Assisted Reproductive Techniques Essay, Research Paper
In-Vitro Fertilization or IVF
IVF is the name for in-vitro fertilization, a procedure that involves retrieving eggs and sperm from the bodies of the male and female partners and placing them together in a laboratory dish for fertilization. The fertilized eggs are then transferred two to six days later into the female partner’s uterus. After the fertilized eggs are set into the uterus embryo development will hopefully occur as in a normal pregnancy.
IVF is actually a four stage practice that begins with ovarian stimulation and monitoring. In order to maximize the patient’s chances for successful fertilization, physicians typically use ovarian stimulation medications instead of following the natural cycle which only produces one egg. Ovarian stimulation causes several mature eggs to be produced for retrieval, fertilization, and transfer to increase the possibility that at least one will result in pregnancy. (See Figure 1)
Ovarian stimulation involves the use of follicle stimulating hormone (FSH). This hormone is necessary to stimulate multiple oocyte, or egg, development. FSH is a gonadotropin, the name for a type of hormone capable of stimulating the ovaries to produce eggs. The female partner is usually stimulated to produce eggs by the use of HMG/ HCG. Careful physician monitoring is necessary to adjust dosages to prevent hyper stimulation and monitor the injections site for possible infection.
The physician carefully monitors the patient with vaginal or abdominal ultrasound and blood tests. The ultrasound scans provide an actual image of the ovaries and aid in monitoring follicle growth beginning approximately day eight of the cycle. The physician is monitoring the growth, number, size of each follicle, and any signs of difficulty that require alterations in treatment. Monitoring also determines the timing of the next step; egg retrieval.
In the second step, once the follicle has ruptured, the physician attempts to remove as many eggs as possible. Not all of the eggs retrieved will be used in the current IVF cycle. Unhealthy eggs and any eggs that fail to fertilize are not used.
The two methods used to retrieve eggs are laparoscopy and ultrasound- guided aspiration. In laparoscopy, a surgical procedure requiring general anesthesia, the physician uses a surgical instrument called the laparoscope inserted into the ovaries. The laparoscope contains an aspiration system that uses light suction to retrieve the egg from the follicle. The result of each attempt to retrieve the egg from the follicle is immediately examined under a powerful microscope. If the egg was not retrieved, fine adjustments are made for following attempts until all the mature follicles have been retrieved. Ultrasound-guided aspiration is also performed under general anesthesia. The ultrasound image allows more accurate aspiration attempts because the physician can guide the needle into each follicle in order to withdraw the egg. After recovering the eggs, they are transferred to a sterile container to await fertilization in the laboratory.
In the third step of In-Vitro Fertilization, a semen sample is collected from the male partner approximately two hours before the female partner’s eggs are retrieved. These sperm are then processed, called sperm washing, using various laboratory techniques. Sperm processing helps selection of the strongest, healthiest, and most active sperm in the semen sample.
The mature, healthy eggs are then placed together in the laboratory with the selected sperm. They are incubated at a temperature identical to that of the female partner’s body. After approximately 48 hours, the eggs that have successfully fertilized and are growing normally, are called embryos. The embryos are then ready for the next step which transfers them into the womb.(See Figure 2)
Finally, embryo transfer occurs, which is done without anaesthesia. The embryos are placed in a catheter, which is a tubular instrument used to transport the embryos from the laboratory container to the womb. The physician inserts the catheter through the female partner’s vagina and cervix, in order to insert the embryos directly into the uterus. Normal implantation and maturation of the embryo is hoped to occur in order to conceive the child. Things must follow their natural course after this, and the process of in-vitro fertilization is finished.
IVF was originally developed in the early 1970’s to treat infertility caused by blocked or damaged fallopian tubes. In 1978, the first IVF baby, Louise Brown, was born in the U.S. Since then, the number of IVF procedures performed each year have increased and the success rate has improved significantly.
Because IVF was the first Assisted Reproductive Technology procedure developed and widely publicized in the U.S., many people mistakenly think that IVF is the only treatment option for infertile couples. In fact, less than 3% of all patients who seek medical treatment actually receive in-vitro fertilization as a treatment option. Most infertile couples who seek evaluation and treatment respond positively to the less involved treatment options; such as hormonal therapies and artificial insemination. Despite this, IVF remains the most commonly used of the ART procedures.
Artificial Insemination or AI
Artificial insemination, AI, is often the best choice of treatment for couples that are infertile due to sperm disorders. AI involves injecting sperm through a narrow catheter into the wife’s reproductive tract. For most couples, artificial insemination is performed with the husband’s sperm. When a man’s ejaculate contains few or no live sperm, the couple may decide to undergo AI with sperm from a donor with the characteristics they desire.
Depending on the husband’s effective sperm count, the wife’s cervical mucus quality at the fertile time of her cycle and estimated time to egg release from the ovarian follicle, the type of AI is selected. The type, intracervical, intrauterine, intrafollicular, or intratubal, are named for the location of insemination
Intrauterine insemination, IUI, is a type of artificial insemination procedure in which the sperm are placed in the uterine cavity through a transcervical catheter. With appropriate laboratory techniques, the sperm can be separated from the seminal fluid and placed in a very small volume of sterile medium which will keep the sperm alive and actively mobile.
IUI may be indicated for the treatment of low sperm count and/or absence of fertile mucus. The rationale for the use of IUI for the treatment of oligospermia (low sperm count) is based upon the knowledge that only about 1% of the total numbers of sperm deposited into the vagina at ejaculation will find their way into the upper female genital tract. IUI places the healthiest sperm into the female genital tract to increase the probability of fertilization. The use of IUI also does not stop the couple from having sexual intercourse nor from using other types of insemination.
IUI is performed by passing a sterile catheter through the cervical canal into the uterine cavity and then injecting the sperm suspension into the uterine cavity. This is a simple procedure which can be performed either by a fertility nurse or physician. Usually the insemination itself causes little if any discomfort. Following the insemination procedure the woman remains lying down with her hips elevated for 45 minutes. After this it is hoped that the sperm reached the egg naturally and pregnancy will occur from it.
Gamete Intrafallopian Transfer or GIFT
Gamete intrafallopian transfer, or GIFT, was developed in 1984 as a variation of in-vitro fertilization. This procedure is most often recommended for couples with unexplained infertility with the female partner having at least one open fallopian tube. GIFT is also recommended for patient’s whose infertility is due to cervical or immunological factors, mild endometriosis, or selected cases of male infertility.
The main difference between IVF and GIFT is that GIFT fertilization occurs naturally within the female partner’s body instead of in the laboratory. GIFT is a procedure that involves ovarian stimulation, egg retrieval, and placing a mixture of the sperm and eggs directly into the woman’s fallopian tubes to foster fertilization inside the female’s body. This procedure has three steps to it.
The first step of GIFT is exactly the same as in IVF. In order to maximize the probability of success, the physician prescribes fertility medications to stimulate the female to produce more than one follicle and egg, and to aid in stimulating the follicles to release the eggs. Follicle stimulating hormone medications are used to stimulate the growth and maturity of follicles and eggs. Then HCG is given to stimulate the release of the eggs from the follicles and determine the time of egg retrieval.
The second step also mirrors the process in IVF. The eggs are examined under a microscope to evaluate maturity before they are combined with sperm. The male semen sample has been collected, evaluated, and sperm processing performed prior to the next step.
Finally, once the physician has determined the eggs are ready for transfer, the selected sperm and eggs are placed together in a catheter, where they unite. These sperm and eggs are called gametes. Using a laparoscope, the physician begins the surgical procedure to insert the catheter directly into the fallopian tube. The sperm and egg are then injected into the fallopian tube, where fertilization occurs within the body. Unlike IVF, in which actual fertilization is observed and confirmed in the laboratory, GIFT does not allow visual confirmation of fertilization. If fertilization occurs, the developing embryos remain in the fallopian tube and then move to the uterus for the natural implantation process to be completed. Like all other types of assisted reproductive techniques, once the egg and sperm are in the female partners uterus, all that is left to do is wait and hope for a child to be conceived.
Zygote Intrafallopian Transfer or ZIFT
Zygote intrafallopian transfer, or ZIFT, is another variation of in vitro fertilization. In this assisted reproductive technique the name zygote is given to the fertilized eggs.
Like IVF, the actual fertilization of the eggs is observed and confirmed in the laboratory. The location of where fertilization takes place, and the ability to confirm actual fertilization, are the main differences between ZIFT and gamete intrafallopian transfer. With GIFT, the actual fertilization cannot be observed because the eggs and sperm are united for fertilization inside the woman’s fallopian tube. The advantage of ZIFT over GIFT is that ZIFT uses zygotes, not an egg and sperm mixture.
The steps in ZIFT are the same as in IVF, except the location of where the embryos are placed changes. With IVF embryos are placed directly in the uterus. With ZIFT, the zygotes are placed directly into the fallopian tube. For ZIFT to be offered as a treatment option, the female must have at least one open and functioning fallopian tube.
ZIFT involves ovarian stimulation, monitoring, and egg retrieval, followed by sperm processing and fertilization in the laboratory and then transfer of the zygotes, or embryos, into the female partner’s fallopian tubes. After this, conception is hoped for.
For women who experience failure of their ovarian function and women over age 40 with poor quality oocyte, or eggs (See Figure 3), the use of donated eggs from another, sometimes younger (See Figure 4), female may be the best option to achieve conception. Use of donor eggs is an IVF procedure involving retrieval of the donor’s eggs, fertilization with the male partner’s sperm, and transfer to the female partner’s uterus. Oocyte donation is used when the female partner has a genetic disorder than can be transmitted to the baby. Women with congenital abnormalities, women who have previously been treated with radiation or chemotherapy for cancer, women who have repeatedly failed with prior IVF attempts, and women with recurrent miscarriages, may also consider this option. One problem with this technique is finding a suitable donor.
Embryo and Oocyte Cryopreservation
Cryopreservation is a process of freezing embryos to preserve them over time. Frozen embryos have been successfully thawed and used in later cycles that resulted in pregnancy. About two thirds of embryos will survive the process of freezing and thawing. An added benefit is the lower cost due to not having to repeat the ovarian stimulation, egg retrieval, and fertilization procedures with the subsequent cycle. These eggs, after being thawed, are placed into the females uterus in the same manner as is in in-vitro fertilization.
Assisted Reproductive Techniques are quite helpful to people who wish to have a child but cannot conceive in the natural way. A man and woman, for example, who wish to be parents but cannot due to the woman’s fallopian tube problems. With the help of in-vitro fertilization the couples dream of having a child might come true. Another example of the help these techniques can give could involve a single woman who wishes to be a mother. With artificial insemination the woman can become the mother she so wishes to be. These techniques are some of the most important scientific discoveries to the twentieth century due to the happiness that they can bring.
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