At any given time, approximately 62% of all women of reproductive age are using some form of a contraceptive for the prevention of an unintended pregnancy.  Out of those women regularly using a contraceptive, around 53% of unplanned pregnancies will still occur.  There are many forms of contraceptives women can chose from more than what was available in the past – birth control pills, other hormonal methods of the patch, implant, injectable and vaginal ring, IUDs and condoms. With so many different options available, why do women who are using contraceptives, still become pregnant?

There are many reasons why contraceptive use is not fail-proof. And usually the blame points back to the woman or couple using the contraceptive rather than the contraceptive itself.  What is known is that couples who do not use any method of contraception have an approximately 85% chance of experiencing a pregnancy over the course of a year. 

Here are five reasons why a woman using a contraceptive can sometimes still get pregnant:

1. Not following instructions – When using any form of birth control, it is imperative to follow the directions on how to use it exactly as directed.  Particularly when using birth control pills as they need to be taken at the exact same time each day in order to work as intended.   Taken correctly, birth control pills are up to 99.9% effective. 

Other birth control methods also need to be used as instructed. Condoms should be inspected to make sure they are in good condition with no tears and are put on correctly.  Women using a diaphragm or cervical cap should make sure the cervix is completely covered before sexual intercourse. 

2. Not using contraceptives consistently – Even though birth control pills are extremely effective for preventing pregnancy, between 2 and 8 percent of women will become pregnant each year using them. And it’s not the fault of the pill but rather mistakes women are making in using them.

If a woman forgets to take her birth control pill or is not taking it at the same time each day, this will put her in a position of risking becoming pregnant.  The pill is not the only problem.  Couples who rely on a barrier method of birth control such as condoms, cervical caps and diaphragms, must use them each and every time during sexual intercourse if they aren’t ready to bring a baby into the world.  Forgetting just one time means you could become pregnant.

In order for any contraceptive to do its job, the user of them must use them consistently to avoid pregnancy.

3. Damage to a condom – Condoms when used correctly are about 98 percent effective.  This makes them more effective than several other forms of contraception such as withdrawal or using spermicides. 

But using a condom that breaks or has even a tiny tear in them can often lead to an unplanned pregnancy.  Causes of condom damage can include using one past its expiration date, improper storage, or inadequate use of a water-based lubricant.  To reduce the risk of pregnancy, it is recommended to also use a vaginal spermicide along with a condom in case condom damage does occur.

4. Using certain drugs or herbs – Any woman using birth control pills should check with their doctor or pharmacist for any possible drug or herbal interactions that could reduce the effectiveness of the contraceptive.  This can also include the use of alcohol when using birth control pills.  Alcohol can reduce the effectiveness of the pill because alcohol is metabolized by the liver and any drug that the liver may also affect the way the pill is absorbed by the body. 

5. Women who do not know when they are ovulating

Ovulation is when a mature egg is released from the ovary and travels into the fallopian tube available to be fertilized.  For many women they may not know exactly when this is occurring. 

A woman’s monthly cycle is measure from the first day of her menstrual period until the first day of her next period. Ovulation can be calculated by starting with the first day of the last menstrual period (LMP) or by calculating 12-16 days from the expected period.  Most women will ovulate anywhere between day 11 and day 21 of their cycle, counting from the first day of the LMP. 

This is usually referred to as the “fertile time” of a woman’s cycle because sexual intercourse during this time increases the chance of pregnancy.  To avoid this from happening, women can track their cycle and make certain they are using a birth control method during that time.  However, researchers from the National Institute of Environmental Health have said there is no “safe time” of the month as the possibility of pregnancy may occur on almost any day of the month including during menstruation.