Assisted Reproductive Technologies: Methods and Advances

Introduction to Assisted Reproductive Technology

Assisted reproductive technology has received a great deal of attention in recent years. Couples who have difficulty conceiving are now seeking out assisted reproductive technologies (ART) to have children. This paper examines the developments and advancements in assisted reproductive technologies, including zygote intrafallopian transfer (ZIFT), donor egg or embryo use, surrogacy and gestational carriers, in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and gamete intrafallopian transfer (GIFT).

Zygote Intrafallopian Transfer (ZIFT)

According to Becker (2000), zygote intrafallopian transfer (ZIFT) is a form of reproductive technology that takes place after controlled ovarian hyperstimulation, oocyte retrieval, and in vitro fertilization. In this procedure, the zygote (the early embryo) is positioned in the fallopian tube through the use of laparoscopy. The purpose of ZIFT is to "combine the advantages of IVF-ET and GIFT by utilizing the fallopian tubes in their physiological role as the site of zygote transport, at the cost of subjecting the patient to two separate anesthesias" (Becker, 2000, p. 264).

According to the American Pregnancy Association, ZIFT is carried out using several steps. First, a woman's ovaries are stimulated with medications to increase the probability of producing multiple eggs (hyperstimulation). The eggs are then gathered via aspiration and fertilized in the same manner as in IVF. The fertilized eggs are then transmitted via a laparoscopic method: a catheter is positioned in the fallopian tube and the fertilized eggs are injected. The patient and physicians then wait to determine whether pregnancy has occurred.

Donor Egg or Embryo

In addition to the ZIFT procedure, donor eggs or embryos are also an option available to infertile couples (Tomlins, 2003). According to Tomlins (2003), eggs can be donated when a woman is unable to produce eggs, when there is a risk that a genetic disease will be passed on to the child, when the eggs a woman produces are not of sufficient quality, when the woman has undergone chemotherapy or other treatments that have rendered her eggs unviable, or when previous attempts at reproductive technologies have been unsuccessful.

In addition to egg donation, embryos can also be donated. In most cases, embryos are donated by couples who have undergone IVF and still have frozen embryos remaining. These couples can choose to donate their embryos, submit them for medical research, or have them destroyed. When embryos are donated, they are given to couples who have difficulty creating their own.

Tomlins (2003) also points out that relying on a donor egg can evoke significant emotions in a woman — emotions comparable to those a man may experience upon learning he is sterile. Using a donor egg or embryo also means the woman will have no genetic link to the child. For this reason, women are often advised to work through these feelings before proceeding with donor eggs or embryos.

Donor eggs are provided to couples through several channels:

Known donor: a donor who is known to the couple — often a sister, sister-in-law, or close friend (Tomlins, 2003).

Advertisement: the donor may be a woman who has responded to an advertisement placed by the couple (Tomlins, 2003).

Anonymous donor: a donor unknown to the couple, such as a woman who has donated eggs to a clinic anonymously (Tomlins, 2003).

In Vitro Fertilization (IVF)

In vitro fertilization (IVF) is one of the most widely used methods of assisted reproductive technology. This method was first developed in 1978 and has since become a well-established procedure. According to Burfoot (1999), IVF involves the following steps:

Women must undergo controlled hyper-ovulation — a process used to produce more than the typical single mature egg per menstrual cycle, yielding as many as twenty eggs per ovary (Burfoot, 1999).

Once the ova are produced, they are retrieved and inseminated with sperm. After forty-eight hours, fertilization and cell division take place, producing a number of embryos (Burfoot, 1999).

Once the quality of the embryos has been verified, a few of the most viable are implanted in the woman's uterus. The remaining embryos can be frozen for future implantation or research (Burfoot, 1999).

Burfoot (1999) explains that IVF was originally created to treat infertility resulting from blocked fallopian tubes; today, however, it is commonly used to address male-factor and idiopathic infertility, as well as female infertility caused by endometriosis. Patient selection is essential to ensure that the right technology is applied to those who will most benefit, particularly patients with idiopathic or tubal infertility, who typically experience the best outcomes following IVF (Burfoot, 1999).

Some studies suggest that women with endometriosis have a less favorable prognosis than women with other types of infertility, with outcomes typically dependent on the severity of the disease — the more advanced the endometriosis, the poorer the prognosis (Burfoot, 1999). Other studies, however, have found that IVF success rates are similar for women with or without endometriosis. For couples facing male-factor infertility, IVF success rates are generally poor; yet if fertilization does occur, implantation and pregnancy rates are comparable to those of couples without male-factor infertility (Burfoot, 1999).

According to the National Institutes of Health (NIH), IVF requires a significant commitment in terms of physical, emotional, financial, and time resources. Depression and stress are two conditions that infertile couples frequently face. In addition, women undergoing the fertility treatments required for IVF may experience abdominal pain, headaches, bloating, and mood swings. The IVF medications are often administered via injection multiple times per day, and these injections may cause bruising.

In some cases, fertility drugs can result in ovarian hyperstimulation syndrome (OHSS), a condition that causes a buildup of fluid in the chest and abdomen. OHSS can lead to a weight gain of ten pounds within three to five days, as well as bloating, abdominal pain, vomiting, shortness of breath, decreased urination, and nausea. Less severe cases can be treated with bed rest, while more severe cases may require draining fluid from the body with a needle. Risks associated with egg retrieval include bleeding, infection, damage to surrounding structures, and adverse reactions to anesthesia. There are also risks associated with multiple pregnancies, which commonly occur when multiple embryos are implanted. Carrying more than one child increases the risk of low birth weight and premature birth. Whether IVF increases the risk of birth defects has not yet been definitively established.

Following embryo transfer, women typically rest for the remainder of the day. Most women can return to their normal routines the following day. Total bed rest is generally not required unless there is a risk of developing OHSS.

Women who undergo IVF must take the hormone progesterone for at least two months following embryo transfer, administered through daily injections or pills. Progesterone is a naturally produced hormone that helps thicken the lining of the uterus, making it easier for the embryo to implant. Insufficient progesterone levels may result in miscarriage.

IVF is also very expensive. The NIH explains that many states require insurance companies to cover the procedure to some degree; however, many insurance plans do not cover any form of infertility treatment. Fees for a single IVF cycle — including costs associated with surgery, medications, anesthesia, blood tests, ultrasounds, processing eggs and sperm, embryo storage, and embryo transfer — can range from $12,000 to $17,000, with costs varying by patient.

Success rates for IVF vary from clinic to clinic. The rates reflect the proportion of women who became pregnant as a result of IVF, though not all of these pregnancies resulted in live births. The Society of Assisted Reproductive Technologies (SART) reports the following live birth rates following IVF: 41–43% for women under 35; 33–36% for women aged 35–37; 23–27% for women aged 38–40; and 13–18% for women over 41.

References

Becker, G. (2000). The Elusive Embryo: How Women and Men Approach New Reproductive Technologies. Berkeley, CA: University of California Press.

Bleiklie, I., Goggin, M. L., & Rothmayr, C. (Eds.). (2003). Comparative Biomedical Policy: Governing Assisted Reproductive Technologies. London: Routledge.

Burfoot, A. (Ed.). (1999). Encyclopedia of Reproductive Technologies. Boulder, CO: Westview Press.

In Vitro Fertilization. National Institutes of Health. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/007279.htm

Sloan, G. A. (1993). Postponing Parenthood: The Effect of Age on Reproductive Potential. New York: Insight Books.

Sparks, R. F. (2000). Sexual Health for Men: The Complete Guide. Cambridge, MA: Perseus Publishing.

Tomlins, J. (2003). The Infertility Handbook: A Guide to Making Babies. Crows Nest, N.S.W.: Allen & Unwin.

Zygote intrafallopian transfer: ZIFT. Retrieved from