Can Contraceptive Pills Cause Cancer?

The contraceptive pill is an extremely effective method of contraception, with a success rate of about 97%, reaching incredible 99.9% if taken correctly. These results become oral contraceptives the most popular methods of contraception throughout the world. Currently, about 10% of women of childbearing age use the pill regularly as contraception.


However, since the beginning of its commercialization, there in the 1960s, the scientific community and the public are concerned about whether there is any direct relationship between the use of the birth control pill and cancer cases, especially those who have close relationship with hormones women, such as breast cancer, ovary or uterus.

After all, the birth control pill increases the risk of having a cancer or does it help prevent its emergence?

In this article we will explain in simple language what the scientific studies conducted over the past decades tell us about the relationship between hormonal contraceptives and the incidence of malignant tumors.

Exist on the market two types of birth control pills: those composed of the hormones estrogen and progesterone and those made only by progesterone, minipill calls.

In the early years of its existence, the dose of existing hormones in the pills was high, which caused a lot of side effects such as cardiovascular disease, stroke and possibly cancer cases. Studies until 1975 pointed to an increased risk of cases of breast cancer and cervical in women taking birth control.

In recent decades, however, the amount of this hormone in oral contraceptives has been falling steadily. Moreover, the variety of synthetic hormones also changed greatly. Only progestin, a synthetic form of progesterone, currently there are about a dozen types.

Therefore, the said studies in the 70 and 80 can not be recovered today, since the composition of contraceptive pills changed substantially. We need to assess what the latest studies tell us. What we describe below are the existing evidence to date for the types of cancer most commonly associated with the use of the pill.

It is estimated that over 300 million women have used the pill during their lives, many of them for several years running. Thus, the public health point of view, it is essential to understand whether such wide use of this method of contraception contributes or not to an increase in the overall incidence of cancers regardless of the specific type.

As we shall see, the pill appears to increase the risk of some types of malignant tumors, but also helps to reduce the occurrence of others. But, on balance, does the pill has increased cases of cancer around the world? We Will, on behalf on birth control, are causing more cases of cancer in the population than would be expected if the birth did not exist?

To try to answer this question a large British study followed about 50,000 women for an average of 24 years. Half of them wore contraceptives and the other half had never taken a pill. The results showed a reduction of about 12% of the total number of all types of cancers and 29% of gynecological cancers in the group that used the pill. Moreover, it observed only when the group of women who used the pill for over 8 years in a row, there was a tendency for increased total cases of cancers, especially those who smoked.

Importantly, the study despite being published in 2007, was started in 1968, still covering many years of use of contraceptives with high doses of hormones. Over 75% of women used pills study with doses of at least 50 mcg of ethinyl estradiol (estrogen), which is a higher dose that most new pills, which usually have between 20 and 40 mcg of ethinyl estradiol.

Endometrium is the name we give to the tissue that lines the intrauterine cavity. Endometrial cancer is the most common type of 6th cancer, with about 300 thousand cases a year worldwide. This cancer usually affects women over 50 years, 61 years the average age at which it is diagnosed.

For several years we know that the use of the contraceptive pill helps to reduce the incidence of endometrial cancer by 50%. Several studies show that the longer the duration of oral contraceptive use, the lower the risk of developing endometrial cancer. Even more impressive is that the protective effect remains for more than 20 years after stopping the pill.

Ovarian cancer is the 7 most common type of cancer in women, with about 230 thousand cases a year worldwide. It is, however, the most lethal gynecological cancer as it is not usually diagnosed in early stages.

Just as occurs in endometrial cancer, the use of hormonal contraceptives also helps reduce the risk of ovarian cancer. Studies show that after 1 year of use, since the risk is reduced by about 10%. After 5 years, the incidence of ovarian cancer becomes 50% smaller and this protective effect remains for more than 30 years after stopping the pill.

Cervical cancer is the 3rd most common type in women, with about 550,000 new cases per year worldwide.

The cervical cancer is closely related to infection by the HPV virus, which is responsible for over 90% of cases. Studies suggest that in women who have HPV, the use of birth control pill increases the risk of developing cervical cancer. The longer the woman takes the pill, the greater the risk. But the good news is that after 10 years of suspension of birth, the risk of cancer turn be the same as the rest of the female population.

As the majority of cervical cancers arise only in women over 45-50 years, the use of oral contraceptives during the 20 and 30 years of age ends being safe, as even if there is an increased risk, the incidence of new cancers in young women continue to be very low. Just that women discontinue the pill around the age of 40, which at the most critical stage, from the age of 50, she will no longer have the negative effect of contraceptive hormones.

In women who do not have the HPV virus there is no evidence that the pill increases the risk of cervical cancer.

Breast cancer is the commonest cancer among women and the second most common in humans.

The relationship between the use of oral contraceptives and breast cancer is not well understood, because the various studies on the subject have shown conflicting results. Older studies, initiates in the 1970s or 1980s, pointed to a small increased risk. As well as in cervical cancer, these studies showed that the increase in risk disappeared after discontinuation of the pill. Latest study, however, showed no increased risk of breast cancer in women of hormonal contraceptives. There are therefore sufficient level of evidence to say that hormonal contraceptives in the current doses, clearly increase the risk of breast cancer.

This difficulty in establishing any causal relationship occurs not only because the pill's hormone levels have been falling over the years, which creates some confusion in long-term studies, but also because breast cancer is uncommon in young women. Even if there is a percentage increase in risk, as the incidence is naturally very low, the end result also basically remains very low.

The use of hormonal contraceptives is clearly linked to an increased risk of hepatic adenoma is a benign liver tumor. This risk, however, has been falling over the years, as estrogen levels of the pills has been progressively reduced. Such benign tumors may bleed or rupture, but the risk of transformation to a cancer is low, less than 10%.

With regard to liver cancer, called hepatocellular carcinoma, there is no evidence that the use of the contraceptive pill is related to an increase in its incidence.