The Definition of key terms
As a result of an ideologically redefinition of contraception, (1) (2) (3) conception (4) (5) and pregnancy, (6) (7) (8) remedial action is required to re-anchor these reproductive terms within an authentic scientific framework.
Contraception (L, contra, against; concipere, to take in) is a process, device or intervention whose action is solely to prevent the unification of sperm and the secondary oocyte, commonly referred to as an ovum.(9)
Condoms, spermicides, cervical diaphragms and male or female sterilization are contraceptive practices because their only action is to impede the sperm and the secondary oocyte from unifying. Note, the term ovum is a colloquial expression that has no true relationship with any stage of female sex cell generation, development or involvement in human embryonic conception. Key embryologists recommend against its use.(10) Note also, in many instances, I have placed the word 'contraception' in apostrophes, to indicate that its use, whilst ubiquitous, is descriptively incorrect.
Zygote a single cell formed by the fusion of the male and female genetic material. The full human chromosomal number of 46 is restored and as a consequence, a new human life has begun.(11) (12) (13) "A zygote is the beginning of a new human being (i.e., an embryo)."(14) The zygote is formed within the Fallopian tube.
Conception is the beginning of a pregnancy, taken to be the precise moment that a spermatozoon enters the female secondary oocyte, resulting in the formation of a viable human zygote.(15) Reputable educationalists concur on this critical point. Moore and Persaud state that: "Human development begins at fertilization, the process during which a male gamete or sperm ... unites with a female gamete or oocyte ... to form a single cell called a zygote. This highly specialized, totipotent cell marks the beginning if each of us as a unique individual."(16)
Prof. R. Rahwan, Emeritus Professor of Pharmacology and Toxicology, Ohio State University concurs with this definition: "... fertilization marks the point of conception in that a new diploid (full chromosomal number) organism (the zygote) is formed which will develop, mature, and undergo senescence at a predictable rate." (17)
O'Rahilly and Muller, authors of Human Embryology and Teratology reflect the same thinking: "Fertilization is an important landmark because, under ordinary circumstances, a new genetically distinct human organism is thereby formed." (18)
Fertilization is the process that begins when a sperm makes contact with a secondary oocyte and concludes with the intermingling of the male and female chromosomes. (19) This process takes approximately 24 hours to complete. (20)
Abortifacient drugs or devices are defined as those whose action is operative after conception has occurred.(21) (22) The pre-eminent embryologists Keith L. Moore and T.V.N. Persaud concur with this description:
"Postcoital birth control pills ("morning after pills") may be prescribed in an emergency (e.g., following sexual abuse). Ovarian hormones (estrogen) taken in large doses within 72 hours after sexual intercourse usually prevents implantation of the blastocyst, probably by altering tubal motility, interfering with corpus luteum function, or causing abnormal changes in the endometrium. These hormones prevent implantation, not fertilization. Consequently, they should not be called contraceptive pills. Conception occurs but the blastocyst does not implant. It would be more appropriate to call them 'contraimplantation pill.' Because the term abortion refers to a premature stoppage of a pregnancy, the term abortion could be applied to such an early termination of pregnancy." (23)
Blastocyst is the precise description of the multicellular human embryo four days after fertilization. The blastocyst moves across the uterus for two days before it begins the process of implantation. Implantation of the human blastocyst begins about six days after fertilization.(24) Implantation takes place during the implantation window. "The implantation window is a short interval during the mid-secretory phase, when the endometrium is most receptive to blastocyst implantation. It begins on days 20-24 of an ideal menstrual cycle or 6-10 days after the LH (luteinising hormone) surge and is believed to last less than 48 hours." (25) This receptive uterine "window" is "... achieved through a coordinated action of P4 (progesterone) and E2 (estrogen)." (26)
(1) "Emergency contraception is not abortion." Lancet 1995; 345: 1381-1382 (Editorial)
(2) Ellertson C, Winikoff B, Armstrong E, Camp S, Senanayake P. Expanding access to emergency contraception in developing countries. Stud Fam Plan 1995; 26, (5) pp. 251-263
(3) Weisberg E, Fraser IS, Carrick SE, Wilde FM. Emergency contraception-general practitioner knowledge, attitude and practices in New South Wales. Med J Aust 1995; 162:136-138.
(4) Harper C, Ellertson C. Knowledge and perceptions of emergency contraceptive pills among a college-age population: a qualitative approach. Fam Plan Perspectives 1995; 27:149-154.
(5) Pruitt SL, Mullen PD. Contraception or abortion? Inaccurate descriptions of emergency contraception in newspaper articles, 1992 - 2002. Contraception. 2005;71:14-21
(6) Ibid, p.149
(7) Ellertson C, Winikoff B, Armstrong E, et al. op.cit., p.251
(8) Grou F, Rodrigues I. The morning-after pill- How long after? Am J Obstet Gynecol 1994; 171:6:p.1529.
(9) Rahwan RG. Chemical contraceptives, interceptives and abortifacients. Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210 USA. 1998
(10) O'Rahilly R, Muller F. Human Embryology and Teratology. (Wiley-Liss, New York, 1994), p.16
(11) Larsen WJ. Human Embryology. (New York: Churchill Livingstone, 1997), p.1
(12) O'Rahilly, op.cit., p.19
(13) Carlson BM. Human Embryology and Developmental Biology. (Mosby's Books) 1994, p.31
(14) Moore KL, Persaud TVN. The Developing Human: Clinically Orientated Embryology (6th edition. Philadelphia: W.B. Saunders Company 1998), p.2
(15) Mosby�s Medical, Nursing and Allied Health Dictionary (5th ed. KN Anderson (ed) St. Louis, Missouri, USA 1998). p.379
(16) Moore, op.cit., p.18
(17) Rahwan, op.cit.
(18) O'Rahilly, op.cit., p.5
(19) Ibid, p.19
(20) Moore, op.cit., p.34
(21) Mosby's, p.393
(22) Rahwan, op.cit.,p.7
(23) Moore, op.cit., p.532
(24) http://embryo.chronolab.com/implantation.htm (Viewed February 27, 2010)
(25) Aghajanova L, Hamilton AE, Giudice LC. Uterine receptivity to human embryonic implantation: Histology, biomarkers, and transcriptomics. Sem Cell Dev Biol. 2008; Apr;19(2):204-11
(26) Tamm K, Room M, Salumets A, Metsis M. Genes targeted by the estrogen and progesterone receptors in the human endometrial cell lines HECIA and RL95-2. Reproductive Biology and Endocrinology. 2009;7:150 http://www.rbej.com/content/pdf/1477-7827-7-150.pdf (Accessed February 21, 2010)
