London, May 12 (IANS) Excessive exposure to air pollution might increase the chance of In-Vitro Fertilisation (IVF) failure, a new study has found.

A team of fertility experts tested more than 7,000 women undergoing IVF in various American hospitals and analysed the results over seven years - from 2000 to 2007, telegraph.co.uk reported.

Dr Duanping Liao, a professor of epidemiology at Penn State College of Medicine, Pennsylvania, who worked on the research, said: "Numerous studies have consistently shown a relationship between air pollution and human health, ranging from mortality, cardiovascular disease and other chronic conditions.

"In the process of searching for the mechanisms responsible for the above associations, we, and others, have reported significant links between air pollution and inflammation and increased blood clotting.

"These intermediate factors are also associated with reproductive health."

Experts say that burning of fossil fuels and diesel are the main causes of nitrogen dioxide production.

The researchers worked out daily pollution concentrations for each patient during the entire IVF process and pregnancy.

Dr Liao added: "Since IVF is a well controlled and highly timed process, we have a much better handle on the assessment of the time of exposures to elevated air pollutants in relationship to fertilisation, pregnancy, and delivery.

"Therefore, the IVF population coupled with detailed assessment of air pollution exposures may provide us an ideal situation to investigate the potential health effects of air quality on human reproduction."