Hormonal birth control has been available to American women since the early 1960s with the introduction of "the pill." Since then, birth control via hormones can also be accomplished with injections, patches, implants and rings, although pills remain the most popular method and the most studied. All hormonal methods are meant to maintain high levels of estrogen and progesterone, which prevent women from ovulating. Controversy exists over what side effects occur with long-term use of birth control pills.
Sexual Side Effects
Although women usually take birth control pills to enhance their sexual experience, there is evidence that with long-term use, it may actually make it less enjoyable for many. In 2006, a study was published in the "Journal of Sexual Medicine" that concluded long-term use of birth control pills can lead to sexual dysfunction. Specifically, the researches commonly found decreased sexual desire, sexual arousal and vaginal secretions/lubrication in the 124 women on birth control pills who were studied. The women also reported reduced sexual satisfaction and an increase in sex-related pain because of the reduced lubrication.
The same research team also took blood samples from the women and realized they had elevated globulin levels, which was chronically suppressing their testosterone levels. The researchers concluded that the synthetic estrogens in birth control pills may cause permanent changes in the way genes function, resulting in a long-lasting reduction in testosterone available to the body.
It is known that some cancers need sex hormones to thrive, which is why an increased risk of breast cancer has been linked to elevated estrogen levels in women. The National Cancer Institute states that some studies have shown an increased risk of breast cancer in women taking oral contraceptives, while other studies have shown no change in risk. Generally, women older than 45 years of age who have been taking birth control pills for most of their adult lives have the highest risk of breast cancer for two reasons: long-term consecutive use of the oral contraceptive and use of earlier versions that had higher levels of sex hormones.
The National Cancer Institute also notes that oral contraceptive use has been shown to increase the risk of cervical cancer and liver cancer. On the other hand, multiple studies indicate a potential decrease in risk of ovarian and endometrial cancers for women on oral contraceptives.
Other Long-Term Side Effects
Other long-term side effects from oral contraceptive use include an increased risk of blood clots, heart attack, stroke, weight gain, hypertension and migraine headaches. These effects seem to be increased by cigarette smoking. Long-term use of synthetic hormones has also been linked to nutritional deficiencies, such as low levels of vitamins B2, B6 and B12, depression and increased feelings of anxiety, according to "Hormone Replacement Therapy and The Brain."