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What Do Birth Control Pills Do?

Birth control pills are a common and effective method of contraception chosen by countless women worldwide. For many, they offer a sense of control over their reproductive health and family planning. However, understanding precisely what these pills do and how they work can sometimes feel confusing.

This comprehensive guide aims to demystify the science behind birth control pills, providing a clear and thorough explanation of their mechanism and effects.

Key Takeaways:

What are Birth Control Pills?

What Do Birth Control Pills Do? what are birth control pills how birth control pills prevent pregnancy preventing ovulation thickening the cervical mucus thinning the uterine lining Beyond Pregnancy Prevention: Other Functions of Birth Control Pills

Birth control pills are hormonal medications taken to prevent pregnancy. These are taken daily at or around the same time. These pills contain synthetic versions of the natural hormones estrogen and progesterone.

There are two main types of birth control pills available to women:

  • Combined Oral Contraceptive Pills (COCPs): These are the most commonly prescribed pills and contain synthetic versions of both estrogen and progesterone (called progestin).

  • Progestin-Only Pills (POPs): These pills, also known as mini-pills, contain only synthetic progestin. They are often recommended for women who cannot take estrogen.

Both COCPs and POPs are over 99% effective when used correctly and consistently.

How Birth Control Pills Prevent Pregnancy

What Do Birth Control Pills Do? what are birth control pills how birth control pills prevent pregnancy preventing ovulation thickening the cervical mucus thinning the uterine lining Beyond Pregnancy Prevention: Other Functions of Birth Control Pills

The primary way birth control pills work is by directly influencing a woman's endocrine system (system of glands that produce or release hormones) to prevent pregnancy. This happens through several key, interconnected mechanisms:

Preventing Ovulation

Combined oral contraceptive pills (COCPs) prevent pregnancy primarily by stopping ovulation - the release of an egg from the ovaries.

They deliver consistent levels of synthetic estrogen and progestin, which act on the brain’s hypothalamus and pituitary gland to suppress the release of Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH). Since FSH helps develop eggs and an LH surge triggers ovulation, their suppression prevents the release of an egg, making conception unlikely.

Progestin-only pills (POPs) may also suppress ovulation, but less consistently. Some only prevent ovulation in 50–70% of cycles, though newer, stronger formulations are more effective.

Thickening the Cervical Mucus

Both COCPs and POPs significantly alter the consistency of the cervical mucus, a fluid produced by the cervix.

The progestin component in both types of pills causes the cervical mucus to become thicker and stickier. Normally, cervical mucus becomes thin and watery around ovulation to allow the sperm to pass through. However, under the influence of the pill's progestin, this mucus transforms into a thick barrier. This physical obstruction at the entrance to the uterus hinders sperm from travelling through the cervix and into the upper reproductive tract (uterus and fallopian tubes) where it typically fertilises the egg.

Thinning the Uterine Lining

The consistent presence of progestin (in both COCPs and POPs) and the regulated estrogen levels in COCPs cause the inner lining of the uterus (also known as endometrium) to become thinner and less developed than it would be during a natural cycle.

In a typical menstrual cycle, the endometrium thickens in preparation for a potential pregnancy, providing a rich, nourishing environment for implantation. The birth control pills thin the uterine lining so that if fertilisation were to occur despite the pill's other mechanisms, the thin lining makes it highly unfavourable for a fertilised egg to successfully attach and develop into a pregnancy. This provides an additional layer of pregnancy protection.

Beyond Pregnancy Prevention: Other Functions of Birth Control Pills

What Do Birth Control Pills Do? what are birth control pills how birth control pills prevent pregnancy preventing ovulation thickening the cervical mucus thinning the uterine lining Beyond Pregnancy Prevention: Other Functions of Birth Control Pills

Birth control pills do much more than just contraception. They perform the following functions too:

Stabilising the Hormonal and Menstrual Cycle

COCPs deliver a consistent, controlled dose of synthetic estrogen and progestin, which effectively stabilises hormone levels throughout the menstrual cycle. Typical dosing regimens of birth control pills include 21 or 24 active pills (that contain hormones), followed by 7 or 4 inactive pills (that do not contain hormones) or no pills. The 7 or 4-day hormone-free interval allows for a period-like withdrawal bleeding to occur. This predictability is particularly beneficial for women who experience highly irregular periods, such as those with Polycystic Ovary Syndrome (PCOS).

Progestin-only pills (POPs) typically include 28 active pills with no inactive pills, although some formulations include 24 active pills with 4 inactive pills. Due to the continuous hormone dosage and lack of estrogen, these pills can often lead to unpredictable bleeding patterns, including spotting or prolonged periods.

Reducing Menstrual Symptoms

COCPs stabilise hormones and thin the uterine lining, significantly alleviating menstrual discomforts. This results in lighter, shorter withdrawal bleeds and reduced intensity of menstrual cramps. Consistent hormone levels can also lessen the emotional and physical symptoms of Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Disorder (PMDD), such as mood swings and bloating. While POPs might sometimes reduce menstrual pain or stop periods, they generally don't offer the same comprehensive relief for broad PMS/PMDD symptoms as COCPs.

Reducing Acne

Certain COCPs are specifically approved for treating hormonal acne in women. Acne is often linked to higher levels of androgens (male hormones). The estrogen in COCPs increases a protein (SHBG) that binds to and reduces these active androgens. This leads to less oil production in the skin and, consequently, clearer skin. POPs are not typically used for managing acne and may sometimes worsen it.

Managing Endometrium Symptoms

COCPs and POPs are frequently used in managing endometriosis. This condition involves tissue similar to the uterine lining growing outside the uterus, stimulated by estrogen. Birth control pills provide a constant hormonal environment that suppresses the growth and activity of these endometrial implants. This thins both the uterine lining and the ectopic tissue, significantly reducing associated pain, heavy bleeding, and other symptoms.

Potential Effects on Cancer Risk

Some research suggests that birth control pills may alter the risk of certain cancers. The consistent hormones provided by birth control pills are thought to reduce the repeated hormonal stimulation cycles of ovarian and endometrial tissues. This may lead to a lower long-term risk of developing ovarian cancer and endometrial cancer in women who have used birth control pills. However, there's a very slight, temporary increase in breast cancer risk that typically subsides after stopping the pill.

The research has mostly been done on COCPs and less extensively on POPs, but the data present suggest similar rates of increased or decreased risks for both pills.

Conclusion

Birth control pills, both combined oral contraceptive pills (COCPs) and progestin-only pills (POPs), offer women effective contraception and can provide additional health benefits.

Like all medications, birth control pills have mild possible side effects. Hence, it is advisable for you to consult your doctor to discuss your individual health needs and determine the most appropriate and safe type of birth control for you.



Frequently Asked Questions (FAQs)

  • Does the pill stop your period?

    COCPs usually regulate periods, making them lighter. Some COCPs can reduce or stop periods if taken continuously. POPs can cause irregular or sometimes stopped periods.

  • What are the disadvantages of the pill?

    Disadvantages of the pill can include temporary side effects like nausea, headaches, breast tenderness, spotting etc. However, these resolve on their own and are usually mild when they do occur.

  • Can birth control pills affect my hormones?

    Yes, birth control pills contain synthetic estrogen and progestin, which influence your natural hormone levels to prevent ovulation, regulate cycles, and manage other conditions.

  • Will I gain weight while taking birth control pills?

    Research doesn't show a strong link to significant weight gain. Some women might experience temporary fluid retention or changes in appetite, any changes related to weight can be linked to this and not fat gain.

Important

This blog, including its text, images, and infographics, is for educational purposes only and not a substitute for professional medical advice. For personalized advice, always consult a doctor.

Further Reading

For more details on this or related topics, refer to the papers listed in references below, or check out the other blogs on our website dulycare.in.

References

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