Mineral status of premature infants in early life and linear growth at age 3

Quality improvement project in a neonatal intensive care unit reduced the prevalence and duration of hypophosphatemia with significant and sustainable results

BACKGROUND

Hypophosphatemia is associated with prolonged mechanical ventilation and may affect growth, bone mineralization, nephrocalcinosis, and mortality in preterm infants. Optimal nutrition practices may decrease risk for hypophosphatemia and improve outcome.

METHODS

A quality improvement project was established to improve parenteral and enteral phosphorus intake with the goal to decrease prevalence and duration of hypophosphatemia in the first 14 days in infants <32 weeks' gestation.

RESULTS

Among 406 preterm infants, the prevalence of moderate hypophosphatemia decreased from 44% to 19% (P < 0.01) over 4 years. The median duration of moderate hypophosphatemia decreased from 72 h (48-128) to 24 (24-53) (P < 0.01). Daily intakes of parenteral calcium and phosphorus on the fourth day of life increased from 1.5 to 2.5 mEq/kg/day (P < 0.01) and 0.6 to 1.3 mmol/kg/day (P < 0.01), respectively. The median postnatal age of first serum phosphorus concentration assessment decreased from 53 h (41-64) to 32 (24-40) (P < 0.01).

CONCLUSION

During this quality improvement project, reduced prevalence and duration of hypophosphatemia in infants <32 weeks' gestation in the first 14 days of life was achieved through the optimization of parenteral and enteral phosphorus intake and improved response to acute hypophosphatemia.

Artificial Neural Network Modeling to Predict Neonatal Metabolic Bone Disease in the Prenatal and Postnatal Periods

IMPORTANCE

Early recognition of metabolic bone disease (MBD) in infants is necessary but difficult; an appropriate tool to screen infants at risk of developing MBD is needed.

OBJECTIVES

To develop a predictive model for neonates at risk for MBD in the prenatal and postnatal periods and detect the pivotal exposed factors in each period.

DESIGN, SETTING, AND PARTICIPANTS

A diagnostic study was conducted from January 1, 2012, to December 31, 2021, in Shanghai, China. A total of 10 801 pregnant women (singleton pregnancy, followed up until 1 month after parturition) and their infants (n = 10 801) were included. An artificial neural network (ANN) framework was used to build 5 predictive models with different exposures from prenatal to postnatal periods. The receiver operating characteristic curve was used to evaluate the model performance. The importance of each feature was examined and ranked.

RESULTS

Of the 10 801 Chinese women who participated in the study (mean [SD] age, 29.7 [3.9] years), 7104 (65.8%) were local residents, 1001 (9.3%) had uterine scarring, and 138 (1.3%) gave birth to an infant with MBD. Among the 5 ANN models, model 1 (significant prenatal and postnatal factors) showed the highest AUC of 0.981 (95% CI, 0.970-0.992), followed by model 5 (postnatal factors; AUC, 0.977; 95% CI, 0.966-0.988), model 4 (all prenatal factors; AUC, 0.850; 95% CI, 0.785-0.915), model 3 (gestational complications or comorbidities and medication use; AUC, 0.808; 95% CI, 0.726-0.891), and model 2 (maternal nutritional conditions; AUC, 0.647; 95% CI, 0.571-0.723). Birth weight, maternal age at pregnancy, and neonatal disorders (anemia, respiratory distress syndrome, and septicemia) were the most important model 1 characteristics for predicting infants at risk of MBD; among these characteristics, extremely low birth weight (importance, 50.5%) was the most powerful factor. The use of magnesium sulfate during pregnancy (model 4: importance, 21.2%) was the most significant predictor of MBD risk in the prenatal period.

CONCLUSIONS AND RELEVANCE

In this diagnostic study, ANN appeared to be a simple and efficient tool for identifying neonates at risk for MBD. Combining prenatal and postnatal factors or using postnatal exposures alone provided the most precise prediction. Extremely low birth weight was the most significant predictive factor, whereas magnesium sulfate use during pregnancy could be an important bellwether for MBD before delivery.

Associated neonatal and maternal factors of osteopenia of prematurity in low resource setting: A cross-sectional study

Objective

Determining neonatal and maternal factors that are associated with the incidence of OFP.

Methods

This study employed a cross-sectional design, in which the participants were identified for clinical variables (sex, gestational age, birth weight, etc.), neonatal morbidity (sepsis, necrotizing enterocolitis (NEC), etc.), and maternal risk factors (premature rupture of membranes, preeclampsia, etc.). The data were analyzed using Chi-square test, independent t-test, and logistic regression test with p < 0.05.

Results

The birth weight ranged from 800 to 1495 g (1219 ± 225 g), of which 5 newborns (17%) were <1000 g. The gestational age ranged from 27 to 32 weeks, with a mean of 29 ± 1.5 weeks. The signs of OFP were observed in 13 (43%) infants, of which 2 (15%) OFP infants had a birth weight <1000 g. There was significant difference in parenteral nutrition duration (p = 0.018), onset of vitamin D supplementation (p = 0.019), and ALP level (p = 0.012) of infants between the OFP group and the non-OFP group. The variables associated with the incidence of OFP were parenteral nutrition duration >15 days (OR = 5.4; 95% CI 1.120-26.044; p = 0.036), ALP level >500 U/L (OR = 2.889; 95% CI 1.703-4.900; p = 0.014), and PROM (OR = 5.4; 95% CI 1.039-28.533; p = 0.045).

Conclusion

The lack of phosphate intake, prolonged parenteral nutrition, ALP level >500 U/L, onset of vitamin D supplementation, and premature rupture of membranes are associated with the incidence of OFP.

Metabolic Bone Disease in Premature Neonates: An Unmet Challenge

Metabolic bone disease (MBD) is an important cause of morbidity in premature, very low birth weight (VLBW) and sick infants and, if left undiagnosed, may lead to structural deformities and spontaneous fractures. MBD is defined as impaired bone mineralization in a neonate with lower than expected bone mineral levels in either a fetus or a neonate of comparable gestational age and/or weight, coupled with biochemical abnormalities with or without accompanying radiological manifestations. MBD has been reported to occur in 16% to 40% of extremely low birth weight neonates and presents by 6-16 weeks after birth. Insufficient calcium and phosphorous stores during the phase of accelerated growth predispose to MBD in neonates along with the use of some medications such as caffeine or steroids, prolonged parenteral nutrition and chronic immobilization. Enhanced physical activity in preterm infants facilitates bone mineralization and weight gain. Biochemical abnormalities tend to worsen significantly, as the severity of disease progresses. These abnormalities may include hypocalcemia, hypophosphatemia, hyperphosphatasia and secondary hyperparathyroidism. In addition, urinary phosphate wasting and hypovitaminosis D can be additional complications. Conversely, biochemical abnormalities may not be accompanied by rachitic changes. Newer diagnostic modalities include non-invasive bone densitometry by quantitative ultrasound over the mid-tibial shaft. The management of MBD includes adequate calcium, phosphorous and vitamin D supplementation, along with optimum nutrition and physical activity. Similarly, preventive strategies for MBD should target nutritional enhancement in combination with enhanced physical activity. MBD usually results in preventable morbidity in preterm and VLBW neonates. Treatment consists of optimum nutritional supplementation and enhanced physical activity.

Higher versus lower protein intake in formula-fed low birth weight infants

BACKGROUND

The ideal quantity of dietary protein for formula-fed low birth weight infants is still a matter of debate. Protein intake must be sufficient to achieve normal growth without leading to negative effects such as acidosis, uremia, and elevated levels of circulating amino acids.

OBJECTIVES

To determine whether higher (≥ 3.0 g/kg/d) versus lower (< 3.0 g/kg/d) protein intake during the initial hospital stay of formula-fed preterm infants or low birth weight infants (< 2.5 kilograms) results in improved growth and neurodevelopmental outcomes without evidence of short- or long-term morbidity. Specific objectives were to examine the following comparisons of interventions and to conduct subgroup analyses if possible. 1. Low protein intake if the amount was less than 3.0 g/kg/d. 2. High protein intake if the amount was equal to or greater than 3.0 g/kg/d but less than 4.0 g/kg/d. 3. Very high protein intake if the amount was equal to or greater than 4.0 g/kg/d.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 8), in the Cochrane Library (August 2, 2019); OVID MEDLINE Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily, and Ovid MEDLINE(R) (to August 2, 2019); MEDLINE via PubMed (to August 2, 2019) for the previous year; and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (to August 2, 2019). We also searched clinical trials databases and the reference lists of retrieved articles for randomized controlled trials (RCTs) and quasi-randomized trials.

SELECTION CRITERIA

We included RCTs contrasting levels of formula protein intake as low (< 3.0 g/kg/d), high (≥ 3.0 g/kg/d but < 4.0 g/kg/d), or very high (≥ 4.0 g/kg/d) in formula-fed hospitalized neonates weighing less than 2.5 kilograms. We excluded studies if infants received partial parenteral nutrition during the study period, or if infants were fed formula as a supplement to human milk.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane and the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We identified six eligible trials that enrolled 218 infants through searches updated to August 2, 2019. Five studies compared low (< 3 g/kg/d) versus high (3.0 to 4.0 g/kg/d) protein intake using formulas that kept other nutrients constant. The trials were small (n = 139), and almost all had methodological limitations; the most frequent uncertainty was about attrition. Low-certainty evidence suggests improved weight gain (mean difference [MD] 2.36 g/kg/d, 95% confidence interval [CI] 1.31 to 3.40) and higher nitrogen accretion in infants receiving formula with higher protein content (3.0 to 4.0 g/kg/d) versus lower protein content (< 3 g/kg/d), while other nutrients were kept constant. No significant differences were seen in rates of necrotizing enterocolitis, sepsis, or diarrhea. We are uncertain whether high versus low protein intake affects head growth (MD 0.37 cm/week, 95% CI 0.16 to 0.58; n = 18) and length gain (MD 0.16 cm/week, 95% CI -0.02 to 0.34; n = 48), but sample sizes were small for these comparisons. One study compared high (3.0 to 4.0 g/kg/d) versus very high (≥ 4 g/kg/d) protein intake (average intakes were 3.6 and 4.1 g/kg/d) during and after an initial hospital stay (n = 77). Moderate-certainty evidence shows no significant differences in weight gain or length gain to discharge, term, and 12 weeks corrected age from very high protein intake (4.1 versus 3.6 g/kg/d). Three of the 24 infants receiving very high protein intake developed uremia.

AUTHORS' CONCLUSIONS

Higher protein intake (≥ 3.0 g/kg/d but < 4.0 g/kg/d) from formula accelerates weight gain. However, limited information is available regarding the impact of higher formula protein intake on long-term outcomes such as neurodevelopment. Research is needed to investigate the safety and effectiveness of protein intake ≥ 4.0 g/kg/d.

Metabolic Bone Disease of Prematurity: Diagnosis and Management

Metabolic Bone Disease (MBD) of prematurity is a multifactorial disorder commonly observed in very low birth weight (VLBW, <1,500 g) newborns, with a greater incidence in those extremely low birth weight (ELBW, <1,000 g). MBD is characterized by biochemical and radiological findings related to bone demineralization. Several antenatal and postnatal risk factors have been associated to MBD of prematurity, although the main pathogenetic mechanism is represented by the reduced placental transfer of calcium and phosphate related to preterm birth. The diagnosis of MBD of prematurity requires the assessment of several biochemical markers, radiological, and ultrasonographic findings. However, the best approach is the prevention of the symptomatic disease, based on the screening of subjects exposed to the risks of developing MBD. Regarding the subjects who need to be screened, there is a substantial agreement on the potential risk factors for MBD. On the contrary, different recommendations exist on the diagnosis, management and treatment of this disorder of bone metabolism. This review was aimed at: (1) identifying the subjects at risk for MBD of prematurity; (2) indicating the biochemical findings to take in consideration for the prevention of MBD of prematurity; (3) suggesting practical recommendations on nutritional intake and supplementation in these subjects. We searched for papers which report the current recommendations for biochemical assessment of MBD of prematurity and for its prevention and treatment. The majority of the authors suggest that MBD of prematurity is a disease which tends to normalize overtime, thus it is not mandatory to mimic the rate of mineral fetal accretion through parenteral or enteral supplementation. The optimization of total parenteral nutrition (TPN) and the early achievement of a full enteral feeding are important goals for the prevention and management of MBD of prematurity.

Infant Feeding Practices and Weight Gain in Toddlers Born Very Preterm: A Pilot Study

PURPOSE

Long-term consequences of prematurity are a public health concern. A pattern of slow initial weight gain followed by a period of rapid weight gain has been associated with poor cardiometabolic health outcomes. The purpose of this study was to examine the relationships between infant feeding practices and weight gain in a sample of 18-to-24-month olds corrected age born very preterm.

DESIGN AND METHODS

A cross-sectional design was used to examine the relationships between infant feeding practices and weight gain. Estimates of effect sizes and model fit estimates were the primary parameters of interest.

RESULTS

Most of the participants received human milk after birth, but most had transitioned to formula before three months. Slightly less than half received complementary foods prior to four months corrected age. Gains in weight and head circumference were rapid after discharge from the neonatal intensive care unit, while gains in length lagged behind. Infant feeding practices did not have a clinically meaningful effect on weight gain.

CONCLUSIONS

While the initiation of human milk feedings was encouraging, the duration fell short of recommendations. Practices such as the early introduction of complementary feedings and the addition of rice cereal to the bottle are troubling. Additionally, the rapid increase in weight gain may have a negative impact on future cardiometabolic health.

PRACTICE IMPLICATIONS

Clinical recommendations include ensuring support for the use of human milk before and after hospital discharge, close monitoring of physical growth, and ensuring adherence to the guidelines for the introduction of complementary foods.

The T helper type 17/regulatory T cell paradigm in pregnancy

T helper type 17 (Th17) and regulatory T (Treg) cells are active players in the establishment of tolerance and defence. These attributes of the immune system enmesh to guarantee the right level of protection. The healthy immune system, on the one hand, recognizes and eliminates dangerous non-self pathogens and, on the other hand, protects the healthy self. However, there are circumstances where this fine balance is disrupted. In fact, in situations such as in pregnancy, the foreign fetal antigens challenge the maternal immune system and Treg cells will dominate Th17 cells to guarantee fetal survival. In other situations such as autoimmunity, where the Th17 responses are often overwhelming, the immune system shifts towards an inflammatory profile and attacks the healthy tissue from the self. Interestingly, autoimmune patients have meliorating symptoms during pregnancy. This connects with the antagonist role of Th17 and Treg cells, and their specific profiles during these two immune challenging situations. In this review, we put into perspective the Th17/Treg ratio during pregnancy and autoimmunity, as well as in pregnant women with autoimmune conditions. We further review existing systems biology approaches that study specific mechanisms of these immune cells using mathematical modelling and we point out possible future directions of investigation. Understanding what maintains or disrupts the balance between these two opponent yet reciprocal cells in healthy physiological settings, sheds light into the development of innovative pharmacological approaches to fight pregnancy loss and autoimmunity.

Extremely preterm infants who are small for gestational age have a high risk of early hypophosphatemia and hypokalemia

AIM

Electrolyte balances have not been sufficiently evaluated in extremely preterm infants after early parenteral nutrition. We investigated the risk of early hypophosphatemia and hypokalemia in extremely preterm infants born small for gestational age (SGA) who received nutrition as currently recommended.

METHODS

This prospective, observational cohort study included all consecutive extremely preterm infants born at 24-27 weeks who received high amino acids and lipid perfusion from birth. We evaluated the electrolyte levels of SGA infants and infants born appropriate for gestational age (AGA) during the first five days of life.

RESULTS

The 12 SGA infants had lower plasma potassium levels from Day One compared to the 36 AGA infants and were more likely to have hypokalemia (58% vs 17%, p = 0.001) and hypophosphatemia (40% vs 9%, p < 0.01) during the five-day observation period. After adjusting for perinatal factors, SGA remained significantly associated with hypophosphatemia (odds ratio 1.39, confidence intervals 1.07-1.81, p = 0.01).

CONCLUSION

Extremely preterm infants born SGA who were managed with currently recommended early parenteral nutrition had a high risk of early hypokalemia and hypophosphatemia. Potassium and phosphorus intakes should be set at sufficient levels from birth onwards, especially in SGA infants.