Lego Baby is a line of bricks by the Lego Group

Lego Group

The LEGO Group is a family-owned company based in Billund, Denmark, and best known for the manufacture of Lego-brand toys.The company was founded in 1932 by Ole Kirk Christiansen...

 for very young children.

In the past it was sold first as Duplo

Duplo

Duplo is a product range of the construction toy Lego, designed for children aged 1½ to 6 years old. Duplo bricks are twice the length, height and width of traditional Lego bricks , as a result being easier to handle – as well as being far harder to swallow – by younger children...

 Primo (1995–1996) then as Lego Primo (1997–1999) and became Lego Baby from 2000.
Lego Baby line had been combined with Lego

Lego

Lego is a line of construction toys manufactured by the Lego Group, a privately held company based in Billund, Denmark. The company's flagship product, Lego, consists of colorful interlocking plastic bricks and an accompanying array of gears, minifigures and various other parts...

 Duplo

Duplo

Duplo is a product range of the construction toy Lego, designed for children aged 1½ to 6 years old. Duplo bricks are twice the length, height and width of traditional Lego bricks , as a result being easier to handle – as well as being far harder to swallow – by younger children...

Line to make "lego explore" during 2002 till mid 2004. Then Lego reused Lego Baby again from mid 2004 until it was discontinued in 2006.

Its compatibility with other Lego elements is fairly minimal. Regular lego bricks of the same length and width can be attached to the bottom of Duplo bricks and adapter pieces are also available. The bricks are larger to prevent babies from swallowing them.