Before the advent of modern contraceptives, reproductive age women spent most of their time either pregnant or nursing.
[7] Although it was evident that the pill could be used to suppress menstruation for arbitrary lengths of time, the original regimen was designed to produce withdrawal bleeding every four weeks to mimic the menstrual cycle.
[9] When a woman takes COCP, the hormones in the pills prevent both ovulation and shedding of the endometrium (menstruation).
During the week of placebo pills, withdrawal bleeding occurs and simulates an average 28-day menstrual cycle.
[10] With bi- and tri-phasic pills, skipping the placebo week results in a sudden change in hormone levels, which may cause irregular spotting or flow.
)[citation needed] Recently, several pharmaceutical companies have gained FDA approval to package COCPs for the intended use of reducing the frequency of or eliminating withdrawal bleeding.
[11] Personal preference is the most common reason extended cycle or continuous use COCPs are prescribed to adolescents.
[13] The Society for Menstrual Cycle Research holds that this use of COCPs does not have sufficient safety studies to justify promotion as a lifestyle choice (as opposed to medical indications), and criticizes what it perceives as negative portrayals of normal menstrual cycles in promotional literature for extended and continuous COCP use.
[14] Women's satisfaction with their contraception, compliance in taking the pills on time, and discontinuation rates are not significantly different between traditional and extended cycle regimens.
[16] There is also limited evidence for benefit of Combined oral contraceptive pill (OCP) as treatment for primary dysmenorrhoea.
Many preclinical and clinical studies reveal that changes in lipoprotein metabolism are a major contributing factor to atherosclerosis.