Size of a newborn’s cerebellum in relation with prenatal exposure to mercury

A prospective study, as extended part of the PHIME study, has been conducted and a total of 137 childbearing women with term, singleton, and uncomplicated pregnancies were included. Maternal hair has been used as a vehicle for measuring prenatal exposure to mercury. Neurosonographic examination was conducted to all newborns and length and width of cerebellum were measured. Women were divided based on their hair levels of methyl-mercury: ≥ 1 mcg/g vs. < 1 mcg/g and their newborns were compared. Mean value of mother’s hair mercury level was 880, 9 mcg/g, ranging from 19 mcg/g to 8710 mcg/ g. with 107 mother with levels < 1 mcg/g. Comparison between the group of newborns born to mothers with levels of mercury ≥ 1 mcg/g and those born to mothers with levels of mercury < 1 mcg/g revealed that there were no significant differences between the two groups considering the width of cerebellum. Mean values of the length of cerebellum were 24, 6 (SD 2.8) and 25, (SD 3, 3), respectively. Statistical analysis revealed no significant difference between the groups related to the length of cerebellum. However obtained result was at the borderline significance (p=0.06). Obtained preliminary results show that majority of our sample consisted of mothers with lower hair levels of mercury (< 1 microgram/g) whose newborns had greater mean values of length and width of cerebellum compared to those whose mothers had higher heir levels of mercury. However difference did not reach the level of statistical significance.