Cytokines are chemicals in the fluid that tell the body's immune system what to do. These (and other biomarkers) can be measured with a small amount (a few drops) of amniotic fluid. The researchers have previously shown that people at risk for preterm labor have higher cytokine levels. However, understanding the in-utero environment currently requires invasive sampling, such as amniocentesis, to determine cytokine concentrations. This procedure has inherent risks, causes patient discomfort and anxiety, and thus does not avail itself to routine use or repeated sampling, especially in non-high risk patients. Therefore, the researchers are looking for non-invasive sampling that can predict the in-utero environment.