Attention, moms-to-be: Your shower routine could cause you to go into labor prematurely.

A new study indicates that many preterm births can be directly connected to phthalates, a chemical found in commonly-used products like shampoos, body washes, and some processed foods.

The study included 130 women in the Boston area who had given birth early, before 37 weeks of pregnancy, and 352 women who delivered at full term between 2006 and 2008. The researchers measured the levels of common phthalates such as DEHP in the women's urine up to three times during their pregnancies.

They found that women who had the highest levels of phthalate metabolites in their urine had a risk of preterm birth that was two to five times higher when compared with women who had the lowest levels.