Oral contraception menstrual cycle

Women who take oral contraceptives typically experience more regular menstrual cycles. In general, oral contraceptive use is associated with less cramping and dysmenorrhea.1,8 Also, women who take oral contraceptives experience fewer days of menstruation each month and as a result experience less blood loss with each menstrual period.1,13 Some studies suggest that oral contraceptive use decreases overall monthly menstrual flow by 60% or more, which may be particularly beneficial in women who are anemic.1... 

Kuukasjarvi, S., Eriksson, C.J.P., Koskela, E., Mappes, T., Nissinen, K. and Rantala, MJ. (2004) Attractiveness of women s body odors over the course of the menstrual cycle The role of oral contraceptives and receiver sex. Behav. Ecol. 15, 579-584. 

The highest mean number of sexual partners while in Spain was shown by females taking oral contraceptives (0.63, N = 8) followed by those not taking contraceptives but in the second half of their menstrual cycle (0.55 N = 11) and finally those in the first half of their menstrual cycle (0.50 N = 12). The differences, however, were not significant (ANOVA F 2 28 = 0.06 P = 0.94). Differences in risk of conception for the three groups were in any case probably minimal, given that the menstrual cycles of well over half of even the women not taking oral contraceptives would be anovulatory (Baker, unpublished data). 

A low dosage of progestin ( mini-pill ) is used, in the form of medroxyprogesterone acetate, which is active at a very low dose. The mini-pill does not inhibit ovulation, but rather interferes with the endometrium and the cervical mucus. The use of this pill prevents most of the side effects of oral contraception, specifically nausea, water retention, and in some cases thrombophlebitis. However, a lower success rate and other frequent side effects have reduced the widespread acceptance of this preparation. Nevertheless, the mini-pill has a role to play in certain specific situations. For example, in an uncommon form of epilepsy called catamenial epilepsy, female patients will experience seizures at particular times during their menstrual cycle, reflecting the fact that seizure focus is stimulated by estrogens but inhibited by progestins. In such women, the mini-pill may afford not only birth control but also improved seizure control. 

The time of year and the point during the menstrual cycle during which vitamin D derivatives are measured may be important. In seven women there was a two-fold rise in the serum concentration of 1,25-dihydroxycolecalci-ferol on day 15 of the menstrual cycle compared with days 1 and 8, without a detectable change in the serum calcium concentration (187). This increase did not occur in five women taking oral contraceptives, and there was a small but significant fall in the serum calcium concentration. 

Body temperature tends to rise slightly in some users of oral contraceptives (286,287) Progesterone has a mild thermogenic effect, reflected in changes in body temperature during the normal menstrual cycle. Mild pyrexia in users of oral contraceptives may reflect this, but the patient should always be examined to exclude infection. 

Mardell M, Zilva JF. Effect of oral contraceptives on the variations in serum-iron during the menstrual cycle. Lancet 1967 2(7530) 1323-5. 

Jochemsen R, van der Graaff M, Boeijinga JK, Breimer DD. Influence of sex, menstrual cycle and oral contraception on the disposition of nitrazepam. Br J Clin Pharmacol 1982 13(3) 319-24. 

Lynestrenol is one of the older progestogens used in oral contraceptives and has been very widely and successfully employed for nearly 40 years as monotherapy it has been used to treat irregularity of the menstrual cycle. 

More recendy, a variation on the length of the oral contraceptive cycle was introduced in which women take the active form of the pill for 84 days, and then take a 7-day placebo.66,70 This provides a 3-month cycle before menstruation, thus reducing the number of menstrual periods to only 4 per year. These long cycle regimens seem to be as effective as the... 

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