Polychlorinated biphenyls (PCBs) have been banned in the US and other developed nations since the 1970s, but persist in the environment due to prior widespread use, use elsewhere in the world, and because of resistance to degradation.

John Meeker of the University of Michigan, USA, has found a correlation between serum PCB concentration and the failure of an embryo generated by in vitro fertilization (IVF) to implant into the uterus. Failure was twice as likely in women with highest total PCB serum levels, the team found, and the chances of a live birth were just 40 % in that group.

• Serum Concentrations of Polychlorinated Biphenyls (PCBs) in Relation to in Vitro Fertilization (IVF) Outcomes
  A. Maity, S. A. Missmer, P. L. Williams, S. Mahalingaiah, S. Ehrlich et al.,
  Environ. Health Persp. 2011.
  DOI: 10.1289/ehp.1002922