HIGH DENSITY LIPOPROTEIN CONCENTRATIONS IN NEWBORN INFANTS

Abstract The lipoprotein pattern was analyzed by agarose gel electrophoresis in 19 newborn infants of varying gestational age. The HDL concentration was determined by rocket Immunoelectrophoresis in another 41 newborn infants. Infants with a gestational age of <33 weeks had very low HDL concentrations compared to preterm infants with a gestational age of 33 weeks and term infants. In the first 5–10 days after birth the HDL concentration increased markedly in preterm infants (gestational age <37 weeks) whereas it remained unchanged in term infants.     

The postnatal hypotransferrinemia of early preterm newborn infants.

Preterm newborns were found to be markedly hypotransferrinemic when compared with normal term infants. At birth the concentration of transferrin in sera from preterm infants of gestational age equal to or less than 32 weeks is 45% of that found in normal term infant sera. The preterm infant transferrin levels slowly rise so that 7-8 weeks after birth they are 78% of the level found in the sera of normal term infants. We also found that the serum transferrin concentrations at birth correlate with gestational age. Therefore, the transferrin levels postnatally in early preterm infants reflect postconceptional rather than postnatal age.     

Skin to calcaneus distance in the neonate

BACKGROUND: Current recommendations for obtaining blood from neonates advise avoidance of the midline area of the heel and are based on postmortem studies. OBJECTIVE: Because of the potential pain and tissue damage from repeated heel pricking in the same area, to investigate using ultrasonography whether the distance from skin to calcaneus is less at the midline than at the borders. METHODS: One hundred consecutive healthy preterm and 105 consecutive healthy term neonates were studied 48-72 hours after delivery. The skin to perichondrium distance (SPD) was measured on two occasions by ultrasound at the external, midline, and internal areas of the heel. FINDINGS: Mean SPD was 0.2 mm less at the midline than at the other sites. The proportion of measurements <3 mm at any of the three sites was the same. Depth was <3 mm in less than 3% of the term and approximately 20% of the preterm infants. The SPD correlated only with gestational age. Of children <33 weeks gestational age, 38% had an SPD <3 mm compared with 8% of older preterm infants. The proportions of preterm infants of > or = 33 weeks gestation and term infants with an SPD <3 mm were similar (8% v 3%). INTERPRETATION: With the use of automated lancets of 2.2 mm length or less, the whole heel plantar surface is safe for obtaining blood in term and preterm infants of > or = 33 weeks gestation. This means that soft tissue damage and pain from repeated pricking in the same area can be reduced.     

Effect of postnatal age and clinical status of newborn infants on bilirubin-binding capacity

Serial determinations of bilirubin-binding capacity were performed in 61 newborn infants during the first 10 days of life. 27 infants were classified as term (gestational age greater than or equal to 36 weeks) and 34 as preterm (gestational age less than or equal to 33 weeks); 34 were classified as 'sick' and 27 as 'well'. Bilirubin-binding capacity was measured by Sephadex gel filtration. In relation to postnatal age, total bilirubin-binding capacity (TBBC) remained stable in well term and preterm infants, decreased slightly in sick preterm infants, and decreased significantly in sick term infants. TBBC, serum albumin, and molr binding ratio (B/A) were significantly higher in well than in sick infants in both term and preterm groups; there were no significant differences between sick term and sick preterm infants. Clinical recovery in 16 infants was associated with a significant rise in TBBC and in B/A. The data suggest that in healthy infants, the serum bilirubin-binding capacity remains relatively unchanged during the first 10 days of life. Clinically ill infants show wide patient-to-patient variability in TBBC. Because of the tendency of TBBC to decrease with postnatal age in sick infants, repeated determinations of TBBC may be indicated for the management of sick jaudiced newborns.     

Placental transfer and decay of varicella-zoster virus antibodies in preterm infants

OBJECTIVES: To compare the placental transfer of maternal varicella-zoster (VZV) antibodies to preterm and term infants and to investigate antibody decay during the first 6 months of life in the preterm infants.Study design: Maternal and umbilical cord blood samples were taken from 113 healthy mother-newborn pairs: 64 term (gestational age > or =37 weeks) and 49 preterm (gestational age < or =35 weeks). Premature infants were further tested at 1, 2, and 6 months. Anti-VZV antibody to membrane antigen was measured with the immunofluorescent technique. RESULTS: Preterm infants of gestational age < or =28 weeks had positive cord antibody and a geometric mean titer significantly lower than those in preterm infants of gestational age 29 to 35 weeks and term infants (25% vs 95% and 95%, respectively, P <.001 for each, and 2.5 +/- 2.2 vs 10.5 +/- 2.4 and 12.6 +/- 2.4, respectively, P <.001 for each). There was no difference between the preterm 29 to 35 weeks of gestation and term groups. Fetal-maternal ratios for both preterm groups were <1 and were significantly less than the fetal-maternal ratio in the term infants. The transfer of maternal antibodies to term infants was significantly greater than to the 29- to 35-week preterm infants (P =.01). At 2 months of age, 25% of 29- to 35-week preterm infants and no preterm infant < or =28 weeks had a positive titer. At 6 months of age, all preterm infants were seronegative, and the geometric mean titer in both groups declined to undetectable levels. CONCLUSION: Transplacental transfer of maternal VZV antibodies is diminished in preterm infants. VZV antibody levels are significantly lower in preterm infants born at < or =28 weeks' gestational age compared with those in preterm infants 29 to 35 weeks' gestational age and term infants. Anti-VZV titers decrease to undetectable levels in preterm infants by 6 months of age or earlier; thus these infants appear to be susceptible to chickenpox before the scheduled 12-month vaccination.     

Value of brain ultrasound studies of newborn infants for prediction of neurological development in the 1st year of life

BACKGROUND: Recent advances in perinatology have been associated with a decrease in perinatal mortality. However, nowadays detailed assessments are of major importance for accurate prediction of neurologic development of extreme low birth weight infants and term infants with severely disturbed postnatal adaptation. This study examined the role of cranial ultrasound for the prediction of developmental progress during the first year of life. PATIENTS AND METHODS: Fifty nine infants with gestational age less than 33. weeks and fifty seven infants with gestational age above 32. weeks were studied. Each infant was classified as normal, suspect or abnormal using cranial ultrasound and a specialized scoring system during the first days and twelve month of life. Repeated structured neurological examination were carried out during the first year of corrected age. By statistical analysis was investigated the correlation between the degree of ultrasound abnormalities and neurological outcome of neonates of both different gestational age groups. RESULTS: We diagnosed the same share of pathological ultrasound scans in both groups within the first days of life. In contrast there were remarkable differences concerning the results of sonographic investigation at the end of the first year of life. We demonstrated a significant higher incidence of abnormal findings in neonates with a gestational age less than 33 weeks at this point of time. The neurological progress of neonates of both groups was significantly disturbed in cases of major sonographic abnormalities. Cases of mild or moderate ultrasound abnormalities were significantly associated with a poor neurologic outcome only in neonates with a gestational age less than 33 weeks. By statistical analysis we proved a significant value of cranial ultrasound for prediction of neurological development of preterm neonates with gestational age less than 33 weeks. The certainty prediction of neurodevelopmental sequelae in neonates with gestational age above 32 weeks was associated with major sonographic abnormalities but not with mild or moderate sonographic pathology. CONCLUSION: The prognostic accuracy of ultrasound scans performed in the first week of life is important for preterm neonates with gestational age less than 33 weeks. In neonates with gestational age above 32 weeks we revealed no significant predictive value of the method. This limits the value of this technique in this patients as a reliable method for recognising of the infants with the need of early rehabilitation.     

Gestational evolution of small intestine motility in preterm and term infants

Continuous perfusion manometry was performed in 31 preterm and term infants to assess the influence of gestational age on small intestinal motility. Gestational ages ranged from 27 to 42 weeks. All 8 term infants had interdigestive cycles that included all three phases. Only 4 of 23 preterm infants had complete interdigestive cycles. The remaining 19 preterm infants had only periods of motor quiescence and nonpropagating contractions. In term infants the interdigestive cycle was significantly shorter and the amplitude of phase 3 activity was significantly greater (p less than 0.01); velocity and duration of phase 3 activity were similar in both groups of infants. Rhythmic nonpropagating activity, or clusters, made up more than 60% of the phase 2 activity in both term and preterm infants. Although clusters did not propagate across three or more leads, approximately 25% of cluster activity was propagated across two leads. The duration of total cluster activity was similar for all gestational ages, but the frequency of clusters decreased and the mean duration of individual clusters increased with gestational age (both p less than 0.01). The amplitude of individual pressure peaks in clusters and phase 3 increased significantly with gestational age (p less than 0.03 and p less than 0.01, respectively). The motility index also increased with gestational age (p less than 0.02). We conclude that small intestinal motility is more immature in preterm infants than in term infants. Furthermore, cluster activity, which increases in duration and amplitude with gestational age, may be an immature form of phase 3 activity. These data and techniques will provide neonatologists with a direct way of tracking preterm intestinal motor function to provide more appropriate enteral nutrition.     

Iron status of the preterm infant during the first year of life

The iron status of 49 preterm infants (mean gestational age 33.1 weeks) was assessed serially during the 1st year of life. Haemoglobin concentration, serum ferritin, serum transferrin, serum iron, and transferrin saturation were measured on nine occasions in each infant. In 16 infants of gestational age 28-32 weeks the haemoglobin concentration was significantly lower at 3, 6, and 9 weeks when compared to 33 infants of gestational age 33-36 weeks. For all other measures of iron status there were no significant differences between these gestational age groups. For the entire group of 49 infants the mean haemoglobin concentration reached a nadir of 11.2 g/dl at 9 weeks. Mean serum iron and transferrin saturation reached peaks of 24 mumol/l and 65%, respectively, at 3 weeks. The mean serum ferritin remained over 100 micrograms/l until after 18 weeks. 13 infants (26%) had iron deficiency defined as either serum ferritin less than 10 micrograms/1 (n = 10) or transferrin saturation less than 10% (n = 5) or both (n = 3).     

Factors associated with weaning in full term and preterm infants

BACKGROUND: The optimal age for the introduction of solid foods (weaning) in infants is poorly researched yet may have implications for both short and longer term health. Many parents do not comply with current guidelines. OBJECTIVE: To determine and compare the age at weaning in term appropriate size for gestational age (AGA), small for gestational age (SGA), and preterm infants, and factors associated with weaning age in these groups. DESIGN: Data from > 2000 infants from seven prospective randomised trails conducted between 1990 and 1997 were used to address the objectives. RESULTS: Most infants, term AGA, SGA, or preterm, received solids before 4 months of age. Only 2% of term infants were exclusively breast fed to 6 months of age. Formula fed infants received solids on average two weeks earlier than breast fed infants. Preterm infants were significantly more likely, and term SGA infants less likely, to receive solids at both 6 and 12 weeks after term than term AGA infants. Weight at 6 weeks of age was a stronger predictor of earlier weaning than either birth weight or weight gain from birth to 6 weeks in term infants. In preterm infants, formula feeding and maternal smoking were associated with earlier weaning. CONCLUSIONS: Infants born in the mid 1990s were weaned on average earlier than the 4 months recommended by the Department of Health. Earlier weaning was associated with less positive health behaviours. Further research is required to provide evidence based weaning guidelines, including specific advice for SGA and preterm infants, and to investigate longer term consequences of weaning practices.     

The cavum septi pellucidi and cavum Vergae in infants -- an investigation with 2-dimensional sector-echo encephalography

Using a two-dimensional sector-scanner the brains of 642 preterm and term infants between 28 weeks of gestation and 12 months of age were examined for the incidence of a cavum septi pellucidi (CSP) and a cavum Vergae (CV). In 100 out of 642 infants we saw a CSP. The highest incidence (52%) was found among the infants of very low gestational age (-33 weeks) within the first seven days of life. After the second month the incidence decreases rapidly (only 1% in infants - months). We saw a CV only in combination with a CSP, less frequent, however, than a CSP alone (26 out of 642 infants): the incidence was 33% in infants of very low gestational age (-33 weeks) within the first seven days of live, only 4% in term neonates and 0% after the second month of life. Finally, the rupture of a septum with CSP and CV by stretching forces is demonstrated in an infant with progressive hydrocephalus. The data of this paper contribute to the knowledge of the morphological development of the normal fetal and newborn brain.     

Neonatal opiate abstinence syndrome in term and preterm infants

Data on 178 term and 34 preterm infants born to methadone-maintained mothers were analyzed to assess the effects of neonatal opiate abstinence in infants of varying gestational ages. More mothers in the term group (79%) than in the preterm group (53%) had abused other drugs during pregnancy (p less than 0.001). Mean (+/- SD) gestational age was 39.5 weeks +/- 1.4 for term infants and 34.3 weeks +/- 2.6 for preterm infants. On the basis of a semiobjective symptom scoring scale, term infants had more severe abstinence symptoms and more prominent central nervous system manifestations than preterm infants. The severity of abstinence symptoms correlated with maternal methadone dosage in both term and preterm infants. Maternal multiple drug abuse (e.g., heroin, cocaine) did not influence severity of abstinence symptoms in either group. More term infants (145/178) than preterm infants (20/34) required treatment for these symptoms (p less than 0.005). In 13 of 178 term infants, compared with 1 of 34 preterm infants, abstinence-related seizures developed. Peak severity occurred 1 to 2 days earlier in term than in preterm infants. A less severe abstinence syndrome in preterm infants may be due to (1) developmental immaturity of either dendritic ramifications, specific opiate receptors, or neurotransmitter function, or (2) reduced total drug exposure during the intrauterine period.     

Intestinal permeability in relation to birth weight and gestational and postnatal age

OBJECTIVE: To determine the relation between intestinal permeability and birth weight, gestational age, postnatal age, and perinatal risk factors in neonates. STUDY DESIGN: Intestinal permeability was measured by the sugar absorption test within two days of birth and three to six days later in preterm and healthy term infants. In the sugar absorption test, the urinary lactulose/mannitol ratio is measured after oral ingestion of a solution (375 mosm) of lactulose and mannitol. RESULTS: A first sugar absorption test was performed in 116 preterm (26-36 weeks gestation) and 16 term infants. A second test was performed in 102 preterm and nine term infants. In the preterm infants, the lactulose/mannitol ratio was not related to gestational age (r = -0.09, p = 0.32) or birth weight (r = 0.07, p = 0.43). The median lactulose/mannitol ratio was higher if measured less than two days after birth than when measured three to six days later (0.427 and 0.182 respectively, p<0.001). The lactulose/mannitol ratio was higher in preterm infants than term infants if measured within the first 2 days of life (0.404 and 0.170 respectively, p < 0.001), but not different three to six days later (0.182 and 0.123 respectively, p = 0.08). In multiple regression analysis of perinatal risk factors, only umbilical arterial pH correlated with the lactulose/mannitol ratio in preterm infants less than 2 days of age (T = -1.98, p = 0.05). CONCLUSIONS: In preterm infants (26-36 weeks gestation), intestinal permeability is not related to gestational age or birth weight but is higher during the first 2 days of life than three to six days later. It is higher in preterm infants than in healthy term infants only if measured within two days of birth. This suggests rapid postnatal adaptation of the small intestine in preterm infants.     

Arterial oxygen saturation in preterm infants at discharge from the hospital and six weeks later.

To obtain normal data on arterial oxygen saturation (SaO2) in preterm infants and to study early developmental changes in SaO2, we obtained overnight tape recordings of SaO2 and breathing movements in 160 preterm infants at their discharge from three special care baby units (mean gestational age at birth 33 weeks; at time of study, 37 weeks). One hundred ten infants (69%) underwent a second recording 6 weeks later. Median baseline SaO2 during regular breathing was 99.5% (range 88.7% to 100%) at discharge, and 100% (range 95.3% to 100%) at follow-up (p less than 0.001). The number of episodes of desaturation, defined as a fall in SaO2 to less than or equal to 80% for at least 4 seconds, corrected to the mean duration of recording (12.2 hours), decreased from a median of 3 (0 to 355) to 0 (0 to 17) (p less than 0.001). The median duration of each episode of desaturation remained unchanged (5.2 (4.0 to 22.7) vs 5.5 (4.2 to 24.0) seconds). At discharge, a small minority of infants had a clinically unrecognized low baseline SaO2 (lowest, 88.7%; 5th percentile, 95.7%) or a high number of desaturation episodes (the highest was six times the 95th percentile value). At follow-up, all outlying values had normalized. Follow-up recordings made between 42 and 47 weeks of gestational age (n = 53) were compared with similar recordings from 67 term infants at the same gestational age. The preterm infants had a significantly higher baseline SaO2 and no more desaturation than the infants born at term. Knowledge of normal ranges of oxygenation and their changes with age may be of value in identifying clinically undetected hypoxemia in preterm infants at discharge from the hospital. The potential influence of such hypoxemia on clinical outcome remains to be determined.     

Longitudinal measurements of bone status in preterm infants

BACKGROUND: Quantitative ultrasound measurement of the speed of sound (SOS) through bone has been investigated as a means of assessing bone status in preterm infants. Few studies report longitudinal measurements. OBJECTIVE: To assess longitudinal changes in bone SOS in preterm infants. METHODS: Sixty preterm infants with gestational ages of < 33 weeks and with birth weight appropriate for gestational age (AGA), and 48 healthy, term AGA infants were enrolled. SOS measurements of the tibia were made within the first week of life in the preterm infants, and within the first 72 hours of life in the term infants. During their hospital stay, weekly measurements of tibial SOS were made in 29 of the preterm infants, who were divided into three gestational age groups: Group 1: 24-26 weeks (n = 8), Group 2: 27-29 weeks (n = 9), and Group 3: 30-32 weeks (n = 12). RESULTS: The median SOS value for the 60 newborn preterm infants was significantly lower than that for the 48 newborn term infants (2,924 versus 3,036 m/sec, p < 0.001). At each time point, SOS values for each of the preterm infant gestational age groups were significantly lower than the term newborn infant SOS values. SOS values decreased significantly over time for the entire cohort of 29 preterm infants (p < 0.001), and for Groups 1 (p = 0.015) and 2 (p = 0.003). At several time points, there was a significant negative correlation between serum alkaline phosphatase levels and SOS values, and a significant positive correlation between serum phosphorus levels and SOS values. CONCLUSION: SOS measurements of the tibia decline during hospitalization in preterm infants, suggesting a progressive loss of bone strength. Longitudinal measurements of bone SOS in combination with serum alkaline phosphatase and serum phosphorus levels may identify infants at risk of developing osteopenia of prematurity.     

新生儿出生后24小时内凝血功能检测的临床意义分析

目的探讨不同胎龄以及不同体重新生儿凝血功能指标的差异,为判断凝血功能指标的临床意义提供参考。方法2015年1月至2018年12月期间,在解放军总医院第五医学中心新生儿科住院治疗的新生儿中,纳入170例胎龄28~42周、出生8 h内入院的新生儿,其中男性87例,女性83例。按胎龄分为早期早产儿组、晚期早产儿组和足月儿组。按新生儿出生体重分为正常出生体重组、低出生体重组和极低出生体重组。按是否小于胎龄分为早产适于胎龄儿组、早产小于胎龄儿组、足月适于胎龄儿组、足月小于胎龄儿组。于生后24 h内抽取静脉血,检测活化部分凝血活酶时间(activatedpartial thromboplastin time,APTT)、凝血酶原时间(prothrombin time,PT)、纤维蛋白原(fibrinogen,FIB)、凝血酶时间(thrombin,TT)及D-二聚体(D-dimer)。结果早期早产儿组的APTT、PT、D-二聚体水平均高于晚期早产儿组及足月儿组(P值均<0.05),FIB水平低于晚期早产儿组及足月儿组(P值均<0.05);晚期早产儿组的APTT、PT水平均高于足月儿组(P值均<0.05),但两组间D-二聚体、FIB水平比较,差异无统计学意义(P值均>0.05)。极低出生体重组的APTT、PT、D-二聚体水平均高于低出生体重组及正常出生体重组(P值均<0.05),FIB水平低于低出生体重组及正常出生体重组(P值均<0.05);低出生体重组的APTT、PT水平均高于正常出生体重组(P值均<0.05),但两组间D-二聚体、FIB水平比较,差异无统计学意义(P值均>0.05)。早产小于胎龄儿组D-二聚体水平高于早产适于胎龄儿组(P<0.05),其余指标比较差异无统计学意义(P值均>0.05);足月适于胎龄儿与足月小于胎龄儿组的凝血指标比较,差异均无统计学意义(P值均>0.05)。早产儿出血发生率高于足月儿[26.6%(29/109)与8.2%(5/61),χ^2=9.019,P=0.003]。结论新生儿凝血指标有胎龄和体重差异,胎龄越小、体重越低的新生儿凝血功能越不完善。     

晚期早产儿早期智能发育结局的研究

目的探讨晚期早产儿(LPI)早期智能发育结局。方法选择2012年1月至2015年1月新生儿病房收治的出生胎龄34~36+6周、治愈出院并定期规律随访的106例早产儿为晚期早产儿组;随机抽取同期120例健康足月儿(FPI)为对照组。对校正年龄40周的晚期早产儿及40周龄的足月儿进行新生儿神经行为测定(NBNA),晚期早产儿校正龄3、6、12月龄或者足月儿3、6、12月龄时采用Gesell发育量表进行评估。结果 LPI组NBNA评分低于37分,低于FTI组(P0.05)。校正龄3月龄时,LPI组大运动、精细运动、个人社交落后于FTI组(P0.05);校正龄6月龄时,LPI组适应性、大运动、精细运动落后于FTI组(P0.05);校正年龄12月龄时,LPI组适应性、大运动、个人社交测评明显低于FTI组(P0.05)。结论晚期早产儿早期智能发育迟缓,需加强神经发育监测。     

Water loss through the skin and rectal temperature under phototherapy with a doped halide radiating lamp

A new metal-halid phototherapy-lamp with a bilirubin-effective radiant energy of 11 W/m2 (focus distance 45 cm) was tested with regard to its influence on transepidermal water loss ("TEWL") and rectal temperatures. 23 term and preterm newborn infants (gestational age 28-40 weeks, body weight 980-3450 g) were examined on the first days after birth using the Evaporimeter-method. The mean value of TEWL in babies weighing greater than 2000 g (33 gestational weeks) calculated by a special graphic method (approximation) was 14 ml H2O/kg X 24 h increasing in the smallest babies in an exponential relationship. We recommend to compensate the raised TEWL with 10 ml/24 h and only in preterm babies weighing less than or equal to 1000 g (less than or equal to 28 gestational weeks) with 15 ml/24 h. Rectal temperatures raised only insignificantly under phototherapy.     

Oxygen saturation and breathing patterns in infancy. 2: Preterm infants at discharge from special care.

Overnight 12 hour tape recordings of arterial oxygen saturation (SaO2, pulse oximeter in the beat to beat mode), breathing movements, and airflow were made on 66 preterm infants (median gestational age 34 weeks, range 25-36) who had reached term (37 weeks) and were ready for discharge from the special care baby unit. No infant was given additional inspired oxygen during the study. The median baseline SaO2 was 99.4% (range 88.9-100%). Eight infants had baseline SaO2 values below 97%, the lowest value observed in a study on full term infants. All but one infant had short-lived falls in SaO2 to less than or equal to 80% (desaturations), which were more frequent (5.4 compared with 0.9/hour) and longer (mean duration 1.5 compared with 1.2 seconds) than in full term infants. There was no evidence that gestational age at birth influenced the frequency or duration of desaturations among the preterm infants. The frequency of relatively prolonged episodes of desaturation (SaO2 less than or equal to 80% for greater than or equal to 4 seconds), however, decreased significantly with increasing gestational age (0.5, 0.4, 0.2, and 0.1 episodes/hour in infants at less than or equal to 32, 33-34, 35, and 36 weeks'' gestational age, respectively). Analysis of the respiratory patterns associated with such episodes showed that 5% occurred despite both continued breathing movements and continuous airflow. Five infants had outlying recordings: three had baseline SaO2 values of less than 95% (88.9, 92.7, and 93.8%), and two had many prolonged desaturations (14 and 92/hour; median for total group 0.2, 95th centile 2.3). None of these five infants had been considered clinically to have dis order of oxygenation. Although these data are insufficient to provide information about outcome, we conclude that reference data on arterial oxygenation in preterm infants are important to enable the identification of otherwise unrecognized hypoxaemia.     

Influence of gestational age on cord serum bilirubin binding studies

The effect of gestational age on bilirubin binding was studied using cord serum from 22 preterm infants and 13 term infants and serum from 17 adults. Using the peroxidase oxidation method, a bilirubin titration curve was obtained by adding bilirubin to serum and measuring the apparent unbound bilirubin concentration. The resultant curve was analyzed using the least-squares fit of the empiric equation Y = aXb. After correction for albumin concentration by plotting the apparent unbound bilirubin concentration against the molar ratio of total bilirubin/albumin, term and preterm infants had identical titration curves, which remained inferior to that of adults. In addition, the apparent primary bilirubin association constant Ka'1 was similar for all infants but was two to three times less than that for adults. We conclude that bilirubin binding by cord serum is equivalent regardless of gestational age. However, adult serum binds bilirubin qualitatively better than does serum from infants of all gestational ages. We suggest that the adverse effect of prematurity on bilirubin binding noted in previous studies may have reflected postnatal complications rather than gestational age as such.     

Postnatal overestimation of gestational age in preterm infants

In a study involving 25 preterm infants, obstetric clinical age (standard gestational age) was determined by history, physical examination, and ultrasonographic evaluation. Postnatally, these infants were then evaluated using the Dubowitz Scoring System (DSS) for gestational age assessment. The DSS, as administered by us, significantly overestimated gestational age compared with the standard gestational age (mean +/- 1 SD: 34.2 +/- 2.9 vs 32.5 +/- 3.9 weeks, respectively) in preterm infants. To illustrate, the gestational ages of 13 newborns (52%) in the total study group were each overestimated by more than two weeks. This percentage increased to 75% among the 16 infants whose gestational ages were less than 34 weeks (by standard gestational age). When the standard gestational age was underestimated by the DSS, this difference never exceeded two weeks. These findings suggest that the present system of postnatal assessment of gestational age in preterm infants needs further investigation.