Country-Specific vs. Common Birthweight-for-Gestational Age References to Identify Small for Gestational Age Infants Born at 24-28 weeks: An International Study

Utilizing daily excessive concentration hours to estimate small for gestational age infants attributable to fine particulate matter in Wuhan, China

Limited studies in China have explored the association between gravidae exposure to PM2.5 and small for gestational age infants (SGA), yielding inconsistent results. This study in Wuhan utilized daily excessive concentration hours (DECH) as a novel measure to assess PM2.5's impact on SGA. Data on air pollutants and pregnant women were collected from the Wuhan Municipal Ecology and Environmental Bureau and Wuhan Children's Hospital, respectively. Logistic regression models were employed to evaluate the contribution of PM2.5-DECH and PM2.5-mean to SGA. Significant correlations were observed between PM2.5-mean and SGA during the second trimester [OR = 1.23 (95% CI: 1.14-1.32)] and the entire pregnancy [OR = 1.15 (95% CI: 1.07-1.24)]. Similar correlations were found between PM2.5-DECH and SGA. These findings suggest that increased PM2.5 exposure is associated with a higher risk of SGA, and DECH may be used as a prospective substitute indicator for daily average concentration in similar studies.

Trends, Characteristic, and Outcomes of Preterm Infants Who Received Postnatal Corticosteroid: A Cohort Study from 7 High-Income Countries

INTRODUCTION

Our objective was to evaluate the temporal trend of systemic postnatal steroid (PNS) receipt in infants of 24-28 weeks' gestational age, identify characteristics associated with PNS receipt, and correlate PNS receipt with the incidence of bronchopulmonary dysplasia (BPD) and BPD/death from an international cohort included in the iNeo network.

METHODS

We conducted a retrospective study using data from 2010 to 2018 from seven international networks participating in iNeo (Canada, Finland, Israel, Japan, Spain, Sweden, and Switzerland). Neonates of 24 and 28 weeks' gestational age who survived 7 days and who received PNS were included. We assessed temporal trend of rates of systemic PNS receipt and BPD/death.

RESULTS

A total of 47,401 neonates were included. The mean (SD) gestational age was 26.4 (1.3) weeks and birth weight was 915 (238) g. The PNS receipt rate was 21% (12-28% across networks) and increased over the years (18% in 2010 to 26% in 2018; p < 0.01). The BPD rate was 39% (28-44% across networks) and remained unchanged over the years (35.2% in 2010 to 35.0% in 2018). Lower gestation, male sex, small for gestational age status, and presence of persistent ductus arteriosus (PDA) were associated with higher rates of PNS receipt, BPD, and BPD/death.

CONCLUSION

The use of PNS in extremely preterm neonates increased, but there was no correlation between increased use and the BPD rate. Research is needed to determine the optimal timing, dose, and indication for PNS use in preterm neonates.

Joint Exposure to Ambient Air Pollutants Might Elevate the Risk of Small for Gestational Age (SGA) Infants in Wuhan: Evidence From a Cross-Sectional Study

Objective: To investigate the effect of exposure to multiple ambient air pollutants during pregnancy on the risk of children being born small for gestational age (SGA). Methods: An Air Pollution Score (APS) was constructed to assess the effects of being exposed to six air pollutants simultaneously, PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ (referred to as joint exposure). A logistic regression model was applied to estimate the associations of APS and SGA. Results: The adjusted odds ratios (ORs) of SGA per 10 ug/m³ increased in APS during the first and second trimesters and the entire pregnancy were 1.003 [95% confidence intervals (CIs): 1.000, 1.007], 1.018 (1.012, 1.025), and 1.020 (1.009, 1.031), respectively. The ORs of SGA for each 10 μg/m³ elevated in APS during the whole pregnancy were 1.025 (1.005, 1.046) for mothers aged over 35 years old vs. 1.018 (1.005, 1.031) for mothers aged under 35 years old. Women who were pregnant for the first time were more vulnerable to joint ambient air pollution. Conclusion: In summary, the results of the present study suggested that joint exposure to ambient air pollutants was associated with the increment in the risks of SGA.

Variations in Neonatal Length of Stay of Babies Born Extremely Preterm: An International Comparison Between iNeo Networks

OBJECTIVE

To compare length of stay (LOS) in neonatal care for babies born extremely preterm admitted to networks participating in the International Network for Evaluating Outcomes of Neonates (iNeo).

STUDY DESIGN

Data were extracted for babies admitted from 2014 to 2016 and born at 24 to 28 weeks of gestational age (n = 28 204). Median LOS was calculated for each network for babies who survived and those who died while in neonatal care. A linear regression model was used to investigate differences in LOS between networks after adjusting for gestational age, birth weight z score, sex, and multiplicity. A sensitivity analysis was conducted for babies who were discharged home directly.

RESULTS

Observed median LOS for babies who survived was longest in Japan (107 days); this result persisted after adjustment (20.7 days more than reference, 95% CI 19.3-22.1). Finland had the shortest adjusted LOS (-4.8 days less than reference, 95% CI -7.3 to -2.3). For each week's increase in gestational age at birth, LOS decreased by 12.1 days (95% CI -12.3 to -11.9). Multiplicity and male sex predicted mean increases in LOS of 2.6 (95% CI 2.0-3.2) and 2.1 (95% CI 1.6-2.6) days, respectively.

CONCLUSIONS

We identified between-network differences in LOS of up to 3 weeks for babies born extremely preterm. Some of these may be partly explained by differences in mortality, but unexplained variations also may be related to differences in clinical care practices and healthcare systems between countries.

Prevalence of small for gestational age infants in 21 cities in China, 2014-2019

Infants who are small for gestational age (SGA) are at increased risk of neonatal and infant death, non-communicable diseases and growth retardation. However, the epidemiological characteristics of SGA remain unclear. We aim to explore the prevalence of SGA and to examine its socioeconomic associations by using data from 21 cities. 10,515,494 single live birth records between 2014 and 2019 from the Guangdong Women and Children Health Information System were included in the study. Descriptive statistical methods were used to analyze the prevalence trend of SGA and its distribution. We also analyze the associations between the prevalence of SGA and per-capita GDP. The prevalence of SGA in Guangdong Province from the years 2014-2019 was 13.17%, 12.96%, 11.96%, 12.72%, 11.45%, 11.30% respectively, and the overall prevalence was 12.28%. The prevalence of term SGA infants in Guangdong Province was 12.50%, which was much higher than that of preterm SGA (7.71%). There was a significant negative correlation between the SGA prevalence and per-capita GDP in 21 cities of Guangdong Province. The level of economic development may affect the prevalence of SGA. The prevalence of SGA in full term infants is significantly higher than in premature infants, suggesting that most SGA infants may be born at a later gestational age.

The effect of influenza virus infection on pregnancy outcomes: A systematic review and meta-analysis of cohort studies

BACKGROUND

Adverse pregnancy outcomes are risk factors for neonatal mortality and morbidity. While some studies have demonstrated notable associations between influenza and adverse pregnancy outcomes, the findings have contrasted with other studies. This meta-analysis was conducted to assess the effect of influenza infection on pregnancy outcomes.

METHODS

We searched PubMed, Embase, Cochrane Library and Web of Science from inception to 4 November 2020. Relative risks (RRs) with 95% confidence intervals (CIs) were pooled using random-effects or fixed-effects models.

RESULTS

A total of 17 studies involving 2,351,204 participants were included. Influenza infection increased the risk of stillbirth (RR = 3.62, 95% CI: 1.60-8.20), with no significant effect on preterm birth (RR = 1.17, 95%CI: 0.95-1.45), fetal death (RR = 0.93, 95%CI: 0.73-1.18), small for gestational age (SGA) (RR = 1.10, 95%CI: 0.98-1.24) and low birth weight (LBW) (RR = 1.88, 95%CI: 0.46-7.66). In a subgroup analysis of LBW, the association was evident in studies conducted during the 2009 H1N1 pandemic (RR = 2.28, 95%CI: 1.81-2.87), with no evidence of an association in pre-pandemic or post-pandemic studies.

CONCLUSIONS

Influenza virus infection was associated with an increased risk of stillbirth, but its effect on preterm birth, fetal death, SGA and LBW is still uncertain.

Neonatal outcomes of extremely preterm twins by sex pairing: an international cohort study

OBJECTIVE

Infant boys have worse outcomes than girls. In twins, the 'male disadvantage' has been reported to extend to female co-twins via a 'masculinising' effect. We studied the association between sex pairing and neonatal outcomes in extremely preterm twins.

DESIGN

Retrospective cohort study SETTING: Eleven countries participating in the International Network for Evaluating Outcomes of Neonates.

PATIENTS

Liveborn twins admitted at 23-29 weeks' gestation in 2007-2015.

MAIN OUTCOME MEASURES

We examined in-hospital mortality, grades 3/4 intraventricular haemorrhage or cystic periventricular leukomalacia (IVH/PVL), bronchopulmonary dysplasia (BPD), retinopathy of prematurity requiring treatment and a composite outcome (mortality or any of the outcomes above).

RESULTS

Among 20 924 twins, 38% were from male-male pairs, 32% were from female-female pairs and 30% were sex discordant. We had no information on chorionicity. Girls with a male co-twin had lower odds of mortality, IVH/PVL and the composite outcome than girl-girl pairs (reference group): adjusted OR (aOR) (95% CI) 0.79 (0.68 to 0.92), 0.83 (0.72 to 0.96) and 0.88 (0.79 to 0.98), respectively. Boys with a female co-twin also had lower odds of mortality: aOR 0.86 (0.74 to 0.99). Boys from male-male pairs had highest odds of BPD and composite outcome: aOR 1.38 (1.24 to 1.52) and 1.27 (1.16 to 1.39), respectively.

CONCLUSIONS

Sex-related disparities in outcomes exist in extremely preterm twins, with girls having lower risks than boys and opposite-sex pairs having lower risks than same-sex pairs. Our results may help clinicians in assessing risk in this large segment of extremely preterm infants.

Effects of small for gestational age status on mortality and major morbidities in ≤750 g neonates

BACKGROUND

Controversy exists regarding the impact of small for gestational age (SGA = birth weight < 10th percentile) status on mortality and major morbidities.

AIM

To assess the effects of SGA on mortality and major morbidities in ≤750 gram (g) neonates.

STUDY DESIGN

Retrospective (01/2005-12/2017), single center study at a tertiary NICU.

SUBJECTS

SGA neonates ≤ 750 g.

OUTCOME

Effect of SGA status on mortality and major morbidities.

RESULTS

183 infants were enrolled. 103 (56.3%) were non-SGA (mean gestational age 25 + 1 weeks ± 9.9 days, mean birth weight 662.6 ± 75.2 g), and 80 (43.7%) SGA (mean gestational age 26 + 6 weeks ± 14.0 days, mean birth weight 543.9 ± 114.7 g). Mortality was 24.1% (non-SGA: 30/103 (29.1%), SGA: 14/80 (17.5%); p = 0.08). Univariable logistic regression analysis revealed a significant protective effect of SGA status on pneumothoraces (OR 0.28, 95%-CI [0.11-0.69]), IVH (≥3) (OR 0.38; 95%-CI [0.15-0.67]), and seizures (OR 0.09, 95%-CI [0.01-0.76]), but NEC (≥2a) occurred more frequently in SGA neonates (p = 0.024). Multiple logistic regression analysis found SGA status to negatively influence ROP (≥3) (OR 2.87, 95%-CI [1.14-7.23]) and need for home monitoring (OR 2.38, 95%-CI [1.05-5.41]). Other major morbidities (IVH, PVL, RDS, BPD, NEC, FIP, sepsis, hearing impairment) and mortality rates were not significantly affected, but distinct organ-specific patterns were seen.

CONCLUSION

SGA had negative effects on the rate of severe ROP and the need for home monitoring, but other major morbidities as well as mortality rates were not significantly affected. In the future, it will be important to delineate underlying pathophysiological mechanisms that contribute to this pattern.

Neonatal Intensive Care Unit-Level Patent Ductus Arteriosus Treatment Rates and Outcomes in Infants Born Extremely Preterm

OBJECTIVES

To assess associations between neonatal intensive care unit (NICU)-level patent ductus arteriosus (PDA) treatment rates (pharmacologic or surgical) and neonatal outcomes.

STUDY DESIGN

This cohort study included infants born at 24-28 weeks of gestation and birth weight <1500 g in 2007-2015 in NICUs caring for ≥100 eligible infants in 6 countries. The ratio of observed/expected (O/E) PDA treatment rates was derived for each NICU by estimating the expected rate using a logistic regression model adjusted for potential confounders and network. The primary composite outcome was death or severe neurologic injury (grades III-IV intraventricular hemorrhage or periventricular leukomalacia). The associations between the NICU-level O/E PDA treatment ratio and neonatal outcomes were assessed using linear regression analyses including a quadratic effect (a square term) of the O/E PDA treatment ratio.

RESULTS

From 139 NICUs, 39 096 infants were included. The overall PDA treatment rate was 45% in the cohort (13%-77% by NICU) and the O/E PDA treatment ratio ranged from 0.30 to 2.14. The relationship between the O/E PDA treatment ratio and primary composite outcome was U-shaped, with the nadir at a ratio of 1.13 and a significant quadratic effect (P<.001). U-shaped relationships were also identified with death, severe neurologic injury, and necrotizing enterocolitis.

CONCLUSIONS

Both low and high PDA treatment rates were associated with death or severe neurologic injury, whereas a moderate approach was associated with optimal outcomes.

Trends in Outcomes for Neonates Born Very Preterm and Very Low Birth Weight in 11 High-Income Countries

OBJECTIVE

To evaluate outcome trends of neonates born very preterm in 11 high-income countries participating in the International Network for Evaluating Outcomes of neonates.

STUDY DESIGN

In a retrospective cohort study, we included 154 233 neonates admitted to 529 neonatal units between January 1, 2007, and December 31, 2015, at 24^0/7 to 31^6/7 weeks of gestational age and birth weight <1500 g. Composite outcomes were in-hospital mortality or any of severe neurologic injury, treated retinopathy of prematurity, and bronchopulmonary dysplasia (BPD); and same composite outcome excluding BPD. Secondary outcomes were mortality and individual morbidities. For each country, annual outcome trends and adjusted relative risks comparing epoch 2 (2012-2015) to epoch 1 (2007-2011) were analyzed.

RESULTS

For composite outcome including BPD, the trend decreased in Canada and Israel but increased in Australia and New Zealand, Japan, Spain, Sweden, and the United Kingdom. For composite outcome excluding BPD, the trend decreased in all countries except Spain, Sweden, Tuscany, and the United Kingdom. The risk of composite outcome was lower in epoch 2 than epoch 1 in Canada (adjusted relative risks 0.78; 95% CI 0.74-0.82) only. The risk of composite outcome excluding BPD was significantly lower in epoch 2 compared with epoch 1 in Australia and New Zealand, Canada, Finland, Japan, and Switzerland. Mortality rates reduced in most countries in epoch 2. BPD rates increased significantly in all countries except Canada, Israel, Finland, and Tuscany.

CONCLUSIONS

In most countries, mortality decreased whereas BPD increased for neonates born very preterm.

Information technology infrastructure, quality improvement and research: the UK National Neonatal Research Database

Technological developments, coupled with strengthened governance and data security have led to increasing recognition of the potential of real-world health data to benefit patient care and health services. Real-world health data are those captured in the course of routine care. Here I describe a mature source of real-world health data, the UK National Neonatal Research Database and provide examples of the many types of uses it supports.

Maternal hypertension and survival in singletons and twins born at 23-29 weeks: not just one answer…

BACKGROUND

To describe the association between maternal hypertension (chronic and gestational, MH) and mortality in very preterm singletons and twins, focusing on how estimates depend on gestational age (GA) and size at birth.

METHODS

We estimated relative risks of in-hospital death in 12,320 singletons (MH: 22.4%) and 4381 twins (MH: 10.6%) born at 23-29 weeks in the Italian Neonatal Network (89 hospitals, 2008-2016).

RESULTS

Babies with MH had higher GA and were more frequently small-for-gestational age (SGA), especially singletons. In crude analyses, MH was associated with lower mortality in singletons. In multivariable analyses, the effects of GA and size differed between twins and singletons with and without MH. The best-fitting models included continuous birth weight (rather than SGA) and were stratified by GA. In these models, MH was associated with lower mortality in singletons-but not twins-born after week 25.

CONCLUSIONS

In this cohort of very preterm infants, the association between MH and mortality differed between singletons and twins and across strata of GA at birth. These estimates cannot be interpreted causally, but suggest that, from a descriptive/predictive standpoint, singletons with MH born after week 25 have lower mortality than singletons born to women without MH.

Intrapartum magnesium sulfate is associated with neuroprotection in growth-restricted fetuses

BACKGROUND

Intrapartum magnesium sulfate administration is recommended for fetal neuroprotection in women with imminent very preterm birth. However, previous studies have not included or separately analyzed the outcomes of pregnancies with fetal growth restriction that were treated with intrapartum magnesium sulfate.

OBJECTIVE

We sought to evaluate the neonatal and neurodevelopmental outcomes of growth-restricted fetuses born <29 weeks' gestation and exposed to maternal intrapartum magnesium sulfate.

STUDY DESIGN

We conducted a retrospective cohort study of infants born <29 weeks' gestation from 2010 through 2011, admitted to participating Canadian Neonatal Network units, and followed by the Canadian Neonatal Follow-up Network centers. Growth restriction was defined either as estimated fetal or actual neonatal birthweight <10th percentile according to fetal or neonatal growth standards for gestational age and sex, respectively. Infants exposed to intrapartum magnesium sulfate were compared with unexposed infants. The primary outcome was composite of death or significant neurodevelopmental impairment at 18-36 months' corrected age. Secondary outcomes were death or any neurodevelopmental impairment at 18-36 months' corrected age. Neonatal morbidities were also compared.

RESULTS

Of the 336 growth-restricted fetuses, 112 (33%) received magnesium sulfate and of the 177 growth-restricted infants, 61 (34%) received magnesium sulfate. Administration of magnesium sulfate was at the discretion of the treating physician. Intrapartum magnesium sulfate was associated with reduced odds of composite of death or significant neurodevelopmental impairment for infants classified according to both fetal standards (adjusted odds ratio, 0.42; 95% confidence interval, 0.22-0.80) and neonatal standards (adjusted odds ratio, 0.44; 95% confidence interval, 0.20-0.98).

CONCLUSION

Intrapartum administration of magnesium sulfate to women with growth-restricted fetuses born <29 weeks' gestation was associated with reduced odds of composite of death or significant neurodevelopmental impairment.

Neonatal Outcomes of Very Preterm or Very Low Birth Weight Triplets

OBJECTIVES

To compare the neonatal outcomes of very preterm triplets with those of matched singletons using a large international cohort.

METHODS

A retrospective matched-cohort study of preterm triplets and singletons born between 2007 and 2013 in the International Network for Evaluation of Outcomes in neonates database countries and matched by gestational age, sex, and country of birth was conducted. The primary outcome was a composite of mortality or severe neonatal morbidity (severe neurologic injury, treated retinopathy of prematurity, and bronchopulmonary dysplasia). Unadjusted and adjusted odds ratios with 95% confidence intervals (CIs) were calculated for model 1 (maternal hypertension and birth weight z score) and model 2 (variables in model 1, antenatal steroids, and mode of birth). Models were fitted with generalizing estimating equations and random effects modeling to account for clustering.

RESULTS

A total of 6079 triplets of 24 to 32 weeks' gestation or 500 to 1499 g birth weight and 18 232 matched singletons were included. There was no difference in the primary outcome between triplets and singletons (23.4% vs 24.0%, adjusted odds ratio: 0.91, 95% CI: 0.83-1.01 for model 1 and 1.00, 95% CI: 0.90-1.11 for model 2). Rates of severe neonatal morbidities did not differ significantly between triplets and singletons. The results were also similar for a subsample of the cohort (1648 triplets and 4944 matched singletons) born at 24 to 28 weeks' gestation.

CONCLUSIONS

No significant differences were identified in mortality or major neonatal morbidities between triplets who were very low birth weight or very preterm and matched singletons.

Small for gestational age and obesity: epidemiology and general risks

Children born small for gestational age (SGA) have several life-long consequences. Previous epidemiological studies investigated from childhood to adulthood reported that a number of chronic diseases originate in the prenatal period. With the emerging era of obesity epidemic, more concerns are related to being obese than being short-statured in SGA children. The exact mechanisms are uncertain; however, growth hormone-insulin-like growth factor axis disturbance by fetal programming and accelerated postnatal weight gain contributed to central adiposity in SGA children. In this review, we summarized the definitions and prevalence of SGA, epidemiology, and general risks of obesity in SGA children. Early interventions, before and after birth, are needed for healthy catch-up growth to prevent later obesity and related complications.

Survival in Very Preterm Infants: An International Comparison of 10 National Neonatal Networks

OBJECTIVES

To compare survival rates and age at death among very preterm infants in 10 national and regional neonatal networks.

METHODS

A cohort study of very preterm infants, born between 24 and 29 weeks' gestation and weighing <1500 g, admitted to participating neonatal units between 2007 and 2013 in the International Network for Evaluating Outcomes of Neonates. Survival was compared by using standardized ratios (SRs) comparing survival in each network to the survival estimate of the whole population.

RESULTS

Network populations differed with respect to rates of cesarean birth, exposure to antenatal steroids and birth in nontertiary hospitals. Network SRs for survival were highest in Japan (SR: 1.10; 99% confidence interval: 1.08-1.13) and lowest in Spain (SR: 0.88; 99% confidence interval: 0.85-0.90). The overall survival differed from 78% to 93% among networks, the difference being highest at 24 weeks' gestation (range 35%-84%). Survival rates increased and differences between networks diminished with increasing gestational age (GA) (range 92%-98% at 29 weeks' gestation); yet, relative differences in survival followed a similar pattern at all GAs. The median age at death varied from 4 days to 13 days across networks.

CONCLUSIONS

The network ranking of survival rates for very preterm infants remained largely unchanged as GA increased; however, survival rates showed marked variations at lower GAs. The median age at death also varied among networks. These findings warrant further assessment of the representativeness of the study populations, organization of perinatal services, national guidelines, philosophy of care at extreme GAs, and resources used for decision-making.