Health Canada and Oral Contraceptives

Oral Contraceptives: A report by the Special Advisory Committee on Reproductive Physiology to the drugs Directorate Health Protection Branch Health Canada is the standard Canadian government reference for OCs.
 
Under the section '2. Hormonal Methods of Contraception' it is written:

OCs may exert their contraceptive action in at least four ways:

• by inhibiting ovulation
• by causing endometrial changes hindering implantation
• by altering the physical and chemical properties of the cervical mucus, thereby inhibiting sperm penetration; and
• by causing subtle changes in the hypothalamic-pituitary-ovarian axis and possibly altering corpus luteum function. The steroid profiles quite often show either insufficient or an absence of luteal activity, or as a significant and graduel decrease in several indices of luteal function.

Probably none of these factors alone accounts for the high degree of anti-fertility effect of any OC. They may all play a part in the production of effective contraception.¹

This is clear evidence that there may be at least four known methods of action. Later in this document is the information written for the consumer, 'Supplementary Information Booklet for Patients Considering the Use of Oral Contraceptives (Birth Control Pills)', which states:

Introduction
This booklet will give you information to make an informed choice on the use of oral contraceptives...

How birth control pills work
Birth Control Pills work in two ways:

1. They inhibit the monthly release of an egg by the ovaries.
2. They change the mucus produces by the cervix. This slows the movement of the sperm through the mucus and through the uterus (womb).²

This Health Canada document first made it clear that there may be at least four mechanisms of action. Yet in the patient information, informed consent (choice) is proclaimed while endometrial changes inhibiting implantation is not mentioned. This information may be misleading.

The Canadian Drug Reference for Health Professionals >>