Saturday, August 27, 2011
A doctor speaks out on the moment of conception and the definition of "abortifacient"
This is the document that is cited in the Filipinos for Life press release that, in turn, forms the basis of the following article on CBCP for Life: Debate over conception settled decades ago, lawmakers told.
The following questions are frequently asked in connection with the debates over the Reproductive Health bill:
1. What's the scientific basis of conception occurring at fertilization?
2. What contraceptives can therefore be considered abortive under that definition?
The following is my response.
The key feature of a human pattern is its organization towards the production of a mature human body. Basic embryology teaches us that the instant of fertilization (the union of the ovum and sperm) is time zero of human development. Fertilization results in the formation of a new cell that is distinct from the cells that give rise to it, because the fertilized ovum/zygote/embryo, as a stage in human development, possesses the material composition (genetic and molecular) and behavior (developmental pathway) necessary for its maturity.
Since LIFE is defined as an organismic state characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction, and it is governed by the law of biogenesis, which states that all life comes from preexisting life, the fertilized ovum/zygote/embryo, whether it has implanted on a woman’s endometrium or not, is ALIVE and is HUMAN.
Historically, the terms fertilization and conception were used interchangeably. However, in the 1960s, the American College of Obstetrics and Gynecology (ACOG) and the International Federation of Obstetrics and Gynecology (FIGO) redefined conception as the implantation of a fertilized ovum, citing that the union of sperm and ovum cannot be detected clinically unless implantation occurs. Pregnancy was subsequently defined as the state from conception to expulsion of the products of that conception. This invariably changed the definition of conception from fertilization to implantation. Coincidentally, this redefinition was not brought about by any scientific breakthrough during that time but was made at around the same time that the first intrauterine device (IUD) was sold in the market and birth control pills were legalized in the US.
It must be emphasized that pregnancy is the state of the mother, not of the unborn. Therefore, non-implantation does not negate the status of the fertilized ovum/zygote/embryo as a living human being.
The confusion over the term conception and whether it refers to fertilization or implantation is not a result of lack of scientific data but of verbal engineering. The implications of redefining conception are seen in the mechanisms of action of contraceptive pills and IUDs and whether they act as abortifacients.
From the pharmacologic standpoint, hormonal contraceptives (pills and injectables) have multiple mechanisms of action. Katzung’s Basic and Clinical Pharmacology 11th ed (2009) states that:
“The combinations of estrogens and progestins exert their contraceptive effect largely through selective inhibition of pituitary function that results in inhibition of ovulation. The combination agents also produce a change in the cervical mucus, in the uterine endometrium, and in motility and secretion in the uterine tubes, all of which decrease the likelihood of conception and implantation. The continuous use of progestins alone does not always inhibit ovulation. The other factors mentioned, therefore, play a major role in the prevention of pregnancy when these agents are used.”
(Note as well that in pharmacology textbooks, conception is used to refer to fertilization and is clearly distinguished from implantation.)
On the other hand, the IUD incites an inflammatory reaction on the endometrial lining. This inflammation acts as a spermicide AND as a means to decrease the likelihood of implantation should fertilization occur (Comprehensive Gynecology, 5th ed 2007).
By virtue of the ACOG/FIGO redefinition of conception, the post-fertilization effect of preventing implantation does not SEMANTICALLY equate to the abortifacient effect of contraceptive pills and IUDs, since abortion is technically defined (again by ACOG and FIGO) as the expulsion of all the products of conception before the twentieth week of pregnancy.
HOWEVER, this is in direct contradiction to the Department of Health and Human Services, US Department of Health, Education and Welfare statement which affirms that life begins at fertilization when it states that:
“All measures which impair the viability of the zygote at any time between the instant of fertilization and the completion of labor constitute, in the strict sense, procedures for inducing abortion.”
It is therefore only logical that, if we subscribe to the scientific fact that human development begins at fertilization, the prevention of implantation terminates life. While it may be argued that the prevention of implantation is not the PRIMARY mechanism of action of these drugs and devices, fertilization can occur, as evidenced by breakthrough ovulations and contraceptive failures. A contraceptive failure is a human being. THUS, the SECONDARY mechanism of preventing implantation constitutes the abortifacient effect of hormonal contraceptives and IUDs.
However, it is logistically, technologically, and ethically impossible to determine which “successful” prevention of pregnancy is due to inhibition of ovulation, fertilization or implantation. This is where World Health Organization (WHO), medical societies and scientific journals use the term “no evidence” in reference to the lack of empirical data, and NOT to the fact that a phenomenon does not occur.
In this light, it is imperative that the precautionary principle, which states that:
“if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking the action,”
be applied. When science finds a plausible risk, social responsibility must compel us to protect the public from exposure to harm, until such time that further scientific findings provide sound evidence that ABSOLUTELY NO HARM TO LIFE will result from the action.
Ultimately, as human beings, our actions must always PROTECT LIFE in order to be truly PRO-LIFE, because we cannot afford to risk even one human life.
Abraham Daniel Campo Cruz, MD
Instructor A, Department of Pharmacology, FEU-NRMF Institute of Medicine
Master of Science (cand.) in Pharmacology, UP Manila
Associate Member, Philippine Society of Experimental and Clinical Pharmacology
Member, Filipinos for Life