Table 1. Metal-on-metal hip implants studies and findings.

Authors [year]	Number of patients	Metals	Birth abnormalities	Cord blood levels detected	Average chromium detected in mother (μg/L)	Average cobalt detected in mother (μg/L)	Average chromium detected in umbilical cord (μg/L)	Chromium reduction from maternal blood to cord blood (%)	Average cobalt detected in umbilical cord (μg/L)	Cobalt reduction from maternal blood to cord blood (%)
deSouza et al. [2012] (8)	3	Cobalt, chromium	0/3	3/3	44.22	38.82	10.03	77.3	18.61	52.1
Brodner et al. [2004] (7)	3	Cobalt, chromium	1/3	0/3	1	0.33	Undetected	100	Undetected	100
Fritzsche et al. [2012] (6)	1	Cobalt, chromium	0/1	1/1	39	138	2.1	94.7	75	45.7
Novak et al. [2014] (9)	3	Cobalt, chromium, titanium, nickel	0/3	3/3	1.87	0.972	0.29	84.5	0.49	49.6
Ziaee et al. [2007] (11)	10	Cobalt, chromium	0/10	10/10	1.28	1.39	0.194	84.9	0.336	73.8
Oppermann et al. [2015] (10)	1	Cobalt, chromium	1/1	1/1	25	51	2.3	91	31	39.3