Neonatal morbidity and small and large size for gestation: a comparison of birthweight centiles

Diazoxide for Severe or Recurrent Neonatal Hypoglycemia: A Randomized Clinical Trial

Importance

Neonatal hypoglycemia is an important preventable cause of neurodevelopmental impairment, but there is a paucity of evidence to guide treatment.

Objective

To evaluate whether early, low-dose oral diazoxide for severe or recurrent neonatal hypoglycemia reduces time to resolution of hypoglycemia.

Design, Setting, and Participants

This 2-arm, placebo-controlled randomized clinical trial was conducted from May 2020 to February 2023 in tertiary neonatal units at 2 New Zealand hospitals. Participants were neonates born at 35 or more weeks' gestation and less than 1 week of age with severe hypoglycemia (blood glucose concentration <22 mg/dL or <36 mg/dL despite 2 doses of dextrose gel) or recurrent hypoglycemia (≥3 episodes of a blood glucose concentration <47 mg/dL within 48 hours).

Interventions

Newborns were randomized 1:1 to receive diazoxide suspension (loading dose, 5 mg/kg; maintenance, 1.5 mg/kg every 12 hours) or placebo, titrated per protocol.

Main Outcome and Measures

The primary outcome was time to resolution of hypoglycemia, defined as enteral bolus feeding without intravenous fluids and normoglycemia (blood glucose concentration of 47-98 mg/dL) for at least 24 hours, compared between groups using adjusted Cox proportional hazards regression. Hazard ratios adjusted for stratification variables and gestation length are reported. Prespecified secondary outcomes, including number of blood glucose tests and episodes of hypoglycemia, duration of hypoglycemia, and time to enteral bolus feeding and weaning from intravenous fluids, were compared by generalized linear models. Newborns were followed up for at least 2 weeks.

Results

Of 154 newborns screened, 75 were randomized and 74 with evaluable data were included in the analysis (mean [SD] gestational age for the full cohort, 37.6 [1.6] weeks), 36 in the diazoxide group and 38 in the placebo group. Baseline characteristics were similar: in the diazoxide group, mean (SD) gestational age was 37.9 (1.6) weeks and 26 (72%) were male; in the placebo group, mean (SD) gestational age was 37.4 (1.5) weeks and 27 (71%) were male. There was no significant difference in time to resolution of hypoglycemia (adjusted hazard ratio [AHR], 1.39; 95% CI, 0.84-2.23), possibly due to increased episodes of elevated blood glucose concentration and longer time to normoglycemia in the diazoxide group. Resolution of hypoglycemia, when redefined post hoc as enteral bolus feeding without intravenous fluids for at least 24 hours with no further hypoglycemia, was reached by more newborns in the diazoxide group (AHR, 2.60; 95% CI, 1.53-4.46). Newborns in the diazoxide group had fewer blood glucose tests (adjusted count ratio [ACR], 0.63; 95% CI, 0.56-0.71) and episodes of hypoglycemia (ACR, 0.32; 95% CI, 0.17-0.63), reduced duration of hypoglycemia (adjusted ratio of geometric means [ARGM], 0.18; 95% CI, 0.06-0.53), and reduced time to enteral bolus feeding (ARGM, 0.74; 95% CI, 0.58-0.95) and weaning from intravenous fluids (ARGM, 0.72; 95% CI, 0.60-0.87). Only 2 newborns (6%) treated with diazoxide had hypoglycemia after the loading dose compared with 20 (53%) with placebo.

Conclusions and Relevance

In this randomized clinical trial, early treatment of severe or recurrent neonatal hypoglycemia with low-dose oral diazoxide did not reduce time to resolution of hypoglycemia but reduced time to enteral bolus feeding and weaning from intravenous fluids, duration of hypoglycemia, and frequency of blood glucose testing compared with placebo.

Trial Registration

ANZCTR.org.au Identifier: ACTRN12620000129987.

Growth charts for use at birth and in the neonatal period: Recommendations of the French Neonatal Society

INTRODUCTION

The use of different growth charts can lead to confusion in discussions between professionals. There are obstetric charts (of fetal growth) and neonatal charts (of measurements at birth and of postnatal growth). These charts can be descriptive (derived from an unselected population) or prescriptive (derived from of a population at low risk and with optimal conditions for growth).

OBJECTIVES

(1) To describe available charts for infants at birth and in the neonatal period and compare them, and (2) to recommend one or more charts for use in neonatology in France.

METHODS

Bibliographic research was conducted on MEDLINE and completed by the guidelines of professional societies.

RESULTS

Antenatal information about fetal growth restriction (FGR) or fetuses identified as small-for-gestational-age using Intrauterine charts must be integrated into the identification of newborns at risk, but the use of Intrauterine charts to evaluate birthweight is not recommended to allow consistency with postnatal charts used in neonatal practice. Z-score variations using the updated Fenton postnatal charts are the most appropriate for the assessment of birthweight and postnatal growth for infants born preterm. These charts are sex-specific, include the three measurements (length, weight, and head circumference) and enable longitudinal follow-up of growth up to 50 weeks of corrected age and are linked to the WHO charts at term. The French Audipog charts, although are individualized, accessible online and can be used in maternity units to evaluate birthweight for term infants, but do not allow the follow-up of postnatal growth, while Fenton charts may be used to evaluate birthweight and postnatal growth in the first month for hospitalized term infants.

CONCLUSION

The updated Fenton charts are the neonatal charts that best suit the objectives of pediatricians in France for monitoring the growth of preterm newborns. The use of the Audipog charts at term remains an alternative in maternity wards, while Fenton charts can be used for hospitalized term newborns.

Mortality Risk in US Neonatal Intensive Care Unit Infants by Birth Size Classifications Comparing Three Growth Curves

INTRODUCTION

Three widely referenced growth curves classify infant birth anthropometric measurements as small (SGA), appropriate (AGA), or large (LGA) for gestational age (GA) differently. We assessed how these differences in assignment affect the identification and prediction of neonatal intensive care unit (NICU) mortality risk in US preterm infants.

METHODS

Birth data of infants admitted to NICUs from the Pediatrix Clinical Data Warehouse (2013-2018) were analyzed. Birth weight, length, and head circumference of 46,724 singleton infants (24-32 weeks GA) were classified as SGA, AGA, or LGA using the Olsen, Fenton, and INTERGROWTH-21st curves. NICU mortality risk based on birth size classification was analyzed using unadjusted and adjusted logistic regression stratified by GA.

RESULTS

Odds of mortality were increased with SGA classification at all GAs, size measurements, and curve sets, compared with AGA infants. LGA classification for weight was associated with lower mortality risk at 24 weeks GA and higher risk at 30 weeks GA. Odds of mortality did not differ significantly across curve sets. Classification of size at birth alone had relatively low predictive ability to identify mortality risk, with unadjusted AUCs near 0.5 for all analyses.

CONCLUSION

There were no significant differences across curve sets in predicting mortality. Classification of size at birth is a relatively imprecise method to identify infants at risk for NICU mortality.

Combined maternal central adiposity measures in relation to infant birth size

Improvement of prenatal identification of large-for-gestational-age (LGA) infants could lower the risk for adverse outcomes. Therefore, we sought to evaluate the association of a combination of maternal waist circumference (WC) and abdominal fat depths with infant birth size. A cohort study including 1240 women was performed between 2015 and 2018 at Uppsala University Hospital, Sweden. Maternal WC was measured at the first antenatal visit, and visceral (VF) and subcutaneous (SCF) fat depths by ultrasound at the second-trimester anomaly scan. Waist circumference, VF, and SCF were categorized as low or high (cut-offs WC ≥ 88 cm, VF ≥ 54 mm, SCF ≥ 21 mm). Outcomes were birth weight standard deviation score (BWSDS) and LGA (BWSDS > 90th and > 97th percentile). Secondary outcome was small-for-gestational-age (SGA, BWSDS < 10th and < 3rd percentile). Univariate analysis of variance and logistic regression analyses were performed adjusted for maternal weight, height, parity, smoking, country of birth, pregestational diabetes, and chronic hypertension. For both high and low WC, high VF was positively associated with BWSDS and LGA. There was no association with SGA. The results did not demonstrate any value of the combination of WC and fat depth measures in predicting infant birth size but suggested VF as a marker for large infants.

Stillbirth risk and smallness for gestational age according to Hadlock, INTERGROWTH-21st, WHO, and GROW fetal weight standards: analysis by maternal ethnicity and body mass index

BACKGROUND

Appropriate growth charts are essential for fetal surveillance, to confirm that growth is proceeding normally and to identify pregnancies that are at risk. Many stillbirths are avoidable through antenatal detection of the small-for-gestational-age fetus. In the absence of an international consensus on which growth chart to use, it is essential that clinical practice reflects outcome-based evidence.

OBJECTIVE

This study investigated the performance of 4 internationally used fetal weight standards and their ability to identify stillbirth risk in different ethnic and maternal size groups of a heterogeneous population.

STUDY DESIGN

We analyzed routinely collected maternity data from more than 2.2 million pregnancies. Three population-based fetal weight standards (Hadlock, Intergrowth-21st, and World Health Organization) were compared with the customized GROW standard that was adjusted for maternal height, weight, parity, and ethnic origin. Small-for-gestational-age birthweight and stillbirth risk were determined for the 2 largest ethnic groups in our population (British European and South Asian), in 5 body mass index categories, and in 4 maternal size groups with normal body mass index (18.5-25.0 kg/m2). The differences in trend between stillbirth and small-for-gestational-age rates were assessed using the Clogg z test, and differences between stillbirths and body mass index groups were assessed using the chi-square trend test.

RESULTS

Stillbirth rates (per 1000) were higher in South Asian pregnancies (5.51) than British-European pregnancies (3.89) (P<.01) and increased in both groups with increasing body mass index (P<.01). Small-for-gestational-age rates were 2 to 3-fold higher for South Asian babies than British European babies according to the population-average standards (Hadlock: 26.2% vs 12.2%; Intergrowth-21st: 12.1% vs 4.9%; World Health Organization: 32.2% vs 16.0%) but were similar by the customized GROW standard (14.0% vs 13.6%). Despite the wide variation, each standard's small-for-gestation-age cases had increased stillbirth risk compared with non-small-for-gestation-age cases, with the magnitude of risk inversely proportional to the rate of cases defined as small for gestational age. All standards had similar stillbirth risk when the small-for-gestation-age rate was fixed at 10% by varying their respective thresholds for defining small for gestational age. When analyzed across body mass index subgroups, the small-for-gestation-age rate according to the GROW standard increased with increasing stillbirth rate, whereas small-for-gestation-age rates according to Hadlock, Intergrowth-21st, and World Health Organization fetal weight standards declined with increasing body mass index, showing a difference in trend (P<.01) to stillbirth rates across body mass index groups. In the normal body mass index subgroup, stillbirth rates showed little variation across maternal size groups; this trend was followed by GROW-based small-for-gestation-age rates, whereas small-for-gestation-age rates defined by each population-average standard declined with increasing maternal size.

CONCLUSION

Comparisons between population-average and customized fetal growth charts require examination of how well each standard identifies pregnancies at risk of adverse outcomes within subgroups of any heterogeneous population. In both ethnic groups studied, increasing maternal body mass index was accompanied by increasing stillbirth risk, and this trend was reflected in more pregnancies being identified as small for gestational age only by the customized standard. In contrast, small-for-gestation-age rates fell according to each population-average standard, thereby hiding the increased stillbirth risk associated with high maternal body mass index.

Reference Values for Birth Weight in Relation to Gestational Age in Poland and Comparison with the Global Percentile Standards

INTRODUCTION

Percentiles of birth weight by gestational age (GA) are an essential tool for clinical assessment and initiating interventions to reduce health risks. Unfortunately, Poland lacks a reference chart for assessing newborn growth based on the national population. This study aimed to establish a national reference range for birth weight percentiles among newborns from singleton deliveries in Poland. Additionally, we sought to compare these percentile charts with the currently used international standards, INTERGROWTH-21 and WHO.

MATERIALS AND METHODS

All singleton live births (n = 3,745,239) reported in Poland between 2010 and 2019 were analyzed. Using the Lambda Mu Sigma (LMS) method, the Generalized Additive Models for Location Scale, and Shape (GAMLSS) package, smoothed percentile charts (3-97) covering GA from 23 to 42 weeks were constructed.

RESULTS

The mean birth weight of boys was 3453 ± 540 g, and this was higher compared with that of girls (3317 ± 509 g). At each gestational age, boys exhibited higher birth weights than girls. The weight range between the 10th and 90th percentiles was 1061 g for boys and 1016 g for girls. Notably, the birth weight of Polish newborns was higher compared to previously published international growth standards.

CONCLUSION

The reference values for birth weight percentiles established in this study for Polish newborns differ from the global standards and are therefore useful for evaluating the growth of newborns within the national population. These findings hold clinical importance in identifying neonates requiring postbirth monitoring.

Portuguese versus Fenton Curve: Which one better explains maternal and neonatal outcomes in Portuguese women with gestational diabetes?

BACKGROUND AND AIMS

Growth charts are commonly used to identify foetal growth alterations, playing an important role as extreme growth centiles correlate with worse foetal and neonatal outcomes. This study aim was to compare birthweight classification (small for gestational age (SGA), adequate for gestational age and large for gestational age (LGA)) from women with gestational diabetes mellitus (GDM) by applying the population-based growth chart (Fenton Curve) and the standard chart customised for our country (Portuguese Curve). Moreover, we compared obstetric and neonatal outcomes according to birthweight classification between these curves.

METHODS

A multicentre observational study with prospectively collected data from 19,470 pregnant women diagnosed with GDM (30 Portuguese institutions) was conducted.

RESULTS

The proportion of SGA neonates was higher with Fenton Chart than with Portuguese standard chart (12.7% vs 10.9%) and the prevalence of LGA was higher using the Portuguese Chart (4.1%vs 10.9%). Statistically significant differences in the classifications given by the two curves and for maternal/neonatal outcomes were found. The Area Under the Curve and Akaike Information Criterion pointed out to a better correlation between weight classification of the Portuguese Curves and the majority of expected maternal and neonatal outcomes: gestational hypertension, preeclampsia, hydramnios, vaginal dystocic labour, hyperbilirubinemia, respiratory distress syndrome, trauma from delivery, admission in neonatal intensive care unit, prematurity and neonatal morbidity.

CONCLUSION

Our study highlights the importance of having a standard birthweight curve specifically designed for each population. Neonates' weight classification carries prognostic implication and misclassification could lead to potential mistreatment or overtreatment.

Performances of birthweight charts to predict adverse perinatal outcomes related to SGA in a cohort of nulliparas

Background

Small-for-gestational-age neonates (SGA) are at increased risk of neonatal morbidity. Nulliparity represents a risk factor for SGA; birthweight charts may perform differently for the detection of SGA among nulliparas. This study aimed at describing the prevalence of SGA in nulliparas according to different birthweight charts and evaluating the diagnostic performance of these charts to maternal and perinatal outcomes.

Methods

This is a secondary analysis of a Brazilian cohort of nulliparas named Preterm SAMBA study. Birthweight centiles were calculated using the Intergrowth-21st, WHO-Fetal Growth Charts, Birth in Brazil population chart and GROW-customised chart. The risks of outcomes among SGA neonates and their mothers in comparison to neonates with birthweights between the 40^th-60^th centiles were calculated, according to each chart. ROC curves were used to detect neonatal morbidity in neonates with birth weights below different cutoff centiles for each chart.

Results

A sample of 997 nulliparas was assessed. The rate of SGA infants varied between 7.0–11.6%. All charts showed a significantly lower risk of caesarean sections in women delivering SGA neonates compared to those delivering adequate-for-gestational-age neonates (OR 0.55–0.64, p < .05). The charts had poor performance (AUC 0.492 – 0.522) for the detection of neonatal morbidity related to SGA born at term.

Conclusion

The populational and customised birthweight charts detected different prevalence of small-for-gestational-age neonates and showed similar and poor performance to identify related neonatal adverse outcomes in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04943-1.

Evaluating the Growth Assessment Protocol for stillbirth prevention: progress and challenges

Many stillbirths are associated with fetal growth restriction, and are hence potentially avoidable. The Growth Assessment Protocol (GAP) is a multidisciplinary program with an evidence based care pathway, training in risk assessment, fetal growth surveillance with customised charts and rolling audit. Antenatal detection of small for gestational age (SGA) has become an indicator of quality of care. Evaluation is essential to understand the impact of such a prevention program. Randomised trials will not be effective if they cannot ensure proper implementation before assessment. Observational studies have allowed realistic evaluation in practice, with other factors excluded that may have influenced the outcome. An award winning 10 year study of stillbirth data in England has been able to assess the effect of GAP in isolation, and found a strong, causal association with improved antenatal detection of SGA babies, and the sustained decline in national stillbirth rates. The challenge now is to apply this program more widely in low and middle income settings where the main global burden of stillbirth is, and to adapt it to local needs and resources.

Customized GROW vs INTERGROWTH-21st birthweight standards to identify small for gestational age associated perinatal outcomes at term

BACKGROUND

Fetal growth restriction is associated with stillbirth and other adverse pregnancy outcomes, and use of the correct weight standard is an essential proxy indicator of growth status and perinatal risk.

OBJECTIVE

We sought to assess the performance of two international birthweight standards for their ability to identify perinatal morbidity and mortality indicators associated with small for gestational age (SGA) infants at term.

STUDY DESIGN

This retrospective cohort study used data from a multi-center perinatal quality initiative including a multi-ethnic dataset of 125,826 births from 2012-2017. Of the singleton term births, 92,622 had complete outcome data including stillbirth, neonatal death, 5-minute Apgar <7, neonatal glucose instability and need for newborn transfer to a higher level of care or NICU admission. The customized (GROW) and INTERGROWTH-21^st (IG21) birthweight standards were applied to determine SGA (<10^th centile) according to their respective methods and formulae. Associations with adverse outcomes were expressed as relative risk (RR) with 95% confidence interval (CI) and population attributable fraction (PAF).

RESULTS

GROW classified 9,578 (10.3%) and IG21 classified 4,079 (4.4%) pregnancies as SGA, respectively. For all of the outcomes assessed, GROW identified more SGA infants with adverse outcomes than IG21, including more stillbirths, perinatal deaths, low Apgar scores, glucose instability, newborn seizure and transfers to a higher level of care. Thirteen of the 27 stillbirths (48%) that were SGA by either method were identified as SGA by GROW but not by IG21. Similarly, additional cases of all other adverse outcome indicators were identified by GROW as SGA, while only in one category (glucose instability) did IG21 identify 9 of 295 cases (3.1%) which were not identified as SGA by GROW.

CONCLUSION

Customized assessment using GROW results in increased identification of small for gestational age term babies that are at significantly increased risk of an array of adverse pregnancy outcomes.

Strategies to improve neurodevelopmental outcomes in babies at risk of neonatal hypoglycaemia

Neonatal hypoglycaemia is associated with adverse development, particularly visual-motor and executive function impairment, in childhood. As neonatal hypoglycaemia is common and frequently asymptomatic in at-risk babies-ie, those born preterm, small or large for gestational age, or to mothers with diabetes, it is recommended that these babies are screened for hypoglycaemia in the first 1-2 days after birth with frequent blood glucose measurements. Neonatal hypoglycaemia can be prevented and treated with buccal dextrose gel, and it is also common to treat babies with hypoglycaemia with infant formula and intravenous dextrose. However, it is uncertain if screening, prophylaxis, or treatment improves long-term outcomes of babies at risk of neonatal hypoglycaemia. This narrative review assesses the latest evidence for screening, prophylaxis, and treatment of neonates at risk of hypoglycaemia to improve long-term neurodevelopmental outcomes.

Neurodevelopmental outcomes of singleton large for gestational age infants <29 weeks' gestation: a retrospective cohort study

OBJECTIVE

To compare neurodevelopmental outcomes of large and appropriate for gestational age (LGA, AGA) infants <29 weeks' gestation at 18-24 months of corrected age.

STUDY DESIGN

Retrospective cohort study using the Canadian Neonatal Network and Canadian Neonatal Follow-Up Network databases. Primary outcome was a composite of death or significant neurodevelopmental impairment (NDI), defined as severe cerebral palsy, Bayley III cognitive, language and motor scores of <70, need for hearing aids or cochlear implant and bilateral visual impairment. Univariate and multivariable logistic analyses were applied for outcomes.

RESULTS

The study cohort comprised 170 LGA and 1738 AGA infants. There was no difference in significant NDI or individual components of the Bayley III between LGA and AGA groups. LGA was associated with the increased risk of death by follow-up, 44/170 (25.9%) vs. 320/1738 (18.4%) (aOR: 1.60 95% CI: 1.00-2.54).

CONCLUSIONS

Risk of NDI was similar between LGA and AGA infants.

Reduction in perinatal mortality among small for gestational age babies in New Zealand

BACKGROUND

A significant reduction in perinatal mortality among births ≥1000 g has been observed in New Zealand.

AIM

To determine, in a national cohort, if perinatal mortality has reduced in small for gestational age (SGA) and non-SGA babies.

MATERIALS AND METHODS

Retrospective cohort, 2008-2016, of singleton non-anomalous births and perinatal deaths from 26+0 weeks gestation at birth in New Zealand. Perinatal deaths from the Perinatal and Maternal Mortality Review Committee data set were merged with the Ministry of Health national maternity data set. SGA was defined as less than the 10th customised birthweight centile using New Zealand coefficients. Perinatal mortality was defined as stillbirth from 26 weeks gestation and neonatal death up to the 27th day of life.

RESULTS

There was a 30% reduction in perinatal mortality among SGA singleton non-anomalous babies at 26 weeks or more from 10.38/1000 births in 2008 to 7.28/1000 in 2016 (P = 0.046) but no significant change in mortality among appropriate and large for gestational age babies.

CONCLUSION(S)

There has been a significant reduction in perinatal mortality among SGA babies in New Zealand. The mechanism for this reduction is unclear.

Detection of small for gestational age babies and perinatal outcomes following implementation of the Growth Assessment Protocol at a New Zealand tertiary facility: An observational intervention study

BACKGROUND

Timely detection of small for gestational age (SGA) fetuses is important for reducing severe perinatal morbidity and mortality, and better tools are needed to detect SGA in maternity care.

AIM

We evaluated the effect of the introduction of the Perinatal Institute's Growth Assessment Protocol (GAP) in the Counties Manukau Health region, South Auckland, New Zealand, on antenatal detection of SGA and maternal and perinatal outcomes.

MATERIALS AND METHODS

Uncontrolled before and after study in women booked under hospital community midwife care with a singleton, non-anomalous pregnancy. Antenatal detection of SGA (birthweight <10th customised centile) was compared pre-GAP (2012, N = 1105) and post-GAP (2017, N = 1082). Composite adverse neonatal outcome was defined as neonatal unit admission >48 h, five-minute Apgar score <7, and/or any ventilation. Analyses were adjusted for maternal age, body mass index, deprivation, smoking and ethnicity.

RESULTS

SGA rates were similar across epochs (13.8% vs 12.9%) but antenatal detection of SGA increased from 22.9% (35/153) to 57.9% (81/140) post-GAP (adjusted odds ratio (aOR) = 4.8, 95% CI 2.82-8.18). Rates of induction of labour and caesarean section increased between epochs but were similar in SGA, non-SGA, and detected and non-detected SGA subgroups. Among SGA babies, there was some evidence that antenatal detection of SGA may be associated with lower composite adverse neonatal outcome (detected SGA: aOR 0.44 95% CI 0.17-1.15; non-detected SGA: aOR = 1.81 95% CI 0.73-4.48; interaction P = 0.03). Pre-term birth did not appear to be influenced by GAP.

CONCLUSION

Implementation of GAP was associated with a nearly five-fold increase in SGA detection without increasing obstetric intervention for SGA.