Complex sentence: A study published in 2014 about the transfer of POPs from the mother to the unborn fetus found that POP concentrations in serum from the mother were higher than from the umbilical cord and the placenta.
Split into simpler sentences: A study published in 2014 studied the transfer of POPs from the mother to the unborn fetus. In general, the serum from the mother had higher concentrations of POPs than the serum from the umbilical cord and the placenta.