Impact of antenatal corticosteroid therapy in very low birth weight infants on chronic lung disease and other morbidities of prematurity

Retrospective Analysis of Neonatal Surgery at Tottori University over the Past Ten Years

Background

In recent years, the number of neonatal surgeries has been on the rise despite the decline in the number of births, and we examined the actual trends and problems at Tottori University Hospital located in the Sanin region.

Methods

Medical records were retrospectively searched for patients who underwent major surgery during the neonatal period (within 30 days of age) at the Tottori University Hospital over the past 10 years (Jan. 2011 to Dec. 2020).

Results

Sixty-five cases were included. Early birth infants (< 37 gestational weeks) comprised 15 cases (23%) and low birth weight (< 2500 g) infants involved 27 cases (42%). In the latter half (2016-2020), early birth and low birth weight infants were significantly less than in the first half (2011-2015). The common diseases were anorectal malformation (14 cases), esophageal atresia (10), duodenal atresia (10), and diaphragmatic hernia (9). Prenatal diagnosis was obtained in 26 cases (40%), with high diagnostic rate obtained in duodenal atresia (100%), abdominal wall defect (100%), ileal atresia (75%), meconium peritonitis (67%), and diaphragmatic hernia (67%). Fifty-five cases (85%) were operated on within 7 days of age. Other major malformations were associated in 23 cases (35%). There were 6 deaths (9%), of which 3 cases were low birth weight infants with gastrointestinal perforation, 2 cases with severe chromosomal abnormalities (esophageal atresia, omphalocele), and 1 case with diaphragmatic hernia with severe pulmonary hypertension. Home medical care has been required with gastrostomy tube in 2 cases.

Conclusion

Neonatal surgery at Tottori University has been well performed as required with acceptable results along with the progression of other perinatal care. However, further investigation for improvements in premature delivery or organ hypoplasia may be required.

Beyond Fetal Immunity: A Systematic Review and Meta-Analysis of the Association Between Antenatal Corticosteroids and Retinopathy of Prematurity

Background: Retinopathy of prematurity (ROP) is a major cause of childhood blindness. Antenatal corticosteroids (ACS) exposure is known to ameliorate the risk of and mortality of neonatal morbidities. However, the effect of ACS on ROP development is currently unknown. We conducted a meta-analysis with up-to-date evidence to assess the association between ACS exposure and the development of ROP in at-risk preterm infants.

Methods: PubMed, EMBASE, Scopus, Web of Science, and the Cochrane Library were systematically searched from inception to May 2021, supplemented with manual search from reference lists. Studies with a control group reporting ROP rate in ACS-exposed infants were included. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated utilizing a random-effects model. The Newcastle-Ottawa Scale was used for assessment of risk of bias in the included studies. Meta-regressions were performed to explore the predictive role of confounders for between-study variance.

Results: A total of 63 studies, involving 196,264 infants, were included. Meta-analysis showed ACS exposure was not associated with ROP occurrence (uOR 0.92, 95% CI 0.80–1.07; aOR 0.87, 95% CI 0.7–1.08). Results from extremely immature subgroups revealed significant reduced risks of ROP occurrence in ACS-exposed infants. ACS exposure was associated with significantly lower odds of ROP progression in adjusted analysis (aOR 0.48, 95% CI 0.26–0.89) instead of unadjusted analysis (uOR 0.86, 95% CI 0.68–1.08). Meta-regression showed birth weight and patent ductus arteriosus of the cohort were associated with ROP occurrence, sample size and study design strongly associated with ROP progression in ACS-exposed infants.

Conclusion: ACS treatment may decrease, but not prevent, the severity of ROP. Findings from severe ROP should be interpreted with caution owing to limited studies and the possibility of false-positive results. Considering the particular benefits in extremely immature infants, we recommend routine usage of ACS in mothers with threatened delivery to this particular birth cohort to prevent ROP occurrence. Future studies adjusting for major confounders are warranted to mitigate risk of bias in such observational evidence.

Maternal Asthma, Preterm Birth, and Risk of Bronchopulmonary Dysplasia

OBJECTIVE

To study the relationship between maternal asthma and the development of bronchopulmonary dysplasia (BPD).

STUDY DESIGN

Using a large population-based California cohort, we investigated associations between maternal asthma and preterm birth subtype, as well as maternal asthma and BPD. We used data from 2007-2010 maternal delivery discharge records of 2 009 511 pregnancies and International Classification of Diseases, Ninth Revision codes. Preterm birth was defined as <37 weeks gestational age (GA), with subgroups of <28 weeks, 28-32 weeks, and 33-37 weeks GA, as well as preterm subtype, defined as spontaneous, medically indicated, or unknown. Linkage between the 2 California-wide datasets yielded 21 944 singleton preterm infants linked to their mother's records, allowing estimation of the risk of BPD in mothers with asthma and those without asthma.

RESULTS

Maternal asthma was associated with increased odds (OR, 1.42; 95% CI, 1.38-1.46) of preterm birth at <37 weeks GA, with the greatest risk for 28-32 GA (aOR, 1.60; 95% CI, 1.47-1.74). Among 21 944 preterm infants, we did not observe an elevated risk for BPD in infants born to mothers with asthma (aOR, 1.03; 95% CI, 0.9-1.2). Stratification by maternal treatment with antenatal steroids revealed increased odds of BPD in infants whose mothers had asthma but did not receive antenatal steroids (aOR, 1.54; 95% CI, 1.15-2.06), but not in infants whose mothers had asthma and were treated with antenatal steroids (aOR, 0.85; 95% CI, 0.67-1.07).

CONCLUSION

Asthma in mothers who did not receive antenatal steroid treatment is associated with an increased risk of BPD in their preterm infants.

Neurodevelopmental outcomes of extremely low birth weight infants exposed prenatally to dexamethasone versus betamethasone

OBJECTIVE

We compared the development of adverse neurodevelopmental outcomes at corrected ages of 18 to 22 months for extremely low birth weight infants exposed prenatally to dexamethasone, betamethasone, or no steroid.

METHODS

Study infants were extremely low birth weight (401-1000 g) infants who were in the care of National Institute of Child Health and Human Development Neonatal Research Network centers between January 1, 2002, and April 30, 2003; they were assessed neurodevelopmentally at corrected ages of 18 to 22 months. Outcomes were defined as Bayley Scales of Infant Development-II Mental Development Index of < 70, Bayley Scales of Infant Development-II Psychomotor Development Index of < 70, bilateral blindness, bilateral hearing aid use, cerebral palsy, and neurodevelopmental impairment. Neurodevelopmental impairment was defined as > or = 1 of the aforementioned outcomes.

RESULTS

A total of 1124 infants met entry criteria. There were no statistically significant associations between prenatal dexamethasone exposure and any follow-up outcome, compared with no prenatal steroid exposure. Prenatal betamethasone exposure was associated with reduced risks of hearing impairment and neurodevelopmental impairment and with increased likelihood of unimpaired status, compared with no prenatal steroid exposure. Compared with betamethasone, dexamethasone was associated with a trend for increased risk of Psychomotor Development Index of < 70, increased risk of hearing impairment, and decreased likelihood of unimpaired status.

CONCLUSIONS

Prenatal betamethasone exposure was associated with increased likelihood of unimpaired neurodevelopmental status and reduced risk of hearing impairment at corrected ages of 18 to 22 months among extremely low birth weight infants, compared with prenatal dexamethasone exposure or no prenatal steroid exposure. Pending a randomized, clinical trial, it may be in the best interests of infants to receive betamethasone, rather than dexamethasone, when possible.

Antenatal steroids and risk of bronchopulmonary dysplasia: a lack of effect or a case of over-adjustment?

Although antenatal steroids reduce risk factors for bronchopulmonary dysplasia (BPD) in preterm infants, their effect on BPD is conflicting. We hypothesised that the lack of protective effect found in some studies could derive from over-adjustment during analysis, caused by controlling for factors intermediate in the causal pathway between treatment and outcome. We prospectively studied a cohort of infants 23-32 weeks gestation <1500 g, admitted to 10 tertiary-level neonatal units in Lombardy (Italy) in 1999-2002; 1118 neonates out of 1314 survived to 36 weeks; 15.9% developed BPD (oxygen requirement at 36 weeks); 82% were treated with steroids. In univariable analysis, steroids were not significantly protective against BPD; some intermediate factors (mechanical ventilation, greater severity of illness as measured by Clinical Risk Index for Babies score, patent ductus arteriosus) were significantly positively associated with (i.e. were risk factors for) BPD (OR = 11.0, 1.55, 4.42, respectively, all P < 0.001), and negatively associated with (i.e. prevented by) steroids (OR = 0.58, 0.92, and 0.58, respectively, all P < 0.01). In multiple logistic regression models using propensity scores, without the above-mentioned intermediate risk factors, steroid-treated infants had a lower risk of BPD (OR 0.59 [95% CI 0.36, 0.97], P = 0.036); male sex (OR = 2.08), late-onset sepsis (OR = 4.26), and birthweight (OR = 0.63 for 100 g increase) were also associated with BPD, all P < 0.001. When intermediate risk factors for BPD were also added to the model, the effect of steroids disappeared; ventilation (OR = 3.03), increased illness severity (OR = 1.11), and patent ductus arteriosus (OR = 1.90) were significant risk factors. This study suggests that including variables that are potential mediators in the causal chain can obscure the ability to detect a protective effect of treatment. We observed such a phenomenon in our analyses of the relationship between antenatal steroids and BPD, suggesting that steroid effect is partly mediated through a reduction in the classical risk factors.

Evidence-based review of retinopathy of prematurity prevention in VLBW and ELBW infants

Retinopathy of prematurity (ROP) continues to be a significant complication in preterm neonates despite advances in neonatal care. Very low birth weight and extremely low birth weight infants continue to suffer from the sequelae of premature birth, including ROP. Controversy and uncertainty surround prevention of ROP. Possible preventive strategies include the use or restriction of oxygen therapy; steroid therapy; changes in blood transfusion protocols; reduced exposure of the retina to light; and administration of nutritional factors, indomethacin, and D-penicillamine. This article reviews recent studies that have proved or disproved the effectiveness of these preventive measures. It also identifies the implications of the study results for clinical practice and makes recommendations for future research.

Adverse neonatal outcomes associated with antenatal dexamethasone versus antenatal betamethasone

OBJECTIVE

Antenatal dexamethasone and betamethasone may not be equally efficacious in the prevention of adverse neonatal outcomes. We compared the risks of periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP), and neonatal death among very low birth weight infants who were exposed to dexamethasone, betamethasone, or neither steroid.

METHODS

Infants (401-1500 g) in the National Institute of Child Health and Human Development Neonatal Research Network were studied. Multivariate logistic regression analyses compared the 3 groups with regard to PVL, IVH, ROP, and neonatal death, adjusting for network center and selected covariates.

RESULTS

A total of 3600 infants met entry criteria. Compared with no antenatal steroids, there were trends for a reduced risk for PVL associated with dexamethasone and betamethasone but no difference in risk between dexamethasone and betamethasone. Dexamethasone reduced the risk for IVH and severe IVH, compared with no antenatal steroid exposure. Betamethasone reduced the risk for IVH, severe IVH, and neonatal death, compared with no antenatal steroids. Compared with betamethasone, dexamethasone had a statistically significant increased risk for neonatal death. There were trends for greater risks associated with dexamethasone compared with betamethasone for IVH and severe ROP.

CONCLUSIONS

Betamethasone was associated with a reduced risk for neonatal death, with trends of decreased risk for other adverse neonatal outcomes, compared with dexamethasone. It may be in the best interest of neonates to receive betamethasone rather than dexamethasone when available.

Population-based study of bronchopulmonary dysplasia in very low birth weight infants in Switzerland

In Switzerland, data are collected prospectively by collaborators from all nine neonatal intensive care units and their affiliated paediatric units caring for neonates, to determine survival and (pulmonary) outcome of infants with birth weights ranging from 501 to 1500 g. To assess the pulmonary outcome of very low birth weight (VLBW) infants in Switzerland in 1996 and 2000, factors associated with bronchopulmonary dysplasia (BPD) were identified and compared with pulmonary outcomes from the Vermont Oxford Network data. BPD was defined as a requirement for supplemental oxygen at 36 weeks postmenstrual age. Complete data were available for 600 and 636 VLBW infants in 1996 and in 2000, respectively. Mortality rates in Switzerland were significantly higher (1996: 19.2%, 2000: 20.8%) than in the Vermont Oxford Network (1996: 14%, 2000: 14%). Expressed as percentage of infants still hospitalised at 36 weeks postmenstrual age, 16.7% and 13.2% of Swiss VLBW infants were diagnosed with BPD in 1996 and 2000, respectively. These rates were significantly lower than in the Vermont Oxford Network (1996: 28%, 2000: 35%). Infants exposed to factors previously shown to be associated with BPD were investigated: in Switzerland, infants with a history of surfactant replacement therapy and/or mechanical ventilation had a significantly higher rate of BPD in both cohorts. Infants with postnatal transport, sepsis proven by positive blood culture and patent ductus arteriosus had a higher BPD rate only in the 1996 cohort. Between 1996 and 2000, mortality rates and incidence of BPD in VLBW infants remained unchanged in Switzerland. BPD rates in Switzerland are lower than those found in the Vermont Oxford Network whereas a mortality rate comparison displays an inverted picture. We suspect that these effects are interrelated and may be due in part to a selective approach of Swiss neonatologists to resuscitation of infants in the smallest birth weight stratum.

CONCLUSION

The factors listed above have apparently become less important in the context of bronchopulmonary dysplasia and other influences, including prenatal conditions, will need to be investigated.

Clinical microbiology of bacterial and fungal sepsis in very-low-birth-weight infants

Twenty percent of very-low-birth-weight (<1500 g) preterm infants experience a serious systemic infection, and despite advances in neonatal intensive care and antimicrobials, mortality is as much as threefold higher for these infants who develop sepsis than their counterparts without sepsis during their hospitalization. Outcomes may be improved by preventative strategies, earlier and accurate diagnosis, and adjunct therapies to combat infection and protect the vulnerable preterm infant during an infection. Earlier diagnosis on the basis of factors such as abnormal heart rate characteristics may offer the ability to initiate treatment prior to the onset of clinical symptoms. Molecular and adjunctive diagnostics may also aid in diagnosing invasive infection when clinical symptoms indicate infection but no organisms are isolated in culture. Due to the high morbidity and mortality, preventative and adjunctive therapies are needed. Prophylaxis has been effective in preventing early-onset group B streptococcal sepsis and late-onset Candida sepsis. Future research in prophylaxis using active and passive immunization strategies offers prevention without the risk of resistance to antimicrobials. Identification of the differences in neonatal intensive care units with low and high infection rates and implementation of infection control measures remain paramount in each neonatal intensive care unit caring for preterm infants.

[Bronchopulmonary dysplasia and corticosteroid therapy]

Inflammation plays a major role in the pathogenesis of bronchopulmonary dysplasia of preterm infants. Having a strong anti-inflammatory effect, corticosteroids have been proposed in the management of this disease. Antenatal steroids protect the newborn against its development. Postnatal systemic administration of steroids reduces the duration of mechanical ventilation and oxygen therapy, but is associated with short term and long term adverse effects. Early administration of dexamethasone (before 7 days of life) reduces the incidence and the severity of chronic lung disease at 28 days of life and 36 weeks of post-conceptional age. Inhaled steroids are associated with less adverse effects than dexamethasone administration, but they are also less effective.

Perinatal glucocorticoid therapy and neurodevelopmental outcome: an epidemiologic perspective

A relatively brief course of antenatal glucocorticoids (ACS), given to reduce the severity of respiratory distress syndrome in preterm infants, improves survival and appears to protect against brain damage. In clinical trials as well as observational studies, ACS have been associated with a decreased risk of intraventricular haemorrhage and cerebral palsy. In observational studies a decreased risk of white-matter damage, identified with cranial ultrasound, has been observed. There is some evidence, from observational studies, that repeated courses of ACS (typically given at weekly intervals) can reduce the rate of fetal head growth, and experiments in animals provide further support for this possibility. In contrast to the effects of a brief course of ACS, postnatal glucocorticoids (PCS), given to preterm infants to reduce the severity of chronic lung disease have been associated with an increased risk of neurologic impairment. Available evidence suggests that PCS does not improve survival. Further study is needed of the neurodevelopmental consequences of both multiple courses of ACS, as well as PCS.