Are antenatal steroids beneficial to severely growth restricted fetuses?

Antenatal corticosteroids in specific groups at risk of preterm birth: a systematic review

OBJECTIVE

This study aimed to synthesise available evidence on the efficacy of antenatal corticosteroid (ACS) therapy among women at risk of imminent preterm birth with pregestational/gestational diabetes, chorioamnionitis or fetal growth restriction (FGR), or planned caesarean section (CS) in the late preterm period.

METHODS

A systematic search of MEDLINE, EMBASE, CINAHL, Cochrane Library, Web of Science and Global Index Medicus was conducted for all comparative randomised or non-randomised interventional studies in the four subpopulations on 6 June 2021. Risk of Bias Assessment tool for Non-randomised Studies and the Cochrane Risk of Bias tool were used to assess the risk of bias. Grading of Recommendations Assessment, Development and Evaluations tool assessed the certainty of evidence.

RESULTS

Thirty-two studies involving 5018 pregnant women and 10 819 neonates were included. Data on women with diabetes were limited, and evidence on women undergoing planned CS was inconclusive. ACS use was associated with possibly reduced odds of neonatal death (pooled OR: 0.51; 95% CI: 0.31 to 0.85, low certainty), intraventricular haemorrhage (pooled OR: 0.41; 95% CI: 0.23 to 0.72, low certainty) and respiratory distress syndrome (pooled OR: 0.59; 95% CI: 0.45 to 0.77, low certainty) in women with chorioamnionitis. Among women with FGR, the rates of surfactant use (pooled OR: 0.38; 95% CI: 0.23 to 0.62, moderate certainty), mechanical ventilation (pooled OR: 0.42; 95% CI: 0.26 to 0.66, moderate certainty) and oxygen therapy (pooled OR: 0.48; 95% CI: 0.30 to 0.77, moderate certainty) were probably reduced; however, the rate of hypoglycaemia probably increased (pooled OR: 2.06; 95% CI: 1.27 to 3.32, moderate certainty).

CONCLUSIONS

There is a paucity of evidence on ACS for women who have diabetes. ACS therapy may have benefits in women with chorioamnionitis and is probably beneficial in FGR. There is limited direct trial evidence on ACS efficacy in women undergoing planned CS in the late preterm period, though the totality of evidence suggests it is probably beneficial.

PROSPERO REGISTRATION NUMBER

CRD42021267816.

Dose completion of antenatal corticosteroids and neonatal outcomes in non-small-for-gestational age or small-for-gestational age very-low-birthweight infants: A Korean population-based cohort study

BACKGROUND

The protective effect of antenatal corticosteroids (ACS) in preterm infants has been well established but it remains unclear in growth-restricted fetuses. Furthermore, a substantial number of pregnant women receive only incomplete ACS treatment because of late presentation or imminent delivery at arrival to the delivery site. How this affects neonatal outcomes in small for gestational age (SGA) infants is not rigorously described. We evaluated the influence of ACS completion on in-hospital neonatal outcomes in very low birthweight (VLBW) infants, depending on appropriately or inappropriately grown singletons.

METHODS

Electronic data were retrieved from the Korean Neonatal Network database between 2013 and 2017. We assessed perinatal and neonatal characteristics and neonatal mortality and morbidities. Multivariable logistic regression analyses were performed to evaluate neonatal outcome variables influenced by an incomplete as compared to a complete course of ACS in non-SGA and SGA infants.

RESULTS

In total, 4441 VLBW infants were included in the study. Complete ACS treatment significantly reduced the risk for death before 28 days of life [odds ratio (OR) = 0.525, 95% confidence interval (CI) = 0.414-0.666], death before neonatal intensive care unit discharge (OR = 0.606, 95% CI = 0.489-0.750), respiratory distress syndrome (OR = 0.634, 95% CI = 0.507-0.793), severe intraventricular hemorrhage (OR = 0.539, 95% CI = 0.424-0.684)], and necrotizing enterocolitis (OR = 0.720, 95% CI = 0.561-0.924) in non-SGA infants. ACS completion did not change the risk for neonatal outcomes in SGA infants.

CONCLUSIONS

This study suggests that a complete course of ACS has a favorable effect on several neonatal outcomes in non-SGA VLBW infants. There were no significant differences between the complete exposure and incomplete exposure group in SGA infants.

Sex differences in modulation of fetoplacental vascular resistance in growth-restricted mouse fetuses following betamethasone administration: comparisons with human fetuses

BACKGROUND

Maternally administered corticosteroids are routinely used to accelerate fetal lung maturation in pregnancies at risk of early preterm delivery. Although, among the subgroup with growth restriction, a majority show a temporary improvement in umbilical artery Doppler waveforms that may be sustained up to 7 days, a minority will acutely decompensate in response to corticosteroids in association with deteriorating umbilical and fetal Doppler waveforms. The basis for such acute Doppler changes is presently unknown. Our group has developed a noninvasive ultrasound methodology to measure wave reflections in the umbilical artery and have established that wave reflection metrics are sensitive to structural changes in the placental vasculature and to acute changes in vascular tone. Using this approach, we demonstrated in healthy pregnant mice that fetoplacental vascular resistance decreased in betamethasone-treated mice compared with saline-treated controls.

OBJECTIVE

This study aimed to investigate the effects of betamethasone administration on the wave reflection metrics in a mouse model of fetal growth restriction and to compare these findings with equivalent measurements in human fetuses.

STUDY DESIGN

Pregnant CD-1 mice were housed from embryonic day 14.5 to embryonic day 17.5 in either a normoxic (21% O₂, n=24) or hypoxic environment (11% O₂, n=22), the latter being an established mouse model of fetal growth restriction. To investigate the effect of maternally administered betamethasone on the fetoplacental vasculature, ultrasound imaging was performed at baseline and 4 hours after treatment (either betamethasone or sterile saline). Umbilical artery wave reflection metrics were compared between the groups and for the effect of fetal sex. In addition, a cohort of 10 pregnant women with elevated umbilical artery pulsatility index and evidence of fetal growth restriction and 6 controls were imaged before and after corticosteroid administration.

RESULTS

In the mouse model, after betamethasone administration, the female fetuses from the hypoxia group showed a 15% increase in umbilical artery diameter, a 98% increase in umbilical artery blood flow, and a 27% decrease in umbilical artery reflection coefficient, whereas the males from the hypoxia group showed no substantial changes. In agreement with our mouse findings, umbilical artery reflections were found to be larger in human growth-restricted fetuses than controls in women at risk of preterm birth.

CONCLUSION

Our studies provide insight into the mechanism whereby the human growth-restricted fetus may exhibit a temporary favorable fetoplacental vascular response to maternally administered corticosteroids. Further investigations are needed to understand why the male growth-restricted fetus seems unable to mount this favorable vascular response.

Antenatal corticosteroids in preterm small-for-gestational age infants: a systematic review and meta-analysis

OBJECTIVE

This study aimed to estimate the effect of antenatal corticosteroid administration on neonatal mortality and morbidity in preterm small-for-gestational age infants through a systematic review and meta-analysis.

DATA SOURCES

A predefined, systematic search was conducted through Ovid MEDLINE, Embase, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trial Registry Platform, and ClinicalTrials.gov yielding 5324 articles from 1970 to 2019.

STUDY ELIGIBILITY CRITERIA

Eligible studies compared neonatal morbidity and mortality among small-for-gestational age infants delivered preterm who received antenatal corticosteroids with those who did not.

METHODS

The primary outcome was neonatal mortality. Secondary outcomes were respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage and periventricular leukomalacia, bronchopulmonary dysplasia or chronic lung disease of prematurity, or neonatal sepsis. We assessed heterogeneity by means of Higgins I² statistic and Cochran's Q test and calculated pooled odds ratios with 95% confidence intervals using random effects models.

RESULTS

A total of 16 observational cohort and case-control studies published from 1995 to 2018 met the selection criteria for the systematic review and included 8989 preterm small-for-gestational age infants. Antenatal corticosteroid administration was explicitly reported among 8376 small-for-gestational age infants; 4631 (55.3%) received antenatal corticosteroids and 3741 (44.7%) did not. Of note, 13 studies including 6387 preterm small-for-gestational age infants were then included in the meta-analysis. Neonatal mortality was significantly lower among infants who received antenatal corticosteroids than those who did not (12 studies: 12.8% vs 15.1%; pooled odds ratio, 0.63; 95% confidence interval, 0.46-0.86), with significant heterogeneity between studies (I²=55.1%; P=.011). There was no significant difference in respiratory distress syndrome (12 studies: odds ratio, 0.89; 95% confidence interval, 0.69-1.15), necrotizing enterocolitis (7 studies: odds ratio, 0.93; 95% confidence interval, 0.70-1.22), intraventricular hemorrhage and periventricular leukomalacia (10 studies: odds ratio, 0.82; 95% confidence interval, 0.56-1.20), bronchopulmonary dysplasia or chronic lung disease of prematurity (8 studies: odds ratio, 1.11; 95% confidence interval, 0.88-1.41), or neonatal sepsis (6 studies: odds ratio, 1.13; 95% confidence interval, 0.86-1.49).

CONCLUSION

These data indicate that antenatal corticosteroid administration reduces neonatal mortality in small-for-gestational age infants delivered preterm, with no apparent effect on neonatal morbidity. This supports the use of antenatal corticosteroids to reduce neonatal mortality in pregnancies with small-for-gestational age infants at risk of preterm birth.

The effect of antenatal corticosteroids on small-for-gestational age preterm neonates

Objective: Treatment of preterm small-for-gestational age (SGA) neonates with antenatal corticosteroids (ACS) is not entirely straightforward. We sought to examine the effect of a full course of ACS on outcomes of SGA and non-SGA preterm singletons.Patients and methods: We compared maternal characteristics and outcomes of preterm births at <28 and 28 + 0-33 + 0 weeks' gestation that received a complete course of ACS within a week before birth. We further divided our cohort into those with or without a SGA neonate.Results: We included 290 infants: 73 (25.2%) and 217 (74.8%) born at <28 and 28 + 0-33 + 0 weeks' gestation, respectively. Analysis of maternal characteristics showed a strong association of maternal body mass index (p = .01), along with smoking during pregnancy (OR 0.4, 95% CI 0.2, 0.9), with being SGA. Spontaneous onset of delivery more commonly occurred in non-SGA preterm neonates, whereas iatrogenic induction of labor prevailed with SGA neonates (p < .01). There was no significant difference between SGA and non-SGA infants in all the tested neonatal variables except for necrotizing enterocolitis, which prevailed in the SGA group.Conclusion: A full course of ACS appears to have the same effect in SGA and non-SGA preterm singletons in our studied cohort on all neonatal outcomes but for necrotizing enterocolitis, where its role in SGA preterm neonates seems to be detrimental rather than beneficial to the fetus.

Antenatal glucocorticoids, magnesium sulfate, and mode of birth in preterm fetal small for gestational age

A diagnosis of fetal growth restriction and subsequent preterm birth is associated with increased risks of adverse perinatal and neurodevelopmental outcomes and potentially long-lasting effects to adulthood. Most such cases are associated with placental insufficiency and the fetal response to chronic intrauterine hypoxemia and nutrient deprivation leads to substantial physiological and metabolic adaptations. The management of such pregnancies, especially with respect to perinatal interventions and birth mode, remains an unresolved dilemma. The benefits from standard interventions for threatened preterm birth may not be necessarily translated to pregnancies with small-for-gestational-age fetuses. Clinical trials or retrospective studies on outcomes following administration of antenatal glucocorticoids and magnesium sulfate for neuroprotection when preterm birth is imminent either have yielded conflicting results for small-for-gestational-age fetuses, or did not include this subgroup of patients. Experimental models highlight potential harmful effects of administration of antenatal glucocorticoids and magnesium sulfate in the pregnancies with fetal small for gestational age although clinical data do not substantiate these concerns. In addition, heterogeneity in definitions of fetal small for gestational age, variations in the inclusion criteria, and the glucocorticoid regime contribute to inconsistent results. In this review, we discuss the physiologic adaptions of the small-for-gestational-age fetus to its abnormal in utero environment in relation to antenatal glucocorticoids; the impact of antenatal glucocorticoids and intrapartum magnesium sulfate in pregnancies with fetal small for gestational age; the current literature on birth mode for pregnancies with fetal small for gestational age; and the knowledge gaps in the existing literature.

Efficacy of Antenatal Corticosteroid Treatment on Neurodevelopmental Outcome according to Head Circumference at Birth

BACKGROUND

There are concerns about the efficacy of antenatal corticosteroid treatment (ACT) in the growth-restricted fetus.

OBJECTIVE

To evaluate the effect of ACT on neurodevelopmental outcome at 2 years of corrected age according to the z score of birth head circumference (ZS HC) in a large prospective cohort of preterm infants.

METHODS

This study was conducted as a population-based, prospective, multicenter study, including 4,965 infants born between 24 and 33 weeks' gestation and whose status regarding ACT and the measurement of head circumference at birth were available. They were evaluated at 2 years of corrected age to assess neurological outcome. Three approaches were considered to estimate the effect of ACT on neurodevelopment: (i) logistic regression with adjustment on propensity score, (ii) weighted logistic regression using the inverse probability of treatment weighting method, and (iii) 1:1 matching of gestational age, ZS HC, and propensity score between treated and nontreated infants.

RESULTS

ACT was documented in 60% of infants. Three groups of infants were considered according to their ZS HC: between -3 and -1 standard deviation (SD), -1 and +1 SD, and +1 and +3 SD, respectively. ACT was associated with a significant improvement of neurodevelopmental outcome only for infants with an ZS HC of between +1 and +3 SD (adjusted OR 1.72; 95% CI 1.06-2.79). Moreover, ORs estimated in the -3 to -1 and +1 to +3 categories were significantly different.

CONCLUSION

We found beneficial effects of ACT on neurodevelopmental outcomes at 2 years of corrected age only in preterm infants with a ZS HC >1 SD.

Antenatal Corticosteroids and Outcomes of Small-for-Gestational-Age Neonates

OBJECTIVE

To assess the association of antenatal corticosteroids and neonatal outcomes of preterm small-for-gestational-age (SGA) neonates and estimate whether the association is similar to that observed in appropriate-for-gestational-age (AGA) neonates.

METHODS

We conducted a retrospective cohort study using data collected on singleton neonates born between 24 0/7 and 33 6/7 weeks of gestation and admitted to tertiary neonatal units in Canada between 2010 and 2014. Outcomes of SGA neonates (birth weight less than the 10th percentile) who received antenatal corticosteroids 1-7 days before birth (n=698) were compared with those of SGA neonates who did not receive antenatal corticosteroids (n=220). A similar comparison was performed between AGA neonates (birth weight between 10th and 90th percentile) who received antenatal corticosteroids 1-7 days before birth (n=3,781) and AGA neonates that did not receive antenatal corticosteroids (n=1,868). The association of antenatal corticosteroid exposure with outcomes was assessed using multivariable logistic regression and adjusted odds ratios (ORs) were compared between SGA and AGA groups.

RESULTS

Of the 6,567 neonates eligible for the study, 918 (14.0%) were SGA. Women in the SGA group who were exposed to antenatal corticosteroids had a lower rate of neonatal death (7% compared with 12%, P=.01) compared with those not exposed to antenatal corticosteroids, whereas the rate of composite outcome was similar between the two groups (28% compared with 30%, P=.56). After adjustment for potential confounders, exposure to antenatal corticosteroids 1-7 days before birth was associated with beneficial effects among both the SGA and AGA groups with similar reduced odds of neonatal death (SGA: adjusted OR 0.29 [95% confidence interval (CI) 0.15-0.57] compared with AGA: adjusted OR 0.40 [95% CI 0.29-0.54], P=.40), composite outcome (SGA: adjusted OR 0.53 [95% CI 0.33-0.87] compared with AGA: adjusted OR 0.51 [95% CI 0.42-0.62], P=.85), need for mechanical ventilation (SGA: adjusted OR 0.60 [95% CI 0.39-0.91] compared with AGA: adjusted OR 0.54 [95% CI 0.46-0.64], P=.70), and severe brain injury (SGA: adjusted OR 0.42 [95% CI 0.22-0.84] compared with AGA: adjusted OR 0.39 [95% CI 0.30-0.51], P=.80). Similar reduction in the odds of neonatal death was observed in the subgroup of neonates with birth weight less than the fifth percentile for gestational age and sex: adjusted OR 0.38 (95% CI 0.16-0.92).

CONCLUSION

For SGA preterm neonates, exposure to antenatal corticosteroids 1-7 days before birth was associated with decreased odds of neonatal mortality and morbidity similar in magnitude to that observed among AGA neonates.

The role of antenatal corticosteroids in twin pregnancies complicated by preterm birth

BACKGROUND

Data regarding the effects of antenatal corticosteroids in twin pregnancies are limited because of the insufficient number of women with twins enrolled in randomized controlled trials on antenatal corticosteroids. Furthermore, the interpretation of available data is limited by the fact that the interval from the administration of antenatal corticosteroids to delivery is greater than 7 days in a large proportion of twins, a factor that has been shown to affect the efficacy of antenatal corticosteroids and has not been controlled for in previous studies.

OBJECTIVE

The objective of the study was to compare neonatal mortality and morbidity in preterm twins receiving a complete course of antenatal corticosteroids 1-7 days before birth to those who did not receive antenatal corticosteroids and to compare these outcome effects with those observed in singletons.

STUDY DESIGN

We performed a retrospective cohort study using data collected on singleton and twin neonates born between 24(0/7) and 33(6/7) weeks' gestational age and were admitted to tertiary neonatal units in Canada between 2010 and 2014. A comparison of neonatal outcomes between twin neonates who received a complete course of antenatal corticosteroids 1-7 days before birth (n = 1758) and those who did not receive antenatal corticosteroids (n = 758) and between singleton neonates who received a complete course of antenatal corticosteroids 1-7 days before birth (n = 4638) and those did not receive antenatal corticosteroids (n = 2312) was conducted after adjusting for gestational age, sex, hypertension, outborn status, small for gestational age, parity, and cesarean birth. Adjusted odds ratios and 95% confidence intervals for various neonatal outcomes were calculated.

RESULTS

Administration of a complete course of antenatal corticosteroids within 1-7 days before birth in both twins and singletons was associated with similar reduced odds of neonatal death (for twins adjusted odds ratio 0.42 [95% confidence interval, 0.24-0.76] and for singletons adjusted odds ratios, 0.38 [95% confidence interval, 0.28-0.50]; P = .7 for comparison of twins vs singletons), mechanical ventilation (for twins adjusted odds ratio, 0.47 [95% confidence interval, 0.35-0.63] and for singletons adjusted odds ratio, 0.47 [95% confidence interval, 0.41-0.55]; P = .9), respiratory distress syndrome (for twins adjusted odds ratio, 0.53 [95% confidence interval, 0.40-0.69], and for singletons adjusted odds ratio, 0.54 [95% confidence interval, 0.47-0.62]; P = .9) and severe neurological injury (for twins adjusted odds ratio, 0.50 [95% confidence interval, 0.30-0.83] and for singletons adjusted odds ratio, 0.45 [95% confidence interval, 0.34-0.59]; P = .7). Administration of a complete course of antenatal corticosteroids was not associated with a reduced odds of bronchopulmonary dysplasia, severe retinopathy of prematurity, or necrotizing enterocolitis in both twins and singletons.

CONCLUSION

Administration of a complete course of antenatal corticosteroids 1-7 days before birth in twin pregnancies is associated with a clinically significant decrease in neonatal mortality, short-term respiratory morbidity, and severe neurological injury that is similar in magnitude to that observed among singletons.

Review of the antenatal and postnatal use of steroids

Antenatal and postnatal corticosteroids play an extremely important role in the management of premature infants. The antenatal administration of steroids has been universally implemented. They have not only been shown to reduce the incidence and severity of respiratory distress syndrome (RDS), but also have an impact on the incidence of intraventricular hemorrhage (IVH), patent ductus arteriosus (PDA), necrotizing enterocolitis (NEC), and possibly retinopathy of prematurity (ROP) by reducing the need for supplemental oxygen due to improved lung function. The postnatal use of dexamethasone in ventilated infants has been adopted with caution, as there have been several reports of long-term neurodevelopmental complications with this therapy. Hence, changes in dosage and indications and the search for alternative therapies has emerged. Hydrocortisone appears to be a good alternative, with reassuring long-term evaluations thus far.