Prenatal methylmercury poisoning. Clinical observations over five years
L. Amin-Zaki, M. A. Majeed, S. B. Elhassani, T. W. Clarkson, M. R. Greenwood and R. A. Doherty
Thirty-two infants prenatally exposed to methylmercury and their mothers
were examined over a five-year period after the Iraqi methylmercury
epidemic. Severity of poisoning in mothers was related to the peak mercury
concentration in their hair and in the infants to the maximum concentration
in maternal hair during pregnancy. In nine cases of cerebral palsy,
methylmercury exposure occurred only during the last trimester. All infants
except three (two were orphaned soon after birth and one was bottle-fed)
were exposed postnatally via suckling. Whereas the mother's symptoms
usually improved, the damage to the fetal nervous system appears to be
permanent. Milder cases previously not identified in other studies are
reported. The syndrome consists of varying degrees of developmental
retardation in addition to exaggerated tendon reflexes and the pathologic
extensor plantar reflex (minimal brain damage syndrome).
