Oral Contraceptive Pill Singapore

Authored By: Dr. Jana Lim
Last updated: June 5, 2025

Oral contraceptive pills (OCPs), or birth control pills, are medications that help prevent pregnancy by regulating hormones that influence ovulation and the menstrual cycle. These pills contain synthetic versions of oestrogen and progestin, or only progestin. They work by preventing ovulation, thickening cervical mucus to hinder sperm movement, and altering the uterine lining to reduce the likelihood of implantation.

Oral contraceptives are taken daily for ongoing pregnancy prevention, while emergency contraception (morning-after pill) is used immediately after unprotected sex to reduce the risk of pregnancy. Progestin may also be used in the form of period delay pills, which temporarily postpone menstruation but do not provide contraception.

Oral contraceptive pills prevent pregnancy by regulating hormone levels to interfere with ovulation, sperm movement, and implantation. These changes make it more difficult for fertilisation and implantation to occur.

1. Preventing Ovulation – The steady levels of synthetic oestrogen and progestin in oral contraceptive pills prevent the surge of luteinising hormone (LH) and follicle-stimulating hormone (FSH), which are necessary for the maturation and release of an egg. Without ovulation, fertilisation cannot occur.
2. Creating a Barrier to Sperm – Progestin increases the thickness of cervical mucus, making it harder for sperm to move through the cervix and reach the fallopian tubes where fertilisation typically occurs.
3. Altering the Uterus – The endometrium (uterine lining) remains thinner due to hormonal regulation, making it less receptive to implantation if fertilisation occurs.

Combined Oral Contraceptive Pills (COCPs)

Combined oral contraceptive pills contain both synthetic oestrogen and progestin, primarily working by inhibiting ovulation. They come in different formulations:

• Monophasic Pills – Each active pill contains a consistent hormone dose, providing stable hormone levels throughout the cycle, which may reduce side effects like mood swings.
• Multiphasic Pills – Multiphasic formulations, including triphasic and quadriphasic pills, adjust hormone levels in a stepwise manner throughout the cycle to mimic the body's natural hormonal fluctuations. This approach may help reduce breakthrough bleeding and minimise certain side effects.
• Extended-Cycle Pills – Designed to reduce the frequency of menstrual periods by allowing users to have a period only every few months, making them beneficial for those with heavy or painful periods.

In addition to preventing pregnancy, oral contraceptive pills are commonly used to manage hormone-related health conditions. These non-contraceptive benefits vary depending on the formulation and individual health needs. Common uses include:

• Menstrual Regulation – May help regularise irregular periods, relieve menstrual pain (dysmenorrhoea), and reduce heavy bleeding (menorrhagia).
• Premenstrual Symptoms – May provide relief from premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD) through stabilisation of hormone levels.
• Polycystic Ovary Syndrome (PCOS) – Can help regulate menstrual cycles and reduce androgen levels, which may improve symptoms such as acne and hirsutism (excess hair growth) commonly associated with PCOS.
• Endometriosis Management – May alleviate pelvic pain caused by endometriosis by suppressing ovulation and reducing the growth of endometrial tissue.
• Menstrual-Related Migraines – Extended or continuous-use formulations may reduce hormone fluctuations that trigger migraines in some individuals.

These uses are based on individual medical needs and may not be appropriate for everyone. It is advisable to consult a doctor for personalised medical guidance on whether oral contraceptive pills are suitable for your condition.

Oral contraceptive pills are generally well tolerated, but some individuals may experience side effects as the body adapts to hormonal changes. These effects are usually mild and tend to subside after consistent use. Common side effects include:

• Nausea and headaches – Hormonal fluctuations can sometimes trigger nausea or headaches, especially in the early weeks of pill use.
• Bloating and breast tenderness – Fluid retention and hormonal changes may cause bloating or tenderness in breast tissue.
• Mood changes – Hormonal shifts can influence neurotransmitters like serotonin, which play a role in mood regulation.
• Spotting between periods – Light bleeding may occur, particularly in the first few months, as the body adjusts to changes in the menstrual cycle and uterine lining.

Although serious complications are uncommon, oral contraceptives may increase the risk of venous thromboembolism (VTE), stroke, myocardial infarction, and developing high blood pressure, as well as worsening existing hypertension. The risk is particularly higher in individuals with pre-existing factors such as smoking, cardiovascular disease, or a history of blood clots.

If you experience persistent side effects or have concerns about long-term use, consulting a doctor can help determine if oral contraceptive pills are suitable for you.

At ATA Medical, we offer a range of contraceptive and hormone-related treatments, including oral contraceptive pills, emergency contraceptive pills, period delay pills, and hormone tests. Our pricing is as follows:

To ensure consistent protection, oral contraceptive pills should be taken at the same time every day. There are two common regimens: the 21-day pack and the 28-day pack.

21-Day Regimen:

1. Take 1 active pill daily for 21 consecutive days.
2. Stop for 7 days (no pills taken) to allow for withdrawal bleeding.
3. Start the next pack on the 8th day, even if bleeding has not ended.

28-Day Regimen:

1. Take 1 pill every day for 28 days without a break.
2. The last 4 to 7 pills are placebo pills (non-hormonal) that trigger a withdrawal bleed.
3. Begin the next pack immediately after finishing the previous one.

If you start the pill outside the first 5 days of your period, use additional contraception (e.g. condoms) for the first 7 days.

If switching from another contraceptive method (such as an injection, implant, or patch), consult your doctor for guidance on when to start to ensure continuous protection.

Missing pills may reduce the effectiveness of oral contraceptives, especially if more than one pill is missed or if the delay exceeds 12 hours. Follow these guidelines for combined oral contraceptives:

Less than 12 hours late:

1. Take the missed pill as soon as you remember.
2. Take the next pill at the usual time (you may need to take two pills in one day).
3. No additional contraception is needed.

More than 12 hours late:

If you missed a pill entirely after 12 hours, follow these steps based on the week of your pack:

If you vomit or have diarrhoea within 3 to 4 hours of taking a pill, it may not have been absorbed properly and should be treated as a missed dose.

If you're unsure what to do or your pill has different instructions, always refer to the product leaflet or consult a doctor for individual guidance.