By Anna Ringstrom and Veronica Ek

STOCKHOLM (Reuters) - Tobacco products maker Swedish Match (SWMA.ST: Quote, Profile, Research) posted a bigger-than-expected drop in first-quarter earnings on Friday as launch costs in the United States weighed, sending its shares lower.

But the firm stood by a forecast for higher core sales and operating profit in 2008 versus 2007.

Pretax profit fell to 427 million Swedish crowns ($72.4 million) from 468 million a year ago, undershooting a mean forecast of 504 million seen in a Reuters poll.

The operating margin for the firm's biggest and most lucrative product, wet snuff, rose to 38.7 percent from 34.9 percent, but missed forecasts for 42.9 percent.

Wet snuff -- a tobacco sold mainly in the United States and Scandinavia but banned elsewhere in the European Union -- comes loose or in pouches and is placed under the upper lip.

Marketing costs for a nationwide launch in the United States of Red Man snuff, which the firm started rolling out in 2007, cut snuff margins in the country significantly, the firm said.

Andreas Lundberg, analyst at Handelsbanken, said profits for snuff as well as cigars were disappointing.

Shares in Swedish Match dropped 4 percent to 124.75 crowns at 1453 GMT, bringing year-to-date losses to 19 percent. The broader market in Stockholm was up.