Facebook, which is preparing for an initial public offering that could value it at up to $100 billion, said spending roughly doubled over the past 12 months, outpacing the 45 percent revenue increase during the period.
Net income slid 12 percent to $205 million in the quarter, from $233 million a year earlier at the company, which is aggressively expanding and adding employees.
Facebook said in an updated filing with the U.S. Securities and Exchange Commission on Monday that its advertising business, which accounts for the bulk of its revenue, typically slows down in the first three months of the year. The rapid growth in advertising may have "partially masked" such trends to date, and that seasonal impacts may be more pronounced in the future, it noted.
Revenue, which totaled $1.06 billion in the three months ended March 31, declined 6 percent from the fourth quarter.
Facebook said its total number of monthly active users surpassed 900 million in the first quarter.
Facebook added more than 1,000 employees in the year ended in March, taking its headcount to 3,539.
Facebook's mobile users also increased, surpassing 500 million mobile users as of April 20.