Anheuser-Busch InBev , the world's largest brewer, suffered a first drop in beer sales for a year and half as price hikes, rain in Brazil and high U.S. unemployment deterred drinkers.

However, the maker of Budweiser, Stella Artois and Beck's said it expected volumes to improve from the second quarter and forecast continued benefits from price rises carried out in its main U.S. and Brazilian markets at the end of last year.

First-quarter overall group shipments fell 0.4 percent on a like-for-like basis, the first decline for the company since the third quarter of 2009 and against market expectations of a slight increase.

The Belgium-based brewer said on Wednesday a high jobless rate, notably among its core consumer group of young males, reduced volumes in the United States, while heavy rain kept growth to a minimum in Brazil. Beer consumption typically rises in warm and sunny weather.

Price hikes cut AB InBev's share of its two largest markets, but their net impact was positive, driving up revenue in both. Some U.S. consumers also shifted to premium beers.

Group revenues rose 5.6 percent to $9.0 billion and core profit (EBITDA) by 6.5 percent to $3.41 billion. Both were in line with average forecasts in a Reuters poll.

AB InBev shares dropped by as much as 3.8 percent to a three-week low of 42.2450 euros and they were among the weakest in the FTSEurofirst 300 index <.FTEU3> of leading European stocks. At 1048 GMT, they were down 3.1 percent.

The volumes were weak and the net profit was hit by certain financial items, said Bernstein Research analyst Trevor Stirling. Some people are worried about the volumes, although I would expect volumes to pick up.

IMPROVEMENT FROM Q2

Chief Financial Officer Felipe Dutra said they would.

We said in March that we were expecting soft points in the first quarter of the year with improvements starting from the second quarter going into the second half and that remains valid, he told a conference call.

In terms of price, adjustments in the main markets took place at the end of last year so we already had that benefit in the first quarter and so that should continue into the second quarter and going forward as well.

AB InBev repeated that the cost of sales per hectoliter should increase by a low single-digit percentage this year as its hedging mitigated the impact of global commodity costs.

The futures price for malt barley is more than 50 percent higher than a year ago.

The company said revenue per hectoliter should grow by more than inflation. It also said sales and marketing investments would be a mid to high single-digit percentage higher in 2011 than in 2010.

We continue to believe that a recovery in the U.S. economy is a question of when and not if. In the meantime, we will remain focused on building the health of our brands and driving forward with all our major initiatives, Dutra said.

U.S. employers stepped up hiring in March, when the jobless rate fell to a two-year low.

AB InBev's first quarter performance contrasts with that of world numbers two and three, SABMiller and Heineken , both of which increased beer sales, although largely because of benefits in different regions.

MillerCoors , a U.S. joint venture of SABMiller and Molson Coors Brewing Co and the second largest U.S. brewer, suffered a decline of volumes, albeit less than AB InBev and an improved trend compared with the previous five quarters.

Molson Coors reported lower-than-expected quarterly profit on Tuesday, hurt by a sales decline in Canada.

The world's fourth largest brewer Carlsberg , with a heavy presence in Russia, reports its first-quarter results next Wednesday.

(Reporting by Philip Blenkinsop; Editing by Dan Lalor and Mike Nesbit)