Persons who smoke AND are over 35 Years old and above shouldn’t use Xulane. Also, persons with a body mass index (BMI) of 30 kg/m2 or more. Check your BMI here.  Women with a BMI of 30 kg/m2 or more who use the patch birth control have a higher risk for developing side effects like blood clots compared to women with a BMI lower than 30 kg/m2  and the patch doesn’t work as well and those with a BMI or 30 or more.