Can breastfeeding be continued if mother is undergoing treatment for Wilson's disease?

Wilson's disease (WD) is an autosomal recessive copper toxicosis caused by a mutation in ATP7B that is essential for copper transport, as a result, copper accumulates in the hepatocytes, and the serum levels of copper and ceruloplasmin decrease. Standard treatment involves administration of a chelator (penicillamine or trientine) or zinc throughout the patient's lifetime. Kodama et al evaluated the safety of breastfeeding by mothers undergoing treatment for Wilson's disease and revealed normal copper and zinc concentrations in breast milk from mothers undergoing treatment for WD.

Patients with Wilson's disease (WD) are required to adhere to therapeutic regimens throughout their life, including during pregnancy and after delivery. However, clinical practice guidelines for WD indicate that breast feeding is not recommended in mothers with WD under drug therapy. Moreover,the product instructions for penicillamine note that 'nursing should be discontinued during treatment with this drug, because it is unknown whether penicillamine can pass into the breast milk'.This is also the case for zinc acetate too.

Eighteen Japanese mothers with WD who were treated with trientine, penicillamine or zinc, and 25 healthy mothers as controls, were enrolled in this study. The numbers of patients with WD with hepatic or neurological manifestations were 14 and 4, respectively. The numbers of patients treated with trientine, penicillamine, zinc or a combination of zinc and trientine were 4, 7, 6 and 1, respectively. All infants were born without complications and breast fed by mothers undergoing treatment during lactation.

A 20µL aliquot of the copper-penicillamine complex solution (1.14mM), copper-trientine complex solution (1.67mM) or whey was used for high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) to analyse the distribution of copper, and zinc concentrations in the diluted breast milk samples were analysed by atomic absorption spectrometry.

The distribution profiles of breast milk copper complexes were similar between the mothers with WD and control mothers; all milk samples showed a pattern similar to that of mature breast milk from healthy mothers. The copper and zinc concentrations were normal in mature breast milk from mothers treated with trientine and penicillamine, despite the low copper concentrations in the serum of the mothers. It was observed that the copper concentration in the colostrum from mothers treated with penicillamine or zinc was also slightly high, however, the difference compared with controls was not significant.

The zinc concentration in control milk was significantly high in the colostrum, after which it decreased to normal concentration .The zinc concentration in the mature milk of patients treated with zinc was significantly higher than the zinc concentration in control group.

It was noted that the serum copper concentrations and ceruloplasmin levels were low in all mothers in this study. However, the copper concentrations were nearly normal in breast milk from mothers with WD treated with trientine, penicillamine and zinc. In addition, babies breast fed by mothers with WD undergoing treatment exhibited normal development at followup.

Authors conclude-" These results suggest that mothers undergoing treatment for WD can safely breast feed their infants".

Source: Kodama H, Anan Y, Izumi Y, et al. Copper and zinc concentrations in the breast milk of mothers undergoing treatment for Wilson's disease: a prospective study. BMJ Paediatrics Open 2021;5:e000948. doi:10.1136/ bmjpo-2020-000948