Birth Control Patch can be described as a contraceptive transdermal insulation releasing synthetic hormones to prevent pregnancy. This patch has a failure rate of less than 15 and the unfortunate ones are predominantly the obese and overweight women. 

Medical studies have found that these patches are less effective for women weighing more than 198 pounds or 90 kilograms. The effectiveness of this patch is highly dependent upon the health condition and weight of the woman. If you look into the way how the patch works you can easily estimate the reasons behind its failure for overweight women. It is worn on the skin of buttocks, stomach, upper arm and upper torso. The size of the patch is around 1.75 square inches. It needs to be affirmed firmly with the skin.

The smaller size becomes a problem for overweight women. They cannot place the patch firmly attached with skin. That is the reason why contraception chance does not match to the desired level. However, overweight should not be half hearted with this. There are several other oral birth contraceptives available. They can use these pills without any chance of failure.