Exploring Rats' Baby Bump: How PBDEs Affect Thyroid Hormones in Pregnancy

Every day, we're exposed to chemicals called PBDEs. Though we try to stop using them, they still sneak into our bodies and even into our babies when they're still inside the womb. Scientists studied pregnant rats to see how PBDEs enter the placenta which connects mom and baby. They divided the rats into groups: some got a little PBDE, some got a lot, and some got none. They checked the placenta at two points during pregnancy, GD15 and GD20. They found specific PBDEs like BDE-47, -99, -100, and -209 in both mom's and baby's parts of the placenta. At GD15, baby's side had more PBDEs, but by GD20, it was the mom's side with more.PBDEs affected thyroid hormones (THs) in the placenta. At GD15, low dose exposure reduced both TH types (T3 and T4) in mom's placenta. By GD20, only high doses still reduced T3 in mom's side. The study shows that as pregnancy goes on, PBDEs move around differently in the placenta, and they change thyroid hormones in different ways.