Beginning of pregnancy controversy
5471132
221027070
2008-06-22T18:53:48Z
Rjwilmsi
203434
gen fixes + format *date= in cite news/web/paper templates - full explanation [[User:Rjwilmsi#My_correction_of_dates_in_templates|here]] using [[Project:AutoWikiBrowser|AWB]]
Controversy over the '''beginning of pregnancy''' usually occurs in the context of the [[abortion]] debate. Depending on where pregnancy is considered to begin, some methods of [[birth control]] or infertility treatment might be considered [[abortifacient]]. The controversy is not primarily a scientific issue since knowledge of human reproduction and development has become very refined, but rather is primarily a linguistic and definitional question. The issue may also have social, medical, political and legal ramifications, but only if one equates the "beginning of pregnancy" with the "beginning of an individual human being's life".<ref>Sagan, Carl. [http://www.2think.org/abortion.shtml "Is it Possible to be both 'Pro-life' and 'Pro-Choice?'”] ''in'' [[Billions and Billions]] (Ballantine 1997): "Despite many claims to the contrary, life does not begin at conception: It is an unbroken chain that stretches back nearly to the origin of the Earth, 4.6 billion years ago. Nor does ''human'' life begin at conception: It is an unbroken chain dating back to the origin of our species, hundreds of thousands of years ago. Every human sperm and egg is, beyond the shadow of a doubt, alive. They are not human beings, of course. However, it could be argued that neither is a fertilized egg." (Emphasis as in original.)</ref>
==Definitions of pregnancy beginning==
Traditionally, doctors have measured [[pregnancy]] from a number of convenient points, including the day of last [[Menstrual cycle|menstruation]], ovulation, [[fertilisation|fertilization]], implantation and chemical detection. This has led to some confusion about the precise length of human pregnancy, as each measuring point yields a different figure.
At its 2004 Annual Meeting, The [[American Medical Association]] considered a controversial resolution in favor of making "Plan B" [[emergency contraception]] available over-the-counter, and one of the claims in the resolution was that [[hormonal contraception]] that may affect implantation "cannot terminate an established pregnancy."<ref>[http://www.ama-assn.org/ama1/pub/upload/mm/15/res_hod443_a04.doc FDA Rejection of Over-The-Counter Status for Emergency Contraception Pills] ''American Medical Association House of Delegates'' Resolution:443. Retrieved April 30, 2007</ref> The resolution passed by a majority vote, despite the opposition of the [[American Academy of Family Physicians]].<ref>[http://www.aafp.org/PreBuilt/amadelegation_report.pdf AAFP AMA Delegation Report, 2003–2004 Annual Report, opposing Resolution 443] ''American Academy of Family Physicians'' Retrieved February 4, 2008</ref>
Similarly, the [[British Medical Association]] has defined an "established pregnancy" as beginning at implantation.<!--
--><ref name="BMA2005-AbortionTimeLimit">{{cite web | author=BMA | authorlink=British Medical Association | title=Abortion time limits: A briefing paper from the British Medical Association | year=2005 | month=May | url=http://www.bma.org.uk/ap.nsf/Content/AbortionTimeLimits}} "The term 'abortion' is used throughout this paper to refer to the induced termination of an established pregnancy (i.e. after implantation)."</ref><!--
--> The legal definition in the United Kingdom is not clear.<!--
--><ref>{{cite web | author =Hope, T. and Savulsecu, J. | url=http://web.archive.org/web/20060323042032/http://www.ethox.org.uk/education/teach/pregnancy/pregnancy3.htm | title =Handout 3: Outline of Legal Positions in England and Wales | work =Medical Ethics and Law Teaching Materials: Termination of Pregnancy | pages =Appendix 3: Some key points in the law on abortion and fetal damage | publisher =The Oxford Centre for Ethics and Communication in Health Care Practice, Oxford University}} - "It is generally assumed that when the Act states that ‘pregnancy has not exceeded its 24th week’ it means 24 weeks since the first day of the woman's last period. But this is not clear - particularly if there is evidence that conception had taken place on a day after this....The Attorney General said, in 1983 (see Brazier 1992 page 293-4) that there is no pregnancy until implantation. This is persuasive but not binding precedence."</ref> Other definitions exist. The American Heritage Stedman's [[Medical Dictionary]] defines "pregnancy" as "from conception until birth."<ref>The American Heritage Stedman's Medical Dictionary, 2002</ref> There has been some debate on the matter of definition in medical journals.<!--
--><ref> Larimore, Walter L., MD, et al. [http://www.stfm.org/fmhub/fm2004/November/Walter690.pdf "Response: Does Pregnancy Begin at Fertilization?"] Family Medicine, November-December 2004.</ref>
Finally the standard historical method of counting the [[gestational age|duration of pregnancy]] begins from the last menstruation and this remains common with doctors, hospitals, and medical companies.<!--
--><ref>''Doctor:''{{cite web | author=George P. Pettit, M.D. | title=Due Date Calculator | year=2002 | url=http://www.drpettit.com/ddcalc.html}}<br />
''Hospital:''{{cite web | author=Northwestern Memorial Hospital | title=What is a trimester? | year=2006 | url=http://www.nmh.org/nmh/adam/pregnancy/000006.htm}}<br />
''Medical company:''{{cite web | author=The Merck Manuals Online Medical Library | title=Stages of Development: Pregnancy | year=2003 | url=http://www.merck.com/mmhe/sec22/ch257/ch257c.html}}</ref> This system is convenient because it is easy to determine when the last menstrual period was, while both fertilization and implantation occur out of sight. An interesting consequence is that the dating of pregnancy measured this way begins two weeks before ovulation.
==History==
Previously, pregnancy was defined in terms of conception. However, in the absence of an accurate understanding of human development, early notions about the timing and process of conception were often vague. For example, ''Webster's Dictionary'' defined "pregnant" (or "pregnancy") as "having conceived" (or "the state of a female who has conceived"), in its 1828 and 1913 editions.<ref>[http://machaut.uchicago.edu/websters Webster’s Revised Unabridged Dictionary.]</ref>
Both the 1828 and 1913 editions of ''Webster's Dictionary'' said that to "conceive" meant "to begin the formation of the embryo." It was only in 1875 that [[Oskar Hertwig]] discovered that fertilization includes the penetration of a spermatozoon into an ovum. Thus, the term "conception" was in use long before the details of [[fertilization]] were discovered. By 1966, a more precise meaning of the word "conception" could be found in common-use dictionaries: the formation of a viable [[zygote]].<ref>Webster’s Third New International Dictionary (1966), defining conception as the "act of becoming pregnant (formation of a viable zygote); state of being conceived; that which is conceived (embryo, fetus)..." quoted in Mallett Shelley, [http://www.press.umich.edu/titleDetailLookInside.do?id=23496 Conceiving Cultures], p. 284 (U. Mich. 2003).</ref>
In 1959, Dr. Bent Boving suggested that the word "conception" should be associated with the process of implantation instead of fertilization.<ref>Boving, B.G., "Implantation Mechanisms", in ''Mechanics Concerned With Conception''. Hartman, C.G., ed. (Pergamon Press 1963), page 386.</ref> Some thought was given to possible societal consequences, as evidenced by Boving's statement that "the social advantage of being considered to prevent conception rather than to destroy an established pregnancy could depend on something so simple as a prudent habit of speech." In 1965, the [[American College of Obstetricians and Gynecologists]] (ACOG) adopted Boving’s definition: "conception is the implantation of a fertilized ovum."<ref>American College of Obstetricians and Gynecologists Terminology Bulletin. Terms Used in Reference to the Fetus. No. 1. Philadelphia: Davis, September, 1965.</ref>
The 1965 ACOG definition was imprecise because, by the time it implants, the zygote is called a [[blastocyst]],<ref name="Biggers">Biggers, J., "Ambiguity of the Word Conception: Implications if S. 158 is Enacted", ''[http://books.google.com/books?vid=OCLC08250373&id=LmkTAAAAIAAJ&q=%22Human+Life+Bill%22+and+biggers&dq=%22Human+Life+Bill%22+and+biggers&pgis=1 The Human Life Bill Appendix, Hearings Before the Subcommittee on Separation of Powers of the Committee on the Judiciary, United States Senate]'', p. 281-288 (1982). </ref> so it was clarified in 1972 to "Conception is the implantation of the blastocyst."<ref>Hughes, E.C. "Gametogenesis and Fertilization", in ''Obstretric-Gynecologic Terminology''. Philadelphia: Davis, 1972: 299-304.</ref> Some dictionaries continue to use the definition of conception as the formation of a viable zygote.<ref>[http://dictionary.reference.com/browse/conception Dictionary.com].</ref>
==Birth control - mechanism of action==
:''See also [[Combined oral contraceptive pill#Mechanism of action|COCP: Mechanism of Action]]
Birth control methods usually prevent fertilization. This cannot be seen as [[abortifacient]] because, by any of the above definitions, pregnancy has not started. However, some methods might have a back-up effect of preventing implantation, thus allowing the [[zygote]] to die. Those who define pregnancy from fertilization subsequently conclude that the agents should be considered abortifacients.
Speculation about post-fertilization mechanisms is widespread, even appearing on patient information inserts for hormonal contraception, but there is no clinical support. One small study, using fourteen women, might be considered as providing evidence of such an effect for IUDs<!--
--><ref>{{cite journal | author = Stanford J, Mikolajczyk R | title = Mechanisms of action of intrauterine devices: update and estimation of postfertilization effects | journal = Am J Obstet Gynecol | volume = 187 | issue = 6 | pages = 1699–708 | year = 2002 | pmid = 12501086 | doi = 10.1067/mob.2002.128091}}, which cites:
:{{cite journal | author = Smart Y, Fraser I, Clancy R, Roberts T, Cripps A | title = Early pregnancy factor as a monitor for fertilization in women wearing intrauterine devices | journal = Fertil Steril | volume = 37 | issue = 2 | pages = 201–4 | year = 1982 | pmid = 6174375}}</ref> and a study of the [[combined oral contraceptive pill]] has been proposed.<!--
--><ref>{{cite paper | author = Lloyd J DuPlantis, Jr | title = Early Pregnancy Factor | publisher = Pharmacists for Life, Intl | date = 2001 | url = http://www.lifeissues.net/writers/dup/dup_01earlypregfacts.html | accessdate = 2007-01-01 }}</ref>
===Possibly affected methods===
*[[Hormonal contraception]], including [[emergency contraception]], works primarily by preventing ovulation, but may have a secondary effect of interfering with fertilisation or implantation of embryos.
*[[Intrauterine device]]s work primarily by spermicidal/ovicidal effects, but may have a secondary effect of interfering with the development of pre-implanted embryos.
*The [[lactational amenorrhea method]] works primarily by preventing ovulation, but is also known to cause [[luteal phase defect]] (LPD). LPD is believed to interfere with the implantation of embryos.<!--
--><ref name="Diaz, S. et. al">{{cite journal | author = Díaz S, Cárdenas H, Brandeis A, Miranda P, Salvatierra A, Croxatto H | title = Relative contributions of anovulation and luteal phase defect to the reduced pregnancy rate of breastfeeding women. | journal = Fertil Steril | volume = 58 | issue = 3 | pages = 498–503 | year = 1992 | pmid = 1521642}}</ref>
*[[Fertility awareness]] methods work primarily by preventing conception, but it has been speculated they have a secondary effect of creating embryos incapable of implanting (due to aged gametes at the time of fertilization).<!--
--><ref>{{cite journal | author=Luc Bovens | title=The rhythm method and embryonic death | journal=[http://jme.bmjjournals.com/ Journal of Medical Ethics] | year=2006 | volume=32 | pages=355–356 | url=http://jme.bmj.com/cgi/content/full/32/6/355 | format= }}</ref>
==In vitro fertilisation==
The advent of [[in vitro fertilisation]] (IVF) allowed fertilisation [[in vitro|to occur in laboratory glassware]] instead of inside a female. Creating an embryo in vitro showed that fertilization is an event that does not automatically result in pregnancy.
==Viability and established pregnancy==
A related issue that comes up in this debate is how often fertilization leads to an established, viable pregnancy. Current research suggests that fertilized embryos naturally fail to implant some 30% to 60% of the time.<!--
--><ref>Kennedy, T.G. [http://publish.uwo.ca/~kennedyt/t108.pdf Physiology of implantation]. <u>10th World Congress on in vitro fertilization and assisted reproduction</u>. Vancouver, Canada, 24-28 May 1997.</ref><!--
--><ref>{{cite journal | author = Smart Y, Fraser I, Roberts T, Clancy R, Cripps A | title = Fertilization and early pregnancy loss in healthy women attempting conception | journal = Clin Reprod Fertil | volume = 1 | issue = 3 | pages = 177–84 | year = 1982 | pmid = 6196101}}</ref> Of those that do implant, about 25% are [[miscarriage|miscarried]] by the sixth week [[gestational age|LMP]] (after the woman's Last Menstrual Period).<!--
--><ref>Wilcox AJ, Baird DD, Weinberg CR. ''Time of implantation of the conceptus and loss of pregnancy.'' New England Journal of Medicine. 1999;340(23):1796-1799. PMID 10362823.</ref> As a result, even without the use of [[birth control]], between 48% and 70% of [[zygotes]] never result in established pregnancies, much less birth.
==Ethics of preventing implantation==
The intention of a woman to prevent pregnancy is an important factor in whether or not the act of contraception is seen as abortive by some [[pro-life]] groups. Hormonal contraceptives have a possible effect of preventing implantation of a blastocyst, as discussed previously. Use of these drugs with the intention of preventing pregnancy is seen by some pro-life groups as immoral. This is because of the possibility of causing what they believe to be an abortion.<!--
--><ref>{{cite web | last = Finn | first = J.T. | title = "Birth Control" Pills cause early Abortions | work = Pro-Life America — Facts on Abortion | publisher = prolife.com | date = 2005-04-23 | url = http://www.prolife.com/BIRTHCNT.html | accessdate = 2006-08-25 }}</ref>
However, hormonal contraception can also be used as a treatment for various medical conditions. When implantation prevention is unintentionally caused as a side effect of medical treatment, such pro-life groups do not consider the practice to be immoral, citing the bioethical [[principle of double effect]].<!--
--><ref>[http://www.epm.org/articles/BreastfedAbortions.html Doesn't breastfeeding do the same thing as the Pill?] Eternal Perspective Ministries, 2006. Accessed May 2006.</ref> Likewise, when a hormonal contraceptive is used with the intention of preventing fertilisation, the intended reduction in implantation failures, miscarriages and deaths from childbearing may outweigh the possibility that the method might cause some implantation failures.
A related application of the principle of double effect is [[breastfeeding]]. Breastfeeding greatly suppresses ovulation, but eventually an ovum is released. Luteal phase defect, caused by breastfeeding, makes the uterine lining hostile to implantation and as such may prevent implantation after fertilization.<ref name="Diaz, S. et. al"/> Some pro-choice groups have expressed concern that the movement to recognize [[hormonal contraception|hormonal contraceptives]] as abortifacient will also cause breastfeeding to be considered an abortion method.<!--
--><ref>{{cite web | title=Emergency Contraception & Conscience: Christian Right Attacks on Contraceptives | work=About.com ''Religion & Spirituality'' Agnosticism / Atheism | url=http://atheism.about.com/od/abortioncontraception/p/MorningAfter.htm | accessdate=2006-06-22}}</ref><!--
--><ref>{{cite news | first=Russell | last=Shorto | title=Contra-Contraception | pages=4 of 9-page online article |date=2006-05-07 | publisher=New York Times Magazine | url=http://www.nytimes.com/2006/05/07/magazine/07contraception.html?pagewanted=1&ei=5088&en=fd92772f01a5c709&ex=1304654400&adxnnl=0&partner=rssnyt&emc=rss&adxnnlx=1151015936-QF5/uHStQAb9tAkPSzv7uw }}</ref>
==Detectable pregnancy==
A protein called [[early pregnancy factor]] (EPF) is detectable in a woman's blood within 48 hours of ovulation if fertilization has occurred. However, testing for EPF is time consuming and expensive; most early pregnancy tests detect [[human chorionic gonadotropin]] (hCG), a hormone that is not secreted until after implantation. Defining pregnancy as beginning at implantation thus makes pregnancy a condition that can be easily tested for.
==External links==
* [http://www.noroomforcontraception.com/pregnancy/Physicians-Pregnancy-Petri-Dish.htm Physicians, Petri Dishes, and Pregnancy] - ''No Room for Contraception'' (a pro-life group) essay on the beginning of pregnancy controversy
==Notes==
<references />
[[Category:Abortion debate]]
[[Category:Birth control]]
[[Category:Pregnancy]]
[[Category:Controversies]]