Friday, December 3, 2010
A Doctor responds to POGS on Abortifacient Contraceptives
From the blog of Dr. Liza Manalo, Caduceus:
Apparently, the Philippine Obstetric and Gynecologic Society is in favor of the RH Bills. They are disseminating email to colleagues sending the link to the PCHRD/Philippine Star article on "Noted OB-Gyne says Contraceptives Not Abortifacient."
On the other hand, being an epidemiologist and a teacher of Evidence Based Medicine (EBM) and Bioethics, I have been doing my own share of searching the available literature on this matter and I have found two well designed and well-written researches and publications in well-known peer reviewed scientific journals that prove the contrary:
Postfertilization Effects of Oral Contraceptives and Their Relationship to Informed Consent
Walter L. Larimore, MD; Joseph B. Stanford, MD, MSPH
The primary mechanism of oral contraceptives is to inhibit ovulation, but this mechanism is not always operative. When breakthrough ovulation occurs, then secondary mechanisms operate to prevent clinically recognized pregnancy. These secondary mechanisms may occur either before or after fertilization. Postfertilization effects would be problematic for some patients, who may desire information about this possibility. This article evaluates the available evidence for the postfertilization effects of oral contraceptives and concludes that good evidence exists to support the hypothesis that the effectiveness of oral contraceptives dependsto some degree on postfertilization effects. However, there are insufficient data to quantitate the relative contribution of postfertilization effects. Despite the lack of quantitative data, the principles of informed consent suggest that patients who may object to any postfertilization loss should be made aware of this information so that they can give fully informed consent for the use of oral contraceptives. (Arch Fam Med. 2000;9:126-133)
Mechanisms of action of intrauterine devices: Update and estimation of postfertilization effects
Joseph B. Stanford, MD, MSPH,a and Rafael T. Mikolajczyk, MDb
Salt Lake City, Utah, and Magdeburg, Germany
There are many potential mechanisms of action for the intrauterine device (IUD), which vary by type of IUD (inert, copper, or hormonal). This paper reviews the evidence for each potential mechanism of action. On the basis of available data for fertilization rates and clinical pregnancy rates, the relative contribution of mechanisms acting before or after fertilization were quantitatively estimated. These estimates indicate that, although prefertilization effects are more prominent for the copper IUD, both prefertilization and postfertilization mechanisms of action contribute significantly to the effectiveness of all types of intrauterine devices. (Am J Obstet Gynecol 2002;187:1699-708.)
Weighing the available evidence therefore, who are we supposed to believe? This noted OB-Gynecologist or these other researchers from the US and Germany? Check out the quality of their researches and make your own judgment. What is important is the openness to the truth and to life.