NEW YORK (CNNMoney.com) – U.S. retailers Thursday blamed an Easter holiday shift for much weaker-than-expected sales at their stores last month. But some analysts say the softness, particularly among teen sellers, may be the first serious sign that consumer spending is slowing down.

With this year's Easter holiday occurring in April versus in March last year, the calendar shift probably shaved 2 to 3 percent off last month's comparable sales numbers, said Ken Perkins, retail analyst and president of research firm Retail Metrics.

"For the teen names, March was an inflexion point," Perkins said. "The teen chains like Abercrombie & Fitch and Aeropostale are coming up against very difficult one and two year comparisons. Their challenge is in order for these retailers to keep pulling upper single-digit comparable sales, they have to consistently hit fashion trends right on the head."

However, Perkins said the broader implication of the sales misses in the teen space doesn't bode well for consumer spending in the months ahead since spendthrift teenagers typically are a good barometer of consumers' discretionary spending.

"Retailers could now be experiencing the lag effect of the Fed rate hikes. There could be one or two more to come. I think the effect of the rate hikes is floating into the housing market and consumers have less money to pull from their home equity and put into stores," he said. And the less confident parents feel about their economy, the less likely they are to happily handover that weekly allowance to their teenage kids.

There are already some signs of consumers turning cautious, Perkins said, alluding to February's government consumer spending report which showed consumer spending in the month grew at a much slower pace versus January.

"I don't see spending pick up pace in the months ahead and retailers are going to feel the squeeze," he said.

Chris Donnelly, partner with Accenture's retail practice, agreed with Perkins.

"The February-March time frame is a difficult period to interpret because of the calendar shift. April will be very telling because a weak April would make it three consecutive months of soft sales," said Donnelly. "Three months is a quarter and that could definitely be a cause for concern that maybe we're seeing the first harbinger of a spending slowdown."

Many of the top teen chains last month posted sales that widely missed analysts' expectations.

Aeropostale (Research) logged a steep 9.3 percent drop in its sales at stores open at least a year – a key retail measure known as same store sales -- much worse than the 3.1 percent decline forecast by Thomson Financial.

In the same space, American Eagle Outfitters (Research) posted a lower-than-expected 3 percent gain in March. Analysts were looking for a 3.8 percent gain.

And Hot Topic (Research) reported its sales tumbled 12.7 percent.

With this year's Easter holiday occurring in April versus in March last year, retail analysts had warned that shoppers would likely shift their holiday shopping into this month, adversely impacting sales last month.

According to Perkins, the Retail Metrics Same Store Sales Index of 57 retailers was up just 1.9 percent in March marking the most sluggish monthly comparable sales growth since November of 2004 and falling below expectations for a two percent increase.

Among the other disappointments, Federated Department Stores (Research), which operates the Macy's and Bloomingdales chains, posted March sales that were flat, in-line with the company's previous guidance of flat to up 1 percent.

Beleaguered home furnishings retailer Pier 1 Imports (Research) posted a 2 percent drop in its same-store sales and a loss in its fourth quarter. Analysts on average were expecting the retailer to post a profit for the period.

But there were some winners. Wholesale club operator Costco (Research) posted a strong 7 percent gain in March sales.

Sales at Wal-Mart (Research), the world's largest retailer, were in-line with its earlier forecasts. The discount leader posted a 1.4 percent gain in its same-store sales, although this was at the low end of its pervious guidance of a 1 to 3 percent.

For April, Wal-Mart said it expects sales to rise between 4 to 6 percent. Additionally, the retailer reaffirmed its first-quarter profit forecast. Wal-Mart said it still expects earnings in the period of between 58 cents to 62 cents a share. Analysts, on average, expect the company to post a profit of 60 cents a share for the quarter.

Wal-Mart's archrival Target (Research) faired marginally better, posting a 2.2 percent sales increase.

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