bioethics.com
home |  about |  contact |   
your global information source on bioethics news and issues
Bioethics 101
Categories


WWW
Bioethics.com
Authors
Archives
Recommended Reading

February 14, 2007

Reproductive Technologies 101

Dennis M. Sullivan, MD, MA (Ethics)

Cedarville University

Infertility is often not considered a “disease” in our society, yet it causes great pain in couples who desire to begin a family. Couples are infertile when they have actively tried to conceive without success for a year, a condition that affects 10-15% of the U.S. population.1,2 Treatments designed to help couples conceive are referred to as Assisted Reproductive Technologies, or ART.

Couples may be candidates for ART after undergoing a thorough medical evaluation. In about one-third of cases, the problem resides within the woman, and may be related to failure to ovulate, or to failure of ova to enter the Fallopian tube (one of a pair of tubes connecting the ovary to the uterus). Another third of cases are due to male factors, such as azoospermia (an absence of sperm production) or oligospermia (inadequate numbers of sperm). In the remainder of cases, the cause is a combination of factors or is unknown.2

The simplest form of ART is hormonal stimulation of the ovaries. This is accomplished by the use of “fertility drugs” that hyperstimulate the ovaries. If a woman has failed to ovulate, such drugs may help. The down side of such treatments is that they may induce the ovaries to release more that one ovum3 per cycle, increasing the possibility of a multiple pregnancy (e.g., twins or triplets).

If the male partner is incapable of sexual intercourse, or if he has azoospermia or oligospermia, the couple may be candidates for artificial insemination. Sperm are obtained from the woman’s partner, or may be provided by an anonymous donor. Artificial insemination by donor (AID) is a popular technique, though it introduces the gametes of an outside party into the relationship, which raises ethical questions (not addressed here).

A more complex intervention is intracytoplasmic sperm injection (ICSI). This may be done in the case of a decreased sperm count or decreased sperm motility. In ICSI, one sperm is injected directly into a harvested ovum (obtained by techniques described shortly), producing a zygote (fertilized ovum). The zygote is then allowed do develop into an embryo in culture, and implanted into the woman’s uterus on the third day. This technique is rare, making up less than 1% of all ART interventions.

Of historical interest are GIFT (gamete intrafallopian transfer) and ZIFT (zygote intrafallopian transfer), where either gametes (ova and sperm) or a zygote are placed directly into the Fallopian tube. These are rarely done today because of advances in IVF.

In vitro fertilization (IVF) is a very popular form of ART, where fertilization of ova takes place outside of the uterus in a Petri dish (a shallow laboratory container made of Pyrex – in vitro means literally “in glass” from the Latin). Powerful endocrine hormones are used to hyperstimulate a woman’s ovaries. Developing follicles are followed by ultrasound over a period of weeks. When the developing ova are ready, they are harvested by means of a needle inserted trans-vaginally, under direct ultrasound guidance.

Harvested ova are placed into a Petri dish, and where ejaculated sperm are placed as well, causing fertilization. The resulting zygotes / embryos are allowed to develop in culture. Sometimes these are implanted at the three-day old (morula) stage, which is technically easier but results in a lower success rate. The success rate can be improved by waiting until the five-day (blastocyst) stage, though this is technically more demanding. By the way, in the “natural” scheme of things, it takes about 6 days for an embryo to travel down the Fallopian tube until it implants in the uterine wall.

The overall success rate for IVF is usually less than 50% per attempt. In order to improve the possibilities, some fertility centers implant six or more embryos, allowing them to develop in the womb for a few more weeks. After multiple embryos have implanted and developed, a specialist then goes into the uterus with a needle (under ultrasound guidance), and destroys smaller or less robust embryos, leaving about three. The practice is called selective reduction, and raises sanctity of life ethical concerns.

The cost of IVF for one hyperovulatory cycle may be $10,000 to $12,000, and this is not always covered by medical insurance. If previously frozen embryos are used, the cost per attempt may be only $2,000 to $3,000. Since a large number of ova (8 to 12) may be harvested at one time, cost and sanctity of life considerations make freezing embryos an attractive option, rather than simply discarding those that are not implanted. This involves special techniques of cryopreservation, and may preserve embryos for many years. However, cryopreservation of embryos raises legal questions about their status, and decreases the successful implantation percentage for each embryo.

It is not known how many “leftover embryos” are sitting in cryogenic storage in fertility centers. Some estimates are as high as 400, 000 in the U.S. alone.4 Though it is unclear how many of these embryos will be discarded in the next few years, their presence has fueled the debate over human embryonic stem cell research.


References:
1. McConchie D. “An Overview to Reproductive Technologies” http://www.cbhd.org/resources/reproductive/overview.htm. The Center for Bioethics & Human Dignity, Bannockburn, IL, 1999.

2. American Society for Reproductive Medicine http://www.asrm.org/whatsnew.html.

3. Note that the term ovum (pl. ova) is used here for simplicity. The actual biological entity is a secondary oocyte.

4. “Fact Sheet: The Legend of the 400, 000 Embryos” http://www.stemcellresearch.org/facts/2004-06-11.htm. Do No Harm Coalition, Washington, D.C.

7 Responses to “Reproductive Technologies 101”

  1. james braxton Says:

    There was no mention in there of the effect of STDs or advanced parental age on fertility. Why not?

  2. Albert Diddams, M.D. Says:

    This is an excellent article. I will use it to discuss this subject at our local Crisis Pregnancy Center this summer.
    Thank you.

  3. Dennis Sullivan Says:

    My response to James Braxton: Point well taken. Certainly STDs and advanced age will both increase the incidence of infertility, especially in women. A full discussion of the causes of infertility would go beyond the purposes of this article, which is specifically about reproductive technologies.

    But since you mention STDs, it is worth noting that scarring from chronic inflammation (as might happen with STDs or endometriosis) can occlude the opening into the Fallopian tubes, making it impossible for an ovum to enter. In such a case, it is sometimes possible to perform a fimbrioplasty, a surgical procedure to open up the tubes and permit fertilization to occur.

  4. Dennis Sullivan Says:

    UPDATE: Recent correspondence with an ethicist in the U.K. questioned my statement that ICSI is rare, “making up less than 1% of all ART interventions.” In fact, this is a much more common method in the U.K. I wondered if the same is true in the U.S., so I sent out some inquiries.

    One specialist replied that in 2004 (the last year for which he had data), 58% of IVF cycles used ICSI. “The reason for this is that there is little downside to ICSI, and if there is any question at all about the health of the sperm or their ability to fertilize, it’s a ‘better safe than sorry’ approach.”

    The author of the comment went on to say that, in his opnion, ICSI is somewhat overused, since it may lead to a small increase in the risk of birth defects. He himself tends to reserve the technique for male-factor issues (as I wrote in the original article.

    My thanks to the writers for these clarifications.

  5. sarah owen Says:

    I love this website. I am writing a research paper on reproductive technology, and this is by far the most useful, informational, website I have come across yet.
    Thanks!

  6. Sam Opar Says:

    I am glad that you’ve done a good job in the article,especially in regards to IVF.I am writing a paper on the bioethical concerns on IVF as a reproductive technology.If you may have more info on the topic id appreciate.
    Thanks!

  7. Angela Johnson 189 Says:

    Reproductive Technologies has come a long ways. I simpathis with the people who can’t have children. Thank God there are many different sulutions to their problems. I have two sons, Bryan (28) and Keddrick (14). They are the apple of my eyes.

Leave a Reply

You must be logged in to post a comment.

 

The Bioethics Poll
Should individuals and/or institutions be allowed to patent human genes?
Yes
Yes, with some qualifications
No
Undecided


View results

Which area of research should more money be invested in:
Animal-Human Hybrids
Gene Therapy
Reproductive Technology
Stem Cell Research
"Therapeutic" Cloning
None of the above


View results
 
RSS
 

Bioethics Websites
home |  about |  contact |   
your global information source on bioethics news and issues