NOT that pregnant women needed any more incentive to quit smoking, but British researchers have just found another.

Puffing away during pregnancy damages the placenta and affects a hormone that results in smaller babies with smaller brains.

“In particular, the reduced brain size that we saw in smokers’ babies could lead to impaired cognitive ability of the child,” said one of the researchers.

The study also included women who quit smoking only when they discovered they were pregnant. These babies, researchers said, were able to develop normally as a result.