How does the Evra Patch Work?

The contraceptive patch secretes synthetic hormones into your blood stream via skin contact and these have an effect on your menstrual cycle. The two hormones that are released are progesterone and oestrogen. During a usual cycle, levels of these hormones dictate the processes that occur throughout the month such as when an egg should be released. By adding a continuous rate of these hormones, you make your body believe that it has already ovulated. As you only release one egg a month, an egg will not be matured and released. Therefore it is very unlikely that you will get pregnant, as there is no egg for the sperm to fertilize in the first place.

The contraceptive patch has other mechanisms apart from just stopping ovulation, to prevent pregnancy. One of which is that it thickens the mucus lining of your cervix- the entrance to your womb. This makes it significantly more difficult for sperm to penetrate this lining and swim towards the fallopian tubes. Therefore if they can’t get past this barrier, they can’t have a chance at fertilization. This thickened mucous barrier is sometimes referred to as a “mucous plug” and can be beneficial as it can also stop some bacterial infections. However, it will not stop you contracting any sexually transmitted infections so always use a condom. Also, the patch has an effect on your womb lining. During a normal pregnancy, the uterus lining would become thicker so that the egg has a chance of becoming implanted into the wall and has the chance to grow. The hormones thin this uterus lining so that at the very slim chance an egg does get fertilized, it will find it much harder to successfully embed into the lining and will not develop into a foetus.


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