I forgot to put on a new patch after my patch free week so i put one on a new day the day after. i had sex that same day. possibility of pregnancy?

Pregnancy : Unlikely but possible . Would do a pregnancy test at home if you miss. Good Luck

Possible: Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully

Yes, possibility: Because you started your week 1 patch a day late, there is the possibility of pregnancy. Back up contraception such as a condom and spermicide or diaphragm and spermicide is recommended for 7 days before returning to the patch only. Also, note that the day they apply the new patch becomes the new patch change day. Emergency contraception is worth considering too.