Birth control pills contain synthetic hormones which are naturally produced by females. These pills are used to prevent ovulation by maintaining a level hormone balance, so no egg is released. Combination pills contain estrogen and progestin, while progestin-only pills (also known as the minipill) don't contain estrogen. Progestins are synthetic hormones that act to mimic the naturally occurring hormone progesterone. Progestin-only pills are recommended in women who cannot take estrogen.
