- Postfertilization Effects of Oral Contraceptives and Their Relationship to Informed Consent
http://archfami.ama-assn.org/cgi/content/full/9/2/126)
“It seems likely that for perfect use of COCs, postfertilization mechanisms would
be likely to have a small but not negligible role. For POPs, COCs with lower
doses of estrogen, and imperfect use of any OCs, postfertilization effects are
likely to have an increased role. In any case, the medical
literature does not support the hypothesis that
postfertilization effects of OCs do not exist.”
- The Physicians' Prescribing information for Yaz and Yasmin, two oral contraceptives
http://berlex.bayerhealthcare.com/ht.../Yasmin_PI.pdf
http://www.berlex.com/html/products/pi/fhc/YAZ_PI.pdf
Combination oral contraceptives (COCs) act by suppression of gonadotropins.
Although the primary mechanism of this action is inhibition of ovulation,
other alterations include changes in the cervical mucus (which increases the/QUOTE]
difficulty of sperm entry into the uterus) and the endometrium (which reduces
the likelihood of implantation).
- Do Contraceptive Pills cause Abortion?
By Patrick McCrystal MPSNI / MPSI
http://www.hliireland.ie/abortifacie...raception.html
One of the ways by which the 'pill' works is by;
"...the rendering of the endometrium unreceptive to implantation" (1)
Put simply this means a newly created embryo is not allowed to implant in its mother's womb. This action takes place after fertilisation (conception), ie after a new life has been created. Thus it can be termed abortifacient (2,3) or abortion-causing. Indeed, the medical literature suggests this abortion-causing mode of action does occur during 'pill' use (4,5,20).
Every chemical contraceptive preparation involving pills, injections, implants and intrauterine devices have this mechanism present as an inherent part of their birth control action.
- The Pill – How it works and fails.
http://www.pfli.org/faq_oc.html
Q. So how do you prove that the pill acts as an abortifacient?
A. The answer to this question can be found by comparing the rate of break-through ovulation and the detected pregnancy rate. The ovulation rate has been reported to be about 27 ovulations in 100 women using the pill for one year. But the detected pregnancy rate is much lower at around 4 pregnancies per 100 women using the pill for one year.
As you can see, there is a big difference between the number of women who ovulation (27) and the number of detected pregnancies (4). What has happened within the woman’s body to reduce the high ovulation rate to such a low number of detected pregnancies? I suggest that one answer to this important question is that pregnancies have begun, because ovulation and fertilization have occurred, but some of these pregnancies are terminated because implantation cannot take place. The pill has damaged the lining of the womb, stopping implanation.
- Mechanisms of action of intrauterine devices: update and estimation of postfertilization effects
http://www.ncbi.nlm.nih.gov/pubmed/12501086
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.
- CVS/Pharmacy
http://www.cvs.com
IUDs are thought to prevent pregnancy by making the womb ‘unfriendly’ to sperm and eggs. Sperm is either killed, or kept from reaching and fertilizing an egg. An IUD also may keep a fertilized egg from attaching to the womb and growing into a baby.
- Mechanism of action of intrauterine contraceptive devices and its relation to informed consent
http://www.ncbi.nlm.nih.gov/pubmed/9...ubmed_RVDocSum
The purposes of this review are to evaluate the available evidence for the mechanisms of action of copper-impregnated intrauterine contraceptive devices and to describe the informed consent consequences of those mechanisms. The medical literature was reviewed with the use of the Bioethics and Medline databases (1966 to present). Reports that supported or refuted the two major postulated mechanisms (interference with implantation of the fertilized ovum or spermicidal inhibition of fertilization) were assessed for their relative strength and support for the exclusivity of one or the other mechanism. The analysis of the evidence strongly suggests that the contraceptive effectiveness of intrauterine contraceptive devices is achieved by both a prefertilization spermicidal action and a postfertilization inhibition of uterine implantation. Patient informed consent for intrauterine contraceptive device insertion should include a discussion of these mechanisms of actions so as to avoid their use in patients with moral objections to postfertilization contraception.