If the egg is fertilized at this time by a man's sperm, the merged cell begins to divide while continuing several days' travel toward the uterus. There, the group of cells can embed in the uterine wall and develop into an embryo and placenta. Contraception interferes with this process at some point along the way. Fertility may be interrupted by pregnancy itself or altered by some medical conditions, medications, surgical procedures or contraception methods. When prevention of pregnancy is desirable, contraception becomes the responsibility of a sexually active couple, not only the woman.
Today there are many options for contraception.
Rates of effectiveness are for one year of use. Periodic abstinence Periodic abstinence, also called fertility awareness , is a natural means of contraception because it relies on natural signs of the woman's fertile cycle. The method is based on avoidance of sexual intercourse during the seven days prior to and including ovulation, as well as the day after. A woman considering periodic abstinence as contraception should make certain that she fully understands the technique and asks questions of her health care provider if something is not clear to her. All women who learn methods of calculating their own fertile days can use this information to support other means of contraception, or even to improve chance of pregnancy if desired.