A new study finds that chemicals used in furniture could be linked to reduced fertility. Polybrominated diphenyl ethers, or PBDEs  (which is much easier to say), have most often been used in furniture, electronics, fabrics, carpets as a treatment to make household items flame-retardant.

In a study where researchers measured PBDE levels in the blood from 223 pregnant women, those with the highest concentrations of the chemicals experienced a longer delay in getting pregnant. Other studies suggest that 97% of Americans have some levels of PBDE’s in their blood, however many manufacturers are phasing out their use and California has banned some of the chemicals.

One of the strongest associations of PBDEs is with thyroid hormone,” said Kim Harley, lead author of the study and a director at UC Berkeley’s School of Public Health. “Thyroid hormone does seem to play an important role in fertility. Either too low or too high levels can impair fertility. PBDEs also seem to mimic estrogen. It could be through a hormonal mechanism. But we need more research on that.”