Repeat doses of prenatal corticosteroids for women at risk of preterm birth for improving neonatal health outcomes

BACKGROUND

Infants born preterm (before 37 weeks' gestation) are at risk of respiratory distress syndrome (RDS) and need for respiratory support due to lung immaturity. One course of prenatal corticosteroids, administered to women at risk of preterm birth, reduces the risk of respiratory morbidity and improves survival of their infants, but these benefits do not extend beyond seven days. Repeat doses of prenatal corticosteroids have been used for women at ongoing risk of preterm birth more than seven days after their first course of corticosteroids, with improvements in respiratory outcomes, but uncertainty remains about any long-term benefits and harms. This is an update of a review last published in 2015.

OBJECTIVES

To assess the effectiveness and safety, using the best available evidence, of a repeat dose(s) of prenatal corticosteroids, given to women who remain at risk of preterm birth seven or more days after an initial course of prenatal corticosteroids with the primary aim of reducing fetal and neonatal mortality and morbidity.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials, including cluster-randomised trials, of women who had already received one course of corticosteroids seven or more days previously and were still at risk of preterm birth, randomised to further dose(s) or no repeat doses, with or without placebo. Quasi-randomised trials were excluded. Abstracts were accepted if they met specific criteria. All trials had to meet criteria for trustworthiness, including a search of the Retraction Watch database for retractions or expressions of concern about the trials or their publications.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Pregnancy and Childbirth methods. Two review authors independently selected trials, extracted data, and assessed trial quality and scientific integrity. We chose primary outcomes based on clinical importance as measures of effectiveness and safety, including serious outcomes, for the women and their fetuses/infants, infants in early childhood (age two to less than five years), the infant in mid- to late childhood (age five to less than 18 years) and the infant as an adult. We assessed risk of bias at the outcome level using the RoB 2 tool and assessed certainty of evidence using GRADE.

MAIN RESULTS

We included 11 trials (4895 women and 5975 babies). High-certainty evidence from these trials indicated that treatment of women who remain at risk of preterm birth seven or more days after an initial course of prenatal corticosteroids with repeat dose(s) of corticosteroids, compared with no repeat corticosteroid treatment, reduced the risk of their infants experiencing the primary infant outcome of RDS (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.74 to 0.90; 3540 babies; number needed to treat for an additional beneficial outcome (NNTB) 16, 95% CI 11 to 29) and had little or no effect on chronic lung disease (RR 1.00, 95% CI 0.83 to 1.22; 5661 babies). Moderate-certainty evidence indicated that the composite of serious infant outcomes was probably reduced with repeat dose(s) of corticosteroids (RR 0.88, 95% CI 0.80 to 0.97; 9 trials, 5736 babies; NNTB 39, 95% CI 24 to 158), as was severe lung disease (RR 0.83, 95% CI 0.72 to 0.97; NNTB 45, 95% CI 27 to 256; 4955 babies). Moderate-certainty evidence could not exclude benefit or harm for fetal or neonatal or infant death less than one year of age (RR 0.95, 95% CI 0.73 to 1.24; 5849 babies), severe intraventricular haemorrhage (RR 1.13, 95% CI 0.69 to 1.86; 5066 babies) and necrotising enterocolitis (RR 0.84, 95% CI 0.59 to 1.22; 5736 babies).  In women, moderate-certainty evidence found little or no effect on the likelihood of a caesarean birth (RR 1.03, 95% CI 0.98 to 1.09; 4266 mothers). Benefit or harm could not be excluded for maternal death (RR 0.32, 95% 0.01 to 7.81; 437 women) and maternal sepsis (RR 1.13, 95% CI 0.93 to 1.39; 4666 mothers). The evidence was unclear for risk of adverse effects and discontinuation of therapy due to maternal adverse effects. No trials reported breastfeeding status at hospital discharge or risk of admission to the intensive care unit.  At early childhood follow-up, moderate- to high-certainty evidence identified little or no effect of exposure to repeat prenatal corticosteroids compared with no repeat corticosteroids for primary outcomes relating to neurodevelopment (neurodevelopmental impairment: RR 0.97, 95% CI 0.85 to 1.10; 3616 children), survival without neurodevelopmental impairment (RR 1.01, 95% CI 0.98 to 1.04; 3845 children) and survival without major neurodevelopmental impairment (RR 1.02, 95% CI 0.98 to 1.05; 1816 children). An increase or decrease in the risk of death since randomisation could not be excluded (RR 1.06, 95% CI 0.81 to 1.40; 5 trials, 4565 babies randomised). At mid-childhood follow-up, moderate-certainty evidence identified little or no effect of exposure to repeat prenatal corticosteroids compared with no repeat corticosteroids on survival free of neurocognitive impairment (RR 1.01, 95% CI 0.95 to 1.08; 963 children) or survival free of major neurocognitive impairment (RR 1.00, 95% CI 0.97 to 1.04; 2682 children). Benefit or harm could not be excluded for death since randomisation (RR 0.93, 95% CI 0.69 to 1.26; 2874 babies randomised) and any neurocognitive impairment (RR 0.96, 95% CI 0.72 to 1.29; 897 children). No trials reported data for follow-up into adolescence or adulthood.  Risk of bias across outcomes was generally low although there were some concerns of bias. For childhood follow-up, most outcomes had some concerns of risk of bias due to missing data from loss to follow-up.

AUTHORS' CONCLUSIONS

The short-term benefits for babies included less respiratory distress and fewer serious health problems in the first few weeks after birth with repeat dose(s) of prenatal corticosteroids for women still at risk of preterm birth seven days or more after an initial course. The current available evidence reassuringly shows no significant harm for the women or child in early and mid-childhood, although no benefit. Further research is needed on the long-term benefits and risks for the baby into adulthood.

Transplacental versus direct fetal corticosteroid treatment for accelerating fetal lung maturation where there is a risk of preterm birth

BACKGROUND

Despite major advances in medical technology, the incidence of preterm birth remains high. The use of antenatal corticosteroid administered transplacentally, by intramuscular injection to women at risk of preterm birth, has reduced the incidence of respiratory distress syndrome and increased the survival rates of preterm infants. However, this intervention also comes with its own risks and side effects. Animal studies and early studies in pregnant women at risk of preterm birth have reported the use of an alternative route of administration, by direct intramuscular injection of corticosteroid into the fetus under ultrasound guidance, in an attempt to minimise the side-effect profile. Direct fetal corticosteroid administration may have benefits over maternal administration in terms of safety and efficacy.

OBJECTIVES

To assess if different routes of corticosteroid administration (maternal versus direct fetal) have effects on health outcomes for women and their babies.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (25 October 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (25 October 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials comparing maternal with direct fetal routes of antenatal corticosteroid administration in women at risk of preterm birth.

DATA COLLECTION AND ANALYSIS

The two review authors independently assessed study eligibility. In future updates of this review, at least two review authors will extract data and assess the risks of bias in included studies. We will also assess the quality of the evidence using the GRADE approach.

MAIN RESULTS

We did not identify any eligible randomised controlled trials to include in this review.

AUTHORS' CONCLUSIONS

The available clinical studies carried out so far on animals and human have shown that direct intramuscular injection of corticosteroid into the fetus under ultrasound guidance is feasible, but data on health outcomes are lacking. Uncertainty therefore persists as to which method could provide better efficacy and safety. Randomised controlled trials are required focusing on the benefits and harms of transplacental versus direct fetal corticosteroid treatment. Until the uncertainties have been addressed, it is advisable to stay with the current standard of antenatal transplacental maternally-administered corticosteroid treatment.

Direct intramuscular fetal or maternal antenatal corticosteroid therapy: short-time effects on fetal behavior and oxygenation: a comparative study

OBJECTIVE

To compare the effects of antenatal administration of corticosteroids used in two different regimens, on fetal biophysical profile (BPP), baseline fetal heart rate (BFHR), nonstress test (NST) and perinatal outcomes.

STUDY DESIGN

We evaluated the effects of single direct intramuscular (i.m.) fetal dose of dexamethasone (4 mg/kg), or four doses of 6 mg dexamethasone given to the mother 12 hours apart on the parameters of fetal BPP 0-4 hours before and after antenatal contraction stress (ACST). We evaluated two groups of 41 fetuses in the 31st gestation week at risk of fetal hypoxia at the Department of Gynecology/Obstetrics, Clinical Center of Serbia in 2013.

RESULTS

In fetal ACST group, we found significantly different changes in fetal breathing movement before (D0-f) and after therapy (D1-f), p  =  0.019 (-11.75; -1.12), 95% confidence interval (CI), as well as in the maternal ACST group, p  =  0.001; (-11.75; -1.12), 95% CI. We found significant difference between BPP 0-m and BPP1-m in the maternal group, p =  0.000. Neonatal asphyxia occurred more often with the increased frequency of fetal breath movements after both ACST (p  =  0.04 versus p  =  0.07).

CONCLUSION

Fetal ACST results in increased fetal breathing movements. Maternal ACST can result in changes to BPP. The increase in fetal breathing movements determinates neonatal asphyxia regardless of the ACST.

Repeat doses of prenatal corticosteroids for women at risk of preterm birth for improving neonatal health outcomes

BACKGROUND

It has been unclear whether repeat dose(s) of prenatal corticosteroids are beneficial.

OBJECTIVES

To assess the effectiveness and safety of repeat dose(s) of prenatal corticosteroids.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2011), searched reference lists of retrieved studies and contacted authors for further data.

SELECTION CRITERIA

Randomised controlled trials of women who had already received a single course of corticosteroids seven or more days previously and considered still at risk of preterm birth.

DATA COLLECTION AND ANALYSIS

We assessed trial quality and extracted data independently.

MAIN RESULTS

We included 10 trials (more than 4730 women and 5650 babies) with low to moderate risk of bias. Treatment of women who remain at risk of preterm birth seven or more days after an initial course of prenatal corticosteroids with repeat dose(s), compared with no repeat corticosteroid treatment, reduced the risk of their infants experiencing the primary outcomes respiratory distress syndrome (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.75 to 0.91, eight trials, 3206 infants, numbers needed to treat (NNT) 17, 95% CI 11 to 32) and serious infant outcome (RR 0.84, 95% CI 0.75 to 0.94, seven trials, 5094 infants, NNT 30, 95% CI 19 to 79).Treatment with repeat dose(s) of corticosteroid was associated with a reduction in mean birthweight (mean difference (MD) -75.79 g, 95% CI -117.63 to -33.96, nine trials, 5626 infants). However, outcomes that adjusted birthweight for gestational age (birthweight Z scores, birthweight multiples of the median and small-for-gestational age) did not differ between treatment groups.At early childhood follow-up no statistically significant differences were seen for infants exposed to repeat prenatal corticosteroids compared with unexposed infants for the primary outcomes (total deaths; survival free of any disability or major disability; disability; or serious outcome) or in the secondary outcome growth assessments.

AUTHORS' CONCLUSIONS

The short-term benefits for babies of less respiratory distress and fewer serious health problems in the first few weeks after birth support the use of repeat dose(s) of prenatal corticosteroids for women still at risk of preterm birth seven days or more after an initial course. These benefits were associated with a small reduction in size at birth. The current available evidence reassuringly shows no significant harm in early childhood, although no benefit.Further research is needed on the long-term benefits and risks for the woman and baby. Individual patient data meta-analysis may clarify how to maximise benefit and minimise harm.