A Danish study has found that perfluorinated alkylated substances (PFAS), found in pizza boxes and burger wrappers could increase the risk of miscarriage by up to 16 times. Of 392 women assessed before the twelfth week of their pregnancy, the 56 women who suffered a miscarriage were found to have much higher levels of these water and grease-resistant chemicals (PFAS), in their blood. PFAS are used widely in greaseproof food packaging, such as that used in fast food and microwaveable popcorn. The chemicals are also used in outdoor clothing to provide waterproof qualities. The EU has practically banned the use of certain perfluorinated compounds, particularly perfluorooctanesulfonic acid (PFOS), in consumer products such as stain repellents and fabric protectors. However, Jensen claims that the use of other compounds, such as perfluorononanoic acid (PFNA), is still widespread. A 2014 Danish study which assessed more than 90,000 pregnancies found that a quarter of miscarriages could be avoided by reducing risk factors including being over 30 years old at conception, working night shifts and drinking alcohol during pregnancy.