In utero lead exposure and auditory neural myelination in premature infants.

Extensive data shows a direct link between low-level lead exposure during early development and deficits in neurobehavioral-cognitive performance evident late in childhood through adolescence. Our previous studies confirmed the transfer of lead from the mother to the fetus as well as the effect of low lead exposure on neuropsychological behavior in school children. Such results led us to design a longitudinal survey to evaluate the effect of prenatal and/or postnatal lead exposure on early cognitive development among selected group of children from birth to 2 years of age. During the first stage of this study (between March and July 2004), we measured lead levels in 653 umbilical cord blood samples taken from healthy Saudi mothers delivering at King Khalid Hospital, Al-Kharj. This gave a good opportunity to look at the prevalence of increased blood lead levels in umbilical cord blood and to identify risk factors for prenatal lead exposure. The mean cord lead levels were 2.21 +/- 1.691 microg/dl in the range of 0.284-17.276 microg/dl. Only 1.23% of the newborns had blood lead levels >10 microg/dl, the Center for Disease Control level of concern. To investigate risk factors affecting cord blood lead levels, only subjects with lead levels above the 75th percentile (2.475 microg/dl) were selected in the multiple regression models. We observed that cord blood lead levels were significantly influenced by maternal age, the location of residence and intake of prenatal supplements. Controlling for newborn's head circumferences confounders, it was found that cord blood lead levels were significantly and negatively associated with newborn's head circumference (beta = -0.158, p = 0.036). The negative association was seen between intake of prenatal supplements and cord blood lead levels emphasizing the role of prenatal supplementations during pregnancy. The significant reductions in newborns, head circumferences due to lead exposure may have serious implications for their future performance and achievement. This study reveals that even at low prenatal lead exposure, all possible measures to inspect lead sources in our environment and reduce lead exposure should be taken.

Context: Environmentally prevalent lead is a potentially hazardous metal. Depending on its absorption and desorption, lead causes detrimental effects. The growth of fetus and newborn is seriously impacted in utero due to lead exposure in mothers. Aims: (1) To determine the lead levels in cord blood and (2) to determine the relationship of blood lead levels with anthropometry in newborns. Settings and Design: Cross-sectional study, department of pediatrics for 6-month period (May 2022 to October 2022). Subjects and Methods: The study included term and preterm babies above 28 weeks of gestation, born to mothers without risk factors. Cord blood samples from 83 newborns were analyzed for lead levels by inductively coupled plasma optical emission spectrometry. Statistical Analysis: Taking power as 80% and alpha error as 5%, sample size (n = 83) was obtained using regression methods. Results: The average lead concentration in the cord blood was detected to be 0.4 μg/dL (0.05–1.90 μg/dL). Using Pearson’s correlation coefficient, decrease in birth weight with increasing lead levels was statistically significant (P = 0.0005, r = −0.464). The correlation between gestational age, length, head circumference, chest circumference of newborn, and cord blood lead level (r = −0.364, P = 0.001); (r = −0.343, P = 0.001); (r = −0.435, P = 0.0005); and (r = 0.446, P = 0.0005), respectively, was highly significant. A moderately significant correlation was found between abdominal circumference and cord blood lead level (r = −0.343, P = 0.001). Conclusions: Reduction in neonatal anthropometric measurements, especially the birth weight, length, chest circumference, and head circumference, was noted with increasing lead levels in umbilical cord blood.

Association of food consumption during pregnancy with mercury and lead levels in cord blood

Gender specific differences in neurodevelopmental effects of prenatal exposure to very low-lead levels: The prospective cohort study in three-year olds

Maternal nutritional status during pregnancy and surma use determine cord lead levels in Karachi, Pakistan

After completing this article, readers should be able to: 1. Describe the epidemiology and pathophysiology of gastroesophageal reflux (GER) in preterm neonates. 2. Delineate the associations of GER with apnea, chronic lung disease, behavior, and growth of preterm infants. 3. Review the investigations used to evaluate GER in preterm infants. 4. Describe nonpharmacologic and pharmacologic therapies for GER. Gastroesophageal reflux (GER) is a normal physiologic event occurring across the age spectrum. It may contribute to a variety of disorders, including esophagitis, feeding problems, and airway disease in all age groups. (1) A large number of symptoms and signs have been purported to be caused by GER despite a lack of data showing a clear association between a specific symptom and GER. In preterm infants, empiric therapy often is administered using agents of unproven efficacy and safety to treat symptoms that likely are unrelated to GER. In a survey on management practices for GER in preterm infants, common treatment strategies included positioning (98%) and slopes (96%), histamine 2 (H 2) receptor antagonists (100%), feed thickeners (98%), antacids (96%), prokinetics (79%), proton pump inhibitors (PPIs) (65%), and dopamine receptor antagonists (53%). (2)(3) The safety, efficacy, and appropriate dosing recommendations for most medical therapies remain uncertain in neonates. In this review, we attempt to summarize the current literature regarding physiology, pathophysiology, and diagnostic and management strategies for GER pertinent to the neonate, with an emphasis on the preterm infant. GER describes the retrograde movement of stomach contents (air or feeding, liquid or semisolid, acid or alkaline, enzymes or bile salts) into the esophagus. GER disease (GERD) occurs when GER causes symptoms or signs such as pain, poor weight gain, esophagitis, hematemesis, and airway symptoms, including apnea, aspiration, recurrent pneumonia, chronic lung disease (CLD), or large airway inflammation. However, any of these symptoms or signs …

Interpeak latencies (IPL), as measured by the auditory brainstem-evoked responses (ABR) test, represent the conduction time, and therefore the maturation of the brainstem auditory pathway. We aimed to study the effect of various risk factors for the neurodevelopmental delay on the conduction time in the auditory pathway among normal hearing premature infants, at term postmenstrual age (PMA). Retrospective analysis of 239 premature infants (gestational age 32.5 ± 2.1 weeks, birth weight 1827 ± 483 g). Interpeak latencies, demographic data, and risk factors were recorded. Sex, PMA at ABR test, being small for gestational age (SGA), intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL), and days of invasive ventilation were found to significantly affect the IPL's in the auditory pathway in a univariate analysis. Multivariable regression analysis revealed that male sex and less advanced PMA at the examination were independent factors associated with prolonged IPL's, while bronchopulmonary dysplasia, IVH or PVL and being SGA shortened the IPL's. Non-invasive mechanical ventilation, did not affect the caudal part of the auditory pathway, despite its high noise level. Among various risk factors for the neurodevelopmental delay, male sex was associated with delayed, while IVH or PVL, BPD and SGA could be associated with accelerated auditory brainstem maturation. Auditory brainstem-evoked response (ABR) test, among normal hearing infants, can serve as a clinical tool to assess brainstem auditory maturation. Different neurodevelopmental risk factors could have different effects on the maturity of the auditory pathway. Male sex is significantly associated with prolonged interpeak latencies (IPL) among preterm and term infants, while intraventricular hemorrhage or periventricular leukomalacia, bronchopulmonary dysplasia, and being small for gestation age may be associated with shortened IPL The corrected age at ABR testing is of significance, among preterm and term infants.

Macular OCT Characteristics at 36 Weeks’ Postmenstrual Age in Infants Examined for Retinopathy of Prematurity

Antenatal steroids result in fetal lung maturation, but may retard brain development. Auditory brainstem-evoked response (ABR) is a noninvasive assessment of brainstem maturation. The objective of this study was to determine if antenatal steroids affect brainstem maturation in infants </=32 weeks gestational age (GA). Bilateral monaural ABR were performed within the first 24 hours using 80 db nHL unfiltered click stimuli at a repetition rate of 39.9/seconds. ABR waveforms were categorized into Response Types based on response replicability and peak identification. Absolute wave latencies and interpeak latencies were measured when applicable. Data were collected for antenatal steroid exposure, mode of delivery, chorioamnionitis in utero, exposure to illicit drugs, exposure to magnesium sulfate, mechanical ventilation and 5 minute Apgar score <5 minute. Infants with TORCH infections, unstable conditions, and chromosomal disorders were excluded. Of 186 infants studied, 130 received antenatal steroids. Data were analyzed in 2 week GA intervals. There was a significant difference (P<0.05) in race (29 vs 39% African-American), birth weight (1231 vs 1416 gm) and use of magnesium sulfate (60 vs 32%) among infants who did and did not receive antenatal steroids, respectively. There was no significant difference in the other parameters measured. Even after controlling for confounding variables, there was no difference between absolute wave latencies or interpeak latencies between groups at either 28 to 29 weeks' or 30 to 31 weeks' postmenstrual age. There was no significant difference in frequency distribution of ABR waveform Response Types between groups. Antenatal steroids have neither a deleterious nor beneficial effect on brainstem maturation as measured by ABR in infants at </=32 weeks GA.

SummaryObjectives:Lead can pass from a mother to her developing foetus and is associated with well-established risks for the foetus. This study aimed to evaluate maternal and cord iron and lead levels and study the association of maternal and cord blood lead levels (BLLs) with newborn anthropometric measurements.Methods:This cross-sectional study was conducted at Basra Maternity and Children Hospital, Basrah, Iraq, and included women and their newborns over the period from January through June 2023. Blood samples from mothers and umbilical cords were collected and sent to determine the complete blood count and lead and iron levels. Linear regression and Pearson correlation were used to assess the association of maternal and cord BLLs with different maternal and neonatal variables.Results:A total of 140 women and their newborns were included in this study. There was a significantly lower maternal haemoglobin (10.6 ± 1.4 g/dL) and serum iron (93.5 ± 44.8 μg/dL) levels compared to newborn levels (13.3 ± 1.8 g/dL and 135.0 ± 76.5 μg/dL, respectively; P <0.001). A significant negative correlation between maternal haemoglobin and cord BLLs (R2 = 0.12; P < 0.001) and a significant positive correlation between maternal and cord iron (B = 0.41; P < 0.05) levels and maternal BLLs with both cord iron (B = 4.78; P <0.05) and cord BLLs (R2 = 0.29; P <0.001) were reported. Furthermore, the Pearson correlation revealed a significant negative correlation between cord BLLs and infant birth weight (R2 = 0.06; P = 0.01).Conclusions:This study found that maternal BLLs were positively associated with both cord iron and cord BLLs. The cord BLL was negatively associated with maternal haemoglobin levels and infant birth weight. Preventive measures to reduce human lead exposure and monitor lead levels in pregnant women are important.

Low-Level Prenatal Lead Exposure and Neurobehavioral Development of Children in the First Year of Life: A Prospective Study in Shanghai

Part I. Background: The lead and manganese are the common neurotoxic metals in the environment. Co-exposure to lead and manganese could injure child neurodevelopment and cause behavior problems. Additionally, temperament performance in infant period may be a predictor of behavior problems in childhood. However, it is not clear that association between prenatal lead and manganese co-exposure and temperament performance in early childhood. Aims: The purpose of this study is to understand the effect of prenatal exposure to lead and manganese on child temperament. Methods: A total of 275 newborns from the Taiwan Birth Panel Study (TBPS) were followed up in northern Taiwan. We collected their cord blood for measuring lead and manganese levels by an Agilent 7500C ICP-MS. We used the Chinese Toddler Temperament Scale which was collected from parental reports for measuring temperament at infants and toddlers. We examined the association between lead and manganese co-exposure and child temperament by linear regression and mixed-effect models. Results: We found that under the higher manganese level, lead level in cord blood was associated with the adaptability (B=-0.385, p-value =0.058). We also found that the co-exposure of lead and manganese was associated with threshold of responsiveness (B=-0.404, p-value=0.015). Conclusions: Lead and manganese prenatal exposure may have an effect on early child temperament performance. Mechanistic studies are needed to elucidate the causal relationship. Part II. Background: The lead and manganese are the common neurotoxic metals in the environment. Co-exposure to lead and manganese could injure child neurodevelopment and cause behavior problems. Additionally, temperament performance in infant period may be a predictor of behavior problems in childhood. However, it is not clear that association between prenatal lead and manganese co-exposure and temperament performance in early childhood. Aims: The purpose of this study is to understand the effect of prenatal exposure to lead and manganese on child temperament. Methods: A total of 275 newborns from the Taiwan Birth Panel Study (TBPS) were followed up in northern Taiwan. We collected their cord blood for measuring lead and manganese levels by an Agilent 7500C ICP-MS. We used the Chinese Toddler Temperament Scale which was collected from parental reports for measuring temperament at infants and toddlers. We examined the association between lead and manganese co-exposure and child temperament by linear regression and mixed-effect models. Results: We found that under the higher manganese level, lead level in cord blood was associated with the adaptability (B=-0.385, p-value=0.058). We also found that the co-exposure of lead and manganese was associated with threshold of responsiveness (B=-0.404, p-value=0.015). Conclusions: Lead and manganese prenatal exposure may have an effect on early child temperament performance. Mechanistic studies are needed to elucidate the causal relationship.

Blood lead levels of both mothers and their newborn infants in the middle part of China

There have been few studies investigating the association between atopic dermatitis (AD) and prenatal exposure to heavy metals. We aimed to evaluate whether prenatal exposure to heavy metals is associated with the development or severity of AD in a birth cohort study. A total of 331 subjects were followed from birth for a median duration of 60.0 months. The presence and severity of AD were evaluated at ages 6 and 12 months, and regularly once a year thereafter. The concentrations of lead, mercury, chromium, and cadmium in umbilical cord blood were measured by inductively coupled plasma mass spectrometry. Cord blood mononuclear cells (CBMCs) were isolated and stimulated for analysis of cytokine production using ELISA. Heavy metal levels in cord blood were not associated with the development of AD until 24 months of age. However, a positive correlation was observed between the duration of AD and lead levels in cord blood (p=0.002). AD severity was also positively associated with chromium concentrations in cord blood (p=0.037), while cord blood levels of lead, mercury, and cadmium were not significantly associated with AD severity (p=0.562, p=0.054, and p=0.055, respectively). Interleukin-13 production in CBMCs was positively related with lead and chromium levels in cord blood (p=0.021 and p=0.015, respectively). Prenatal exposure to lead and chromium is associated with the persistence and severity of AD, and the immune reaction toward a Th2 polarization.

P-271 Introduction: The hemochromatosis gene (HFE) regulates iron absorption and metabolism. Common variants in this gene have been associated with decreased bone and blood lead levels in adults. HFE genotype effects on umbilical cord lead levels or genotype-specific effects on placental lead transfer have not been reported to our knowledge. Methods: This study was nested within a randomized controlled trial of calcium supplementation in breastfeeding mothers in and around Mexico City. Mothers were recruited during pregnancy and followed longitudinally. Peripheral maternal and infant umbilical cord blood samples were collected at delivery and used to measure lead concentration and for HFE genotyping. Two HFE polymorphisms (C282Y and H63D) were genotyped. Results: Paired data on umbilical cord and maternal blood lead levels were available on 265 mother infant pairs of whom 237 pairs were genotyped. Mean (STD) umbilical cord and maternal blood lead levels were 6.6 (3.6) ug/dL and 8.7(4.1) ug/dL respectively. As expected, maternal blood lead at delivery was strongly predictive of umbilical cord lead (beta=0.7, p<0.0001; R2=0.74). All genotypes were in Hardy-Weinberg Equilibrium. Carriers of either C282Y or H63D were combined into a single variable denoting presence or absence of either variant. Presence of an HFE variant in the mother was associated with a 0.6 ug/dL lower umbilical cord blood lead level (p=0.04) when HFE genotype was entered into the model as an independent predictor, adjusting for maternal blood lead levels. Infant HFE genotype did not predict infant cord blood lead levels when entered as an independent variable. Infant HFE genotype also did not modify the association between maternal and infant blood lead levels at delivery. However, Maternal HFE genotype did modify this association-interaction beta (HFE genotype X maternal blood lead) = −0.3 p<0.0001), such that mothers with HFE variants had infants with lower umbilical cord blood lead levels for a given maternal blood lead level, suggesting that the Maternal HFE variant regulates transplacental lead transfer. Discussion: In this population of urban Mexican children, mothers with at least one copy of an HFE variant allele transferred less lead across the placenta as evidenced by its modification of the association between maternal and umbilical cord lead levels. Our results are consistent with maternal HFE genotype regulating placental lead transfer. In contrast, infant HFE genotype did not modify placental lead transfer.