Artificial Insemination

Infertility In Men

Artificial insemination/Assisted reproductive technologies

Artificial Insemination

Artificial insemination (AI) places sperm directly in the cervix (called intra cervical insemination) or uterus (called intrauterine insemination or IUI). It is useful for women who have structural problems, when the cervical mucus is unreceptive, when donor sperm are required, when the male partner's semen contains very low numbers of sperm, or when unexplained infertility exists in both partners.

In order to prepare for AI, a woman usually takes fertility drugs in advance. The man must produce sperm at the time the woman is ovulating. The sperm are subjected to certain so-called "washing" procedures and are then inserted into the uterine cavity through a long, thin catheter.

Assisted Reproductive Technologies (ART)

General Guidelines

Assisted reproductive technologies (ART) are procedures that either use donated eggs or employ techniques that retrieve eggs from the ovary and re implant them. Fertilization may occur either in the laboratory or in the uterus. The most common procedure is in vitro fertilization (IVF). More recent ART procedures include gamete intra fallopian transfer (GIFT), zygote intra fallopian transfer (ZIFT), and intra cytoplasmic sperm injection (ICSI).

Success Rates

The success rates of ART procedures are now approaching that of normal couples in appropriate candidates. Many women, however, are not good candidates for GIFT and ZIFT. These procedures are also more invasive than IVF. It should be noted that even women who become pregnant may require more than one fertility cycle.

In general, the success rates with ART are lower for older women and those with uterine abnormalities as the primary cause of infertility. The chances of success are also greater with the clinic's own success rate, if eggs are the women's own, or if a previous pregnancy was successful. Age, however, is the most important determinant when a woman uses her own eggs. Rates for ART are relatively high for both pregnancies and live births among women in their 20s but they decline after 30 and go sharply downward toward the end of the decade and afterward.

The use of donor eggs has made it possible for many older women, even some who are postmenopausal, to bear a child. (Success rates using donor eggs depend on the age of the donor, not the age of the recipient.) Freezing eggs allows them to remain viable for long periods; after thawing, about half are able to be fertilized.

Assisted Reproductive Technologies

Specific Procedures

In Vitro Fertilization (IVF). About 71% of ART procedures use in vitro fertilization (IVF) with the woman's own eggs. An in vitro procedure is one that is performed in the laboratory. With in vitro fertilization (IVF), the partners' sperm and egg are placed together in a laboratory dish, where, it is hoped, fertilization will occur. It is the most common assisted reproductive treatment. The best candidates for IVF are women with damaged fallopian tubes, and some experts believe it is a better option than attempting surgical repair. It is also used when infertility is unexplained and when the male partner has the infertility problem. Most IVF programmers do not take women over 42. The physician induces super ovulation using fertility drugs so that several eggs can be harvested from the ovary before they have been released from the follicles. (Some women prefer to try a natural cycle, which produces only one egg.) It does not appear that using higher doses of fertility drugs for subsequent cycles is beneficial in women who have a poor response the first time. To harvest eggs, the physician uses either laparoscopy, inserting the instruments through an incision at the navel, or a probe inserted into the vagina and guided by ultrasound. The physician uses a needle to drain the liquid from the follicles and retrieves several eggs. The process requires light anesthesia and is performed on an outpatient basis. The eggs and sperm are combined in a petri dish, and 48 hours later, when the eggs are fertilized, they are re implanted into the woman's uterus as embryos. Most centers now implant three to four embryos at a time, and the remainder can be frozen for future use. Experts are devising a formula to reduce the risk for multiple births based on the woman's age and the number and quality of embryos that should be transferred back into the uterus.

Gamete/Zygote Intra fallopian Transfer. Gamete intra fallopian transfer (GIFT) and zygote intra fallopian transfer (ZIFT) are adaptations of IVF. A woman must have at least one functioning fallopian tube; GIFT and ZIFT are used in unexplained infertility, severe endometriosis, and in male infertility. In GIFT, the eggs are harvested as in IVF but not fertilized. They are mixed with the sperm and immediately injected back into the fallopian tube through a long, thin catheter. The sperm and egg are placed exactly where they would be in natural fertilization. The success rate is slightly higher for GIFT than for IVF. The ZIFT procedure fertilizes the eggs in the laboratory, as in IVF, but then implants them in the fallopian tubes, as in GIFT. The advantage to this procedure over GIFT is that the physician and couple are assured that fertilization has taken place and the eggs can be examined for defects.

Intracytoplasmic Sperm Injection

Intracytoplasmic sperm injection (ICSI) is a highly sophisticated technique for injecting one single sperm into an egg using microscopic and micromanipulation instruments. It is used for couples who have failed IVF or when the man has severe infertility problems and now constitutes about 30% of ART cycles that use the woman's own eggs. It is the most effective procedure when male infertility is the problem.

Other Experimental ART Procedures

New techniques involving micromanipulation of sperm are being developed for the one-third of infertile men who have severely low sperm counts, a high percentage of abnormal sperm, tubular obstruction, or no vas deferens. One investigative approach involves culturing poor sperm with the egg in very small micro chambers, thereby increasing the odds that the sperm will find the egg. A technique called sub zonal sperm microinjection injects one to 15 sperm under the zona (the tough outer shell of the egg). Zona dissection involves puncturing the zona and then incubating the egg in a droplet of 10,000 to 50,000 highly motile sperm. There is concern that puncturing the egg may damage it. Also, since a small number of sperm are randomly selected and not competing in a hostile environment, a weak sperm will have as good a chance as the strongest. This increases the risk for genetic defects in the infant. An experimental technique called FASIAR (follicle aspiration, sperm injection, and assisted follicular rupture) may prove to be a significantly less expensive treatment and also reduce the risk of multiple births. After ovulation induction, the physician punctures the follicle and retrieves the eggs and fluid in a syringe that also contains sperm. The mixture is then re injected near the ruptured follicle. The procedure can be done in the physician's office. Procedures called round spermatic nuclear injection (ROSNI) and elongated spermatic (ELSI) use immature sperm aspirated from the testes and injected into the egg using ICSI. The sperm can either be fresh or frozen. The procedures are controversial. However some countries are prohibiting this approach. Some centers are developing IVF techniques that allow a longer time for the embryo to develop in the laboratory (five days instead of two to three). This enables the embryo to reach the blast cyst stage, which is the natural embryonic stage for implantation in the uterus.

Preparing Sperm for IUI and ART

Before fertilization using IUI or ART can take place, the sperm must be collected and prepared for optimal chances for success. Sperm can be fresh or frozen in advance. Studies are reporting that frozen sperm provides excellent results and can be used confidently for fertilization procedures. A number of methods have been devised for this.

It should be noted that in some cases of severely low sperm count, a biopsy is used to remove sperm from the testicles. If multiple incisions are required, the size of the testes may be reduced afterward and may even reduce androgen levels to the extent that replacement therapy may be needed. Men should be aware that success rates are lower than average in such cases. New techniques using needle aspiration may prove to be effective for sperm retrieval in some men and reduce such risks.

Sperm Washing

A sperm's energy output is twenty times greater once it is removed from the seminal fluid, so researchers have devised methods for washing sperm that have a dramatic effect on the ability of sperm to move towards the egg. The simplest method involves mixing the sperm with nutrient fluid or culture media in a test tube and then centrifuging (spinning) it for about five minutes. The heavy sperm settle on the bottom, forming a dense button of millions of pure sperm. The fluid left on top is siphoned off. This procedure may be repeated again. This simple method of sperm washing, however, does not eliminate heavy debris, such as dead sperm, white blood cells, or bacteria.

Swim-Up Technique

The swim-up technique is not only a useful diagnostic procedure but also achieves the goal of removing sperm from semen. It is superior to sperm washing, because the live sperm will swim up to the culture media leaving behind most of the debris, although some may float up into the medium. The strongest sperm, which are those at the top of the medium, can be collected for in vitro fertilization or artificial insemination. A good swim test yields about 1/2 million very active sperm.

Percutaneous Epididymal Sperm Aspiration (PESA)

A technique called percutaneous epididymal sperm aspiration (PESA) uses a needle to obtain mature sperm from areas in the upper parts of the epididymis. PESA is useful in men with tubular obstruction and even in those with no vas deferens.

Other Methods of Separation

One technique uses a special device called a Jondet tube, which contains a doughnut-like plug at the bottom with the opening in the center forming a tiny well. The sperm are placed on the plug and a culture media is added to the tube. Active sperm attempt to swim off the plug and up into the culture media, but gravity pulls them into the well at the bottom of the tube from which they cannot escape. Another method uses layers of a very dense fluid called Percoll, which is centrifuged with the sperm and forces the best sperm to the bottom of the test tube.

Sperm Enhancement

A number of techniques can improve the ability of sperm to fertilize an egg. Injections of stimulants, such as caffeine, may enhance motility for a period of time. (No one has yet been able to show increased fertilization rates from this process, but the timing of the enhancement has not been perfected.) Calcium improves sperm cap citation and is sometimes added to the sperm washing solution, although like the stimulants, the precise degree of improvement is not clear. Sperm stored for 24 hours in a solution containing slightly heated egg yolk have a higher fertilization rate in IVF procedures Treatment with platelet activating factor (PAF) has also been shown to increase the penetration ability of sperm.

Highlights

Infertility