Hip arthroplasty with high chromium and cobalt blood levels--Case report of a patient followed during pregnancy and lactation period.

Metal-on-metal arthroplasty may lead to elevated blood chromium (Cr) and cobalt (Co) levels (>7 μg/l). Since carcinogenic, mutagenic, and teratogenic effects have been suggested, there is concern of pregnancy hazards for women with this condition. The 34-year-old patient has had a unilateral hip replacement for seven years. Before her pregnancy high Cr (47 μg/l) and Co (103 μg/l) blood concentrations were measured, but she did not develop any symptoms. A male infant was delivered after 41 weeks with first degree hypospadias. His levels were increased at 3 weeks of age: 14 μg/l (Cr) and 20 μg/l (Co), but decreased by 9 weeks to 6.7 μg/l (Cr) and 10.0 μg/l (Co). Maternal levels at delivery were 25 μg/l (Cr) and 51 μg/l (Co). The child was fully breast-fed and developed normally. An association between hypospadias and Cr/Co has to be considered speculative. The otherwise favorable outcome of this case may be reassuring for pregnant and breast-feeding patients with metal-on-metal hip replacements.