I am obese and am on nexplanon and had sex for the first time can i be pregnant? how soon do have to get the implant removed?

You can rarely be: Since Nexplanon is a vey highly effective method of contraception, your risk of getting pregnant is quite low even if you are obese (0.05% or less than 1 pregnancy per 100 women in 1yr); but it is not zero. A blood betaHCG pregnancy test should answer your question. If your pregnancy test is indeed positive, it is recommended to remove the implant. If negative, keep it safely and securely