SPUtility.SendEmail is not working with HTMl email properly

I build html strings which has around 200000 + characters in its HTML body. I send email using (IAlertNotifyHandler) and

SPUtility.SendEmail(web, true, false, ahp.headers["to"].ToString(), "IMMEDIATE EMAIL", htmlString);It skips one characters from he html body at every 2035 th place. This makes the html content not presenting what I want in the email. Please advise.