* First-qtr net loss $0.03/share vs $0.11 profit year earlier
* Sales fall 5 pct to $946.2 mln vs est. $952.9 mln
* North America sales down 2 pct (Adds details, background)
April 17 (Reuters) - Mattel Inc, the world's largest toymaker, reported a net loss for the first quarter due to a fall in sales of its iconic Barbie dolls and Fisher-Price toys for preschoolers.
Worldwide sales of Barbie fell 14 percent in the quarter ended March 31, but those of American Girl dolls rose 5 percent.
Sales of Fisher-Price toys declined 6 percent.
Mattel said its sales in North America, which accounts for half of its total revenue, fell 2 percent. International sales were down 7 percent.
As demand for its Barbie dolls and preschool toys slows, Mattel is shifting focus to the fast-growing market for building block toys to boost sales.
In February, the company offered to buy Canada's Mega Brands Inc for about $460 million to better compete with Denmark's Lego, which leads the building block toys market.
Mattel reported a net loss of $11.2 million, or 3 cents per share, for the first quarter compared with a net income of $38.5 million, or 11 cents per share, a year earlier.
Worldwide sales fell 5 percent to $946.2 million.
Analysts on average had expected sales of $952.9 million, according to Thomson Reuters I/B/E/S.
Mattel's shares closed at $37.88 on the Nasdaq on Wednesday. The stock has fallen about 20 percent this year. (Reporting by Shailaja Sharma in Bangalore; Editing by Kirti Pandey)