Birth Control Pills

Birth control pills also called oral contraceptives use synthetic hormones to prevent pregnancy.

What are the different kinds of birth control pills?

  • The minipill contains only progestin. In each pack, all the pills contain the same amount of progestin and all the pills are active. The progestin dose in a minipill is lower than the progestin dose in any combination pill.
  • Combination birth control pills contain both estrogen and progestin. Combination birth control pills come in different mixtures of active and inactive pills, depending on how often you want to have periods:
    • 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 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 that contain only active pills are available.

Most combination birth control pills contain 10 to 35 micrograms of ethinyl estradiol, a kind of estrogen. Women who are sensitive to hormones may benefit from taking a pill that contains a dose of estrogen at the lower end of this range. However, low-dose pills may result in more breakthrough bleeding — bleeding or spotting between periods — than higher dose pills.

  • The extended-cycle pill is a combination pill that reduces the number of menstrual periods from 13 periods a year to only four a year. That means someone who takes this pill will menstruate only once each season.

    They use a combination of two hormones that are commonly used in other hormonal contraceptives. But the pill is taken continuously for 12 weeks, followed by 1 week of inactive pills, which results in a menstrual cycle.

How do the different birth control pills work?

Combination birth control pills prevent your ovaries from releasing an egg. They also slow an egg’s progress through the fallopian tubes, thicken cervical mucus and thin the lining of the uterus (endometrium). These actions help keep sperm from fertilizing the egg.

Combination pills are either monophasic (one phase) or multiphasic (many phases).Both are equally effective at preventing a pregnancy.

  • Monophasic pills deliver an even level of hormones throughout the month.
  • Multiphasic ones have slightly different levels of hormones in active pills. They mimic normal hormonal changes that happen during your menstrual cycle.

The minipill slows an egg’s progress through the fallopian tubes, thickens cervical mucus and thins the endometrium. This prevents sperm from reaching the egg. The minipill sometimes also suppresses ovulation.

What are the side effects of birth control pills?

There are side effects of birth control pills, although most are not serious:

  • Nausea
  • Sore or swollen breasts
  • Small amounts of blood, or spotting, between periods
  • Lighter periods
  • Mood changes
  • Mild headache

What if I forget to take my birth control pill?

If you forget to take some of the pills, you will have menstrual bleeding at irregular times, and the likelihood of pregnancy increases.  When you forget to take a pill, take it as soon as you can. Take your next pill at the usual time. If you forget to take two or more pills in a row, you should refrain from sexual intercourse or use a backup method of contraception. You also should contact your health care professional on what to do next.

How effective is the pill?

If pills are taken every day at the same time, and each pack is started on time, oral contraceptives are 99% effective in preventing pregnancy.  On average, oral contraceptives are 93-97% effective because women often miss pills or do not start a new pack on time. Contact your healthcare provider if you are experiencing any pregnancy symptoms.

What Are Levonorgestrel and Ulipristal?

Unlike the other pills, these aren’t intended for regular birth control. Levonorgestrel (Fallback Solo, Next Choice One Dose, Opcicon One-Step, Plan B One-Step) and ulipristal acetate (Ella) can greatly lower your chances of getting pregnant if you had unprotected sex or if you’re concerned that your usual birth control method didn’t work.

Levonorgestrel is about 88% effective if you use it as directed. You need to take it as soon as possible within 3 days of having sex.

Ulipristal is about 60% to 70% effective if you use it correctly. You need to take it ASAP within 5 days of having sex.

Levonorgestrel side effects:

  • Menstrual changes
  • Headache
  • Nausea and vomiting
  • Dizziness
  • Breast pain
  • Tiredness
  • Lower belly pain
Ulipristal side effects:

  • Headache
  • Nausea
  • Belly pain
  • Menstrual pain
  • Tiredness
  • Dizziness

Things to Keep in Mind When Taking Birth Control Pills

  • Keep another form of birth control, like spermicidal foam and condoms, on hand in case you forget to take a pill.
  • Carry your pills with you if you don’t always sleep at the same place.
  • Take your pill at the same time every day.
  • Get your refills soon after you start the last prescription. Don’t wait until the last minute.
  • Birth control pills are medications. Always tell your doctor or pharmacist you are on the pill if you see them for any reason.

What about the pill and sexually transmitted diseases (STDs)?

Oral contraceptives do NOT provide any protection against any sexually transmitted diseases, including HIV.


Want to Know More?


Mayo Clinic: Choosing a Birth Control Pill

WebMD: Birth Control Pills