What should I do ? Am I send a letter to editor and submit my paper or attend for registration in 2018 and add it to my manuscript ?

I finished my manuscript but finally noticed that I must attend a registration code for clinical trials before recriutment (in 2016) .The journal which I intended to sent my work obligated that authors are requested to register the clinical trial presented in the manuscript in a public trial registry and include the trial registration number at the end of the abstract. Trials initiated after July 1, 2005, must be registered prospectively before patient recruitment has begun. For trials initiated before July 1, 2005, the trial must be registered before submission.