Sexual Health

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The Birth Control Pill

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What is the pill?

The pill is a hormonal birth control method that you get by prescription from your health care provider.


How does it work?

The birth control pill is an artificial form of the two hormones (estrogen and progestin) that cause the ovaries to release an egg each month. The pill prevents pregnancy by:

  • stopping the ovaries from releasing an egg
  • causing mucus in the cervix to thicken making it hard for sperm to enter the uterus
  • causing the lining of the uterus to get thinner making it hard for the fertilized egg to attach


What are the advantages to using the pill?

  • 99% effective in preventing pregnancy if used correctly (92-97% effective with typical use)
  • Lighter, shorter, more regular periods
  • Less cramping with your periods
  • Improvement in acne
  • Lower risk of cysts of the ovaries or breasts and of cancer of the ovaries or the lining of the uterus
  • Lower risk of endometriosis, tubal pregnancy and anemia.


What are the side effects or risks of taking the pill?

Side effects from the pill most often occur in the first three months of use. Unless the side-effects are severe, it is recommended to take the pill for three months before you think about a change in pills. Some of the possible side effects:

  • Spotting or bleeding between periods
  • Missing a period
  • Headaches (if severe of more frequent than usual, contact your health care provider)
  • Breast tenderness, fluid retention, headaches or moodiness.
  • Nausea



Seek medical attention right away if you notice any of the following:

  • Severe pain in your legs or abdomen
  • Severe chest pain, cough or shortness of breath
  • Blurring or loss of vision, speech problems
  • Depression
  • Jaundice (yellowing of skin)


When do I start taking my pills?

  • You have 3 options – your doctor or nurse practitioner will suggest which one is best for you.


Option 1: Quick Start

  • Take your first birth control pill the day of your clinic appointment
  • Use condoms for birth control for the first seven days.


Option 2: First Day Start

  • Take your first birth control pill the day you begin your period.


Option 3: Sunday Start

  • Take your first birth control pill on the first Sunday after your period begins
  • You may still be bleeding when you start the pill
  • If your period starts on a Sunday, take your first pill that day.


Are there times when the pill may not be effective?

Yes. Many prescription, non-prescription and herbal medicines may interfere with the pill. Always check with the Sexual Health Clinic, your health care provider, or a pharmacist before taking medication.

You should use condoms for additional protection:

  • When waiting to start the pill
  • For the first seven (7) days after starting the pill
  • If you vomit within one hour of taking your pill, or have diarrhea for two or more days.

If you have unprotected sex during a time when the pill may not be effective, contact the Sexual Health Clinic, your healthcare provider or a pharmacist about the need for emergency contraception (ECP).


Will I gain weight on the pill?

It is a common myth that the pill causes weight gain, but studies show that there is no relationship between the pill and weight gain. Estrogen hormone in the pill may make some women feel bloated initially, but this usual gets better. Many women start the birth control pill in their teens when their body is growing into adulthood which is normal. Eating a healthy diet and staying active will help to maintain a healthy weight.


Things to Remember

  • The pill does not protect against sexually transmitted infections (STIs). Always use condoms every time you have sex.
  • It is important to have a yearly physical, while you are on the pill.
  • Women who use hormonal contraceptives are strongly advised not to smoke. Cigarette smoking can increase the risk of serious adverse effects on the heart and blood vessels. This risk increases with age.

Page Last Modified: Wednesday, 12 March 2014.