Considering the narrow window of time where a woman is able to become pregnant, it's astounding that so many manage to do so, despite taking precautions.

Often it's down to the incorrect use of certain contraceptives, but frequently it's because couples take a chance on using unreliable forms of birth control. These include the rhythm method, douching, the safe time and withdrawal.

While there are numerous reasons why couples choose to use such methods, they should always be prepared for the possibility of a pregnancy.


Rhythm method

The age old rhythm method is also known as natural family planning. This form of birth control relies on couples abstaining from intercourse during the woman's fertile days. It’s entirely reliant on the woman being in tune with her body, namely her monthly cycles, her temperature and cervical discharge, which indicate when ovulation (when the egg is released) is taking place or about to occur.

Although the egg is only available for fertilization for up to 24 hours, sperm can live much longer, anything up to five days. Therefore, having intercourse on the days before, during and just after ovulation can all lead to a pregnancy, making this an unreliable form of birth control for many couples.

Douching

Douching comes from a French word ‘douche’ meaning to wash or soak. Although douching is commonly used as a method of cleaning out the vagina, it is also sometimes mistakenly used as a method of birth control.

According to womenshealth.gov, the majority of doctors and the American College of Obstetricians and Gynecologists (ACOG) don’t recommend the practice of douching. This is because it can interfere with the delicate balance of vaginal organisms and cause infections, possibly damaging the fallopian tubes. While some research shows douching may make it more difficult for a pregnancy to occur, it by no means prevents pregnancy and shouldn't be used as a form of contraception.

Safe time

This unreliable form of contraception is a little like the rhythm method in that couples have intercourse at certain times of the month. Only in this case, the 'safe time' means having intercourse while the woman is menstruating. This is based on the idea that while she is having her period, she can't be ovulating at the same time and will be unable to conceive.

While this is true in the majority of cases, it isn't always so. For example, sperm can live inside the body for around five days. Therefore, if intercourse took place during her period and she subsequently ovulated soon after it ended, she could conceive. This is more common in women with irregular cycles who may have more than one period a month.

Withdrawal method

The withdrawal method or 'coitus interruptus' may be one of the oldest methods of contraception. The man withdraws from the woman's vagina before ejaculating, thereby preventing the sperm from reaching the egg. According to plannedparenthood.org, four percent of women will become pregnant using the withdrawal method even when always using it correctly. However, this rises to 27 percent when couples slip up occasionally.

Using this method, the onus is on the man to time it exactly right. He must be able to predict the exact point of no return and pull out in time. It's also possible for preseminal fluid, which may contain leftover sperm from a previous ejaculation, to leak into the vagina during intercourse. Therefore, the withdrawal method should be considered an unreliable form of birth control.

Before modern contraceptive devices and medications became available, methods such as douching, withdrawing and natural family planning were all that couples really had to really on. However, it's now known how unreliable they can be in preventing conception and none of them provide any protection against sexually transmitted diseases.

Ideally, such unreliable forms of birth control should only be used between couples whose sexual history is known and where the event of an unplanned pregnancy would be welcomed by both parties.