Neonatal morbidity and growth in very low birth-weight infants after multiple courses of antenatal steroids

Inflammation induces stunting by lowering bone mass via GH/IGF-1 inhibition in very preterm infants

BACKGROUND

Sustained systemic inflammatory response (SIR) was associated with poor postnatal growth in very preterm infants (VPI). We hypothesize that VPI with sustained SIR will exhibit linear growth retardation related to lower bone mass accrual mediated by GH/IGF-1 axis inhibition at term corrected age (CA).

METHODS

C-reactive protein (CRP), procalcitonin (PCT), growth hormone (GH), insulin-like growth factor 1 (IGF-1), calcium, phosphorus, alkaline phosphatase, anthropometric, nutritional, neonatal and maternal data were collected prospectively in 23 infants <32 weeks gestational age. Body composition using dual-energy X-ray absorptiometry was performed at term CA. Analysis was undertaken with multiple linear regression models.

RESULTS

At term CA 11 infants with sustained SIR compared with 12 infants without sustained SIR present significantly lower IGF-1, length z-score (LZS), bone mineral content (BMC) and lean mass (LM), and higher GH and fat mass (FM). LZS was associated significantly with PCT, BMC with IGF-1, FM and LM with CRP, GH with bronchopulmonary dysplasia and CRP, and IGF-1 with invasive mechanical ventilation, CRP and PCT.

CONCLUSIONS

In addition to the known effect on linear growth failure, sustained SIR induces lower bone mass accrual related to higher GH and lower IGF-1 levels in VPI.

IMPACT

Very preterm infants (VPI) with sustained systemic inflammatory response (SIR) compared with VPI without SIR present stunting, lower bone mass, higher GH and lower IGF-1 levels at term corrected age. SIR may help to explain the influence of non-nutritional factors on growth and body composition in VPI. SIR induces postnatal stunting related to lower bone mass accrual via GH/IGF-1 axis inhibition in VPI. VPI with SIR need special attention to minimize inflammatory stress, which could result in improved postnatal growth. Research on inflammatory-endocrine interactions involved in the pathophysiology of postnatal stunting is needed as a basis for new interventional approaches.

The growth of very-low-birth-weight infants at 5 years old in Taiwan

BACKGROUND

The goal of this study was to compare the growth and effect of growth on cognitive performance at 5 years of age of a group of very-low-birth-weight (VLBW) infants and a group of healthy full-term infants.

METHODS

Beginning in 1995, under the sponsorship of the Premature Baby Foundation, the Society of Neonatology, Taiwan, conducted a multicenter follow-up study of VLBW infants in Taiwan. The study enrolled 322 VLBW infants and 103 controls for assessment of growth data and cognitive performance at several time points from birth through to 5 years of age. Growth data were assessed with measurements of weight, height, and head circumference taken at the ages of 6 months, 12 months, 24 months, and 60 months. Cognitive performance was assessed at the age of 5 years. The VLBW infants were regarded as "failed" if a measurement was 2 standard deviations below the mean measurement of the control group. Neonatal and perinatal data had been collected prospectively as part of a longitudinal study. Cognitive performance was assessed using the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-R).

RESULTS

From 6 months to 5 years, VLBW infants had lower weight, height, and head circumference than the controls. Two hundred twenty-four VLBW infants (69.6%) returned for assessment at 5 years old. Of the 224 VLBW infants, complete sets of measurements of weight, height, and head circumference were obtained for 126 cases (56.3%), 127 cases (56.7%), and 106 cases (47.3%), respectively. Of these, 13 patients (10.3%) failed in weight, 11 patients (8.7%) failed in height, and 17 patients (16.0%) failed in head circumference at the age of 5 years. The mean WPPSI-R scores at the age of 5 years for VLBW children were: 94.1 ± 16.4 (performance IQ), 87.2 ± 12.8 (verbal IQ), and 89.5 ± 14.6 (full IQ). All of these values were also lower than those of the control group, with the differences being statistically significant (p < 0.05). The WPPSI-R scores of VLBW children who failed in head circumference were notably lower than those of VLBW children whose head circumference had caught up with that of their peers.

CONCLUSION

The growth of VLBW infants was lower than that of healthy full-term infants through 5 years of age. The cognitive performance for VLBW children was also decreased compared to that of the control group, and there was an association between slower growth and decreased cognitive ability.

Antenatal dexamethasone has no adverse effects on child physical and cognitive development: a long-term cohort follow-up investigation

OBJECTIVE

Antenatal corticosteroids are extensively given in pregnancies with threatened preterm labour as a prophylactic method to reduce some kinds of neonatal diseases. Dexamethasone is one kind of commonly used corticosteroid, but controversies still remain whether it leads to adverse effects on neonatal long-term development or not. The purpose of this study was to investigate the influence of prenatal exposure to one or two dosages of dexamethasone on neonatal physical and cognitive development of children at 1, 3 and 6 years of age.

METHODS

This was a retrospective cohort study. The body length, head circumference and body weight were measured in every infant and child to evaluate physical development. The mental development index (MDI) and a psychomotor development index (PDI) were used to evaluate mental and cognitive development in children of ages 1 year and 3 years while verbal intelligence quotient (VIQ) and performance intelligence quotient (PIQ) scores were used to evaluate mental and cognitive development in children of age of 6 years. There were 1554 infants at 1 year, 1328 children at 3 years and 1297 preschool children at 6 years followed.

RESULTS

There were no significant differences between antenatal dexamethasone exposure groups and antenatal dexamethasone non-exposure groups on physical development index and MDI, PDI, VIQ and PIQ.

CONCLUSIONS

The results of this investigation suggested that one or two dosages of antenatal dexamethasone is safe for the use of inevitable preterm birth.

Does in utero exposure to synthetic glucocorticoids influence birthweight, head circumference and birth length? A systematic review of current evidence in humans

Synthetic glucocorticoids are the mainstay treatment for stimulating lung maturation in threatened preterm delivery. Animal studies suggest that in utero exposure to glucocorticoids leads to a reduction in birth size. Smaller birthweight has been associated with higher risk of many chronic diseases. Therefore, the authors undertook a systematic review of human studies examining the association between synthetic glucocorticoid treatment and birth size. Medline, EMBASE, PubMed, Cochrane, Google scholar and Institute of Life Science databases were searched for studies published between 1978 and 2009 investigating the association between synthetic glucocorticoids and birthweight, head circumference, birth length and ponderal index. All studies controlling for gestational age were examined. Seventeen studies were included in the analysis. Nine out of 17 studies reported a reduction in birthweight (range 12-332 g), five of nine a reduction of head circumference (range 0.31-1.02 cm) and two of four a reduction of 0.8 cm in birth length. Despite methodological inconsistencies and limitations that impede clear conclusions, the evidence suggests an association between in utero exposure to synthetic glucocorticoids and reduced birth size.

Placental inflammatory response is associated with poor neonatal growth: preterm birth cohort study

OBJECTIVE

We sought to determine whether placental markers of intrauterine inflammation were associated with poor weight gain among premature infants in the neonatal period.

METHODS

We reviewed 697 preterm births prospectively enrolled as part of an ongoing molecular epidemiological study. Placental markers and serial weight gain were analyzed for premature infants who were hospitalized for >/=21 days (N = 256). Placentas were examined for maternal inflammatory response (MIR), defined as subchorionitis, chorioamnionitis, deciduitis, or free membranitis, and fetal inflammatory response (FIR), defined as inflammation extending to the umbilical cord or chorionic plate. Multivariate linear regression and stratified analyses were performed.

RESULTS

Decreases in weight gain at day 21 were associated with the presence of either MIR or FIR (beta coefficient = -4.63 +/- 1.41; P = .001). The association was stronger with FIR than MIR (P for trend = .0027) and persisted in the remaining hospitalized infants at day 28 (n = 223; beta coefficient = -5.53 +/- 1.85; P = .0028). Mean body weights were similar among the 3 groups by corrected age of 36 weeks or discharge, whichever came first. Associations between placental inflammation and poor growth persisted among infants with prenatal corticosteroid exposure and/or neonatal complications and remained marginally significant in the nonexposed groups. Among infants without intrauterine growth restriction, significant association persisted (n = 186; beta coefficient = -5.68 +/- 1.56; P = .0003).

CONCLUSIONS

Placental inflammation is associated with poor neonatal growth. MIR and FIR may be useful markers for identifying infants at risk for postnatal growth failure.

Blood pressure support in extremely premature infants is affected by different courses of antenatal steroids

OBJECTIVE

To examine the effects of partial, single and multiple courses of antenatal corticosteroids (ANS) on the need for blood pressure support in extremely premature infants.

METHODS

Extremely premature infants with gestational age of 24 to 28 weeks were included in this study during a 5-year period. The main outcome measure of the study was the amount of blood pressure support during the first 3 days of life.

RESULTS

The study infants (n = 163) were divided into: infants not exposed (ANS; n = 27) and exposed to ANS (ANS; n = 136). Blood pressure support was significantly lower in ANS compared with No ANS (65% vs 96%; p = 0.003) and in single course (SANS; n = 73) and >or=2 courses (MANS; n = 34) compared with partial course of ANS (PANS; n = 29) (62%, 56% vs 86%; p = 0.03). The number of infants who received volume support and the amount of volume support were significantly lower in ANS compared with that in No ANS (p < 0.001) and in SANS and MANS compared with that in PANS (p < 0.02).

CONCLUSION

Exposure to multiple courses of ANS was as beneficial as single course of ANS in decreasing the need for blood pressure support in extremely premature infants.

The role of antenatal corticosteroids for improving the maturation of choroid plexus capillaries in fetal mice

We investigated whether the use of antenatal corticosteroids could improve the maturation of choroid plexus capillaries in fetal mice. The study was carried out in two groups of preterm mice. The study group consisted of pregnant mice that received dexamethasone at a dose of 4 mg/kg intraperitoneally. This group was further subdivided into four subgroups according to the timing of steroid administration as follows: day 13, day 14, day 15, and day 16 of pregnancy, and each subgroup included 12 premature mice. All animals received a second injection 24 hours after the first injection. The control group was given normal saline. The pregnant mice were operated on to obtain premature mice. The choroid plexus capillaries were assessed for integrity and thickness of their basement membranes by electronmicroscopy. We found that, in the study group, the maturity of the basement membrane of the choroid plexus capillaries was more precise, in that capillaries were better in control animals at term for the following reasons: (a) the basement membrane becomes more intact, (b) thickness of the basement membrane increased, and (c) the protein particles become tighter. Antenatal dexamethasone improved the maturation of the choroid plexus capillaries in fetal mice but also decreased the incidence of periventricular-intraventricular hemorrhage (PIVH). Using two doses of steroids had no influence on birthweight or brainweight of the mice. In conclusion, these findings provide an experimental basis for the use of antenatal steroids for decreasing the incidence of PIVH in premature infants.

Auditory neural maturation after exposure to multiple courses of antenatal betamethasone in premature infants as evaluated by auditory brainstem response

OBJECTIVE

Our goal was to determine if multiple courses of antenatal betamethasone affect auditory neural maturation in 28 to 32 weeks' gestational age infants.

PATIENTS AND METHODS

A retrospective cohort study was performed to compare auditory neural maturation between premature infants exposed to 1 course of betamethasone and infants exposed to > or = 2 courses of betamethasone. Inclusion criteria included all 28 to 32 weeks' gestational age infants delivered between July 1996 and December 1998 who had auditory brainstem response testing performed (80-dB click stimuli at a repetition rate of 39.9/second) within 24 hours of postnatal life as part of bilirubin-auditory studies. Infants with toxoplasmosis, rubella, cytomegalovirus, herpes infections, chromosomal disorders, unstable conditions, exposure to antenatal dexamethasone, and exposure to < 1 complete course of betamethasone were excluded. Auditory waveforms were categorized into response types on response replicability and peak identification as types 1 through 4 (type 1 indicating most mature). Absolute and interpeak wave latencies were measured when applicable. Categorical and continuous variables were analyzed by using the chi2 test and Student's t test, respectively.

RESULTS

Of 174 infants studied, 123 received antenatal steroids. Of these, 50 received 1 course and 29 received > or = 2 courses of betamethasone. There were no significant differences in perinatal demographics between the 2 groups. After controlling for confounding variables, there was no significant difference in mean absolute wave latencies, mean interpeak latencies, or distribution of response type between the 2 groups. There also was no significant difference in any auditory brainstem response parameters between infants exposed to 1 course of betamethasone (n = 50) and infants exposed to > 2 courses of betamethasone (n = 17).

CONCLUSION

Compared with a single recommended course of antenatal steroids, multiple courses of antenatal betamethasone are not associated with a deleterious effect on auditory neural maturation in 28 to 32 weeks' gestational age infants.

Influence of a single course of antenatal betamethasone on the maternal-fetal insulin-IGF-GH axis in singleton pregnancies

OBJECTIVE

We examined the hypothesis that a single course of antenatal betamethasone influences the maternal-fetal insulin-IGF-GH axis.

DESIGN

A prospective, observational, pilot study consisting of four groups of pregnant women: (I) received betamethasone and delivered <2 weeks post treatment; (II) received betamethasone and delivered >2 weeks post treatment; (III) untreated women who delivered <37 weeks (preterm controls); (IV) untreated women who delivered >37 weeks (term controls). Maternal and mixed umbilical cord blood was collected at delivery and analyzed for insulin, glucose, IGF-I, IGF-II, IGFBP-1, IGFBP-3, GH, and GHBP.

RESULTS

Betamethasone increased maternal insulin, glucose and IGF-I levels without affecting IGFBPs. In the fetal compartment, betamethasone treatment was associated with a delayed suppressive effect on GH and a sustained suppressive effect on IGF-II levels. There were no differences in infant size or neonatal morbidities between patients who delivered <2 weeks or >2 weeks post betamethasone treatment. In Group IV, birth weight correlated positively with cord IGF-I levels (r2=0.41, p=0.0098) and negatively with cord IGFBP-1 levels (r2=0.51, p=0.0039), and ponderal index correlated negatively with cord IGFBP-1 levels (r2=0.27, p<0.05).

CONCLUSIONS

A single course of antenatal betamethasone influences the maternal-fetal insulin-IGF-GH axis, particularly fetal IGF-II levels, without measurable anthropometric changes at birth. Whether these effects have implications beyond the neonatal period remains to be determined.