal Ligation.
- Unexplained Infertility.
- Male factor infertility, i.e. severe oligozoospermia.
Your doctor is most likely to recommend intracytoplasmic sperm injection (ICSI) in situations where male infertility is a primary obstacle in achieving a pregnancy. Intracytoplasmic sperm injection is an in vitro process – fertilization in the lab, not within a woman’s body. A single sperm is drawn up into a very tiny hypodermic needle, and is then injected directly into a harvested egg. The fertilized egg will then be introduced to the prospective mother’s womb, and then both doctor and hopeful parents will wait to see if implantation has occurred and the pregnancy is progressing normally.
Advantages of ICSI
The advantages of this method apply to situations where sperm is either limited in amount, or in some way unable to naturally penetrate the egg. There are many situations that match this description. If a man has had a prior vasectomy that can’t be reversed, or has scarring of the vas deferens from a prior infection, for example, sperm will have difficulty passing from the testicles during sex. Similarly, when a woman has chosen to be fertilized by a sperm donor, ICSI is an efficient way of making maximum use of a limited sample.
ICSI and Male Factor
It’s also not unusual for sperm to be unable to penetrate the egg. When the sperm has very low motility, or is sufficiently abnormal in shape as to make penetration difficult, injecting the sperm directly into the egg can overcome the physical challenge to fertilization in the most direct possible fashion.
Sperm Retrieval for ICSI
Sperm samples are acquired in a variety of ways. In most cases, the usual methods of male contribution will be sufficient, demanding little more than privacy and a fertile imagination. The primary exception occurs when there is some form of blockage preventing sperm from traveling from the testicles through the vas deferens. In this situation, doctors must harvest sperm directly from the testis, again using a very fine hypodermic needle to vacuum up sperm straight from the source. The procedure is done under sedation and is not uncomfortable; however, there can be some swelling and soreness afterward.
Fertilization with ICSI
Once your doctor has both sperm and egg samples the process is fairly simple: an egg is held steady using a microscopically small pipette. Another needle-sharp pipette immobilizes a single sperm, draws it into the pipette, and injects it directly into the egg. Once your doctor observes that natural fertilization has occurred, the egg will be transferred to the uterus.
When ICSI might be Required
This information is key to knowing whether or not this is something you should do. Remember, intracytoplasmic sperm injection is used in the following situations:
- When sperm is only present in very low levels.
- When sperm motility is very low.
- When sperm is blocked by a prior vasectomy.
- When sperm is blocked by scarring from past infections or operations.
- When sperm is blocked through a natural deformation of the vas deferens.
- When sperm formation is sufficiently abnormal to prevent direct natural penetration of the egg.
- When a limited sperm sample from a normally unavailable donor makes the high efficiency of ICSI a sensible precaution.