If there is a subject that causes all kinds of doubts due to the clash between the comforts that its operation implies and the fear of its supposed repercussions on health, it is oral hormonal contraceptives, better known as the “pill”. Despite being one of the most effective methods today to avoid unwanted pregnancies, the range of doubts and hoaxes that surround it is very wide (and sometimes alarming).

But here’s Cursed Science to try and clarify what’s true and what’s not supported by all that stuff we’ve heard about the pill.

No, the pill does NOT protect against sexually transmitted diseases.

Despite the fact that it is a highly effective contraceptive method, the function of the pill is limited to that, to prevent or hinder pregnancy, but it is in no way related to protection against the spread of any sexually transmitted disease ( STDs) such as chlamydia, genital herpes, gonorrhea, human immunodeficiency virus (HIV) and thus acquired immunodeficiency syndrome (AIDS), human papillomavirus (HPV) or syphilis.

The person responsible for the spread of these infections is the exchange of bodily fluids through sexual contact without using any type of protective barrier. To protect yourself from them, the most effective and recommended method is to use latex or polyurethane male or female condoms every time you have vaginal, oral or anal sex, since this reduces (although in some cases does not completely eliminate) the chances of contagion.

No, the pill does not affect fertility

One of the most common concerns among those considering starting the pill is whether it will affect their fertility in the long term. The answer that the experts have given us coincides: “What influences the greater or lesser possibility of becoming pregnant after its use is the passing of the years“, sums up Francisca Martínez, head of the contraception unit of the clinical area of ​​the service of reproductive medicine at the Dexeus Mujer gynecological clinic.

In other words, if a woman takes the pill for many years, the problem will not be the alleged effects that the medication may have had on her reproductive system, but rather the passage of time, a factor that does indicate fertility.

Regarding whether it is more complicated to get pregnant during the first months after stopping treatment, Carles Catllá, head of the Reproduction Service of the Institut Maqués, explains to Maldita Ciencia that, after two months, the pregnancy rate is the same . In other words, after stopping the contraceptive pill, the options of becoming pregnant are the same as those of a woman who has not taken it.

Yes, taking the pill can decrease the frequency of your period and make your period “fake” bleeding

Approximately every month, while she is fertile, the woman’s body regulates and fine-tunes the conditions necessary for a possible pregnancy to occur. Among other processes, the internal lining of the uterus increases its thickness until, in case of fertilization of the egg, it can adhere to its walls and begin to develop. However, if this does not happen, the body undoes this coating and the unfertilized ovum in the form of bloody fluid : this is menstruation.

In the body of a woman taking the pill, such bleeding occurs on “off days” when she turns to placebo pills. The radical withdrawal of the hormonal supply induces bleeding, but this is not a rule as such: it is lighter and usually lasts fewer days.

There are treatments that do not include a week of monthly placebo and its corresponding bleeding, but all the pills are active (they have hormones). These are known as the extended-cycle pill regimen and allow you to have that bleeding longer, depending on the treatment you take.

No, taking the pill doesn’t make you fat.

The idea of ​​finding themselves with a few extra kilos, without rhyme or reason, causes many women to back down when starting a treatment of oral hormonal contraceptives or abandon it. However, science does not agree: although many women say they feel “more bloated” or “have gained weight because of it”, no study to date has been able to establish a cause-effect relationship between the pill and the increase weight in the long term. 

It may happen that, during the first weeks or months and due to the hormonal changes that start treatment entails, the body retains more fluids, but not fat. Furthermore, this side effect should cease by the third month at the latest. 

“If someone blames their weight gain on the pill, for whatever reason, they can switch to a more diuretic or antiandrogenic progesterone. There is enough variety to find the most suitable pill for each patient,” says Ros.

Yes, the pill can affect acne positively or negatively depending on its composition 

Through CHCs (combined hormonal contraceptives) we introduce into our body an extra estrogen, the hormone responsible for the physical changes of women during adolescence through the development of secondary sexual characteristics. But progesterone also has effects on the woman’s body.

“Depending on the type of progesterone that the pill contains, it can cause different physical changes,” explains Ros. “If it’s an anti- male (anti-androgenic) hormone progesterone, the patient probably has less acne and fewer pimples all over the body, overall.” But if progesterone is not antiandrogenic, it could increase acne, although it would be reversible, when treatment is discontinued.

“Not all contraceptives act the same, but  the ones that dermatologists usually recommend (with an antiandrogenic effect ) do manage to reduce acne,”   Sara Gómez Armayones, a dermatologist at the Hospital Clinic , explains to Maldita Ciencia . There are patients in which this problem is solved without resorting to stronger treatments, only with CHCs”, she adds. 

Thanks to them, the sebaceous glands produce less sebum, since they reduce the level of testosterone. Even so, the effects are not visible overnight, but can take up to three months to be appreciated. 

The pill and the risk of cancer: it varies for each type of cancer

The answer to the question of whether or not the pill affects the risk of suffering cancer is complex since, for the moment, there are no studies that can deny or affirm in a resounding and forceful way if the probability is greater, lesser, of what It depends on this or what types of cancer it could affect.

In fact, according to the National Cancer Institute (NIH), data from population studies (you can read more about what those studies look like here) cannot definitively establish that exposure to the pill causes or prevents cancer. cancer since, in addition to CHC use, the risk may also depend on other factors not covered by research.

At the moment, there are studies that suggest that, during the period in which a woman takes the pill, the risk of suffering cancer could increase or decrease depending on the type of tumor we are talking about. “In principle, oral contraceptives prevent ovarian and endometrial cancer,” explains Maldita Ciencia Catllá. “On the other hand, there is a higher prevalence of cervical cancer, caused by HPV (human papillomavirus): as people tend to use oral contraceptives instead of condoms, the risk is greater, being exposed to an external germ”.

Overall, as Modesto Rey Novoa, president of the Northern Contraception Society (SEC), explains to Maldita Ciencia , global mortality from cancer in women users of this type of contraceptive decreases. “For example, the protective effect against ovarian and endometrial cancer is prolonged, even beyond the time of use, also depending on the time during which they have been used: the more years, the more protection.” He adds that, in addition, a decrease in colon cancer has been shown.

The pill and the risk of thrombosis: possible but unlikely

One of the most frequent doubts and fears is  whether taking this type of contraceptive affects circulation and increases the risk of suffering a venous thrombosis  (blood clot that forms in a deep vein). The answer is yes, it can influence; but no, it doesn’t always  (and, in fact, it’s unlikely to). 

According to the Spanish Agency for Medicines and Health Products (AEMPS), the possibility  is somewhat higher during the first year, and increases again when taking it again if there has been an  interruption of more than 4 weeks  and in the case of  smoking, overweight women , who have recently given birth  or whose  close relatives have suffered.

“The risk is greater, especially  if there is a family  or genetic history and  if they have genetic alterations, “explains Catllá. “In the rest of the population this can increase between 5 and 10%.” 

However, there are no safety reasons that make it necessary to discontinue the hormonal contraceptive in women who regularly use it without having presented problems. As explained here by the AEMPS, the latest European review on the risk of suffering a venous thromboembolism from the use of this type of contraceptive confirmed that  it is very small.

The pill helps reduce (or eliminate) menstrual pain

This is another of the most recurring questions regarding the treatment: whether or not it is true that it reduces or even eliminates the pain associated with the period. Indeed, it does and, in fact, taking the pill is one of the main indications against menstrual pain. 

Menstrual discomfort can be due, mainly, to two reasons: either you have a lot of menstruation (so the uterus has to move a lot to expel it), or because you suffer from a disease associated with this pain for other causes, for example, endometriosis. 

“In these diseases (endometriosis), the first-line treatment of choice is continuous contraceptives or continuous regimens, with 2 or 3 periods a year,” explains Ros. “In the event that the reason for the pain is the quantity, in women with very abundant periods that can cause anemia, the treatment of choice is also this type of contraceptive,” she adds.

Do they influence mood swings?

Premenstrual syndrome is a set of symptoms that manifest in the days before menstruation and usually disappear with it. During these, alterations and mood swings can occur in women. ” The hormonal changes characteristic of the female sexual cycle sometimes cause mood swings, manifesting greater irritability,” explains Rey.

But is it true that starting the pill can also negatively affect your mood? Despite the fact that there are numerous studies that have tried to answer a question, there is still no definitive consensus on whether or not it is true. In fact, currently the pill is prescribed as one of the solutions to minimize the symptoms of premenstrual syndrome. “There are psychiatrists who prescribe CHCs to those who suffer from this type of cyclical psychiatric disorders,” says Ros.

Rey explains that the pill eliminates the hormonal variability that occurs during the normal sexual cycle, so many women can notice a noticeable improvement in those mood swings. Even so, during the first three months of treatment it is normal to suffer this and other consequences related to it. “There are unique responses, especially in women taking combined cyclical contraceptives,” Rey says.

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