* Rally takes a break after string of modest gains
* Euro zone crisis "not over," ECB official says
* Indexes down: Dow 0.1 pct, S&P 0.4 pct, Nasdaq 0.5 pct
By Caroline Valetkevitch
NEW YORK, March 12 (Reuters) - U.S. stocks edged lower on Tuesday as investors paused after a seven-session string of gains, led by losses in large-cap technology shares.
Investors' confidence has grown in recent months, leading to a gain of more than 10 percent for the year by the Dow and nearly 9 percent by the S&P 500. Signs of improvement in the economy and the Federal Reserve's quantitative easing have helped to drive the advance.
Tuesday's modest retreat was "not surprising, given the rally we have had," said Stephen Massocca, managing director of Wedbush Equity Management LLC in San Francisco.
Tech shares, which have lagged the rally, pulled indexes lower as heavyweights such as Apple and Google tumbled.
Apple dropped 1.8 percent to $429.82. An analyst said the company has a 25 percent chance of missing its quarterly revenue forecast as iPhone sales slow.
The Dow Jones industrial average was down 19.57 points, or 0.14 percent, at 14,427.72. The Standard & Poor's 500 Index was down 6.00 points, or 0.39 percent, at 1,550.22. The Nasdaq Composite Index was down 16.56 points, or 0.51 percent, at 3,236.31.
After a light economic calendar the last couple of days, investors will turn their attention to retail sales data on Wednesday to get a sense of how consumers are faring. Sales are expected to have increased 0.5 percent in February.
Adding to Tuesday's weakness, Jens Weidmann, head of the Bundesbank and a member of the European Central Bank's governing council, said the euro zone crisis was not over.
Pullbacks during the rally so far this year have not been too deep as investors look for a good place to buy. Market moves have often been muted in recent days, even as stocks have ground higher.
The healthcare sector rose 0.4 percent. Traditionally considered a defensive bet, the sector has been one of the leaders of the rally so far this year, accelerating by nearly 12 percent.
In the short-term, however, healthcare appears to be overbought, suggesting investors may start to put their money elsewhere or take profits. Based on the relative strength index, healthcare has been overbought since the beginning of the month.
The drop in tech shares brought the sector below the overbought level after briefly crossing above it on Monday.
Merck (Other OTC: MKGAY - news) shares gained 3.2 percent to $45.04 to help curb declines on both the Dow and S&P after the pharmaceutical company said an outside board had allowed it to continue a trial assessing its Vytorin cholesterol drug.
Yum Brands Inc rose 1.3 percent to $68.75 after the parent company of the KFC restaurant chain reported an unexpected rise in February sales in China.