Neostigmine and glycopyrrolate are quaternary ammonium compounds, which do not penetrate the blood-brain barrier and are not expected to cross into milk ducts.6, 21 Of note, neonatal abdominal cramping has been reported in myasthenia gravis patients taking cholinesterase inhibitors while lactating, but serum breast milk cholinesterase levels were undetectable.21 The gene discussed is BCHE; the disease is myasthenia gravis.