UPDATE 1-Less sparkle in Tiffany and Zale jewelry holiday sales

Jan 10 (Reuters) - Tiffany & Co said on Thursday that its net worldwide sales during the holiday season had risen 4 percent, continuing a trend of disappointing gains this fiscal year, and the upscale jeweler said it would plan conservatively for 2013.

A difficult global economy prompted the retailer to scale back its sales and profit forecasts three times earlier this fiscal year. A year ago, the retailer reported a 7 percent rise in holiday sales. It said this year's sales growth during its most important season was below its own expectations.

With the notable exception of Asia outside Japan, sales gains were modest in Tiffany's key markets, even falling 2 percent at its Fifth Avenue flagship in November and December, the company said.

In Europe, sales at stores open at least a year were flat, while in Japan, Tiffany's second biggest market, they rose 1 percent, excluding the impact of currency fluctuation. In Asia, same-store sales were up 7 percent.

Tiffany's mid-tier rival, Zale Corp, also reported modest gains, with U.S. same-store sales at its fine jewelry stores up 2.2 percent, well below last holiday season's 9 percent gain. It was also weaker than the U.S. same-store sales reported earlier this week by Kay Jewelers parent Signet Jewelers Ltd, where U.S. comparable sales rose 4.7 percent.

Tiffany & Co Chief Executive Michael Kowalski cited "uncertainty" about the economy in all of its major markets as the reason Tiffany is planning "conservatively" for next year's sales growth, and expects net earnings will grow between 6 percent and 9 percent in 2013.

The company now expects profit to come in at the low range of its earlier profit forecast of $3.20 to $3.40 per share for the fiscal year ending Jan. 31.

Tiffany shares were down 8.4 percent to $57.92 in premarket trading.