Thyroid function and its influencing factors in preterm infants

To investigate the influencing factors and reference ranges for thyroid function in preterm infants at the age of 7 days, with the aim of avoiding unnecessary clinical reexamination and intervention. A retrospective analysis was performed for the data of 685 preterm infants from January 2020 to January 2023. According to gestational age and birth weight, they were divided into a high-risk group (gestational age <34 weeks or birth weight<2 000 g; 228 infants) and a low-risk group (gestational age ≥34 weeks and birth weight ≥2 000 g;457 infants). The influencing factors for thyroid function were analyzed, and 95% reference range was calculated. Gestational age, birth weight, birth season, sex, and assisted reproduction were the influencing factors for thyroid function (P<0.05). For the preterm infants in the high-risk group, the reference ranges of free triiodothyronine (FT3), free thyroxine (FT4), total triiodothyronine (TT3), total thyroxine (TT4), and thyroid stimulating hormone (TSH) were 2.79-5.40 pmol/L, 8.80-25.64 pmol/L, 0.80-2.15 nmol/L, 50.06-165.09 nmol/L, and 0.80-18.57 μIU/mL, respectively. For those in the low-risk group, the reference ranges of these indicators were 3.08-5.93 pmol/L, 11.17-26.24 pmol/L, 1.02-2.27 nmol/L, 62.90-168.95 nmol/L, and 0.69-13.70 μIU/mL, respectively. FT3, FT4, TT3, and TT4 were positively correlated with gestational age (P<0.05); FT3, FT4, TT3, and TT4 were positively correlated with birth weight (P<0.05); TSH was negatively correlated with birth weight (P<0.05). Thyroid function in preterm infants at the age of 7 days is affected by the factors such as gestational age and birth weight, and the reference ranges of thyroid function in preterm infants at the age of 7 days should be established based on gestational age and birth weight.

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 …

Placental transfer and decay of varicella-zoster virus antibodies in preterm infants

Melatonin plays an important role in organism functioning, child growth, and development. Of particular importance is melatonin for preterm infants. The aim of our research was to study the peculiarities of melatonin levels depending on various factors in preterm infants with gestational age (GA) of less than 34weeks. The study involved 104 preterm infants with GA less than 34weeks who were treated in the neonatal intensive care unit (NICU). The level of melatonin in urine samples was determined by an enzyme-linked immunosorbent assay. Melatonin concentration was significantly lower in extremely and very preterm infants compared to moderate preterm (3.57 [2.10; 5.06] ng/ml vs. 4.96 [3.20; 8.42] ng/ml, p = 0.007) and was positively correlated with GA (Spearman r = 0.32; p < 0.001). Positive correlations were revealed between melatonin levels and Apgar scores at the 1st(Spearman r = 0.31; p = 0.001) and 5thminutes after birth (Spearman r = 0.35; p < 0.001). Melatonin levels were lower in newborns with respiratory distress syndrome (p = 0.011). No significant correlations were found between melatonin concentration and birth weight (Spearman r = 0.15; p = 0.130). There were no associations of melatonin concentrations and mode of delivery (p = 0.914), the incidence of early-onset sepsis (p = 0.370) and intraventricular hemorrhages (p = 0.501), and mechanical ventilation (p = 0.090). The results of multiple regression showed that gestational age at birth was the most significant predictor of melatonin level in preterm infants (B = 0.507; p = 0.001). Gestational age and the Apgar score were associated with decreased melatonin levels in preterm infants. The level of melatonin in extremely and very preterm infants was lower compared to moderate preterm infants.

After completing this article, readers should be able to: 1. Describe how circadian rhythms are generated. 2. Describe how lighting influences the circadian system. 3. Delineate the period during which the origin of circadian rhythms develops. 4. Describe the relationship between maternal circadian rhythms and the development of circadian rhythms in infants. 5. Characterize the potential sequelae of impaired fetal and early neonatal circadian rhythms related to sleep patterns. 6. Describe beneficial lighting patterns for preterm infants in the neonatal intensive care nursery. Circadian rhythms are endogenously generated rhythms that have a period length of about 24 hours. Evidence gathered over the past decade indicates that the circadian timing system develops prenatally, with the suprachiasmatic nuclei (SCN) in the anterior hypothalamus, the site of a circadian clock, present by mid-gestation in primates. Recent evidence also shows that the circadian system of primate infants is responsive to light at very early stages (as early as 25 to 28 weeks’ gestation in humans) and that low-intensity lighting can regulate the developing clock. After birth, circadian system outputs mature progressively, with rhythms in sleep-wake cycles, body temperature, and hormone production generally developing between 1 and 3 months of age. The importance of light in regulation of circadian rhythm in infants is highlighted by the early establishment of rest-activity patterns that are in phase with the 24-hour light-dark cycle in preterm infants exposed to low-intensity cycled lighting. With the continued elucidation of circadian system development and influences on human physiology and illness, it is anticipated that consideration of circadian biology will become an increasingly important component of neonatal care. ### The Circadian Timing System Notable examples of circadian rhythms include the sleep-wake cycle and daily rhythms in body temperature and hormone production. Circadian rhythms are also involved in the pathogenesis of illnesses, such as reactive airway disease (eg, asthma) and myocardial infarction. The system responsible …

Objectives: To investigate the association of ghrelin, leptin, and insulin levels in the umbilical cord blood of the preterm and term infants with anthropometric measurements and glucose metabolism.Methods: Sixty-nine infants who were born between November 2004 and June 2005 were included in the study. Pregnancy ages, birth weights, heights, head circumferences, and Ponderal Indexes (PI) were identified. Ghrelin, leptin, insulin, and glucose levels in the umbilical cord blood were studied.Results: Eighteen infants out of 69 infants were preterm (34.6 ± 0.43 weeks), and 33 infants were term (38.7 ± 0.14 weeks). All preterm infant weights were appropriate for gestational age (AGA); 33 of the term infants’ weights were AGA and 18 were large for gestational age (LGA). Leptin, insulin, and glucose levels of term infants were significantly higher compared with the preterm infants (p < .0001, p < .001, and p < .0001, respectively); no significant difference was detected in the ghrelin levels between the two groups (p > .05). The leptin and insulin levels of the term LGA infants were higher compared with the term AGA and preterm AGA infants (p < .05, for all). No difference was detected between the three groups regarding serum ghrelin levels (p > .05). No difference was found in the glucose levels between term AGA and LGA infants (p > .05); however, the serum glucose levels of term AGA and LGA infants were higher compared with levels in preterm AGA infants (p < .05, for both). A positive correlation was demonstrated in all study groups between leptin and insulin with gestational age, body weight, height, head circumference, and PI. A positive correlation was found between serum leptin levels with gestational age and insulin levels in preterm infants, and between serum leptin levels and insulin and glucose levels in term infants. No association was found between ghrelin and anthropometric measurements, leptin, insulin, and glucose levels (p > .05, for all).Conclusions: The increase of leptin production with increased gestational age, and the strong association with anthropometric measurements supports the opinion that leptin behaves as a fetal growth factor. Leptin in intrauterine life is in close association with insulin and glucose metabolism. Although ghrelin was at measurable levels in preterms, no association with fetal growth and glucose metabolism could be demonstrated in preterm and term infants.

Among premature infants, formula feeding increases the risk for necrotizing enterocolitis, delayed brainstem maturation, decreased scoring on cognitive and developmental tests, and delayed visual development. With this in mind, many interventions are designed to increase breast milk consumption in preterm infants. Breastfeeding initiation rates among US premature infants are not collected nationally, however, and published data on breastfeeding rates in this population are limited. In addition, national surveys calculate breastfeeding rates among term infants according to maternal race/ethnicity, but maternal birthplace is not recorded. This is likely to be important, because breastfeeding is the cultural norm in the countries of origin for many non-US-born US residents. Massachusetts has a diverse racial/ethnic population, including many non-US-born women. The goals of this study were to compare breastfeeding initiation rates among preterm and term infants in Massachusetts in 2002 and to determine the effect of maternal race/ethnicity and birthplace on breastfeeding initiation rates among term and preterm infants. Massachusetts Community Health Information Profile, an online public health database that was created by the Massachusetts Department of Public Health, includes breastfeeding initiation data that are obtained from the electronic birth certificate, which we used to compare breastfeeding rates among preterm and term infants. Birth-linked demographics and data that also were accessed were maternal age, race/ethnicity, birthplace, and health insurance (public or private) as an indicator of socioeconomic status and infant's gestational age. We assessed the association between breastfeeding initiation and maternal birthplace, as well as race/ethnicity and the other potential confounders, using logistic regression. There were 80,624 births in Massachusetts in 2002, and 8.2% (6611) of newborns had a gestational age <37 weeks. The state's overall breastfeeding initiation rate was 74.6%. We excluded records of mothers who were younger than 15 years and older than 39 years, nonsingleton births, infants with a gestational age <24 weeks and >42 weeks, and records with missing data. Of the total births in Massachusetts, 67,884 (84%) met inclusion criteria for this study. Breastfeeding initiation rates were lowest among preterm infants of the youngest gestational ages. Breastfeeding initiation was 76.8% among term infants born at 37 to 42 weeks, 70.1% among infants born at 32 to 36 weeks, and 62.9% among infants born at 24 to 31 weeks. In univariate analysis, among preterm infants, a lower proportion of US-born black, Asian, and Hispanic mothers initiated breastfeeding than US-born white mothers; non-US-born black and non-US-born Hispanic mothers had the highest breastfeeding initiation rates. Among term infants, US-born black mothers had the lowest initiation rates, and non-US-born black and non-US-born Hispanic mothers had the highest. In multivariate logistic regression, however, after controlling for mother's age, race, birthplace, and insurance, US-born white mothers were least likely to breastfeed either term or preterm infants when compared with any other racial/ethnic group, including US-born black mothers. The likelihood that non-US-born Hispanic mothers would breastfeed was almost 8 times greater than that for US-born white mothers for a preterm infant and almost 10 times greater for a term infant. In multivariate logistic regression analysis stratified by gestational age for both preterm and term infants, older mothers and mothers with private health insurance were most likely to breastfeed. In Massachusetts, preterm infants were less likely to receive breast milk than term infants, and the likelihood of receiving breast milk was lowest among the youngest preterm infants. In multivariate logistic regression, mothers who were born outside the United States were more likely than US-born mothers to breastfeed either term or preterm infants in all racial and ethnic groups. In an unexpected finding, US-born white mothers were less likely to breastfeed term or preterm infants than US-born black mothers or mothers of any other racial or ethnic group.

AIMS:Matrix metalloproteinases (MMP) have been associated with neonatal lung morbidity and MMP dysregulation contributes to the pathology of chronic and acute lung disorders. Most of the previous studies were performed in the 1st weeks of life of the preterm newborns. There are no data on the serum levels of MMP-2, MMP-9 or tissue inhibitors of matrix metalloproteinases (TIMP-1) from preterm infants recovering from lung morbidities. We aimed to compare MMP-2, MMP-9 and TIMP-1 levels in preterm and term infants hospitalized with their first episode of wheezing.METHODS:We prospectively evaluated 18 preterm infants with a history of chronic lung disease, respiratory distress syndrome or oxygen therapy and 14 age- and sex-matched term infants who were admitted for a first episode of wheezing. We quantified total serum concentrations of MMP-2, MMP-9 and TIMP-1 to assess whether these serum markers levels were associated with the first episode of wheezing in infants with a history of oxygen therapy during the neonatal period.RESULTS:Upon hospitalization, MMP-2 and TIMP-1 levels were higher in preterm infants than in term infants. In contrast, there was no significant relationship between MMP-9 levels or the MMP-9/TIMP-1 ratio between preterm and term infants. The area under the receiver operating characteristic curve for MMP-2 was 0.70 (95% confidence interval [CI] 0.51-0.89). The area under the curve for TIMP-1 was 0.78 (95% CI 0.61-0.94). MMP-9, MMP-2 and TIMP-1 levels did not correlate with gestational age, gender or severity of wheezing.CONCLUSION:The negative proportion of MMP-9 to TIMP-1 that we detected in term infants was not present in preterm infants. The balance of MMP-9 to TIMP-1 may have been disrupted by lung damage in the premature infants. Overproduction of MMP-2 and TIMP-1 in the serum may be associated with the pathogenesis of wheezing in preterm infants.

Retinopathy of Prematurity and the Peripheral Retina

To study the effect of levothyroxine sodium tablets on the growth and development and thyroid function in preterm infants with thyroid dysfunction. A retrospective analysis was performed for 82 preterm infants who were born in the Department of Obstetrics of the First People's Hospital of Yunnan Province, from January 1, 2013 to December 31, 2017, and these infants were hospitalized after birth in the Department of Neonatology of the hospital. They were regularly followed up to observe growth and development and thyroid function at the outpatient service of the Department of Neonatology. According to thyroid function test results, they were divided into an abnormal thyroid function group (observation group; n=31) and a normal thyroid function group (control group; n=51). The infants in the observation group were given oral administration of levothyroxine sodium tablets, while those in the control group were not given any treatment. The two groups were compared in terms of the physical and intelligence development and thyroid function of preterm infants with various gestational ages (28-<32 weeks, 32-<34 weeks, and 34-<37 weeks) after regular follow-up to the corrected age of 12 months. There were no significant differences in physical development indices (body length, body weight, and head circumference) between the observation and control groups at various gestational ages after follow-up to the corrected age of 12 months (P>0.05). There were no significant differences between the two groups in the scores of each functional area of the Gesell Developmental Scale among the preterm infants with a gestational age of 28-<32 weeks and 32-<34 weeks after follow-up to the corrected age of 12 months (P>0.05). For the preterm infants with a gestational age of 34-<37 weeks, compared with the control group, the observation group had a significantly lower score of gross motor ability at the age of 3 and 12 months, significantly lower scores of fine motor ability, language ability, and adaptation ability at the age of 12 months (P<0.05), and a significantly lower score of personal-social ability at the age of 3 months (P<0.05). However, the score of personal-social ability in the observation group was not significantly different from the control group at the age of 12 months (P>0.05). After 2-4 weeks of treatment with levothyroxine sodium tablets, the thyroid function of the 31 preterm infants with thyroid dysfunction returned to normal. Among the 31 infants, 21 (68%) achieved complete drug withdrawal, with normal results of neonatal screening (100%); 10 infants (32%) failed to achieve drug withdrawal, and only 2 (20%) out of the 10 infants had normal neonatal screening results (P<0.05). Early diagnosis and reasonable treatment can reduce the impact on growth and development in preterm infants with thyroid dysfunction. Most preterm infants tend to have transient thyroid dysfunction, while those with positive results of neonatal screening are more likely to develop permanent thyroid dysfunction.

Background With advanced pre- and post-natal care, the survival rate of extreme preterm infants has increased significantly. As a result, the incidence of respiratory morbidity and complications has also risen and should require further apprehension during follow up of these premature infants as they grow. Due to the lack of facility and normal reference values for lung function tests in the infant population, data for preterm infants in Taiwan are virtually non-existent. In this study, we investigated respiratory function in preterm and term infants until the age of 18 months. The evolution of longitudinal pulmonary function changes were also investigated. Materials and methods During the period of October of 2012 to September of 2013, infants with informed consent were enrolled in our birth cohort study. After sedation, respiratory function tests were performed by using JAEGER MasterScreen Paediatric, which obtained measurements for the tidal breathing, passive respiratory mechanism, and forced tidal expiration. Tests were measured in preterm infants at corrected ages of 6, 12, and 18 months and term infants at similar age points. Results Respiratory function exams were performed in 56 term and 20 preterm infants. Several parameters of the tidal breathing were found to be significantly different between term and preterm infants in the same chorological age. Increased airway resistance and reduced lung compliance were observed in the preterm babies when compared to term infants. Values of maximal expiratory flow at functional residual capacity in preterm infants were also significantly lower than those of term infants. Discussion Premature babies are known to pose a higher risk for pulmonary developmental anomaly. As shown in our study, most preterm infants demonstrated poor performance in several respiratory function exams despite appearing clinically asymptomatic. With the newly developed technique for measuring forced expiratory flows from raised lung volumes in young infants, it is now possible to better understand the natural history and pathophysiology of young infants who were born prematurely. Additionally, the use of pulmonary function test as a clinical diagnostic tool for diseases such as bronchopulmonary dysplasia will be highly predictive and serves as the primary outcome measures.

Circulating adipocyte fatty acid binding protein levels in healthy preterm infants: Positive correlation with weight gain and total-cholesterol levels

After completing this article, readers should be able to: 1. Delineate the rationale for inhaled nitric oxide (iNO) use in respiratory distress syndrome. 2. List the toxicities of iNO. 3. Describe the primary findings of iNO therapy in major clinical trials. Respiratory distress syndrome (RDS) has been a major factor determining the limits of viability in the preterm infant. RDS is, in large part, the result of surfactant deficiency. Surfactant replacement and antenatal steroid use are the two major advances in the treatment of RDS to date and have resulted in significant decreases in mortality and chronic lung disease (CLD). Surfactant replacement became widely available in 1991, and antenatal steroids achieved widespread use following the National Institutes of Health Consensus Conference in 1994. (1) However, substantial mortality and CLD still are seen in the very low-birthweight infant (Fig. 1). Figure 1 National Institute of Child and Human Development (NICHD) Neonatal Research Network mortality and CLD rates for 2003 in preterm infants born at 23 to 30 weeks’ gestation. Following the identification of nitric oxide (NO) as the vascular endothelial relaxing factor, use of the agent has moved rapidly from bench to bedside. Inhaled nitric oxide (iNO) was found to improve oxygenation in adult and pediatric patients who had hypoxic respiratory failure. (2)(3)(4) Subsequent randomized, controlled trials in term and near-term infants who had hypoxic respiratory failure demonstrated an improvement in oxygenation as well as a significant decrease in death or the need for extracorporeal membrane oxygenation. (5)(6)(7) Following United States Food and Drug Administration review of these trials, iNO was approved for use in term and near-term infants who had hypoxic respiratory failure. The role of iNO in the preterm infant who has RDS has been an active area of investigation over the last decade. This …

Establishing a reference range for triiodothyronine levels in preterm infants

BackgroundElevated concentrations of matrix metalloproteinases (MMP) have been associated with neonatal morbidity. There are no data on the serum levels of MMP-2, MMP-9, tissue inhibitors of matrix metalloproteinase (TIMP-1) from...