Send-Mailmessage powershell adds line breaks

Question

Got a really strange problem. In my PowerShell script I use the Send-Mailmessage function;

Send-MailMessage -To $($Row.SubjectID) -From '[email protected]' -Subject $($Row.SubjectType) -Body $($Row.MessageData) -SmtpServer 'localhost' -Port 2500
write-Output $($Row.MessageData)

My Output $($Row.MessageData) says;

Hi test2! Account created here is the activation link http://localhost/register/activate.php?token=e8987ecebbf54a2b096ae5fd4af34f50be0eab90a989c69da864221cd49cee92

When I look a mailslurper it displays this:

Hi test2! Account created here is the activation link http://loca=
lhost/register/activate.php?token=3De8987ecebbf54a2b096ae5fd4af34=
f50be0eab90a989c69da864221cd49cee92

Anybody knows why the message is changed?