Metal Ions and Placenta

Transplacental transfer of cobalt and chromium in patients with metal-on-metal  hip arthroplasty

A CONTROLLED STUDY

H. Ziaee, J. Daniel, A. K. Datta, S. Blunt, D. J. W. McMinn
From The McMinn Centre, and Birmingham Women’s Healthcare NHS Trust, Birmingham, England

Metal-on-metal bearings are being increasingly used in young patients. The potential adverse effects of systemic metal ion elevation are the subject of ongoing investigation. The purpose of this study was to investigate whether cobalt and chromium ions cross the placenta of pregnant women with a metal-on-metal hip resurfacing and reach the developing fetus. Whole blood levels were estimated using high-resolution inductively-coupled plasma mass spectrometry.

Our findings showed that cobalt and chromium are able to cross the placenta in the study patients with metal-on-metal hip resurfacings and in control subjects without any metal implants. In the study group the mean concentrations of cobalt and chromium in the maternal blood were 1.39 µg/l (0.55 to 2.55) and 1.28 µg/l (0.52 to 2.39), respectively. The mean umbilical cord blood concentrations of cobalt and chromium were comparatively lower, at 0.839 µg/l (0.42 to 1.75) and 0.378 µg/l (0.14 to 1.03), respectively, and this difference was significant with respect to chromium (p < 0.05).