Mortgage rates have been volatile in recent months, but aside from rates, these five trends could make the mortgages themselves more expensive in the upcoming months.

• A new federal regulation that restricts how loan officers are compensated might result in higher costs for borrowers.
• Borrowers who have low credit scores, small down payments or little equity relative to their home's value will be subject to higher interest rates on so-called conforming loans that lenders can sell to Fannie Mae or Freddie Mac.
• The Federal Housing Administration has raised its annual mortgage insurance premium by one-quarter of a percentage point on all 15-year and 30-year loans.
• Another development that eventually might lead to higher loan costs is the federal government's definition, proposed in late March, of a qualified residential mortgage, or QRM.
• Borrowers who live in a relatively expensive housing market and who want a loan of more than $625,500 will pay more for their mortgage later this year. Effective Oct. 1, the top limit for conforming loans is set to drop from the temporary $729,750 to the general $625,500 in high-cost housing markets. For more about mortgage costs, see "Watch for rising mortgage costs."