Oxidative stress in term small for gestational age neonates born to undernourished mothers: a case control study

Background  

The objective of this study was to assess the status of oxidative stress in term small for gestational age (SGA) newborn infants born to undernourished mothers by estimating levels of erythrocyte superoxide dismutase (SOD), catalase, reduced glutathione, and serum malondialdehyde (MDA) in cord blood and comparing them to healthy appropriate for gestational age (AGA) controls. This was done in a case control design at a tertiary level teaching hospital.     

Peripheral nerve conduction velocity and brainstem auditory evoked responses in small for gestational age preterm infants

Ulnar nerve conduction velocity (NCV) and brainstem auditory evoked responses (BAER) were measured in each of 11 preterm small for gestational age (SGA) infants born at less than 35 weeks gestation. The mean motor NCV in the SGA infants was similar to that reported for infants who were appropriately grown for their gestational age (AGA). However, the mean central conduction time of the BAER in SGA infants was significantly shorter than that of AGA infants of the same post-menstrual age. Thus, the precocious development of auditory brainstem neural function in preterm SGA infants is not accompanied by changes in functional maturation of the peripheral motor nerves.     

Energy substrate production in infants born small for gestational age

AIM: To investigate energy substrate production and its hormonal regulation in infants born small for gestational age. METHODS: Eleven infants, aged 24.4 +/- 5.3 hour, were studied following a fast of 4.0 +/- 0.6 hour. Gestational age was 35.4 +/- 2.8 weeks and birth weight 1804 +/- 472 g (<-2 SD). Rates of glucose production and lipolysis were analyzed using [6,6-(2)H(2)]-glucose and [2-(13)C]-glycerol. RESULTS: Plasma levels of glucose and glycerol were 4.1 +/- 1.1 mmol x L(-1) and 224 +/- 79 micromol x L(-1), respectively. Glucose appearance averaged 30.3 +/- 8.2 and glucose production rate 21.1 +/- 6.1 micromol x kg(-1) x minutes(-1). Glycerol production rate was 5.6 +/- 1.6 micromol x kg(-1) x minutes(-1), correlating strongly to birth weight (r = 0.904, p < 0.001). Of the glycerol produced, 55 +/- 22% was converted to glucose, corresponding to 8 +/- 3% of the glucose production. CONCLUSIONS: Even though the infants could produce energy substrates, lipolysis was reduced and the glucose production was in the low end of the normal range compared with infants born appropriate for gestational age. The correlation between glycerol production and birth weight indicates that lipolysis depends on the amount of stored fat. Data on insulin and insulin-like growth factor binding protein 1 support the view that insulin sensitivity in these infants is reduced in the liver but increased peripherally.     

Transepidermal water loss in newborn infants. VIII. Relation to gestational age and post-natal age in appropriate and small for gestational age infants

In 68 appropriate for gestational age (AGA) and 33 small for gestational age (SGA) infants, transepidermal water loss was studied during the first four weeks after birth. The method used to measure evaporation rate is based on measurement of the water vapour pressure gradient close to the skin surface. All measurements were made at an ambient humidity of 50% and with the infants calm and quiet. At all the investigated post-natal ages in both AGA and SGA infants, an exponential relationship was found between transepidermal water loss (g/m2 h) and gestational age, this loss being much higher in the pre-term infants than in those born at term. The transepidermal water loss was generally lower in SGA than in AGA infants during the first week of post-natal life, irrespective of gestational age at birth. There was a gradual decrease in transepidermal water loss with increasing post-natal age in both pre-term AGA and pre-term SGA infants. Three weeks after birth this water loss tended to be higher in pre-term SGA infants than in pre-term AGA infants of corresponding gestational age.     

Bone ultrasound velocity of infants born small for gestational age

BACKGROUND: Quantitative ultrasound is increasingly used to assess bone status. Bone speed of sound (SOS), a biophysical property of bone, has been used to predict bone breakability. While decreased bone mineral content and delayed epiphyseal growth have been reported in small for gestational age (SGA) infants, there are no data on bone SOS in this group of infants. OBJECTIVE: To test the hypothesis that SGA infants have lower bone SOS than appropriate for gestational age (AGA) infants. METHODS: Bone SOS was measured within the first 96 hours of life at the right tibial midshaft in 22 singleton SGA infants. We compared these data with data obtained in 73 AGA controls. We used the Omnisense instrument which measures axially transmitted SOS. Infants ranged in gestational age (GA) from 25 to 42 weeks and in birth weight (BW) from 500 to 2,585 g. Statistical analyses included paired t-tests between the actual value obtained in every child and the theoretical, computed average normal value for GA, BW, or knee-sole length (KSL) based on our curves for AGA singletons. A p value < 0.05 was considered significant. RESULTS: Bone SOS measured in SGA infants was higher than the predicted computed average SOS of AGA singletons with significant differences in all of the parameters studied. CONCLUSIONS: Contrary to our hypothesis, SGA infants have higher bone SOS than AGA controls. Since bone mineral density is reported to be low in these infants, we speculate that intrauterine growth restriction may affect bone mineral density and bone protein matrix in opposite directions.     

Breastfeeding and catch-up growth in infants born small for gestational age

Postnatal growth was prospectively measured from birth to 1 y in 54 term infants born small for gestational age (SGA), fed either breast milk or a standard term infant formula. Breastfeeding was associated with a 0.36 and 0.64 standard deviation (SD) increase in weight at 2 weeks and 3 months of age. respectively, which persisted beyond the breastfeeding period (0.64 SD at 1 y). Breastfed infants also showed greater catch-up growth in head circumference [SD score (SDS) 0.53 higher at 3 months], and greater body length gain (SDS 0.68 higher at 6 months). This increased growth was independent of potentially confounding obstetric, social and demographic factors. Our findings suggest that breastfeeding may promote faster growth in infants compromised by poor growth in utero. SGA infants may be programmed for a number of adverse outcomes; the possibility that such events are altered by choice of postnatal diet is a key issue for future research.     

Longitudinal follow-up of height up to five years of age in infants born preterm small for gestational age; comparison to full-term small for gestational age infants

OBJECTIVE: This aims to conduct a comparative study of the height catch-up rate in preterm small for gestational age (SGA) infants during early childhood by gestational age and identify the factors affecting short stature in comparison to full-term SGA infants. METHODS: 449 SGA infants (214 full-term infants, 73 infants with gestation of less than 32 weeks, and 162 infants with gestation of more than 32 weeks but less than 37 weeks) from 25 institutions in Japan were assessed for catch-up (> or = -2SD) rate in growth by measuring for length/height at 1 year, 3 years and 5 years of age and the risk factors for no catch-up (< -2SD) at 5 years. RESULTS: The overall length/height catch-up rate was 68% at 1 year, 89% at 3 years and 88% at 5 years. The catch-up rate at 3 and 5 years of age in the group with gestation of less than 32 weeks had a rate of 74%, which was significantly less than the other two groups (approximately 90%). A significant factor associated with short stature at 5 years in the group with gestation of less than 32 weeks was the lower length SD score at time of birth, and for preterm infants born more than 32 weeks of gestation and full-term infants, significant factors were the lower maternal height and head circumference at birth. CONCLUSION: SGA infants born less than 32 weeks of gestation had a higher risk of no catch-up and different factors affecting catch-up compared to preterm SGA infants of gestation more than 32 weeks and full-term SGA infants.     

Brainstem auditory evoked response at term in preterm infants after perinatal hypoxia-ischaemia

AIM: To examine brainstem auditory function in preterm infants after perinatal hypoxia-ischaemia (HI). METHODS: Brainstem auditory evoked response (BAER) was studied at 37-42 wk postconceptional age in preterm infants who suffered perinatal HI, and were compared with those in preterm and term infants without any major perinatal problems. RESULTS: None of the latencies of waves I, III and V in the BAER in preterm infants after perinatal HI differed significantly from those in preterm and term controls. There were also no significant differences in the I-V and I-III interpeak intervals between preterm infants after HI and the controls. However, III-V interval in infants after HI tended to increase, and was significantly longer than in term controls (p<0.01), although it did not differ significantly from that in preterm controls. Similarly, the III-V/I-III interval ratio was greater than in term controls (p<0.05), but was similar to that in preterm controls. All amplitude variables did not differ significantly from the controls. CONCLUSION: BAER in preterm infants after perinatal HI did not differ significantly from that in preterm infants without perinatal problems, but differed slightly from that in normal term infants. The prolonged III-V interval as compared with the term controls suggests a minor impairment in central auditory function.     

Normal visual evoked potentials in preschool children born small for gestational age

Aim: Previous studies have shown visual evoked potential (VEP) abnormalities in infants and animals born small for gestational age (SGA) compared with controls. The current exploratory study aims to investigate whether VEP abnormalities persist in older ages. Methods: Pattern VEP latencies were obtained in 21 children (11 girls, 10 boys), born SGA and moderately preterm, at an average age of 5 years and 8 months. Fifty‐one children (24 girls, 27 boys, mean age of 5 years and 7 months), also born moderately preterm but with normal height and weight at birth, served as controls Results: Visual evoked potential results showed no significant differences in latency between children born SGA and controls born appropriate for gestational age (AGA) for either binocular stimulation, right eye or left eye stimulation. Conclusions: Our findings do not indicate any differences in VEP latency at preschool age for children born SGA compared with children born AGA. The results may support previous studies, suggesting that children born SGA show accelerated neurophysiologic maturation during their first year of life and that previously delayed VEP latencies after catch‐up stay unchanged compared with controls.     

Sex and gestational age effects on auditory brainstem responses in preterm and term infants

Background

Some studies find delayed development of the auditory brainstem in preterm infants, but others do not.

Aim

To compare auditory brainstem responses (ABRs) in healthy preterm and term infants depending on sex and gestational age (GA).

Methods

Participants were 111 preterm (27–36 weeks GA) and 92 term (37–41 weeks GA) infants. ABR tests were conducted at 6 weeks (corrected age if preterm).

Results

There were no overall differences between term and preterm groups in ABRs. However, males showed longer latencies for waves III, V, and I–III, III–V, and I–V intervals and smaller amplitudes for wave III and V than females in both preterm and term groups (all p values ≤ .01). A 3-way interaction between group, sex, and GA (p < .05) showed that preterm males with later GA had longer wave I–V interval, whereas term females with later GA showed shorter wave I-V interval. Growth velocity predicted wave I–V interval in preterm infants, controlling for other factors (male: p = .07, female: p < .05).

Conclusion

ABRs in preterm and term infants were similar at 6 weeks (corrected age if preterm), but males had less advanced ABRs than females. More rapid growth predicted less mature ABR in later GA preterm infants in this setting where they were unlikely to receive extra iron. The roles of GA, growth, and iron balance in ABR development warrant further study.     

Brainstem auditory evoked responses in infants at risk of sudden infant death

Brainstem auditory evoked responses (BAERs) were recorded from 63 near-miss Sudden Infant Death Syndrome (NMSIDS) infants, 26 siblings of SIDS (SSIBS) infants and 67 control infants between 0 and 30 weeks post-term. The majority of BAERs recorded from the NMSIDS and SSIBS infants had normal form and interpeak intervals (V-I and V-IIn) within normal limits for their age. However, 15% of these infants had interpeak intervals outside the normal range, suggesting abnormal neural function in these cases. The distributions of interpeak intervals for all NMSIDS and SSIBS infants were skewed towards longer times compared to control infants. The distributions of V-IIn intervals for both groups of at risk infants were significantly different to that of control infants. While the observations confirm that the recording of BAERs is not suitable for identifying infants at risk of SIDS, they suggest, however, that maturation of neural processing in the brainstem of these infants may be delayed.     

Brainstem auditory evoked responses in very low birthweight infants with chronic lung disease.

Very low birthweight (VLBW) infants who had prolonged oxygen dependence due to chronic respiratory problems, typically neonatal chronic lung disease (CLD), are at high risk of neurodevelopmental impairment. To assess the effect of CLD on neonatal auditory function we studied brainstem auditory evoked response (BAER) in VLBW infants who suffered CLD but no other major perinatal complications or problems. At 37-42 week postconceptional age, the latencies of waves I, III and V in CLD infants were all significantly longer than in normal term infants (all p<0.001). The differences between CLD infants and the term controls were greater for the later waves than for the earlier waves. Abnormally prolonged wave latency (>2.5 SD of the mean measurement) was seen in 7 (21.2%) CLD infants for wave I, suggesting peripheral auditory impairment, 8 (24.2%) for wave III and 14 (42.4%) for wave V. I-V interval in CLD infants was significantly longer than in the term controls (p<0.001). Seven (21.2%) infants had abnormally prolonged I-V interval, suggesting brainstem or central auditory impairment. Of these infants, 2 had both prolonged wave latencies and prolonged I-V interval, suggesting both peripheral and central auditory impairment. Similar abnormalities were found in CLD infants when compared with the BAER in birthweight- and age-matched healthy VLBW infants without CLD. CONCLUSION: Neonatal auditory function is impaired, both peripherally and centrally, at term age in VLBW infants who suffer neonatal CLD.     

Prenatal lidocaine and the auditory evoked responses in term infants

We examined the effects of maternal lidocaine hydrochloride anesthesia on the brain-stem auditory evoked responses (BAERs) in neonates born by cesarean delivery. Sixteen term neonates were enrolled in the study. Eight neonates were delivered by cesarean section following lidocaine anesthesia, and eight were delivered by spontaneous vaginal delivery without maternal anesthesia. A BAER was obtained on all of the neonates on the first day of life. A significant delay was noted in the central neural component of the BAER at 90 dB. The wave I through V interpeak latency for both ears was noted to be 5.3 ms for the neonates exposed to lidocaine and 4.9 ms for the controls.     

Normal auditory brain stem evoked responses in infants of diabetic mothers

Auditory brain stem responses potentials were recorded from 71 newborns within the first 2 weeks after birth; conceptional age ranged from 37 to 41 weeks. Thirty-nine newborns were infants of diabetic mothers (IDMs) (17 White A, 22 White B-D) and 32 healthy term newborns served as control group. IDMs with additional high risk for cochlear or brain stem integrity were excluded. Birthweight for gestational age was significantly higher for IDMs. No differences in auditory brain stem responses wave latencies or amplitudes were observed between healthy infants of the control group and IDMs.