Antenatal corticosteroids and neurodevelopmental outcomes in late preterm births

Impact of corticosteroid exposure on preterm labor in neonates eventually born at term

OBJECTIVE

To evaluate the impact of antenatal corticosteroid therapy (ACS) on birth outcomes in term infants exposed during pregnancy.

STUDY DESIGN

Exposed newborns were compared with non-exposed controls in a 1 to 2 design. Multivariate analysis was used to assess the effect of ACS exposure on neonatal outcomes.

RESULT

408 newborns were included (136 exposed to ACS, 272 non-exposed). Mean ± SD head circumference (HC) was 33.7 ± 1.4 vs 34.3 ± 1.6 cm, p = 0.001 in exposed vs controls; birth weight was 3.1 ± 0.4 vs 3.3 ± 0.4 kg, p = 0.0001; and birth height was 47.9 ± 2.1 vs. 49.1 ± 2.0 cm, p < 0.0001. Hypocalcemia (4.4 vs 0.7%, p = 0.019) and feeding difficulties (5.1 vs 1.5%, p = 0.047) were significantly more common in exposed newborns. Multivariate analysis for HC showed a significant independent association with ACS exposure (β = -0.5, p = 0.009).

CONCLUSION

Term newborns exposed to ACS have lower birth HC and higher risk of neonatal complications.

CLINICAL TRIAL REGISTRATION

NCT05640596.

The proportions of term or late preterm births after exposure to early antenatal corticosteroids, and outcomes: systematic review and meta-analysis of 1.6 million infants

OBJECTIVE

To systematically review the proportions of infants with early exposure to antenatal corticosteroids but born at term or late preterm, and short term and long term outcomes.

DESIGN

Systematic review and meta-analyses.

DATA SOURCES

Eight databases searched from 1 January 2000 to 1 February 2023, reflecting recent perinatal care, and references of screened articles.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials and population based cohort studies with data on infants with early exposure to antenatal corticosteroids (<34 weeks) but born at term (≥37 weeks), late preterm (34-36 weeks), or term/late preterm combined.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently screened titles, abstracts, and full text articles and assessed risk of bias (Cochrane risk of bias tool for randomised controlled trials and Newcastle-Ottawa scale for population based studies). Reviewers extracted data on populations, exposure to antenatal corticosteroids, and outcomes. The authors analysed randomised and cohort data separately, using random effects meta-analyses.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of infants with early exposure to antenatal corticosteroids but born at term. Secondary outcomes included the proportions of infants born late preterm or term/late preterm combined after early exposure to antenatal corticosteroids and short term and long term outcomes versus non-exposure for the three gestational time points (term, late preterm, term/late preterm combined).

RESULTS

Of 14 799 records, the reviewers screened 8815 non-duplicate titles and abstracts and assessed 713 full text articles. Seven randomised controlled trials and 10 population based cohort studies (1.6 million infants total) were included. In randomised controlled trials and population based data, ∼40% of infants with early exposure to antenatal corticosteroids were born at term (low or very low certainty). Among children born at term, early exposure to antenatal corticosteroids versus no exposure was associated with increased risks of admission to neonatal intensive care (adjusted odds ratio 1.49, 95% confidence interval 1.19 to 1.86, one study, 5330 infants, very low certainty; unadjusted relative risk 1.69, 95% confidence interval 1.51 to 1.89, three studies, 1 176 022 infants, I2=58%, τ2=0.01, low certainty), intubation (unadjusted relative risk 2.59, 1.39 to 4.81, absolute effect 7 more per 1000, 95% confidence interval from 2 more to 16 more, one study, 8076 infants, very low certainty, one study, 8076 infants, very low certainty), reduced head circumference (adjusted mean difference -0.21, 95% confidence interval -0.29 to -0.13, one study, 183 325 infants, low certainty), and any long term neurodevelopmental or behavioural disorder in population based studies (eg, any neurodevelopmental or behavioural disorder in children born at term, adjusted hazard ratio 1.47, 95% confidence interval 1.36 to 1.60, one study, 641 487 children, low certainty).

CONCLUSIONS

About 40% of infants exposed to early antenatal corticosteroids were born at term, with associated adverse short term and long term outcomes (low or very low certainty), highlighting the need for caution when considering antenatal corticosteroids.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022360079.

Technical Update No. 439: Antenatal Corticosteroids at Late Preterm Gestation

OBJECTIVE

To update recommendations for administration of antenatal corticosteroids in the late preterm period.

TARGET POPULATION

Pregnant individuals at risk of preterm birth from 340 to 366 weeks gestation.

OPTIONS

Administration or non-administration of a single course of antenatal corticosteroids at 340 to 366 weeks gestation.

OUTCOMES

Neonatal morbidity (respiratory distress, hypoglycemia), long-term neurodevelopment, and other long-term outcomes (growth, cardiac/metabolic, respiratory).

BENEFITS, HARMS, AND COSTS

Administration of antenatal corticosteroids from 340 to 366 weeks gestation decreases the risk of neonatal respiratory distress but increases the risk of neonatal hypoglycemia. The long-term impacts of antenatal corticosteroid administration from 340 to 366 weeks gestation are uncertain.

EVIDENCE

For evidence on the neonatal effects of antenatal corticosteroid administration at late preterm gestation, we summarized evidence from the 2020 Cochrane review of antenatal corticosteroids and combined this with evidence from published randomized trials identified by searching Ovid MEDLINE from January 1, 2020, to May 11, 2022. Given the absence of direct evidence on the impact of late preterm antenatal corticosteroid administration on neurodevelopmental outcomes, we summarized evidence on the impact of antenatal corticosteroids across gestational ages on neurodevelopmental outcomes using the following sources: (1) the 2020 Cochrane review; and (2) evidence obtained by searching Ovid MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception to January 5, 2022. We did not apply date or language restrictions. Given the absence of direct evidence on the impact of late preterm antenatal corticosteroid administration on other long-term outcomes, we summarized evidence on the impact of antenatal corticosteroids across gestational ages on other long-term outcomes by combining findings from the 2020 Cochrane review with evidence obtained by searching Ovid MEDLINE for observational studies related to long-term cardiometabolic, respiratory, and growth effects of antenatal corticosteroids from inception to October 22, 2021. We reviewed reference lists of included studies and relevant systematic reviews for additional references. See Appendix A for search terms and summaries.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix B (Tables B1 for definitions and B2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

Maternity care providers, including midwives, family physicians, and obstetricians.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Antenatal corticosteroids-to-delivery interval associates cord blood S100B levels

AIM

Antenatal corticosteroids (ACS) are recommended for women at risk of preterm birth before 34 weeks' gestation. However, adverse effects of ACS on the fetal brain have also been reported. The time interval from ACS administration to delivery (ACS-to-delivery interval) might alter the effect of ACS on the fetal brain. This study aimed to evaluate the effect of ACS-to-delivery interval on cord blood S100 calcium-binding protein B (S100B) levels as a biomarker of brain damage.

METHODS

Women who delivered between 2012 and 2020 at a tertiary medical center were divided into three groups according to ACS use and ACS-to-delivery interval, retrospectively: non-ACS, ACS ≤7 days, and ACS >7 days. Patients who did not complete the ACS regimen were excluded. The primary outcome was cord blood S100B levels.

RESULTS

Cord blood S100B levels were significantly lower in the ACS ≤7 days group than in the non-ACS and ACS >7 days groups. In the multiple regression analysis, birth ≤7 days after ACS showed a significant negative association with S100B level (p < 0.001).

CONCLUSIONS

Reduced S100B levels were observed in infants born ≤7 days after ACS but not in infants born >7 days after ACS. These findings suggest the importance of ACS timing to optimize its effects on the fetal brain, although further studies are required to identify these mechanisms.

Antenatal Corticosteroid Exposure is Associated with Childhood Mental Disorders in Late Preterm and Term Infants

OBJECTIVES

To study the association between antenatal corticosteroids treatment and childhood mental disorders in infants born at different gestational ages, and to investigate the effect of different administration timing.

STUDY DESIGN

This population-based cohort study used data from the Taiwan National Health Insurance Research Database. All singleton live births born between 2004 and 2010 were enrolled and followed up for at least 6 years. The primary outcome was any childhood mental disorder. Secondary outcomes included 7 specific subgroups of mental disorders.

RESULTS

A total of 1 163 443 singleton infants were included in the analysis, and 16 847 (1.45%) infants were exposed to antenatal corticosteroid treatment. Children exposed to antenatal corticosteroids were found to have a higher risk of developing childhood mental disorders in the entire cohort (hazard ratio [HR], 1.13; 95% CI, 1.08-1.18), the term group (HR, 1.11; 95% CI, 1.05-1.16), and the late-preterm group (HR, 1.15; 95% CI, 1.06-1.25). The administration of corticosteroids in the early stage of pregnancy (<28 weeks of gestation) significantly increased the risk of childhood mental disorders (HR, 1.22; 95% CI, 1.14-1.31).

CONCLUSIONS

Exposure to antenatal corticosteroid treatment increases the cumulative risk of childhood mental disorders and attention deficit hyperactivity disorders, both in term and late preterm infants. The administration of corticosteroids in the early stage of pregnancy tends to increase the risk of mental disorders.

Evaluation of Long-term Outcomes Associated With Preterm Exposure to Antenatal Corticosteroids: A Systematic Review and Meta-analysis

IMPORTANCE

Animal studies have found that antenatal corticosteroids affect many organs across multiple stages of life. However, the long-term outcomes in human children are not well understood.

OBJECTIVE

To conduct a systematic review and meta-analysis of long-term outcomes associated with preterm exposure to antenatal corticosteroids compared with no exposure in all children as well as children with preterm and full-term birth.

DATA SOURCES

Academic databases were searched for articles published from January 1, 2000, to October 29, 2021, including Ovid MEDLINE, Ovid Embase, PsycInfo, CINAHL (Cumulative Index of Nursing and Allied Health Literature), Web of Science, ClinicalTrials.gov, and Google Scholar. References of articles were also searched for relevant studies.

STUDY SELECTION

Randomized clinical trials (RCTs), quasi-RCTs, and cohort studies that assessed long-term neurodevelopmental, psychological, or other outcomes at 1 year or older in those who had preterm exposure to antenatal corticosteroids were included. No language restrictions were set.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted data using a piloted data extraction form. Data on study population, pregnancy characteristics, exposure to antenatal corticosteroids, and outcomes were collected. Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guidelines were followed, and random-effects models were used for the meta-analysis.

MAIN OUTCOMES AND MEASURES

The primary outcome was an author-defined composite of any adverse neurodevelopmental and/or psychological disorder. The secondary outcomes included specific measures of psychological disorders; neurodevelopmental delay; and anthropometric, metabolic, and cardiorespiratory outcomes.

RESULTS

A total of 30 studies met the inclusion criteria, and involved more than 1.25 million children who were at least 1 year of age when the outcomes were assessed. Exposure to a single course of antenatal corticosteroids for children with extremely preterm birth was associated with a significant reduction in risk of neurodevelopmental impairment (adjusted odds ratio, 0.69 [95% CI, 0.57-0.84]; I2 = 0%; low certainty). For children with late-preterm birth, exposure to antenatal corticosteroids was associated with a higher risk of investigation for neurocognitive disorders (n = 25 668 children; adjusted hazard ratio [aHR], 1.12 [95% CI, 1.05-1.20]; low certainty). For children with full-term birth, exposure to antenatal corticosteroids was associated with a higher risk of mental or behavioral disorders (n = 641 487 children; aHR, 1.47 [95% CI, 1.36-1.60]; low certainty) as well as proven or suspected neurocognitive disorders (n = 529 205 children; aHR, 1.16 [95% CI, 1.10-1.21]; low certainty).

CONCLUSIONS AND RELEVANCE

Results of this study showed that exposure to a single course of antenatal corticosteroids was associated with a significantly lower risk of neurodevelopmental impairment in children with extremely preterm birth but a significantly higher risk of adverse neurocognitive and/or psychological outcomes in children with late-preterm and full-term birth, who made up approximately half of those with exposure to antenatal corticosteroids. The findings suggest a need for caution in administering antenatal corticosteroids.

Effect of Antenatal Dexamethasone in Late Preterm Period on Neonatal Hypoglycemia: A Prospective Cohort Study from a Developing Country

OBJECTIVES

This study compared the risk of hypoglycemia within 72 h of life in infants with and without exposure to antenatal dexamethasone in the late preterm period (34-366/7 week's gestational age).

METHODS

This prospective cohort study was conducted in a tertiary care neonatal unit of Eastern India from May 2021 to November 2021. Babies in the exposed group received at least one dose of antenatal dexamethasone in the late preterm period between 7 days before delivery and birth. 'Complete course' of antenatal steroid was defined as four doses of injection dexamethasone at 12 h intervals and <4 doses were considered as 'Partial course'. Primary outcome was incidence of hypoglycemia within 72 h of life, defined as whole blood glucose <45 mg/dl.

RESULTS

Total 298 infants (98 in control, 134 in partial and 66 in complete group) were assessed for final outcome. No significant difference in outcomes were seen in the exposed group compared to unexposed group. However, incidence of hypoglycemia within 72 h (complete vs. partial p= 0.008, complete vs. control p=0.005) and 12 h of life (complete vs. partial p=0.013, complete vs. control p=0.013) was significantly less in complete steroid group. Logistic regression analysis revealed complete course of antenatal corticosteroid significantly decreased the risk of hypoglycemia [adjusted odds ratio, 95% confidence interval (CI) 0.15 (0.03-0.69), p=0.015]. Number needed to be exposed for one additional benefit was 7 (95% CI, 6.35-22.14).

CONCLUSION

Complete course of dexamethasone administered to mothers at risk of late preterm delivery reduces risk of neonatal hypoglycemia within 72 h of life.

Timing of antenatal corticosteroids in relation to clinical indication

PURPOSE

This study aimed at determining the proportion of women who receive antenatal corticosteroids (ACS) within the optimal time window before birth based on the indication for ACS, and to explore in more detail indications that are associated with suboptimal timing.

METHODS

A retrospective cohort study of all women who received ACS in a single tertiary center between 2014 and 2017. The primary outcome was an ACS-to-birth interval ≤ 7 days. Secondary outcomes were ACS-to-birth interval of ≤ 14 days, and the proportion women who received ACS but ultimately gave birth at term (≥ 37^0/7 weeks). The study outcomes were stratified by the clinical indication for ACS.

RESULTS

A total of 1261 women met the study criteria, of whom 401 (31.8%) and 569 (45.1%) received ACS within ≤ 7 days and ≤ 14 days before birth, respectively, and 203 (16.1%) ultimately gave birth at term. The proportion of women who received ACS within 7 days before birth was highest for women with preeclampsia (50.4%), and was lowest for women with an incidental finding of a short cervix (8.4%). In the subgroup of women with an incidental finding of a short cervix, the likelihood of optimal timing was not related to the magnitude of cervical shortening, history of preterm birth, multifetal gestation, presence of cervical funneling, or the presence of cervical cerclage.

CONCLUSION

Over two-thirds of infants who are exposed to ACS do not get the maximal benefit from this intervention. The current study identified clinical indications for ACS that are associated with suboptimal timing of ACS where more research is needed to develop quantitative, indication-specific prediction models to guide the timing of ACS.