Assisted reproductive technologies (ART) are medical techniques that help couples conceive. These procedures involve either:
Fertilization may occur either in the laboratory or in the uterus. In the U.S., the number of live birth deliveries from ART has dramatically increased in the last decade. Nearly 40,000 live births (deliveries of one or more infants) occur in the U.S. each year using assisted reproductive technologies.
Technically, the term ART refers only to fertility treatments, such as in vitro fertilization (IVF) and its variants, which handle both egg and sperm. Therefore intrauterine insemination (artificial insemination) is not officially considered a form of ART.
Before fertilization using intrauterine insemination (IUI) or intracytoplasmic sperm injection (ICSI) can take place, the sperm must be collected and prepared.
When a man has no available sperm in the ejaculate (usually from blockage, vasectomy, or lack of vas deferens), the sperm must be retrieved from the testes or the epididymis. Various microsurgical techniques are used for retrieval. The procedure may be done under local or general anesthesia, using a spring-loaded biopsy device, a thin needle, incisions, or microsurgical techniques. Most procedures can be done on an outpatient basis and the patient returns home the same day. There is no conclusive evidence that one procedure works better than another.
Testicular Fine Needle Aspiration. With testicular fine needle aspiration (TFNA), the surgeon uses a fine needle to remove sperm. This can be performed with local anesthetic and by surgeons who do not have to be experienced in microsurgeries.
Microsurgical Epididymal Sperm Aspiration. Microsurgical epididymal sperm aspiration (MESA) uses microsurgical techniques to collect sperm that are close to blocked portions of the epididymis. It involves an open incision and may be done under general or spinal anesthesia in a hospital setting, although the patient can often go home the same day. The doctor accesses the epididymis and retrieves sperm with an extremely fine needle-like device. It has the advantage that it can retrieve the largest number of sperm compared to other procedures. However, as with any invasive procedure, it carries some risks of complications, such as bleeding or infection.
Percutaneous Epididymal Sperm Aspiration. Percutaneous epididymal sperm aspiration (PESA) uses a needle to obtain mature sperm from areas in the upper parts of the epididymis (the coiled tube where sperm are stored before ejaculation). It is done under local anesthesia, sometimes in the doctor's office, is less expensive than other techniques, and recovery is fairly painless. However, it has less of a chance of achieving sufficient sperm than MESA, and there is also a chance of hitting a blood vessel, causing bleeding.
Testicular Sperm Extraction. Testicular sperm extraction (TESE) is a microsurgery that removes a small amount of tissue from one or more areas of the testes using incisions and microsurgery techniques. The tissue is placed in a culture and chopped into tiny pieces, and the sperm are extracted. It is a complex process, however, and may cause more pain than other sperm retrieval procedures.
Testicular Sperm Aspiration. Testicular sperm aspiration (TESA) uses a needle-like biopsy device to draw a small sample of testicular tissue. Multiple attempts are sometimes required to retrieve sperm.
A sperm's energy output is 20 times greater once it is removed from the seminal fluid. Methods for washing sperm can help improve the ability of sperm to move towards the egg. The simplest method involves:
The swim-up technique is not only a useful diagnostic procedure for testing the ability of sperm to escape from the semen into the cervical mucus, but it also achieves the goal of removing sperm from semen.
The result gives a fair estimation of the number of sperm potentially capable of fertilization. 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. There is also some evidence that such sperm may have fewer genetic abnormalities than those retrieved through sperm washing. 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 half a million very active sperm.
Sperm can be fresh or frozen in advance. Frozen sperm provide excellent results and can be used confidently for fertilization procedures. Fresh sperm, however, are preferred by some centers for cases when low sperm count is not caused by obstruction.
Artificial insemination (AI) is the least complex of fertility procedures and is often tried first in uncomplicated cases of infertility. AI either involves placing the sperm directly in the cervix (called intracervical insemination) or into the uterus (called intrauterine insemination, or IUI). IUI is the standard AI procedure. IUI is less expensive and poses less risk for multiple births than the more advanced assisted reproductive technologies (ART), such as in vitro fertilization.
Intrauterine insemination may be used under the following circumstances:
Those in whom artificial insemination fails, couples with specific fertility defects, or older women may be candidates for more advanced reproductive technologies.
The Artificial Insemination Procedure. The artificial insemination procedure is as follows:
The administration of fertility drugs and sperm retrieval is timed so that the process can coincide with time of ovulation.
Intracytoplasmic sperm injection (ICSI) is an assisted reproductive technology used for couples when male infertility is the main factor. It is used in combination with in vitro fertilization (IVF). It involves injecting a single sperm into an egg obtained from IVF. [For more information, see In-Depth Report #22: Infertility in women.]
The procedure is very simple:
The greatest concern with this procedure has been whether it increases the risk for birth defects. Many, but not all, studies have reported no higher risks of birth defects in children born using ICSI procedures. However, if the fatherâ ' s infertility was due to genetic issues, this genetic defect may be passed on to male children conceived through ICSI.
Because several embryos are implanted to increase the chances for pregnancy success, multiple births are frequently an outcome of IVF/ICSI. Multiple pregnancies increase the risks for a mother and her babies. In particular, there is increased risk for premature delivery and low birth weight. These factors can cause heart and lung problems and developmental disabilities in children.
IVF/ICSI can also pose specific risks for the woman. These risks include ovarian hyperstimulation, a condition induced by the fertility drugs used in the procedure. Ovarian hyperstimulation can result in dangerous fluid and electrolyte imbalances as well as increased blood pressure and higher risk for blood clots.
Another concern has been whether the ICSI procedure is being overused. ICSI use has increased 5-fold over the past decade, even though the proportion of men receiving treatment for male infertility has remained the same. Some doctors recommend ICSI for women who have failed prior IVF attempts or who have few or poor-quality eggs, even if their male partners have normal semen measurements. According to the Society for Assisted Reproductive Technology, there is little evidence that ICSI helps improve pregnancy success for couples who do not have a problem with male factor infertility.
Success Rates. Not all IVF/ICSI cycles result in pregnancy, and not all IVF-achieved pregnancies result in live births. According to the most recent statistics from the U.S.Centers for Disease Control (CDC), 34% of ART cycles (mostly IVF) led to pregnancy, but only 28% resulted in a live birth of one or more babies. Success rates provided by fertility clinics are not always a reliable indicator as they depend on many variables, including the age of the patients. The chances for success are best for women younger than age 37.
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