Biological differences between the sexes are apparent even from the early part of the pregnancy. The crown-rump length is larger in male fetuses compared to females in the first trimester. Placentae ...of male and female fetuses have different protein and gene expressions, especially in adverse conditions. Even within the intrauterine milieu, the same extracellular micro RNA may show upregulation in females and downregulation in male fetuses. There appears to be a natural survival advantage for females. Maternal glucocorticoids (GC) play an important role in fetal growth and organ maturation. However, excess glucocorticoids can not only affect growth but the response may be sex-specific and probably mediated through glucocorticoid receptors (GR) in the placenta. Mild pre-eclampsia and asthma are associated with normal growth pattern in males, but in female fetuses, they are associated with a slowing of growth rate without causing IUGR probably as an adaptive response for future adverse events. Thus, female fetuses survive while male fetuses exhibit IUGR, preterm delivery and even death in the face of another adverse event. It is thought that the maternal diet may not influence growth but may influence the programming for adult disease. There is growing evidence that maternal pre-pregnancy overweight or obesity status is directly associated with a higher risk of obesity in a male child, but not in a female child, at 1 year of age. It is observed that exposure to gestational diabetes is a risk factor for childhood overweight in boys but not in girls. It is fascinating that male and female fetuses respond differently to the same intrauterine environment, and this suggests a fundamental biological variation most likely at the cellular and molecular level.
Despite the global improvements in neonatal outcomes, mortality and morbidity rates among preterm infants are still unacceptably high. Therefore, it is crucial to thoroughly analyze the factors that ...affect these outcomes, including sex, race, and social determinants of health. By comprehending the influence of these factors, we can work towards reducing their impact and enhancing the quality of neonatal care. This review will summarize the available evidence on sex differences, racial differences, and social determinants of health related to neonates. This review will discuss sex differences in neonatal outcomes in part I and racial differences with social determinants of health in part II. Research has shown that sex differences begin to manifest in the early part of the pregnancy. Hence, we will explore this topic under two main categories: (1) Antenatal and (2) Postnatal sex differences. We will also discuss long-term outcome differences wherever the evidence is available. Multiple factors determine health outcomes during pregnancy and the newborn period. Apart from the genetic, biological, and sex-based differences that influence fetal and neonatal outcomes, racial and social factors influence the health and well-being of developing humans. Race categorizes humans based on shared physical or social qualities into groups generally considered distinct within a given society. Social determinants of health (SDOH) are the non-medical factors that influence health outcomes. These factors can include a person's living conditions, access to healthy food, education, employment status, income level, and social support. Understanding these factors is essential in developing strategies to improve overall health outcomes in communities.
Challenging the assumption of uniform nutritional needs in preterm feeding, this study identifies crucial sex-specific disparities in formula milk intake and growth among late preterm infants. ...Premature infants have difficulty regulating their oral intake during feeds, which is why clinicians prescribe feeding volume, calories, and protein via the nasogastric route. However, premature male and female infants have different body compositions at birth, and, subsequently, there is no evidence to suggest that male and female preterm infants differ in their nutritional consumption once they begin feeding ad libitum. This study investigates whether there are any differences in the volume and nutrient intake between the sexes when fed formula ad libitum.
The study involved a retrospective analysis of preterm infants admitted to the NICU and evaluated between 34 0/7 and 36 6/7 weeks of corrected gestation. Late preterm infants appropriate for gestational age who were spontaneously fed formula milk ad-lib and free of any respiratory support for at least two days were included. The study excluded infants with short gut syndrome, severe chromosomal anomalies, or congenital heart conditions. We included 85 male and 85 female infants in this study. The data collected included sex, gestational age, birth weight, anthropometric data at birth, maternal data, nutritional intake, and neonatal morbidity.
This study found that female infants consumed more volume, protein, and calories than male infants. The mean formula intake in female and male infants was 145.5 ± 20.8 mL/kg/d and 135.3 ± 19.3 mL/kg/d, respectively, with
= 0.002. However, ad-lib feeding duration was not different between the sexes. Growth velocity was also higher in female infants.
This study is the first to demonstrate differences in formula milk intake among late preterm infants fed ad libitum. Additional research is needed to confirm our findings and understand sex-specific differences in neonatal nutrition in extremely early preterm infants.
Association Between Weight for Length and the Severity of Respiratory Morbidity in Preterm Infants.
To determine whether higher weight-to-length z-scores after 32 weeks of gestation are associated ...with higher pulmonary scores (PSs) in preterm infants requiring respiratory support using a prospective observational study.
Infants born at <30 weeks, with a post-menstrual age (PMA) of 30-33 weeks, were enrolled. The infant's weight, length, and head circumference were measured weekly. Data on calories/kg/d, protein g/kg/d, weight-for-length percentiles, z-scores, and BMI at 33 through 40 weeks PMA were collected. The PS was calculated.
We analyzed 91 infants. The mean gestational age was 26.9 ± 1.7 weeks. The mean birthweight was 0.898 ± 0.238 kgs. They were predominantly African American (81.3%) and girls (56%). Postnatal steroids were administered in 26.4% of the infants. The mean duration of invasive ventilation was 19.23 days ± 28.30 days. There was a significant association between the PS and W/L z-score (
< 0.0001). For every one-unit increase in W/L z-score, the PS increased by 0.063. There was a significant association between the PS and W/L percentile (
= 0.0017), as well as BMI (
≤ 0.0001). For every unit increase in W/L percentile, the PS increased by 0.002, and for a unit increase in BMI, the PS increased by 0.04. The association remained significant after postnatal steroid use, sex, and corrected and birth gestational ages were included in the regression analysis. Nutrition did not affect the anthropometric measurements.
Our study is the first to demonstrate that a higher BMI and W/L may adversely affect the respiratory severity in preterm infants. Studies with larger sample sizes are needed to confirm our findings.
Diuretic therapy, commonly used in the newborn intensive care unit, is associated with a variety of electrolyte abnormalities such as hyponatremia, hypokalemia, and hypochloremia. Hypochloremia, ...often ignored, is associated with significant morbidities and increased mortality in infants and adults. Clinicians respond in a reflex manner to hyponatremia than to hypochloremia. Hypochloremia is associated with nephrocalcinosis, hypochloremic alkalosis, and poor growth. Besides, the diuretic resistance associated with hypochloremia makes maintaining chloride levels in the physiological range even more logical. Since sodium supplementation counters the renal absorption of calcium and lack of evidence for spironolactone role in diuretic therapy for bronchopulmonary dysplasia (BPD), alternate chloride supplements such as potassium or arginine chloride may need to be considered in the management of hypochloremia due to diuretic therapy. In this review, we have summarized the current literature on hypochloremia secondary to diuretics and suggested a pragmatic approach to hypochloremia in preterm infants.
We sought to determine whether there are sex-based differences in the requirements for calories or protein for optimal growth during the transition phase (TP) when an extremely low birth weight ...(ELBW) infant, defined as a preterm infant with a birth weight of < 1000 g, is progressing from parenteral to enteral feeds. A retrospective review of ELBW infants born from 2014 to 2016 was performed at a tertiary NICU. Infants with necrotizing enterocolitis, short bowel syndrome, or chromosomal anomalies were excluded. TP was defined as the period when the infant's enteral feeds were increased from 30 up to 120 ml/kg/day while weaning parenteral nutrition (PN). Effects of sex and protein-calorie intake on the change in growth parameters from the beginning to the end of TP were analyzed. Pre-TP growth percentiles and calorie and protein intake were similar in both sexes. There was a significant (r = 0.22, p = 0.026) correlation of total calorie intake with a change in weight percentiles (wt.pc) for the whole group, but on sex-specific analysis, this correlation was more robust and significant only in girls (r = 0.28, p = 0.015). Protein intake did not correlate with the changes in wt.pc in either sex. Despite a similar intake of calories and protein during the TP, we found a significant decrease in wt.pc only in girls. More extensive studies are needed to understand the sex-based differences in caloric needs and metabolic rate in ELBW infants.
Since fluid and nutrition needs and delivery in ELBW infants are calculated based on their body weights, there could be a measurable difference in fluid, nutrition, and protein intake calculations ...based on birth weight (BW) or current weight of the infant, especially in the first two weeks of life. Theoretically, the use of current daily weight (CW) for calculations may result in decreased fluid, nutrition, and protein delivery as well as a cumulative protein deficit (cPD) over the first two weeks of life until the infant regains birth weight. However, there have been no clinical studies comparing the clinical and nutritional impact of these two strategies is unknown. Aims. The aims of this study were to quantify the amount of protein intake and to compare growth parameters at hospital discharge (as measured by discharge weight and head circumference percentiles) when using two different methodologies (BW vesrsus current daily weight until BW is regained) for calculating fluid and protein intake in the first two weeks after birth in ELBW infants. Methods. A retrospective review of infants weighing ≤ 1kg at birth was conducted from January 2005 to December 2009 (Phase 1; P1) and January 2012 to December 2014 (Phase 2; P2) in a tertiary care NICU. At this center, in P1 (2005-09) CW was exclusively used for calculating fluid, calorie, and protein administration till BW was regained. In P2 (2012-14), BW was exclusively used for all calculations. Both P1 and P2 periods were compared and analyzed for differences in demographics, nutritional intake, comorbid conditions, and growth outcomes. Results. We studied 146 infants with 84 and 62 infants in P1 and P2 periods, respectively. The mean gestational age was lower during Phase 1 (25.74 ±1.32 vs. 26.47 ±1.82 weeks. P value =0.01). However, the birth weights were not different between the two periods. When the multiple-regression analysis was done using a discharge weight of >10th percentile as the dependent variable, protein intake before regaining of BW (OR of 4.126 with 95th CI of 2.03-8.36, a P value of 0.00) and AGA status at birth (OR of 8.37 with 95th CI of 2.67-26.24) remained significant factors. Compared to P1, babies in P2 received 1g/kg/day more protein till BW was regained. In P1, 27% of babies who were appropriate for gestational age (AGA) for head circumference at birth became microcephalic by discharge, compared to 15.6% in P2 (p=0.03). Similarly, 75.3% of the babies who were AGA for weight at birth in P1 became small for gestational age (SGA) by discharge, compared to 16.7% in P2 (p=<0.0001). The number of days it took to regain BW was 9.6 days in P1 vs. 7 days in P2 (p=<0.0001). Conclusions. Basing nutrition calculations in ELBW on birth weight rather than current daily weight until the birth weight is regained resulted in significantly greater protein delivery, a significant decrease in the incidence of failure to thrive and smaller head circumference percentiles at discharge in ELBW infants.
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