Pregnancy is a personal decision that all women may have to think realistically, sensibly, thoroughly and carefully. Birth control may come to mind when a woman or a couple may be unwilling to have a baby for a period of time. The most common pregnancy control method used among ladies is oral contraceptives. Orthro Tri Cyclen Lo hormonal pills are one example of an oral contraceptive that contains a combination of an estrogen and a progestin works by preventing ovulation thus allowing that no egg be fertilized. Each body structure of a woman is different from one to another, therefore what works for you may not be best for the other person.