RICHMOND , Va., Dec. 18 (UPI) -- An abortion or miscarriage is a significant risk factor for a subsequent low birth weight baby or premature birth, U.S. researchers suggest.

The study, published in the Journal of Epidemiology and Community Health, finds U.S. Women who have miscarried or had an abortion run three times the normal risk of later having a low birth weight baby and the risk increases with increasing number of abortions.

Researchers at Virginia Commonwealth University in Richmond used data from the U.S. Collaborative Perinatal Project -- set up in 1959 to look at the associations between factors during pregnancy and birth and childhood development.

More than 45,500 mother and child pairs were assessed and the researchers found a strong association between miscarriage and abortion and an early or underweight birth, even after adjusting for other risk factors, such as smoking, high blood pressure and heavy drinking.

Women who had one, two, or three or more miscarriages or abortions in the past were almost three, five and 9 times as likely to give birth to an underweight child as those without previous miscarriages or abortions. Women who had one miscarriage or abortion were 67 percent more likely to have a premature birth, compared with those with no history of miscarriage or abortion.