[Indications and concept of follow-up care of home-monitoring for premature and risk infants]. / Indikation und Nachsorgekonzept zur Heimmonitorüberwachung in der Komplexbetreuung von Früh- und Risikoneugeborenen.

The pros and cons of home monitoring especially for premature infants with continuing apneic episodes and/or chronic lung disease are an ongoing discussion. The controversy spans socio-economic requirements, medical indication as well as patient and family needs. Here, the costs of home monitoring and follow-up care on the one hand and longer hospitalization times on the other need to be considered. This article aims to create a basis for this discussion by summarizing current evidence for the indications and considerations for differential diagnoses while also outlining the established follow-up program for these patients at the Dr. v. Hauner Children's Hospital at the Ludwig-Maximilians-University Munich, Germany.

Predictive value of the 1-min Apgar score for survival at 23-26 weeks gestational age.

AIM: Is a 1-min Apgar score ≤1 predictive of mortality in resuscitated extremely premature infants? METHODS: A retrospective case-control review of all infants with gestational ages < 27 weeks over a 5-year period. All values as median [75% CI]. RESULTS: Of 237 infants, 29 had 1-min Apgar scores ≤1 (Group 1) and 208 had scores >1 (Group 2). Despite earlier and more frequent intubation (2 min [2.3; 6.7] vs. 5 min [7.5; 10] and 93% vs. 77%, p = 0.04), mortality was higher in Group 1 (62% vs. 17%; p < 0.0001). Age at death did not differ (Group 1: 3.5days [1; 30] vs. Group 2: 6 days [6; 44]). Birth weight and sex were the best predictors of survival. With a 1-min Apgar score of 1, a male infant at 23 weeks and 500g had a mortality rate of 92%. CONCLUSION: Despite successful resuscitation, infants between 23 and 26 weeks have a very poor prognosis for survival when presenting with bradycardia, cyanosis and no respiratory efforts (1-min Apgar = 1) at birth. According to our data, initiating active treatment for an infant at 23 weeks with bradycardia and apnoea is almost always unsuccessful, whereas by 26 weeks gestation, the chance of survival is higher than the probability of death.

Enteral nutrient supply for preterm infants: commentary from the European Society of Paediatric Gastroenterology, Hepatology and Nutrition Committee on Nutrition.

The number of surviving children born prematurely has increased substantially during the last 2 decades. The major goal of enteral nutrient supply to these infants is to achieve growth similar to foetal growth coupled with satisfactory functional development. The accumulation of knowledge since the previous guideline on nutrition of preterm infants from the Committee on Nutrition of the European Society of Paediatric Gastroenterology and Nutrition in 1987 has made a new guideline necessary. Thus, an ad hoc expert panel was convened by the Committee on Nutrition of the European Society of Paediatric Gastroenterology, Hepatology, and Nutrition in 2007 to make appropriate recommendations. The present guideline, of which the major recommendations are summarised here (for the full report, see http://links.lww.com/A1480), is consistent with, but not identical to, recent guidelines from the Life Sciences Research Office of the American Society for Nutritional Sciences published in 2002 and recommendations from the handbook Nutrition of the Preterm Infant. Scientific Basis and Practical Guidelines, 2nd ed, edited by Tsang et al, and published in 2005. The preferred food for premature infants is fortified human milk from the infant's own mother, or, alternatively, formula designed for premature infants. This guideline aims to provide proposed advisable ranges for nutrient intakes for stable-growing preterm infants up to a weight of approximately 1800 g, because most data are available for these infants. These recommendations are based on a considered review of available scientific reports on the subject, and on expert consensus for which the available scientific data are considered inadequate.

Haemoglobinopathies and newborn haemoglobinopathy screening in Germany.

Germany has been an immigration country since the early 1950s. In December 2007, 6.7 million non-German citizens lived in the country. However, the total number of citizens with a migration background is 15-20 million, about 9 million of whom come from countries where sickle cell disease and thalassaemias are frequent. In a country with 82 million inhabitants health authorities are not worried by the presence of probably 1000-1500 sickle cell and 450 transfusion-dependent thalassaemia patients, and therefore no screening or preventive measures have been taken so far on a national scale. There are plans for a pilot project (1 year) to screen all newborns for sickle cell disease in obstetric hospitals in 4-5 cities with more than 20% migrants. Funding and lack of an infrastructure to provide counselling are major problems.

Perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) in human breast milk: results of a pilot study.

Perfluorinated compounds (PFC) are a large group of chemicals produced for several decades and widely used for many industrial and consumer applications. Because of their global occurrence in different environmental media, their persistence and their potential to bioaccumulate in organisms they are of toxicological and public concern. In the present study, perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) were quantified in 70 breast milk samples. Samples were obtained from Leipzig, Germany (38 archived samples), Munich, Germany (19 fresh samples) and Gyor, Hungary (13 frozen samples). PFOS could be quantified in all 70 samples. The concentration in samples from Germany ranged between 28 and 309 ng/l (median: 119 ng/l). Samples from Hungary showed significantly higher PFOS concentrations (median 330 ng/l, range 96-639 ng/l). In only 11 of 70 samples (16%) PFOA reached the LOQ (200 ng/l); values ranged from 201 to 460 ng/l. If only those samples with PFOA values above the LOQ were considered, we found a significant correlation between the PFOS and PFOA concentrations (r=0.75, p=0.008). Based on the results of the German sample, we estimated an intake of 0.10 microg PFOS/day (using median) or 0.27 PFOS microg/day (using maximum value) via breast milk for an infant of 5 kg bodyweight. Our data suggest that fully breastfed infants are unlikely to exceed the recommended tolerable daily intake of PFC. However, more target-oriented studies are needed to identify the amount and time-trend of PFOS and PFOA in maternal blood during pregnancy, after delivery, as well as in the growing infant and in its diet (e.g., breast milk and formula).

Crash emergency cesarean section: decision-to-delivery interval under 30 min and its effect on Apgar and umbilical artery pH.

PURPOSE: The objective of this study was to investigate the effect of decision-to-delivery interval of crash emergency cesarean section on Apgar and umbilical artery pH in a level-3 university hospital. MATERIALS AND METHODS: In a retrospective analysis, all women undergoing "crash" emergency cesarean section were evaluated. Emergency cesarean sections were performed in the delivery room. Data relating to indication, Apgar score, arterial cord pH, and time intervals between decision-to-deliver and actual delivery were collected retrospectively. RESULTS: All 109 crash emergency cesarean sections were performed within a decision-to-delivery time of 30 min. The median (with 10-90th percentile) time was 10 min (5-19). Thirty-three (30.3%) of the emergency cesarean sections had a gestational age below 32 weeks and 60 (55%) below 37 weeks. An abnormal fetal heart rate pattern was noted in most of the cases (91%). Prolapsed cord (21%) and placental abruption (20%) were the most frequent reasons for emergency cesarean section but in one-fourth (25.7%) no morphological reason could be identified. Very short decision-to-delivery times below 20 min were inversely correlated to fetal outcome, i.e., lower umbilical blood pH and Apgar scores (P < 0.01). CONCLUSION: The 30-min standard for the decision-to-delivery time interval set by Anglo-American countries may be a feasible guideline at least for level-3 hospitals. The 20-min interval set by the German Society of Gynecology and Obstetrics could not be achieved in all cases. The positive effect of very short intervals on neonatal outcome still needs to be proven.

Losses of vitamin A and E in parenteral nutrition suitable for premature infants.

OBJECTIVE: To assess the bioavailability of vitamins A and E administered parenterally with either water-soluble or lipid-soluble preparations. STUDY DESIGN: A water soluble preparation (MVI Pediatric) administered with a glucose-amino acid solution and a lipid soluble preparation (Vitalipid N Infant) infused with a lipid emulsion were subjected to phototherapy light, different flow rates, light protection, different tubing materials and tubing sizes, and concentrations in the effluents were determined. RESULTS: Recovery of retinol in glucose-amino acid solution was poor under all conditions (16-30% without; 21-42% with light protection tubing) and increased to 61% with polyethylene and to 44% with polyurethane tubings. Polyurethane tubings with reduced volume improved retinol delivery to 56%. Retinylpalmitate (Vitalipid) losses were low, with recovery of 86 and 77% with and without light protection, respectively. Recoveries of alpha-tocopherylacetate in GLUC-AA were 103-107% without and 94-102% with light protection and of alpha-tocopherol in LIPID 89% without and 85% with light protection. CONCLUSIONS: Parenteral vitamin A delivery is improved by the infusion of retinylpalmitate with lipids. Light protecting tubings provide only a marginal benefit with artificial light and none with phototherapy light. Polyethylene and polyvinylchloride tubings adsorb less retinol than polyurethane tubings. Small tubing diameters resulting in higher flow rates enhance retinol delivery.

Clinical presentation of congenital sialidosis in a patient with a neuraminidase gene frameshift mutation.

UNLABELLED: Congenital sialidosis is a rare lysosomal storage disease caused by a primary neuraminidase deficiency which results from defects in the neuraminidase gene on chromosome 6p. The inheritance is autosomal recessive. Patients exhibit excessive urinary excretion of bound sialic acid and decreased or undetectable amounts of neuraminidase activity in various tissues. The clinical expression is variable, but ascites and hepatosplenomegaly are hallmarks of the disease. Skeletal abnormalities, facial dysmorphism and inguinal herniae have been described in most of the few reported cases. We describe a baby girl with biochemically proven sialidosis, who in addition to the above clinical features, had severely dilated coronary arteries, excessive retinal vascular tortuosity and an erythematous, macular rash. Homozygosity for a frameshift mutation at residue 623 of the neuraminidase cDNA was found. We speculate that the additional features found in our patient might be associated with the here described genotype of congenital sialidosis. CONCLUSION: Severely dilated coronary arteries, excessive retinal vascular tortuosity and an erythematous macular rash might be associated features of congenital sialidosis.

Disseminated adenovirus infection in two premature infants.

We present two premature infants with disseminated neonatal adenovirus infection, whose epidemiology, clinical course and outcome differ to a great extent. The first infant, born vaginally at 35 weeks gestational age after premature rupture of membranes and maternal illness, developed pneumonia, hepatitis and coagulopathy and died of circulatory failure at the age of 17 days. The other infant, delivered by cesarean section at 36 weeks gestational age, did - in contrast to all documented cases in the literature - not show any signs of pneumonia and survived meningitis without sequelae. The mode of transmission of the viral infection may have been via the maternal birth canal in the first infant and transplacental in the second one. Diagnosis was obtained by direct immunofluorescent test and serology in the first patient and by maternal serology and the detection of viral antigen in tracheal aspirates (ELISA) in the second patient. Disseminated neonatal adenovirus infection has a high mortality and should be considered in the differential diagnosis of neonatal sepsis, especially when pneumonia, hepatitis and neurologic symptoms develop together with thrombocytopenia or disseminated intravascular coagulopathy.

[Congenital skull depression. Case report and review of the literature]. / Konnatale Schädelimpression. Fallbericht und Literaturübersicht.

A 40-week gestational age infant was delivered by cesarean section because of intense contractions and pathological fetal heart rate pattern. The umbilical artery pH was 7.03, Apgar scores were 1/4/7 at 1, 5 and 10 min of age. The 3,250-gram infant had a skull depression of 5 x 7 cm in the left temporal-parietal region with a depth of 1.5 cm. There were no edemas or hematomas in this area; neurological examination was normal. A CT scan did not show a fracture, but the cortex below the depression appeared slightly compressed. At the age of 11 days, the depressed part of the parietal squama was surgically elevated. The child was discharged in good condition 8 days later and remained well at a 6-month follow-up examination.

Randomized comparison of high-frequency ventilation with high-rate intermittent positive pressure ventilation in preterm infants with respiratory failure.

OBJECTIVE: In a randomized, controlled, multicenter trial, we tested the hypothesis that high-frequency ventilation (HFV) with a high lung volume strategy results in fewer treatment failures than intermittent positive pressure ventilation (IPPV) with high rates and low peak inspiratory pressures. STUDY DESIGN: Infants with a gestational age between >/=24 weeks and <30 weeks, requiring mechanical ventilation within 6 hours of birth, were randomly assigned to receive either IPPV or HFV until 240 hours after randomization, extubation, or meeting treatment failure criteria. Treatment failure, the primary end point, was determined when air leaks, an oxygenation index >35 to 45 (depending on gestational age), death, or chronic lung disease occurred. Chronic lung disease was defined as persistent requirement of mechanical ventilation, continuous positive airway pressure, or supplemental oxygen at a postmenstrual age of 36 weeks. Secondary end points included the incidence of intracranial hemorrhage. RESULTS: The third scheduled interim analysis led to termination of the trial after recruitment of 284 infants. Treatment failure criteria were met by 46% of infants receiving IPPV and 54% of infants receiving HFV (1-tailed primary hypothesis, P =.92; 2-tailed chi2 test, P =.15). Air leaks occurred in 31% and 42% (P =.042), CLD in 23% and 25%, and grade 3-4 intracranial hemorrhage in 13% and 14% of IPPV-treated and HFV-treated patients, respectively. The mortality rate before discharge was 10% in both groups. CONCLUSION: HFV with a high lung volume strategy did not cause less lung injury in preterm infants than IPPV with a high rate and low peak inspiratory pressures.

Ureaplasma urealyticum colonization and bronchopulmonary dysplasia: a comparative prospective multicentre study.

UNLABELLED: To determine the role of tracheal colonization at birth with Ureaplasma urealyticum and other pathogenic bacteria with regard to the development of bronchopulmonary dysplasia (BPD), 97 premature infants with very low birth weight (< 1500 g) were followed prospectively over 30 days in a multicentre study. Of those infants, 35 were colonized with Ureaplasma urealyticum (group Ia), 22 with other pathogenic bacteria (group Ib) and 40 infants with sterile tracheal aspirates served as controls (group II). Colonization with Ureaplasma urealyticum or with pathogenic bacteria independently increased the risk of developing BPD as compared to the controls (OR 2.55; 95% CI [1.11, 5.87]). Among Ureaplasma urealyticum and bacterial colonized infants, duration of mechanical ventilation and oxygen requirement were significantly longer than among controls (P < 0.05); during the interval of 11 to 35 days of life, every additional day of ventilation significantly increased the risk of BPD (OR 1.22; CI [1.12, 1.32]). The rate of oxygen supplementation, which was similar in both groups during the first 2 weeks of life, was significantly higher among the colonized infants at day 21 (0.38+/-0.18 and 0.39+/-0.16 vs 0.31+/-0.13, P < 0.05) and at day 28 (0.38+/-0.21 and 0.34+/-0.15 vs 0.28+/-0.12, P < 0.05). For infants still ventilated at age of 28 days, Ureaplasma urealytricum and bacterial colonization were associated with a significant higher risk for BPD than for uncolonized controls (OR 5.53; [1.27, 24.02]. Association of Ureaplasma urealyticum and of bacterial colonization and BPD was not weakened after adjustments were made in a multivariate analysis for other significant risk factors. CONCLUSION: Ureaplasma urealyticum colonization is as an important risk factor in the development of bronchopulmonary dysplasia as bacterial colonization even after treatment with surfactant.

Vaginal Ureaplasma urealyticum colonization: influence on pregnancy outcome and neonatal morbidity.

The effects of Ureaplasma urealyticum colonization on pregnancy and neonatal outcome was prospectively studied in women with impending term or preterm delivery. One hundred and seventy women colonized with U. urealyticum as the only pathogenic microorganism and 83 women with negative cultures were enrolled for study. Compared to the controls, U. urealyticum colonization was associated with a significantly increased rate of amnionitis (2% vs 35%; p < 0.001), chorioamnionitis (0% vs 10%; p < 0.05), premature rupture of membranes (12% vs 35%; p < 0.001) and preterm delivery (10% vs 41%; p < 0.001). The rate of vertical transmission ranged from 38% in term infants to 95% in very low birth weight infants. U. urealyticum colonization at birth was associated with an increased risk for the development of respiratory distress syndrome (9% vs 51%), intraventricular hemorrhage (1% vs 7%) and bronchopulmonary dysplasia (4% vs 17%) in very low birth weight infants (< 1500 g). It is concluded that maternal U. urealyticum colonization is associated with amnionitis, chorioamnionitis and preterm delivery, and that tracheal colonization with U. urealyticum increases the risk for respiratory and neurological complications in very low birth weight infants.

Fatty acid composition of human milk during the 1st month after term and preterm delivery.

UNLABELLED: The fatty acid composition of human breast milk was determined longitudinally after term and preterm delivery by high resolution gas liquid chromatography. Milk samples were obtained at days 5, 10, 20 and 30 after term (n = 38) or preterm (n = 19) delivery. The saturated fatty acids C10:0 and C12:0 and the polyunsaturates linoleic acid (C18:2 omega-6) and alpha-linolenic acid (C18:3 omega-3) increased significantly from day 5 to day 10, whereas arachidonic acid (C20:4 omega-6), total omega-6 long-chain polyunsaturates (LCP), docosahexaenoic acid (C22:6 omega 3) and total omega-3 LCP decreased significantly. Term and preterm milk did not differ in percentage content of linoleic acid, alpha-linolenic acid and LCP at any time point. Preterm milk contained significantly more medium and intermediate chain fatty acids (C10:0, C12:0 and C14:0) than term milk on days 5 (12.28 vs 9.78%; P > 0.05), 10 (16.25 vs 12.62%; P > 0.05) and 20 (17.29 vs 13.47%; P > 0.005). CONCLUSION: The milk of mothers of preterm infants is not better suited to meet the high LCP requirements of their infants during the first weeks after birth. The slightly higher proportion of medium and intermediate chain fatty acids in preterm milk during the 1st month after birth might be advantageous for the fat and calcium absorption of preterm infants.

Two brothers with multiple congenital anomalies and mental retardation due to disomy (X)(q12-->q13.3) inherited from the mother.

We present the phenotypic, cytogenetic and molecular findings in two dysmorphic and mentally retarded brothers with disomy Xq12-->q13.3. The mother and the grandmother carry the same rearrangement of the X chromosome, which was interpreted as an inverted insertion of the segment (X)(q12-->q13.3) into Xq21.2. The X-inactivation-specific-transcript (XIST) is expressed in the probands mother but is absent in her son, confirming the hypothesis that X inactivation is realized only if two X inactivation centers reside on different X-chromosomes (trans-configuration). In the phenotypically normal mother the aberrant X chromosome was late replicating in all cells, indicating functional monosomy of the constitutional segment trisomy. The phenotype of the brothers is considered to be the consequence of a functional disomy Xq12-->q13.3. The trait combination observed in the brothers was compared with the spectrum of clinical and anthropological traits for proximal Xq disomy in males, elaborated by phenotype analyses of the available literature cases.

Plasma values of polyunsaturated fatty acids in extremely low birth weight (ELBW) infants fed breast milk or formula very early in life.

The influence of very early enteral feedings on plasma fatty acid levels in 29 sick, very premature infants with gestational age < 30 weeks was assessed at age 1, 3 and 7 weeks. Eighteen infants (birthweight 963 +/- 245 g, gestational age 27 +/- 1.3 weeks) received breast milk and 11 infants (829 +/- 159 g and 26 +/- 1.3 weeks) received formula, starting with small amounts on the first day after birth. Plasma phospholipid arachidonic acid (AA) levels decreased in both groups, but only the decline at 3 weeks in the formula-fed group was statistically significant (10.6 +/- 0.5 versus 8.0 +/- 0.4% weight, P < or = 0.05). The plasma phospholipid docosahexaenoic acid (DHA) levels of the formula-fed infants also declined from Week 1 to Week 7 (2.1 +/- 0.1 to 1.7 +/- 0.2 weight %; p < or = 0.05). In contrast, human milk-fed infants maintained their plasma phospholipid DHA levels, which were significantly higher at 7 weeks than those of the formula-fed infants (1.7 +/- 0.2 vs 2.3 +/- 0.2; p < or = 0.05). The decline in plasma DHA levels of our formula-fed very premature infants was of similar magnitude to that previously reported for larger premature infants. On the other hand, it is reassuring that very premature infants are able to maintain plasma DHA levels during the first weeks of life, if they receive even small amounts of breast milk.

[Mortality, mode of delivery, pneumothorax and intracranial hemorrhage in 859 extremely premature newborn infants between 1984-1992]. / Mortalität, Geburtsmodus, Pneumothorax und intrakranielle Blutungen bei 859 extrem Frühgeborenen zwischen 1984-1992.

In a retrospective study we investigated the mortality and the most important complications of all very low birth-weight infants (VLBW; < or = 1500 g and/or < or = 32 weeks) born with vital signs between 1984 and 1992 at the Klinikum Grosshadern, Munich University Hospital. During this period 859 premature infants fulfilled the entrance criteria. The perinatal mortality rate was 174/859 infants (20%). During the study period the mortality rate dropped significantly from 25% (1984-1986) to 15% (1990-1992). Premature infants born after 26 gestational weeks showed the most significant decrease in mortality. Excluding non viable infants with extreme immaturity ( < 24 weeks of gestation) or lethal malformations; the mean corrected mortality rate was 11%, decreasing over the years from 16% (1984-1986) to 5% (1990-1992). Caesarean section was performed in 70% of all children (602/859), vaginal delivery in 28% (239/859), delivery by forceps in 1% (7/859), and the mode of delivery was not clearly registrated in 1% (11/859). The incidence of Caesarean section increased significantly from 55% (1984-86) to 79% (1990-92). Evaluating the mode of delivery in relation to mortality, a significant difference was found between the infants delivered vaginally (40%, 95/239) and those delivered by Caesarean section (11%, 67/602). This improved survival after Caesarean section was statistically significant for the group with a birth weight of less than 1500 g. The rate of pneumothorax also declined significantly from 19% to 9%. The rate of intracranial haemorrhage (ICH) remained almost constant during these years, but the incidence of ICH grade 3 and 4 decreased from 15% (1984-1986) to 6% (1990-1992). Probably because of improved antenatal care and the progress in neonatal intensive care, the chance of survival for VLBW infants has substantially improved over the last decade. Estimations of the prognosis of VLBW infants based on data from the 1980s are out of date.

Low density lipoproteins (LDL) heterogeneity and intravenous fat in neonates.

BACKGROUND: The properties of iv-fat emulsions are similar to those of triglyceride-rich plasma lipoproteins and rapidly hydrolyzed by lipoprotein lipase. Neonates frequently do not tolerate iv-fat because of low levels of the key enzymes for fat metabolism. PURPOSE OF THE STUDY: We examined the effect of iv-fat therapy on LDL subclass distribution of 20 neonates unable to tolerate enteral feeding. METHODS: Particle size was determined by non-denaturing gradient gel electrophoresis. RESULTS: The LDL size distribution profiles at baseline showed unexpected diversity in the position of the major lipoprotein peak with three different profiles identified by peak position; profile I with a major peak of large-sized LDL (26.3-28.2 nm), profile II with a major peak at 25.2-26.7 nm and profile III with a major peak of small-sized particles (24.9-25.6 nm). None of the profiles fit the classical LDL pattern A or B found in adult plasma since the skewness associated with the adult pattern was not present. With iv fat feeding and enteral nutrition, no major shift in peak position was observed, even though plasma triglyceride and apo B concentrations increased suggesting that there was an increased number of LDL particles rather than an increase in the size of particles. CONCLUSION: The constancy of the LDL peak position in the face of increases in plasma triglyceride and apo B concentrations during iv fat and the onset of enteral nutrition in neonates suggests that other metabolic events, such as hormone status and lipid and transfer protein activities need to be considered.

Apolipoprotein-specific populations in high density lipoproteins of human cord blood.

High density lipoproteins (HDL) in human cord blood have previously been shown to exhibit particle size profiles distinctly different from those of adult HDL. The adult HDL profile is comprised of separate contributions from two major apolipoprotein-specific populations; one population contains both apolipoproteins AI and AII (HDL(AIwAII], while the other has apolipoprotein AI without AII (HDL(AIw/oAII]. The present studies establish that cord blood HDL are also comprised of HDL(AIwAII) and HDL(AIw/oAII) populations whose particle size profiles closely reflect cholesterol and HDL-cholesterol levels in cord blood. Compared with the adult, cord blood HDL(AIwAII) profiles generally show both a greater subspeciation within HDL2a and HDL3b/3c size intervals as well as relative reduction of material in the HDL3a interval. In the cord blood HDL(AIw/oAII) profile, HDL2b(AIw/oAII) particles also show subspeciation with a major component that is consistently larger than that normally observed in the adult (11.2 vs. 10.3 nm). As in the adult, the HDL3a(AIw/oAII) component is present but, unlike the adult, its relative amount is low; hence, its peak is usually not discernable in the cord blood total HDL profile. Our studies show that the larger-sized HDL2b(AIw/oAII) of cord blood are enriched in phospholipid which probably accounts for their increased size. The protein moiety of the larger-sized HDL2b(AIw/oAII) has a molecular weight equivalent to four apolipoprotein AI molecules per particle similar to the normal-sized adult subpopulation. Phospholipid enrichment of cord blood HDL(AIwAII) subpopulations within the HDL2a size interval was not observed. However, the protein moiety of cord blood HDL2a(AIwAII) is unusual in that it exhibits an apolipoprotein AI:AII molar ratio considerably lower (0.8:1 vs. 1.6:1) than that of adult. We suggest that the unique particle size distribution of cord blood total HDL is due in large part to: (a) a specific enrichment of phospholipid in HDL2b(AIw/oAII) species, producing particles larger than normal adult counterparts and (b) an elevated proportion of apoAII carried by the HDL(AIwAII) particles that may influence subspeciation in the HDL3a/b/c size interval.