Choosing a birth control pill

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Choosing a birth control pill

If you're considering taking birth control pills, you're not alone. Birth control pills are some of the most popular contraceptives. And for good reasons — they're effective and easy to use. The variety of birth control pills available, though, can seem daunting. Fortunately, they can be sorted into just a few categories to make it easier to assess your options.

What are the different kinds of birth control pills?

There are two main kinds of birth control pills — combination birth control pills, which contain estrogen and progestin, and the minipill, which contains only progestin.

Combination birth control pills come in different mixtures of active and inactive pills, depending on how frequently you want to have periods:

  • Conventional. Conventional packs usually contain 21 active pills and seven inactive pills, or 24 active pills and four inactive pills. Bleeding occurs every month when you take the inactive pills.
  • Continuous dosing or extended cycle. These packs typically contain 84 active pills and seven inactive pills. Bleeding generally occurs only four times a year during the time when you take the inactive pills. Formulations containing only active pills — eliminating bleeding — also are available.

Combination birth control pills are also categorized according to whether the dose of hormones stays the same or varies:

  • Monophasic. In this type of combination birth control pill, each active pill contains the same amount of estrogen and progestin.
  • Multiphasic. In this type of combination birth control pill, the amounts of hormones in active pills vary.

Combination birth control pills that contain less than 50 micrograms of ethinyl estradiol, a kind of estrogen, are known as low-dose pills. Women who are sensitive to hormones may benefit from taking a lower dose pill. However, low-dose pills may result in more breakthrough bleeding — bleeding or spotting between periods — than do higher dose pills.

The minipill doesn't offer as many choices. There's a single mixture and formulation, and all the pills in each pack are active.

How do the different birth control pills work?

Combination birth control pills suppress ovulation in most cycles — keeping your ovaries from releasing an egg. Combination birth control pills also thicken cervical mucus and thin the lining of the uterus (endometrium) to keep sperm from joining the egg.

The minipill thickens cervical mucus and thins the endometrium — preventing sperm from reaching the egg. The minipill also sometimes suppresses ovulation. Unlike combination birth control pills, the minipill doesn't contain estrogen. The progestin dose in a minipill is also lower than the progestin dose in any combination oral contraceptive pill.

Are all kinds of birth control pills appropriate for everyone?

No. Your health care provider will ask about your medical history and any medications you take to determine which birth control pill is right for you.

Your health care provider may discourage use of combination birth control pills if you:

  • Are breast-feeding
  • Are older than age 35 and smoke
  • Have poorly controlled high blood pressure
  • Have a history of or current deep vein thrombosis or pulmonary embolism
  • Have a history of breast cancer
  • Have a history of stroke or heart disease
  • Have diabetes-related complications, such as nephropathy, retinopathy or neuropathy
  • Have liver disease
  • Have unexplained uterine bleeding
  • Will be immobilized for a prolonged period due to major surgery
  • Take St. John's wort, or anticonvulsant or anti-tuberculous agents

Your health care provider may discourage use of the minipill if you:

  • Have breast cancer
  • Have unexplained uterine bleeding
  • Take anticonvulsant or anti-tuberculous agents

What are the pros and cons of combination pills?


  • Decreased risk of ovarian and endometrial cancers
  • Improvement in acne
  • Less severe menstrual cramps (dysmenorrhea)
  • Possible decreased risk of postmenopausal hip fracture
  • Reduction in androgen production caused by polycystic ovary syndrome
  • Reduction in heavy bleeding (menorrhagia) and related anemia
  • Relief from premenstrual syndrome (PMS)
  • Shorter, lighter and more predictable periods, or fewer or no periods


  • No protection against sexually transmitted infections
  • Increased risk of blood clots, heart attack and stroke (recent studies suggest that the type of progestin used in the pill may have an impact on the risk of blood clots, with pills containing drospirenone showing a higher risk)
  • Side effects such as irregular bleeding, bloating, breast tenderness, nausea and headache

What are the pros and cons of the minipill?


  • Can be taken if you have health problems, such as a high risk of heart disease, blood clots, high blood pressure or migraines
  • Can be used during breast-feeding
  • Offers a quick return to fertility if you hope to get pregnant


  • No protection against sexually transmitted infections
  • Potentially less effective than combination birth control pills
  • Must be taken at the same time every day (taking the minipill more than three hours later than usual means backup birth control will be needed for at least two days)
  • Side effects such as irregular menstrual bleeding, ovarian cysts, decreased libido, headache, breast tenderness, acne, weight gain, depression and hirsutism
  • Slightly increased risk that if pregnancy occurs it will be ectopic — the fertilized egg implants outside the uterus.

What's the bottom line?

You have many options for birth control. If you choose to take birth control pills, work with your health care provider to decide which type of birth control pill is right for you.

Last Updated: 2012-01-21
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