Some 20 million low-birth-weight babies are born every year mostly in the developing world and nearly 4 million die within the first month of life.

FORBES: Don't Be Ashamed College Students, Profit Is Not A Dirty Word

Mothers of Indian, Pakistani and Bangladeshi origin had a high risk of having low birth-weight babies - their babies are on average 300g lighter than those of white mothers.

BBC: NEWS | Health | More tiny babies being born in UK

Low-birth weight is linked to an increased risk death and disability, and a range of long-term health problems, such as diabetes, heart disease, Attention Deficit Hyperactivity Disorder (ADHD) and depression.

BBC: NEWS | Health | More tiny babies being born in UK

The findings indicated the relationship between birth weight and pollution was dose related - the higher the exposure, the lower the average birth weight.

BBC: Traffic fumes linked to lower birth weight

The overweight women in the study who lost weight post-birth substantially lowered their risk of gestational diabetes compared with those who maintained their weight.

CNN: STORY HIGHLIGHTS

Alternatively, a depressed mother may be more likely to produce a child who is prone to depression - and to have a low birth weight baby because they may be more likely to smoke and drink during pregnancy.

BBC: NEWS | Health | 'Depression link' to small babies

Ryuzo Yanagimachi, a biologist at the University of Hawaii, found that when he cloned a certain strain of mice prone to have diabetes, the clones would look normal at birth, but upon reaching puberty -- which, in mice, is after eight weeks -- they gained weight.

CNN: Cloning experts to tell House committee pros, cons

Compared with women of similar height who maintain their weight, a 5-foot-4 woman who gains roughly 12 to 17 pounds after giving birth more than doubles her odds of developing diabetes during her second pregnancy, the study found.

CNN: STORY HIGHLIGHTS