Toxic dust from the Sept. 11, 2001 terrorist attack on the World Trade Center may be linked to widespread pregnancy issues, according to a recent study.

Researchers from Princeton University's Woodrow Wilson School of Public and International Affairs in New Jersey found that pregnant women living near the World Trade Center during 9/11 experienced higher-than-normal negative birth outcomes. They were more likely to give birth prematurely and deliver babies with low birth weights.

The collapse of the two towers created a zone of negative air pressure that pushed dust and smoke into the avenues surrounding the World Trade Center site.

"Previous research into the health impacts of utero exposure to the 9/11 dust cloud on birth outcomes has shown little evidence of consistent effects," Janet Currie, one of the lead authors of the study, said in a statement. "This is a puzzle given that 9/11 was one of the worst environmental catastrophes to have ever befallen New York City."

For the study, researchers analyzed data on all births that were in utero on Sept. 11 in New York City and compared those babies to their siblings. For mothers in their first trimester during 9/11, exposure to this catastrophe more than doubled their chances of delivering a baby prematurely. Of the babies born, boys were more likely to have birth complications and very low birth weights. They were also more likely to be admitted to the neonatal intensive-care unit (NICU).

Lower Manhattan, Battery Park City, SoHo, TriBeCa, Civic Center, Little Italy, Chinatown and the Lower East Side were neighborhoods most affected by the 9/11 dust cloud.

Other past studies have shown that environmental exposure to the World Trade Center dust cloud was associated with significant adverse effects on the health of adult community residents and emergency workers.

The findings were recently released by the National Bureau of Labor Economics.