Abstrak: Iodine supplementation during pregnancy is a common practice in developed countries. However, scant evidence is available regarding the safety and effectiveness of maternal iodine supplementation with regard to child neuropsychological development. We previously reported an inverse association between iodine supplementation and the psychomotor development of infants in a birth cohort from Valencia, Spain. In the present study, we assessed this association in a wider sample of mother and child pairs from 3 other regions in Spain. Neuropsychological development was assessed using the Bayley Scales of Infant Development in 1,519 infants (median age, 16 months) between 2006 and 2009. In multivariate analyses, maternal consumption of 150 μg/day or more of iodine from supplements was related to a 1.5-fold increase in the odds of a psychomotor score less than 85 (95% confidence interval: 0.8, 2.9) and to a 1.7-fold increase in the odds of a mental score less than 85 (95% confidence interval: 0.9, 3.0). Findings previously reported in the Valencia cohort were only partially verified. The results of the present study suggest that, at least in these regions, iodine supplementation does not improve infant neuropsychological development at 1 year of age. Further research is needed on the risks and benefits of supplementary iodine for both maternal thyroid function and child neurodevelopment.

Abstrak: In utero tobacco exposure has been associated with fetal growth restriction, but uncertainty remains about critical windows of exposure and specific effects on body segments. In the present study, we aimed to examine the association of maternal smoking with fetal biometry in different stages of pregnancy. The study population comprised 2,478 fetuses from a Spanish birth cohort study that was established between 2003 and 2008. Biparietal diameter, femur length, abdominal circumference, and estimated fetal weight were evaluated at 12, 20, and 34 weeks of gestation. Fetal size and growth were assessed by standard deviation scores adjusted by maternal and fetal characteristics. Maternal smoking was assessed using questionnaire and a sample of urinary cotinine at week 32 of gestation. Associations were estimated using multiple regression analysis. Smokers at week 12 of gestation showed decreased fetal growth as reflected by all growth parameters at 20–34 weeks, leading to a reduced fetal size at week 34. The reduction was greatest in femur length, at -9.4% (95% confidence interval -13.4, -5.4) and least in abdominal circumference, at -4.4% (95% CI: -8.7, -0.1). Fetuses of smokers who quit smoking before week 12 showed reduced growth only in femur length (-5.5; 95% CI: -10.1, -0.9). Dose–response curves for smoking versus fetal growth parameters (abscissa: log2 cotinine) were linear for biparietal diameter and femur length.