Prenatal mercury exposure, maternal seafood consumption and associations with child language at five years

Relationships between seafood consumption during pregnancy and childhood and neurocognitive development: Two systematic reviews

“…Gains in verbal IQ appear to have provided most of the contribution to total IQ in at least three of these studies [17,19,20]. Consistent with the findings in improved verbal development, Vejrup et al [40] reported more favorable scores on the Speech and Language Assessment Scale (SLAS), the Ages and Stages Questionnaire (ASQ), and on Twenty Statements about Language-Related Difficulties (language 20) scores when comparing > 14 oz/wk vs. none. These findings were consistent across all levels of fish intake.…”

“…[22], Llop et al [36] and Vejrup et al [40] reported benefits of consumption ≥12 oz/wk despite this intake being associated with higher mercury exposures. Vejrup et al [40] reported that over the entire range (0-56 oz/wk) of intake, higher maternal seafood consumption was associated with more favorable language and communication scores. Greater seafood intake was highly correlated with higher mercury exposures and this study also found that higher maternal mercury blood levels were associated with greater benefits in three scales of language development.…”

“…They represent 24 unique cohorts that met the criteria for inclusion and did not meet criteria for exclusion for this question. Of these 29 studies, seven were conducted in the United States [15,20,22,27,32,34,37]; seven in the United Kingdom [13,14,17,19,35,38,39]; three in Spain [23,31,36]; two in Italy [28,29] three in the Republic of the Seychelles [18,25,26]; and one each in Denmark [21], Norway [40], the Netherlands [33], China [30], Japan [24], the Faroe Islands [16] and another in a consortium of European countries [41]. The sample sizes ranged from 135 [15] to 38,581 mother-child pairs [40] with a median sample size of 498 mother child pairs [24].…”

“…Two studies reported administering an FFQ during first trimester [31,36]. Eight studies reported administering an FFQ during the second trimester [15,18,21,22,[32][33][34]40]. Eight studies reported administering an FFQ during the third trimester [13,14,17,19,31,35,37,38].…”

“…No study reported any adverse effects from maternal consumption of ≥12 oz/wk.Two studies directly reported that the greatest benefits in their cohorts were in consumption categories characterized as ≥ 12 oz/wk [17,19]. One study reported beneficial associations in its highest consumption category with a mean of 14.5 oz/wk [21] while another study reported benefits above 14.1 oz/wk [40]. One study reported beneficial associations > 18 oz/wk [14].…”