There are four methods of birth control that sit at the very top of Planned Parenthood's effectiveness chart, each correlating to success rates of 99% or better: a vasectomy, sterilization, an IUD, and implants. The birth control pill belongs to the next tier of effectiveness, products that over the course of a year have been shown effective 92% to 98% of the time. Along with the pill, the other control techniques in this second bracket are an injection, the contraceptive ring, the contraceptive patch and LAM breastfeeding.

Combination Pills 

The majority of women take so-called combination birth control pills, or ones containing the hormones estrogen and progestin. Together, these hormones act to prevent a woman's ovaries from releasing eggs and also thicken her cervical mucus, a natural impediment to the forward progress of male sperm. The hormones are also designed to make it harder for any egg that might still drop and get through to attach to the uterus, by temporarily thinning out the lining of the latter.

Yaz 

In September of 2010, the Food and Drug Administration approved a new strand of BayerHealth's popular Yaz birth control pills, one that is actually designed mainly to address those 1-in-100 situations where a woman taking the product still gets pregnant. The new Beyaz line contains the folate and B-vitamin compound levomefolate, which feeds new cell development and ensures a lower risk of birth defects. Higher folate levels have been shown to promote a higher level of fetal health during the first few weeks after child is conceived.

Side Effects 

Research into the side effects of birth control pills is ongoing. In 2006, the Mayo Clinic found that the incidence of breast cancer was 44% higher among young women without children taking the contraceptive. While the product can decrease the incidence of ovarian cancer, it has conversely been found to lead to higher occurrences of cervical cancer.