The series of events called the menstrual cycle happens about once every month to prepare a women’s body for pregnancy and changing levels of natural levels of natural chemicals in the blood stream called hormones control these events. The reproductive organs affected by these hormones include the vagina, cervix, uterus, fallopian tubes and ovaries. The ovaries produce to main hormones called estrogens and progesterone, as the level of estrogens begins to raise it causes the normally thick mucus inside the cervix to thin out. Estrogens also trigger other hormones to cause one of the ovaries to release an egg this process is called ovulation. If women have sex at this time the men’s reproductive cell called sperm can pass through the thinner mucus to fertilize an egg. In the uterus estrogens causes the lining to thick in which prepares it to receive a fertilized egg. Rising progesterone levels causes glands in the lining to release fluid that feeds the fertilized egg. Progesterone also causes the thinned out nucleus in the cervix to become thick again which prevents sperm from passing through. If an egg has not been fertilized the levels of both oestrogen and progesterone begin this drop in hormone levels causes menstruation a process where the uterus its inner tissue lining and blood through the vagina.
Birth control pills are medications that a woman takes everyday to prevent pregnancy. The most common and effective type of birth control pill is a combination pill contains both estrogens and progestin, which is a man made hormone similar to progesterone. The estrogens and progestin maintains constant levels of these hormones in the body. These levels prevent the body from releasing similar hormones that cause ovulation, without ovulation there is no egg available for fertilization. So women can’t get pregnant. Progestin also prevents pregnancy by keeping the mucus in the cervix thick so sperm can’t get through it. The major effect of progestin on pregnancy involves its influence on the lining of the uterus; in contrast progesterone progestin is slightly different chemically. Over time it makes the uterine lining thinner instead thicker. As a result the fertilization of egg does takes place the lining may be too thin for it to stay in the uterus so it passes out of the body with the next menstrual period.
Combination pills usually come in 28 day packs depending on the brand of the pill the first 21 and 24 pills are active pills because they contain hormones. The last four to seven pills are inactive for reminder pills that don’t contain any hormones. In active pills allow the hormone levels in the body to drop so that bleeding during the menstrual cycle can occur. Though inactive pills don’t contain any hormones the women remains protected against pregnancy at this time. For the highest protection against pregnancy it is important to take progestin only pills at the same time every day. Both combination and progestin control pills are effective at preventing pregnancy if they are used correctly.