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PubMed1979

Adaptive gluconeogenesis in preterm and term rabbits.

UNLABELLED: Carbohydrate metabolism in the developing rabbit was investigated for deficiencies that may be responsible for the failure of many preterm (28 1/2--29 1/2 day) animals to survive the first hours of life. The preterm animal shows an inability to reverse glycogenolysis or initiate gluconeogenesis from lactate or alanine in the first hours of life. This impairment, coupled with 50% less liver glycogen stores than the term animal, places the preterm animal at jeopardy for energy substrate early on in life. Unexpected was the early, rapid conversion of glycerol to glucose by the preterm animal. This ability seemed to be the primary difference in carbohydrate metabolism between the surviving and nonsurviving preterm rabbit. SPECULATION: Impaired glyconeogenesis from lactate and alanine in the preterm animal coupled with active gluconeogenesis from glycerol suggests that substrates from lipolysis may be very important for early adaptation. Preterm animals endowed with limited fat stores, thus, minimal available glycerol, would be incapable of survival.

Animals↗

PubMed1992

Time course of trough serum gentamicin concentrations in preterm and term neonates.

Trough serum concentrations (Cmin) of gentamicin were followed during up to 96h of treatment in 44 neonates (17 preterm and 27 term), treated with intramuscular gentamicin 2.5 +/- 0.3 mg/kg (mean +/- SD) twice daily, a dosage that was not changed during the follow-up period. Relationships with patients' gestational age, postnatal age, postconceptional age and bodyweight were analysed to identify circumstances in which gentamicin should be monitored. Gentamicin Cmin values after 24h correlated better with neonate's postconceptional age (r = -0.42) or gestational age (r = -0.37) than with postnatal age or bodyweight. Correlations with postconceptional age and gestational age improved after 96h (r = -0.71 and r = -0.67, respectively). From 24 to 96h Cmin increased from 1.5 to 2 mg/L (p < 0.001) in the preterm neonates and from 1.5 to 2.5 mg/L (p < 0.01) in those preterm neonates < or = 32 weeks of gestational age, while differences between neonates < or = 3 days and > 3 days of postnatal age were nonsignificant. The Cmin at 24h was potentially toxic (> 2 mg/L) in 9% of the neonates (12% of preterm and 7% of term neonates). At 96h, the percentage of neonates with toxic Cmin values increased to 25% (65% of all preterm neonates and 100% of preterm neonates < or = 32 weeks of gestational age), whereas in term neonates it decreased to 0%. In conclusion, in preterm neonates < or = 32 weeks of gestational age a dosage of 2.5 mg/kg every 24h should be used, and gentamicin concentrations should be monitored. However, in term neonates > 7 days of postnatal age a dosage of 3.5 mg/kg twice daily should be recommended.

Analysis of Variance↗

PubMed1992

A study of the epidemiology of preterm labor.

A case-control study was designed in order to identify risk factors associated with preterm labor. All cases fulfilling the criteria of eligibility as preterm labor and attending the Ain Shams University Maternity Hospital during the period from January 1991 to June 1991 were included in the study. In the meanwhile, all women delivering after the 37th week of gestation during that period and in the same hospital and matched according to age (+/- 5 years) were included as the control group. Two hundred and thirty four cases and 216 controls were included in the study. An interview was performed to fill an epidemiologic and clinical questionnaire. Results showed that the lower the socioeconomic standard, the more the risk for preterm labor (p < 0.05), smoking whether active or passive is associated with preterm labor (p < 0.001), threatened or induced abortion, unwanted pregnancy, psychological trauma and surgical intervention during current pregnancy are associated with preterm labor (p < 0.001). History of preterm labor is associated with the present condition (p < 0.001). Anemia, hypertension, body weight less than 70 kgm are associated with preterm labor (p < 0.001).

Adult↗

PubMed1992

Amniotic fluid platelet-activating factor (PAF) is elevated in patients with tocolytic failure and preterm delivery.

Certain biological properties of PAF, including its ability to promote PGE2 synthesis and to induce myometrial contractions, support its potential role in parturition. The presence of PAF in amniotic fluid of human pregnancy appears to correlate with normal and pathologic labor. To further refine this relationship, we selected the clinical endpoints of preterm labor, tocolytic failure and preterm delivery, and evaluated amniotic fluid PAF within these groups of patients. We also measured acetylhydrolase (AH), PAF's primary degradative enzyme, to identify any correlation with the observed PAF levels. 39 specimens were collected by amniocentesis: 17 for karyotype, 6 to assess lung maturity at term and 16 in cases of preterm labor; 8 each with intact membranes and ruptured membranes at the time of sampling. PAF and AH were measured by a 3H-serotonin release bioassay and an in vitro enzyme assay using radiolabelled substrate, respectively. A 12-fold increase in PAF was found in the 3 preterm labor patients in whom tocolysis failed (delivery less than 48 hrs after treatment) compared to the 7 patients in whom labor was arrested (mean PAF = 35.0 vs 2.9 ng/ml, respectively; p = .017). Four of 8 patients with membrane rupture had preterm deliveries; their PAF levels were also elevated when compared to those that delivered at term (mean PAF = 19.7 vs 4.95 ng/ml). The 2 patients with positive amniotic fluid gram stains had the highest PAF levels in the entire cohort (30.5, 44.1 ng/ml), with low or undetectable AH. These data suggest that increased PAF production may be associated with preterm labor subsequent to tocolytic failure.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed1992

Elevated maternal plasma corticotropin-releasing hormone levels in pregnancies complicated by preterm labor.

OBJECTIVES: We investigated whether maternal plasma levels of the placental hormone corticotropin-releasing hormone are elevated in pregnancies complicated by preterm labor. STUDY DESIGN: Mean maternal corticotropin-releasing hormone levels were studied in women who met specific criteria for preterm labor and in women with normal pregnancies. Levels were also compared in the latent and active phases during term labor. RESULTS: In pregnancies complicated by preterm labor, maternal corticotropin-releasing hormone levels were higher than in normal pregnancies; this elevation occurred before labor was diagnosed clinically (p less than 0.05). When preterm labor was associated with infection, the mean levels were not elevated. Mean plasma levels were similar in latent and active phases during labor at term. CONCLUSION: Maternal plasma corticotropin-releasing hormone levels are elevated in association with preterm labor. This elevation does not appear to be due to labor itself and may reflect an early activation of the placenta before the onset of preterm labor.

Corticotropin-Releasing Hormone↗

PubMed1992

The natural interleukin-1 receptor antagonist prevents interleukin-1-induced preterm delivery in mice.

OBJECTIVES: Interleukin-1 has been implicated in the mechanisms responsible for preterm parturition in the setting of intrauterine infection. This cytokine is produced by human decidua, stimulates prostaglandin production by intrauterine tissues, and induces preterm parturition in mice. The purpose of this study was to determine whether pretreatment with the natural interleukin-1 receptor antagonist can block interleukin-1-induced preterm parturition in mice. STUDY DESIGN: Balb/CJ female mice impregnated by B6D2 F-1 male mice were randomly allocated to one of the following treatment groups: (1) saline solution (n = 15), (2) human recombinant interleukin-1 alpha or human recombinant interleukin-1 beta (n = 12), (3) human recombinant interleukin-1 receptor antagonist (n = 13), and (4) human recombinant interleukin-1 receptor antagonist plus human recombinant interleukin-1 (n = 24). RESULTS: An interleukin-1 dose of 10 micrograms per mouse induced preterm parturition in all cases. Pretreatment with interleukin-1 receptor antagonist (dose 1 mg per animal) prevented interleukin-1-induced preterm parturition. Interleukin-1 receptor antagonist administration was not associated with demonstrable side effects including behavioral changes, vaginal bleeding, duration of pregnancy, and pregnancy outcome. CONCLUSION: Our results suggest that interleukin-1-induced preterm delivery in mice is mediated by the interleukin-1 receptor.

Animals↗

PubMed1992

Antral and duodenal motor responses to duodenal feeding in preterm and term infants.

In the fasting state, antral motor activity is similar in preterm and term infants, but the antral responses to feeding have not been compared in preterm and term infants. The purpose of this study was to use low-compliance, continuous perfusion manometry to compare antral and duodenal feeding responses in 13 preterm and nine term infants within the first 14 days of life. Confirming our previous studies, fasting antral motor activity was similar in preterm and term infants, but duodenal activity differed. Individual duodenal cluster activity was of shorter duration in preterm than in term infants (p less than 0.01). Motor activity in antrum and duodenum changed in both groups of infants in response to an intraduodenal milk infusion of 4 ml/kg/2 h; however, the nature of the change varied in the two regions. In term infants, the number of antral pressure waves, the duration of antral clusters, and the antral motility index decreased by one third or more during feeding when compared with fasting (all p less than 0.05). In contrast to the decrease in antral activity in response to feeding, the duodenal motility index and cluster activity increased significantly during feeding compared with fasting (both p less than 0.05). The divergent response of antral and duodenal motor activity in response to feedings was also seen in preterm infants. Antral pressure waves, the duration of antral clusters, and the antral motility index were decreased during feeding (all p less than 0.005 or less).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

An assessment of key aetiological factors associated with preterm birth and perinatal mortality.

The 4 main causes of preterm births in 303 women with consecutive deliveries in Flinders Medical Centre were premature rupture of the membranes (39%), spontaneous preterm labour (22%), pregnancy-induced hypertension (17%) and antepartum haemorrhage (12%). Premature rupture of the membranes occurred with equal frequency in singleton and multiple pregnancies and there was no difference in the frequency of this cause between the pregnancies with live outcomes and those with perinatal deaths. Spontaneous preterm labour was more common in multiple pregnancies (39%) than in singleton pregnancies (22%). One in 3 of the preterm births and 79% of the pregnancies with perinatal deaths occurred at less than 32 weeks' gestation. As it is unlikely that any single obstetric and social intervention will be able to reduce these causes of preterm birth research must continue to find markers to predict premature rupture of the membranes and spontaneous preterm labour.

Chi-Square Distribution↗

PubMedDate not supplied

Interleukin-1 alpha and interleukin-1 beta in preterm and term human parturition.

Interleukin-1 (IL-1) has been implicated in the mechanism of human parturition in the setting of infection. The purpose of this study was to determine the effect of labor (term and preterm) and microbial invasion of the amniotic cavity on amniotic fluid (AF) concentrations IL-1 alpha and IL-1 beta. AF was retrieved by transabdominal amniocentesis from the following groups of women: midtrimester genetic amniocentesis (16 to 18 wk) (N = 15), preterm labor with intact membranes (21 to 36 wk) with or without infection (N = 72), preterm premature rupture of membranes (PROM) (N = 88), and term not in labor or in active labor with or without infection (N = 58). AF was cultured for aerobic and anaerobic bacteria as well as Mycoplasmas. IL-1 was measured with a commercially available immunoassay validated for AF (sensitivity: IL-1 alpha, 157 pg/ml; IL-1 beta, 50 pg/ml). All women at midtrimester had undetectable AF IL-1 alpha and IL-1 beta. Among women in preterm labor with positive AF cultures, IL-1 alpha and IL-1 beta were detectable in the AF in 86.6% (13/15) and 100% (15/15), respectively. In contrast, all women with negative AF cultures without labor (N = 36) had undetectable AF IL-1 alpha concentrations and 52.7% (19/36) had undetectable AF IL-1 beta concentrations. Histopathological chorioamnionitis was present in 92.8% (13/14) of patients who had positive AF cultures and detectable IL-1 in the AF. IL-1 was significantly higher in patients with preterm PROM, labor, and positive AF cultures than in the other subgroups of patients with preterm PROM.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗

PubMed1992

Lipoproteins in preterm and small-for-gestational-age infants during the first week of life.

Plasma lipoprotein levels and composition have been determined in preterm and small-for-gestational-age (SGA) infants, and compared to full-term infants, during the first week of life. Significantly lower levels of HDL and higher levels of VLDL were found in both preterm and SGA infants in comparison to full-term healthy infants. These results suggest a low capacity to metabolize VLDL. Preterm infants showed a behaviour similar to full-term infants with regard to the changes in lipoprotein composition. Small-for-gestational-age infants showed a higher lipoprotein lipid content than preterm infants. A low ratio of cholesteryl ester to free cholesterol (CE/FC) was found in both preterm and SGA infants suggesting a reduced lecithin: cholesterol acyl transferase (LCAT) activity. In preterm infants we observed no changes in the CE/FC ratio during the first week of life, whereas in SGA infants this ratio increased after birth.

Apolipoproteins↗

PubMed1992

Neutrophil chemotaxis and adhesion in preterm babies.

To investigate the increased susceptibility to infection of very immature preterm neonates, neutrophil chemotaxis, Mac-1 adhesion receptor expression, and adherence to human umbilical vein endothelial cell monolayers (HUVE) were examined in neonates born at less than or equal to 32 weeks' gestation. Chemotaxis of neutrophils from well preterm neonates towards casein or zymosan activated serum (ZAS) was reduced (mean SE) being for casein 88.6 (3.8) microns; ZAS 76.2 (4.3) microns compared with adults (casein 117.8 (1.4) microns; ZAS 112.1 (1.4) microns), but similar to term neonate neutrophils (casein 92.7 (4.5) microns; ZAS 75.9 (3.1) microns). Stimulated Mac-1 expression showed a similar pattern: reduced on preterm neutrophils compared with adults, but similar to term neonates. Preterm and term neonate neutrophils were both hyperadherent to HUVE when unstimulated, but showed an equally impaired ability to increase adhesion following stimulation. Casein stimulated chemotaxis and stimulated Mac-1 expression 'matured' towards adult levels of performance four weeks after preterm birth. The increased incidence of sepsis in immature preterm infants is not due to greater defects of neutrophil migration.

Caseins↗

PubMed1979

Normalized thyroxine as a screening test for hypothyroidism in full-term and preterm newborn babies.

Thyroid function was assessed in full-term and preterm newborn babies by serum thyroxine (T4), normalized thyroxine (T4N) and thyroid-stimulating hormone (TSH) assays. At age 24 h, there was a significant difference in T4 and TSH values between the full-term and preterm groups; no such difference was found in the T4N values. By 21 days of age, the TSH values were still significantly higher in full-term babies compared with preterm ones, but the T4 values were similar. The T4, T4N and TSH values at 24 h in preterm newborns with respiratory distress syndrome were similar to those in normal preterm babies, and the changes in these values with age had no consistent pattern. In preterm babies with low 24-h T4 and T4N values, these two parameters increased with age, reaching normal adult values by 21 days. We concluded that T4N could serve as a useful thyroid function test in the newborn.

Female↗

PubMed1992

Corticotropin releasing hormone concentrations in umbilical cord blood of preterm fetuses.

Corticotrophin releasing hormone (CRH), dehydroepiandrosterone sulfate (DHEAS) and cortisol were measured in umbilical cord plasma obtained from 90 preterm and 98 term fetuses. Maternal plasma was obtained from 23 women who delivered preterm and from 23 women matched for gestational age who ultimately delivered term infants. Mean umbilical cord plasma CRH concentration was significantly higher in the preterm fetuses (n = 69, 538 +/- 63 pg/ml) compared to the term fetuses (n = 98, 280 +/- 22 pg/ml, P < 0.01). Mean DHEAS level in the preterm fetuses was 208 +/- 22 mg/dl (n = 56), cortisol level was 7 +/- 1 mg/dl (n = 58). Umbilical plasma CRH concentrations (808 +/- 170 pg/ml) were significantly higher at 24-27 weeks than at 28-31 or 31-34 weeks gestation. Cortisol levels (12 +/- 3 micrograms/dl) were highest at 24-27 weeks. Mode of delivery and the presence of labor did not affect fetal CRH levels. The highest fetal CRH levels were measured in the pregnancies complicated by hypertension as well as prematurity; however, fetal CRH levels remained higher in the preterm group compared to the term group when hypertensive pregnancies were excluded. Maternal plasma CRH levels were significantly higher in the group that delivered preterm compared to women who delivered at term matched for gestational age (1058 +/- 184 pg/ml compared to 456 +/- 71 pg/ml, P < 0.00).(ABSTRACT TRUNCATED AT 250 WORDS)

Corticotropin-Releasing Hormone↗

PubMed1975

[Pyridoxal phosphate and activity of pyridoxalkinase in serum of preterm and term infants (author's transl)].

Vitamin B6 nutriture was measured in 14 preterm infants (born between 30th and 35th week of gestation) by means of determination of pyridoxalphosphate and activity of pyridoxalkinase in serum on the 1st and 4th day of life. 11 term infants were included as control group. At the 1st day pyridoxalphosphate and activity of pyridoxalkinase in preterm infants were significantly decreased in comparison with the control group. 50% of preterm infants--all were delivered before the 33rd week of pregnancy--did not show any activity of pyridoxalkinase in serum. On the 4th day, vitamin B6 nutriture of preterm infants was still decreased in comparison with the control group. Measurable activity of pyridoxalkinase, however, was now found in all preterm infants. There was a positive correlation at the 1st and 4th day of life between pyridoxalphosphate and weight and activity of pyridoxalkinase and weight. According to our results pyridoxalkinase is an enzyme which depends on the gestational age of the newborn. After the 32nd week of gestation the enzyme becomes active. Moreover pyridoxalkinase is an enzyme that can be induced by formulas containing vitamin B6. We consider the administration of vitamin B6 to the preterm infant as necessary.

Gestational Age↗

PubMed1978

Echographic ventricular systolic time intervals in normal term and preterm neonates.

Right ventricular and left ventricular systolic time intervals (RVSTIs and LVSTIs) were measured in normal term and preterm infants from 1 hour to 90 days of life. LVSTIs in both term and preterm infants were similar in the first five days of life. The ratio of left pre-ejection period (LPEP) to left ventricular ejection time (LVET) was lower in preterm infants older than age 5 days. Estimated gestational age had no influence on LVSTI. The ratio of right pre-ejection period (RPEP) to right ventricular ejection time (RVET) was lower in preterm infants (0.32) than in term newborns (0.37). The preterm RPEP/RVET ratio decreased with age, but at a slower rate than in term babies. This was consistent with the lower pulmonary vascular resistance present in preterm infants.

Echocardiography↗

PubMed2026

Long-term motor outcomes after parent-administered early physiotherapy in children born very preterm.

OBJECTIVE: This observational follow-up study investigated whether early parent-administered physiotherapy during the neonatal period was associated with motor outcomes in childhood, and compared these outcomes between two preterm groups and a term-born control group. STUDY DESIGN: This is a follow-up of a pragmatic randomised controlled trial that initially included 153 infants born very preterm (≤32 weeks' gestation), randomised to either early parent-administered physiotherapy or standard care, between 34 and 37 weeks' gestation. At 7-10 years, motor outcomes were assessed in 92 children (intervention, n = 43; standard care, n = 49) and in 83 term-born controls. The primary outcome was the Movement Assessment Battery for Children-Second Edition (MABC-2). Group differences were analysed using linear mixed models adjusted for age, sex, and parental education. Odds ratios (ORs) were calculated for scores ≤5th and ≤ 15th percentiles to estimate the likelihood of having or being at risk for movement difficulties. RESULTS: Mean MABC-2 total score was 9.0 (SD3.0) in the intervention group, 9.6 (SD3.0) in the standard care group, and 10.8 (SD2.9) in the control group. Adjusted mean difference between the intervention and the standard care groups did not differ but both the intervention and standard care groups had lower scores than the control group (-1.2; 95% CI: -2.3 to -0.2 and -0.6; 95% CI: -1.6 to 0.3, respectively). Adjusted ORs for scoring ≤5th or ≤15th percentile did not differ in either preterm group compared with the control group. CONCLUSION: At 7-10 years, motor outcomes did not differ between children born very preterm who received three-week parent-administered physiotherapy and those who received standard care during the neonatal period. However, both preterm groups had lower motor scores than term-born peers.

Humans↗

PubMed2026

Maternal anemia and the risk of preterm birth: a meta-analysis.

BACKGROUND: Globally, preterm birth continues to be a primary contributor to neonatal complications and fatalities. Anemia among the most common nutritional disorders in pregnancy has been proposed as a potential contributor to early delivery. Although extensively studied, the available evidence does not yet provide a clear consensus. This study aimed to conduct a meta-analysis to quantitatively assess the relationship between maternal anemia and the risk of preterm birth. METHODS: This meta-analysis was conducted and reported in accordance with the PRISMA guidelines and the MOOSE checklist. A systematic and exhaustive search was performed across multiple electronic databases PubMed, Scopus, Web of Science, Embase, and the Cochrane Library to identify relevant studies published from inception to 1 January 2025. Effect sizes were combined using a random-effects meta-analysis. RESULTS: A total of 45 articles, reporting 60 independent study populations comprising 2,119,392 pregnant individuals were included. Considerable heterogeneity was found across the included studies (I2 = 95.54%, p < 0.001), which justified the application of a random-effects model for pooling effect sizes. Maternal anemia was significantly associated with an increased risk of preterm birth (pooled odds ratio[OR] = 1.28, 95% confidence interval [CI]: 1.20-1.36, p < 0.001). Despite substantial heterogeneity, sensitivity analyses confirmed the robustness of this association. The relationship was strongest in studies conducted in Asia (OR = 1.30, 95% CI: 1.22-1.40; p < 0.001) and the Europe (OR = 1.24, 95% CI: 1.08-1.41; p = 0.001) and reached statistical significance when anemia was assessed during the first trimester (OR = 1.12, 95% CI: 1.03-1.51; p = 0.007) and the third trimester (OR = 1.65, 95% CI: 1.42-1.91; p < 0.001), while no significant associations were found in the second trimesters (OR = 1.10, 95% CI: 0.99-1.22; p = 0.05). Funnel plot asymmetry and a significant Egger's test (p = 0.001) indicated potential publication bias, although Begg's test was not significant (p = 0.425). CONCLUSIONS: The current evidence suggests that maternal anemia, particularly in the third trimester, is significantly associated with an increased risk of preterm birth. These findings emphasize the clinical imperative for comprehensive and timely anemia screening during the third trimester. Integrating targeted interventions such as iron and micronutrient supplementation, is essential to mitigate the risk of preterm delivery and improve neonatal outcomes.

Humans↗

PubMed2025

Characterization of gut microbiota signatures in Indian preterm infants with necrotizing enterocolitis: a shotgun metagenomic approach.

INTRODUCTION: Necrotizing enterocolitis (NEC) is an inflammatory bowel disease that primarily affects preterm infants. Predisposing risk factors for NEC include prematurity, formula feeding, anemia, and sepsis. To date, no studies have investigated the gut microbiota of preterm infants with NEC in India. METHOD: In the current study, shotgun metagenomic sequencing was performed on fecal samples from premature infants with NEC and healthy preterm infants (n = 24). Sequencing was conducted using the NovaSeq X Plus platform, generating 2 × 150 bp paired-end reads. The infants were matched based on gestational age and postnatal age. RESULT: The median time to NEC diagnosis was 9 days (range: 1-30 days). Taxonomic analysis revealed a high prevalence of Enterobacteriaceae at the family level, with the genera Klebsiella and Escherichia particularly prominent in neonates with NEC. No statistically significant differences in alpha or beta diversity were observed between stool samples from infants with and without NEC. Linear regression analysis demonstrated that Enterobacteriaceae were significantly more abundant in stool samples from infants with NEC than without NEC (q < 0.05). Differential abundance analysis using Linear Discriminant Analysis Effect Size (LEfSe) identified Klebsiella pneumoniae and Escherichia coli as enriched in the gut microbiota of preterm infants with NEC. Functional analysis revealed an increase in genes associated with lipopolysaccharide (LPS) O-antigen, the type IV secretion system (T4SS), the L-rhamnose pathway, quorum sensing, and iron transporters, including ABC transporters, in stool samples from infants with NEC. CONCLUSION: The high prevalence of Enterobacteriaceae and enrichment of LPS O-antigen and T4SS genes may be associated with NEC in Indian preterm infants.

Humans↗