ICSI has revolutionized the treatment of male infertility. Many couples do not realize that male factor is such a large contributor to the disease of infertility. Studies have found that there is a contributing male infertility problem in approximately 49% of cases. Many characteristics of sperm contribute to its ability to fertilize eggs.
Given the prevalence and importance of male infertility, a laboratory experienced in reproductive medicine must perform a thorough semen analysis. Commercial laboratories that may be promoted by managed care plans may not have extensive experience evaluating sperm.
In vitro fertilization (IVF) offers hope to couples who cannot become pregnant using methods such as timed intercourse, IUI, fertility drugs, etc. In particular, women with blocked, diseased, or absent Fallopian tubes can now become pregnant using IVF. Another advantage of IVF is that it allows direct visualization of the fertilization process. The embryologist can determine if the eggs are being fertilized. In IVF, the sperm is concentrated around the egg which increases the probably of fertilization.
However, the male still has to produce sufficient quality and quantity of sperm to penetrate an egg and cause fertilization. Intracytoplasmic sperm injection allows men with very low sperm counts to father children. It is also possible for a male with no sperm in his ejaculate (if sperm can be extracted from the testes) to produce a genetically related child. Through ICSI men with severe spinal cord injury can father children and it is also used in cases of unknown infertility, advanced female age, severe endometriosis, and other conditions.
In the ICSI procedure, a small hole is created in the egg membrane, chemically, mechanically, or using a laser and the sperm is inserted directly into the egg using a very fine microscopic needle and delicate micromanipulation tools. Sperm can be obtained directly from the testes in testicular epididymal sperm aspiration. It can also be obtained from the mesothelial lining of the epididymis (tube that transports the sperm). This means that an ejaculate is not always necessary to isolate sperm for use in ICSI.
Intracytoplasmic sperm injection / ICSI is a very safe procedure and studies demonstrate no significant increase in birth defects or other disorders after ICSI. We offer ICSI to our patients as indicated by their clinical diagnosis.
IVF patients undergo drug stimulation with follicle stimulating hormone to cause the recruitment and development of numerous eggs. These eggs are needed for fertilization with the partner's sperm. Once the eggs are fertilized, they are placed in incubators where they remain until ready for transfer to the mother's uterus.
The embryologist and physician closely monitor the embryos in culture while they divide and develops to maturity, usually within three to five days. Until recently, the culture media that was used only supported growth of the embryo up to three days; therefore, most embryo transfers were performed on day three. Culture media is now more advanced and able to support the growth of embryos up to day five, to the blastocyst stage.
A blastocyst is an embryo, which has developed two cell types, 1) surface cells termed the trophectoderm, which will become the placenta and 2) the inner cell mass that will become the fetus. A healthy blastocyst should hatch from its shell (zona pellucida) by the end of six days, or earlier, and implant within the endometrium.
The benefit of a day five transfer is that it allows the embryologist to watch the embryo for a longer period and more realistically assess it's quality. Embryos that appear good quality on day three may not survive to day five and embryos that do not appear good quality on day three may divide well up to the blastocyst stage. If an embryo does survive up to day five, it has a better chance of implanting than a day three embryo so fewer need to be transferred to the uterus. The major advantage of a day five transfer is transferring fewer embryos and a decreased risk of high order multiple births.
The couple must have enough embryos to make blastocyst transfer feasible. For example, if a couple only has 2-3 embryos they will typically all be transferred on day three. If however there are >= eight embryos, it would benefit to choose the best ones and the embryo transfer may be performed on day five.
As the name implies, assisted hatching is the process of "helping" the embryo to break free of the membrane (zona pellucida) surrounding it. The embryo must hatch from the membrane in order to attach to the uterine wall where further development takes place.
Hatching occurs normally in nature but sometimes does not happen properly in infertile females. Hatching is usually used in cases of infertility from unknown causes, advanced female age, or where there is a question of egg quality.
Assisted hatching is accomplished by using a solution of acid Tyrode to etch an opening, puncturing the membrane with a microscopic needle or with the laser.
A major goal of an IVF stimulation cycle is to cause the development of multiple eggs that will be fertilized to create embryos. These embryos will be cultured in incubators until ready for transfer.
Sometimes women produce more embryos than can be safely transferred. Transferring three or more embryos may greatly increase the risk of high order multiple births. The number of embryos transferred is different for specific patients based upon many factors including age, IVF treatment history, "quality of the stimulation" and others.
Fortunately, when there are excess embryos they can by cryopreserved for future use. The cryopreservation process involves moving embryos thought different sequential solutions while gently lowering the temperature. The major goal is to remove water from the cells, which can form ice thus damaging the embryos. Eventually, they are placed in liquid nitrogen for final freezing and storage. When ready for use they are thawed using sequential solutions while raising the temperature.
Cryopreserved embryos are used successfully in IVF cycles; however, the success rates are somewhat lower than fresh embryos (this depends upon multiple factors). When cryopreserved embryos are used it is not necessary for the female to undergo ovulation induction and egg retrieval. This greatly reduces the cost of the IVF cycle. Sometimes, two or more cryopreserved cycles may result from one IVF stimulation.
Embryos are routinely cryopreserved and thawed and used in IVF with good success rates.