title: Prenatal exposure to low-level methylmercury alters the child's fine motor skills at the age of 18 months.
abstract: OBJECTIVE
  To compare motor, cognitive and language characteristics in children aged 18 months who were prenatally exposed to low-level methyl-mercury (MeHg), and to analyze the eventual differences in these characteristics in relation to cord blood THg concentration.
  
  
  METHODS
  The total number of 205 child-mother pairs was included in the study, and total cord blood mercury was measured in 198 of them. Out of the 198 already measured samples, 47 of them have also been tested for methyl-mercury in cord blood. Data regarding the 47 samples of MeHg levels has been used for calculating the correlation between cord blood THg and cord blood MeHg. MeHg and THg showed a significant correlation (r=0.95, p<0.05). One month after the delivery, mothers were asked to complete the questionnaire regarding socioeconomic factors, breastfeeding of their infants, and dietary habits during pregnancy. Neurodevelopmental assessment of motor, cognitive and language skills were conducted on 168 children using The Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). Regarding the cord blood THg concentration, 135 children were divided in 4 quartile groups. Their neurodevelopmental characteristics have been compared.
  
  
  RESULTS
  The cord blood THg concentration median and inter-quartile range was 2.98ng/g (1.41-5.61ng/g). There was a negative correlation between cord blood THg concentration and fine motor skills (rho=-0.22, p=0.01). It is evident that children grouped in 2nd ,3rd and 4th quartile had statistically significant lower fine motor skills assessment related to those grouped in 1st quartile (2nd quartile -1.24, p=0.03; 3rd quartile -1.28, p=0.03; 4th quartile -1.45, p=0.01). The differences in fine motor skills assessments between children in 2nd and 3rd and 3rd and 4th quartile were not statistically significant.
  
  
  CONCLUSIONS
  Intrauterine exposure to low-level THg (MeHg) is associated with alterations in fine motor skills at the age of 18 months.
authors: University Hospital Rijeka, University of Rijeka, Medical Faculty, Istarska 43, 51000 Rijeka, Croatia. Electronic address: igor.prpic@medri.uniri.hr.
authors: Igor
authors: I
authors: Prpić
authors: University Hospital Rijeka, University of Rijeka, Medical Faculty, Istarska 43, 51000 Rijeka, Croatia. Electronic address: ana.milardovic@medri.uniri.hr.
authors: Ana
authors: A
authors: Milardović
authors: University Hospital Rijeka, Centre for Clinical, Health and Organizational Psychology, Istarska 43, 51000 Rijeka, Croatia. Electronic address: inge_v_c@yahoo.com.
authors: Inge
authors: I
authors: Vlašić-Cicvarić
authors: University of Rijeka, Medical Faculty, Oikon Ltd. Institute for Applied Ecology, Trg Senjskih Uskoka 2, 10000 Zagreb, Croatia. Electronic address: zspiric@oikon.hr.
authors: Zdravko
authors: Z
authors: Špiric
authors: University Hospital Rijeka, University of Rijeka, Medical Faculty, Istarska 43, 51000 Rijeka, Croatia. Electronic address: jelaradi@yahoo.com.
authors: Jelena
authors: J
authors: Radić Nišević
authors: University Hospital Rijeka, University of Rijeka, Medical Faculty, Istarska 43, 51000 Rijeka, Croatia. Electronic address: 911petar@gmail.com.
authors: Petar
authors: P
authors: Vukelić
authors: Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, Ljubljana, Slovenia.
authors: Janja
authors: J
authors: Snoj Tratnik
authors: Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, Ljubljana, Slovenia.
authors: Darja
authors: D
authors: Mazej
authors: Institute "Jožef Stefan", Department of Environmental Sciences, Jamova 39, Ljubljana, Slovenia. Electronic address: milena.horvat@ijs.si.
authors: Milena
authors: M
authors: Horvat
mesh_terms: D015331:Cohort Studies; D017523:Croatia / Q000453:epidemiology; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018811:Maternal Exposure; D008767:Methylmercury Compounds / Q000633:toxicity*; D009048:Motor Skills / Q000187:drug effects*; D019957:Motor Skills Disorders / Q000139:chemically induced / Q000453:epidemiology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced / Q000453:epidemiology*
chemical_list: D004785:Environmental Pollutants; D008767:Methylmercury Compounds
keywords: Cord blood; Methyl-mercury; Motor skills; Neurodevelopment; Prenatal exposure