Several types of birth control exist, all of which work by preventing the onset of pregnancy, which begins when a fertilized egg implants in the uterine lining. According to the U.S. Department of Health, different metho... More » Health Women's Health Birth Control states that penicillin sometimes makes birth control pills less effective, which may result in unexpected pregnancy. A backup method of birth control is recommended. More »

A contraceptive that only contains the hormone progestin is safe to use while breastfeeding. BabyCenter states that contraceptives that also include estrogen should be avoided because this hormone may cause a decrease in... More » Health Women's Health Birth Control

Different types of birth control include barrier methods, such as male and female condoms and contraceptive sponges, and hormonal methods, such as birth control pills, vaginal rings and implantable rods. Intrauterine dev... More » Health Women's Health Birth Control

Different categories of birth control for women include barrier methods, hormonal methods, implantable devices and permanent solutions, explains the Office on Women's Health. Examples of barrier methods are female condom... More » Health Women's Health Birth Control

In the calendar or fertility awareness method of birth control, women tracks their menstrual cycles to determine on which days they are fertile and therefore at the highest risk for pregnancy. The calendar method is gene... More »

Women who start taking birth control and then stop are more at risk for pregnancy due to the inconsistent nature of how hormones in the pill are administered, according to the Center for Young Women's Health. The pill, w... More »