The contraceptive pill, commonly known as “the pill,” is a hormonal medication designed to prevent pregnancy. Taken orally on a daily basis, it contains synthetic versions of estrogen and progesterone hormones, functioning to prevent ovulation and alter cervical mucus, collectively providing a highly effective method of birth control. This article will delve into the mechanisms of how the pill works, evaluate its pros and cons and dispel popular misconceptions about its usage.

In the early 1960s, the introduction of the oral contraceptive pill brought about a transformative revolution in the field of women’s health. Indeed, for the first time in history, women had the possibility to control their own fertility. Currently, about 100 million women worldwide are users of hormonal contraceptives, most frequently in Western countries [1].

Contraception is defined as any method that aims to prevent pregnancy. Contraceptive methods can be broadly categorized into two main types: non-hormonal and hormonal options. Non-hormonal contraceptives include permanent sterilization, copper intrauterine devices (IUDs), chemical/physical barriers such as spermicides and condoms, as well as traditional family planning methods including withdrawal and the rhythm method [2]. Hormonal contraceptives typically utilize synthetic versions of naturally occurring hormones such as estrogen and progestin. Progestin prevents pregnancy via inhibiting ovulation, while estrogen is responsible for regulating menstrual bleeding. Elevated levels of estrogen and progestin prevent the release of eggs from the ovaries, rendering fertilization impossible. Progestin additionally alters the consistency of cervical mucus, making it thick and sticky, which inhibits the sperm from reaching the uterus [3]. Oral contraceptive pills (OCP) are the most prevalent form of hormonal contraception, and they usually combine estrogen and progestin hormones (Combined Oral Contraceptives, COC) [4]. The variation among different OCP brands primarily lies in the balance between the quantities of progestin and estrogen they contain. OCP come in three main types: monophasic, biphasic and triphasic pills. Monophasic pills have consistent hormone doses and proportions, making it irrelevant which pill in the packet you take. For biphasic pills and triphasic pills, the order is crucial as they have two or three different hormone phases, with varying doses of progestin and estrogen in each phase [4]. 

The discovery of the beneficial effects of these two hormones when combined was somewhat serendipitous. During the first human trial conducted in Puerto Rico in 1956, the progestin products being tested were accidentally contaminated with mestranol, a synthetic estrogen. Researchers decided to purify the products and decrease the estrogen content, leading to the observation of breakthrough bleeding. Recognizing the potential benefits of estrogen in regulating the menstrual cycle, it was decided to keep the estrogen component in the pill, establishing the principle of using both hormones for effective cycle control [5].

Besides its use for fertility control, the contraceptive pill is often prescribed to manage conditions such as endometriosis, polycystic ovary syndrome (PCOS), and premenstrual syndrome (PMS) due to its hormonal regulation effects. 

For endometriosis (please refer to our previous article to learn more about it), the pill helps by suppressing the growth of the endometrial tissue outside the uterus, reducing pain and inflammation associated with the condition [6]. In the case of PCOS, the pill can regulate menstrual cycles, reduce androgen levels, and alleviate symptoms like irregular periods and acne [7]. Additionally, for PMS, the pill can stabilize hormonal fluctuations, mitigating symptoms such as mood swings and bloating, and providing relief to those experiencing premenstrual discomfort [8].

Most side effects associated with OCPs typically resolve within the initial months of use or upon transition to a different pill formulation. Among the most common side effects, there are breakthrough bleeding or spotting between periods. Women also report nausea, headaches, abdominal cramping and breast tenderness [9]. However, some adverse effects such as decreased libido might not disappear, even after interruption of the pill [10]. Notably, scientific studies provided consistent evidence that the risks of breast and cervical cancers are increased in women who use oral contraceptives [11, 12], whereas endometrial, ovarian and colorectal cancers are reduced [13-15]. 

Numerous misconceptions surround birth control pills, including the belief that they can harm fertility. However, a comprehensive study from 2011 found comparable pregnancy rates between women who had used birth control pills and those who had not [16]. Weight gain is often another commonly expressed concern. However, a study conducted in 2014 concluded that there was no significant change observed in body weight or composition following the use of oral contraceptives [17]. Finally, while hormonal birth control can carry potential risks of blood clots and stroke, these are primarily associated with individuals above the age of 35 who smoke, or have a history of cardiovascular disease and thrombosis; thus, these groups should avoid taking birth control pills [18]. 

In conclusion, the contraceptive pill has revolutionized women’s lives by providing unprecedented control over fertility. With around 100 million users worldwide, it not only serves as a highly effective form of birth control but also helps alleviate conditions such as endometriosis, PCOS and PMS, as well as decreasing the risk of developing breast, endometrial and colorectal cancers. While the pill has numerous positive impacts, it is crucial to acknowledge potential health effects. Common side effects are often temporary, but concerns about cancer risks persist. The pill’s transformative role and its complexity underline the importance of tailored discussions with medical professionals to navigate its individual effects on health.