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How Oral Contraceptive Pill Works?

Oral contraceptives pills, commonly known as birth control pills, are medications taken orally to prevent pregnancy. They’re an effective means of birth control. 

Oral contraceptive pill types

Combination pills

Combination pills are made of synthetic (that is, man-made) forms of oestrogen and progestin hormones. Combination pills are made up of active pills (which contain hormones) and inactive pills (which do not contain hormones). There are a couple of types of combination pills:

  • Monophasic pills: These are used in one-month cycles and each active pill gives the same dosage of the hormone. In the last week of the cycle, the inactive pills are taken to enable the period flow.
  • Multiphasic pills: These are used in one-month cycles. It provides different levels of hormones during the cycle. In the last week of the cycle, the inactive pills are taken to enable the period flow.
  • Extended-cycle pills: These are usually used in a 13-week cycle. Active pills are taken for 12 weeks, and inactive pills in the last week of the cycle and to enable period. Consequently, menstruation only occurs three to four times a year.

Progestin-only pills

Progestin-only pills contain only progestin, no oestrogen. This type is also known as the mini-pill. Progestin-only pills serve as a good option for women who can’t take oestrogen for health or other reasons. In progestin-only pills, there are only active pills in the cycle. So menstruation may or may not occur while taking progestin-only pills.

How to use the oral contraceptive pill?

Contraceptive pills come in a variety of formats, which follow either 21-day, 24-day or 28-day cycles monthly packs. Extended regimens may follow 91-day cycles. For all of these formats, it is one pill per day, at the same time of day.

However, progestin-only pills only come in packs of 28. But usage is sane, one pill per day, at the same time every day.

How oral contraceptive pill works?

For combination pills, there are two ways to it. First, they prevent the body from ovulating. This means that ovaries won’t release an egg each month. Second, they cause the body to thicken the cervical mucus. This prevents sperm from reaching the uterus.

For progestin-only pills, there are also a few different ways it works. However, they mainly work by thickening the cervical mucus and thinning the endometrium. The endometrium is the lining of the uterus where the egg implants after fertilization. If the lining becomes thinner, it becomes harder for an egg to implant in it. This prevents a pregnancy from growing. Also, progestin-only pills may prevent ovulation from occurring.

Oral contraceptive pill effectiveness

When taken correctly and continuously, oral contraceptive pills are highly effective in preventing pregnancy, as high as 99%. According to the Centre for Disease Control, both types of oral contraceptive pill have 9% failure rates with typical use. This means out of 100 women using the pill, only 9 would get pregnant.

Certain medications may, however, make either type of the oral contraceptive pill less effective. These include:

  • Rifampin (an antibiotic).
  • Certain HIV medications like lopinavir and saquinavir.
  • Certain anti-seizure medications like carbamazepine and topiramate.


How do I decide on the oral contraceptive pill type to use?

Not all types of pill are a good fit for every woman. The following factors should be considered when thinking of oral contraceptive pill use:

  • Menstrual symptoms.
  • If you are breastfeeding.
  • Cardiovascular health.
  • Chronic health conditions you may have.
  • Medications you may be taking.

What benefits do I get from using an oral contraceptive pill?

The following are some of oral contraceptive pill advantages:

  • They offer 24/7protection.
  • They’re highly effective.
  • They help to regulate the menstrual cycle. 
  • They’re fully reversible.

Combination pills may offer some protection against:

  • Acne.
  • Ectopic pregnancy.
  • Thinning bones.
  • Non-cancerous breast growths.
  • Endometrial and ovarian cancer.
  • Anaemia.
  • Heavy periods.
  • Severe menstrual cramps.

Progestin-only pills offer other benefits also. For instance, it is safer for women who:

  • Can’t tolerate oestrogen therapy.
  • Smokes.
  • Are above 35 years.
  • Have history of blood clots.
  • Want to or are breastfeeding.

What are the downsides of using an oral contraceptive pill? 

  • They don’t protect against sexually transmitted infections. 
  • Risk of pregnancy if one misses a pill or delay starting a new pack after finishing a cycle.

Are there any side effects from using the oral contraceptive pill?

While oral contraceptive pills are safe for most women, they come with some side effects. Each woman reacts differently to the hormones in oral contraceptive pills. Some of the side effects are:

  • Decreased sex drive.
  • Nausea.
  • Bleeding between periods.
  • Breast tenderness.

Is the use of oral contraceptive pill associated with any complications?

A severe complication of using oral contraceptive pills, especially combination pills, is the increased risk of blood clots. This has the potential of leading to:

  • Deep vein thrombosis.
  • Heart attack.
  • Stroke.
  • Pulmonary embolism.

This risk of blood clot formation is higher for certain women.

  • Those who are highly overweight or obese.
  • Those with high blood pressure.
  • Those who go on bed rest for long periods.

Can I get pregnant after I stop taking an oral contraceptive pill?

Yes. One can get pregnant as soon as she stops taking a contraceptive pill.

Who can use an oral contraceptive pill?

Any healthy woman can use it, especially non-smoking women.

However, it should not be used by:

  • Those who have had a heart attack, stroke or blood clot in their legs or lungs.
  • Women whose family member have had a blood clot in their legs or lungs.
  • Those above 35 years of age. 
  • Women who smoke.
  • Overweight or obese women.
  • Those who suffer from migraines (very bad headaches).
  • Those who use some types of medications or herbal remedies. 
  • Those who have their legs in plaster or use wheelchair.

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