Understanding oral contraceptive pills: How birth control pills work and their effects on women’s health

Oral contraceptive pills, commonly known as birth control pills, have been widely used for decades as an effective method of preventing pregnancy. These medications regulate hormonal activity in the body, creating conditions that prevent ovulation, alter the uterine lining, and modify cervical mucus to reduce the likelihood of fertilisation. While oral contraceptive pills are primarily used for contraception, they also offer additional health benefits, such as regulating menstrual cycles and reducing the risk of certain medical conditions. However, like any medication, they come with potential side effects and risks that require careful consideration.

What Are Oral Contraceptive Pills and How Do They Work?

Oral contraceptive pills contain synthetic hormones that mimic the body’s natural reproductive hormones. These pills are usually taken daily for 21 consecutive days, followed by a seven-day break during which a withdrawal bleed occurs, resembling a menstrual period. By controlling hormone levels, birth control pills prevent the release of eggs from the ovaries, making conception nearly impossible when used correctly.

The primary function of oral contraceptive pills is to suppress ovulation. The hormones in the pill—oestrogen and progestogen—affect the pituitary gland’s ability to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH), both of which are essential for ovulation. Without these hormones, the ovaries do not release an egg, eliminating the possibility of fertilisation. Additionally, oral contraceptive pills thicken cervical mucus, making it more difficult for sperm to travel through the cervix and reach an egg. The hormonal changes also alter the uterine lining, reducing the likelihood of implantation even if fertilisation does occur.

Types of Oral Contraceptive Pills and Their Differences

There are two primary types of oral contraceptive pills: the combined pill and the progestogen-only pill.

The combined pill contains both oestrogen and progestogen. This combination ensures a high level of effectiveness in preventing pregnancy by providing a dual mechanism of action. Oestrogen primarily prevents ovulation, while progestogen modifies the cervical mucus and endometrial lining. The combined pill is taken for 21 days, followed by a seven-day pill-free period that allows for a withdrawal bleed. Some formulations contain a lower dose of oestrogen to reduce the risk of side effects while maintaining contraceptive efficacy.

The progestogen-only pill, often referred to as the “mini-pill,” does not contain oestrogen. This pill is particularly beneficial for women who are unable to take oestrogen due to health concerns such as a history of blood clots or migraines. The progestogen-only pill primarily works by thickening cervical mucus, preventing sperm from reaching an egg. Some variations also suppress ovulation, though not as consistently as the combined pill. This type of pill requires strict adherence to a daily schedule, as missing a dose by just a few hours can reduce its effectiveness.

Benefits of Oral Contraceptive Pills Beyond Birth Control

Oral contraceptive pills offer several health benefits beyond preventing pregnancy. Many women use these medications to regulate irregular menstrual cycles, manage heavy bleeding, and reduce menstrual pain. By stabilising hormone levels, birth control pills help minimise symptoms of premenstrual syndrome (PMS), including mood swings, bloating, and headaches.

Another significant benefit of birth control pills is their ability to reduce the risk of certain health conditions. Studies indicate that long-term use of oral contraceptive pills is associated with a lower incidence of ovarian and endometrial cancers. The hormonal regulation provided by the pill also helps prevent the formation of ovarian cysts and may reduce the severity of acne by balancing androgen levels in the body.

For women with conditions such as polycystic ovary syndrome (PCOS), oral contraceptive pills can help regulate menstrual cycles and manage hormonal imbalances. Additionally, these pills are often prescribed to alleviate symptoms of endometriosis by reducing the growth of endometrial tissue outside the uterus.

Common Side Effects and Potential Risks of Birth Control Pills

While oral contraceptive pills provide numerous benefits, they can also cause side effects in some users. Common mild side effects include nausea, headaches, and breast tenderness, which often subside after a few months of use. Some women experience changes in mood or libido, while others may notice increased pigmentation on the skin.

One of the most concerning risks associated with combined oral contraceptive pills is the potential for blood clots. The presence of oestrogen in these pills can slightly increase the risk of deep vein thrombosis (DVT) and pulmonary embolism. Women who smoke, have a history of cardiovascular disease, or have pre-existing clotting disorders are at higher risk and are often advised to consider alternative contraception methods.

Weight gain is another frequently mentioned side effect, though research suggests that any weight fluctuations are usually due to fluid retention rather than actual fat gain. Some women experience amenorrhoea, or the absence of menstruation, after stopping the pill, but this is typically temporary as hormone levels regulate naturally.

Are Oral Contraceptive Pills the Right Choice for Everyone?

Choosing the right contraceptive method depends on individual health factors, lifestyle preferences, and personal medical history. Oral contraceptive pills are highly effective when taken correctly, but they require consistency. Missing doses or taking the pill irregularly can significantly reduce its effectiveness, increasing the risk of unintended pregnancy.

Healthcare professionals recommend discussing medical history and potential risk factors before starting oral contraceptive pills. Women with a history of migraines, high blood pressure, or certain medical conditions may be advised to opt for alternative contraception methods, such as an intrauterine device (IUD) or contraceptive implants.

For those seeking a non-hormonal option, barrier methods such as condoms or diaphragms provide an alternative means of birth control without the hormonal effects of oral contraceptive pills.

Oral contraceptive pills remain one of the most effective and widely used methods of birth control worldwide. With their ability to prevent pregnancy, regulate menstrual cycles, and provide additional health benefits, they are a preferred choice for millions of women. However, like any medication, birth control pills come with potential risks and side effects that should be carefully considered before use. Consulting a healthcare provider is essential to determine the most suitable contraceptive method based on individual health needs.