The risk of certain chemicals in plastics to health, particularly reproductive health, comes from their effect on the hormones driving many of our bodies' functions. As these hormone disrupting chemicals get more and more attention from researchers, we’re starting to understand the different ways they affect men and women.

One family of these synthetic chemicals, phthalates, has been linked to reductions in sperm quality and quantity, but a new study suggests that they may also have an undesired effect on women’s reproductive health, specifically when it comes to pregnancy using in vitro fertilization (IVF).

Women can lower their exposure by reducing the use of scented personal care products, including baby products and air fresheners.

The disturbing fact about phthalates is that they seem to be everywhere, from PVC piping to makeup to medical tubing. According to the NIH, they’re found in perfume, shampoo, soap, hair spray, nail polish, skin moisturizers, shower curtains, children’s vinyl toys, wallpaper, food packaging and plastic wrap.

It’s probably impossible to avoid phthalates completely, but if you can reduce your exposure, particularly if you are of childbearing age, it’s likely a wise move.

The researchers measured four different phthalates in the urine of 231 women who were undergoing IVF. The compounds were measured at several intervals throughout the treatment, and correlated with three strong markers of fertility: the number of eggs produced following treatment, the rate at which implantation of the fertilized egg failed and the development of the embryo.

What the researchers found was somewhat startling. Women with the highest levels of two of the compounds had reduced odds of implantation. For example, for the phthalate known as DEHP (used in PVC production), women with the highest levels had twice the likelihood of implantation failure as women with the lowest levels.

The results also showed that the number of egg cells (oocytes) women produced decreased as the levels of phthalate metabolites increased, making for what scientists call a “dose-dependent” relationship between phthalate and egg production.

Interestingly, there were no links between the phthalates and fertilization or embryo development. Still, given the results above, the authors caution women to reduce, as much as possible, their exposure to phthalates.

“We are all primarily exposed to phthalates through inhalation and ingestion,” study author Irene Souter said in a statement. “It is extremely difficult if not impossible to avoid exposure to phthalates, since they are in so many products.”

Women can lower their exposure by reducing the use of scented personal care products, including baby products and air fresheners. The authors also recommend avoiding plastic storage containers as much as possible, and being particularly careful not to heat food in them, since this can release more of the chemical into the food. And finally, always read the labels, particularly, the authors say, on children’s toys that are made of vinyl.

Dr. Souter, of Massachusetts General Hospital and Harvard Medical School, reported the study at the European Society of Human Reproduction and Embryology.