What Is It? The birth control pill (also called "the Pill") is a
daily pill that contains hormones to change the way the body
works and prevent pregnancy. Hormones are chemical substances
that control the functioning of the body's organs. In this case,
the hormones in the Pill control the ovaries and the uterus. How
Does It Work? Most birth control pills are "combination pills"
containing a combination of the hormones estrogen and
progesterone to prevent ovulation (the release of an egg during
the monthly cycle). A woman cannot get pregnant if she doesn't
ovulate because there is no egg to be fertilized. The Pill also
works by thickening the mucus around the cervix, which makes it
difficult for sperm to enter the uterus and reach any eggs that
may have been released. The hormones in the Pill can also
sometimes affect the lining of the uterus, making it difficult
for an egg to attach to the wall of the uterus. Most combination
pills come in either a 21-day pack or a 28-day pack. One hormone
pill is taken each