Activated protein C resistance in cord blood from healthy and complicated newborns

Objectives. Newborns are susceptible to thrombosis secondary to the immature hemostatic system and maternal and fetal complications. The contribution of activated protein C resistance (APCR) to thrombosis tendency has not yet been established. This study was conducted to investigate the effects of maternal and fetal complications on APCR levels.

Methods. APCR levels were determined in cord blood from healthy term infants and compared with those in healthy preterm and complicated neonates as well as that in adult venous blood.

Results. The mean value of APCR in cord blood from healthy term infants (166 ± 40 s) was not significantly different from that in adult venous blood (173 ± 40 s). No significant differences in the mean cord blood APCR values were observed between healthy term and preterm infants, infants with vaginal and cesarean delivery, infants from preeclamptic and non-eclamptic mothers, and infants with or without perinatal asphyxia. The activity levels of protein C, protein S, and antithrombin III were not significantly different between these groups except for lower levels in preterm babies.

Conclusions. The level of APCR in cord blood is comparable to that in adults and not influenced by maternal and fetal complications. It appears that APCR does not contribute to the thrombotic tendency in newborns.     

Maternal and placental responses before preterm birth: adaptations to increase fetal thyroid hormone availability?

Background: During pregnancy, maternal thyroid hormone supply is crucial for fetal development. Preterm infants often present with hypothyroxinemia. Preterm birth, either spontaneous or medically indicated, is always the result of a complicated pregnancy. We hypothesized that in preterm birth, the maternal transplacental thyroid hormone supply is influenced by the pregnancy complication and we questioned whether maternal and placental compensatory mechanisms are activated to increase thyroid hormone transfer.

Methods: Observational case-control study in mother–infant-dyads with complicated pregnancies ending in spontaneous preterm birth (n?=?31) or indicated preterm birth due to vascular complications (n?=?45) and normal pregnancies (healthy term controls; n?=?41). At delivery, maternal and cord blood and placenta samples were collected. Cord and maternal plasma concentrations of thyroid stimulating hormone (TSH), total T4, fT4/FTI, total T3, and T4 binding globulin (TBG), and maternal serum concentrations of thyroid peroxidase (TPO)-antibodies were measured. Placental maturity was evaluated histologically and mRNA and/or protein levels of thyroid hormone deiodinases (DiO) 1, 2 and 3, and transporters (MCT8, MCT10, and OATP1c1) were quantified.

Results: In indicated and spontaneous preterm births, cord plasma T4 concentrations were lower than in healthy term controls (p?≤?.001), whereas T3 was only decreased in spontaneous preterm birth (p?≤?.001). Compared with spontaneous preterm births and healthy term controls, indicated preterm birth was characterized by higher maternal plasma TSH (p?≤?.05), earlier placental maturation, higher placental DiO2 gene and MCT10 protein levels and lower DiO3 gene levels (all p?≤?.01).

Conclusions: Low T4 was observed in preterm infants irrespective of the cause of preterm birth, while maternal (TSH) and placental (DiO2, DiO3, and MCT10) compensatory responses were only activated in indicated preterm birth due to vascular complications. This may have mediated the normal fetal T3 availability in preterm infants born after indicated preterm birth but not after spontaneous preterm birth.     

The vitamin C status of formula-fed preterm infants

Forty-two pairs of maternal and cord plasma vitamin C levels were determined after term, preterm, and multiple gestation pregnancies and 95 determinations of plasma ascorbate were performed on 36 premature infants who were fed a recommended infant formula throughout the first month of life. There were no significant changes of the cord or maternal ascorbate levels or of the cord/maternal ascorbate ratio between term, preterm, and multiple gestation cases. A significant negative correlation was found between the maternal ascorbate levels and the cord/maternal ascorbate ratio, supporting previous observations that high fetal blood levels of vitamin C are maintained even in cases where the maternal vitamin nutrition is poor. A rapid decline from cord levels was evident during the first week of life, followed by maintenance of relatively low plasma ascorbate levels, despite supplementation of recommended vitamin nutrition. Further monitoring of ascorbate levels in premature infants is suggested for better adjustment of the recommendations for vitamin C supplementation.     

Biologically active corticotropin-releasing hormone in maternal and fetal plasma during pregnancy

Corticotropin-releasing hormone was measured in the plasma of 110 pregnant women and in the umbilical cord plasma of 25 premature infants and 43 infants born at term. Mean maternal plasma corticotropin-releasing hormone was undetectable (less than 41 pg/ml) until mid-second trimester, rose to a mean of 204 +/- 24 pg/ml by 30 weeks' gestation, to 326 +/- 41 by 35 weeks, and then rose sharply near term, with a mean of 2930 pg/ml at 38 to 40 weeks' gestation. Sequential measurements in seven pregnant women confirmed that plasma corticotropin-releasing hormone rose in a predictable pattern, with a dramatic increase in the final weeks of pregnancy. There was little hour-to-hour variability in maternal plasma concentrations. Corticotropin-releasing hormone was also detectable in umbilical cord plasma; mean corticotropin-releasing hormone was 194 +/- 44 in the preterm infants and 150 +/- 19 in the term infants. The corticotropin-releasing hormone extracted from both the maternal and fetal circulation was biologically active in vitro and caused the dose-dependent release of adrenocorticotropic hormone and beta-endorphin from cultured rat anterior pituitary cells. A significant correlation was found between maternal plasma corticotropin-releasing hormone and cortisol levels the morning after betamethasone administration, a finding that supports a physiologic role for maternal plasma corticotropin-releasing hormone. We conclude that the placenta secretes large amounts of biologically active corticotropin-releasing hormone into both the maternal and fetal circulation during pregnancy. We demonstrate that this corticotropin-releasing hormone is secreted into the maternal plasma in a reproducible pattern during normal term pregnancy and suggest that sequential corticotropin-releasing hormone measurements may prove to be of clinical utility. In addition, placental corticotropin-releasing hormone may be an important modulator of the hypothalamic-pituitary-adrenal axis during pregnancy.     

Implication of cord blood myeloperoxidase but not of soluble p-selectin levels in preterm deliveries

Although maternal amniotic and vaginocervical cytokines are known to play a role in triggering preterm delivery, the effects of activating fetal phagocytes and platelets are not clear. In an attempt to clarify this issue, we measured levels of myeloperoxidase (MPO), a phagocyte activation marker, and soluble p-selectin (sCD62p), a platelet activation marker, in umbilical cord blood samples from 2200 consecutive cord blood collections, 106 of which were from preterm infants. MPO and sCD62p levels were correlated to gestational age and preterm delivery. It was found that MPO levels were significantly higher in preterm infants and were not significantly correlated to gestational age. In contrast, sCD62p levels were lower in preterm infants and were negatively correlated to gestational age. In summary, we showed that fetal phagocyte activation as demonstrated by higher cord blood MPO levels is associated with preterm delivery, but platelet activation as shown by lower sCD62p levels is not. This suggests that fetal phagocyte activation may be implicated in preterm delivery, and subsequently in prematurity-related inflammatory insults.     

Plasma adrenomedullin levels in pregnancies with appropriate for gestational age and small for gestational age infants.

AIMS: To evaluate whether maternal and fetal plasma adrenomedullin levels in pregnancies with small for gestational age (SGA) infants are different from those in pregnancies with appropriate for gestational age (AGA) infants. METHODS: Maternal and fetal circulating adrenomedullin levels were compared between 62 pregnancies with AGA (43 delivered vaginally and 19 delivered by elective cesarean section) and 28 pregnancies with SGA (20 delivered vaginally and 8 delivered by elective cesarean section) at birth. Plasma adrenomedullin levels were measured from maternal and cord venous blood samples using a radioimmunoassay. Umbilical artery blood pH was also measured. RESULTS: There were no significant differences for maternal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. There were also no significant differences for fetal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. In the AGA group delivered vaginally, fetal mature/total adrenomedullin ratio (mean +/- standard error, 16.6 +/- 0.7%) was significantly higher than the maternal ratio (13.8 +/- 0.6%) (p < 0.05). In the SGA group delivered vaginally, fetal mature/total adrenomedullin ratio (18.5 +/- 1.0%) was also significantly higher than the maternal ratio (14.5 +/- 0.6%) (p < 0.05). There was no significant difference in umbilical artery blood pH among the groups. CONCLUSIONS: These results suggest that maternal and fetal plasma circulating adrenomedullin levels may play a role in maternal and fetal cardiovascular adaptation during delivery in pregnancies with both AGA and SGA infants.     

Chronic maternal smoking and cord blood amino acid and enzyme levels at term

OBJECTIVE: To assess the influence of chronic active maternal smoking on cord blood amino acid and enzyme levels at term. METHODS: The concentrations of 24 free amino acids, total protein, and five enzymes were measured in samples of maternal and fetal cord venous plasma from 24 nonsmokers who were not exposed to tobacco smoke and 24 chronic smokers. Cotinine levels were also measured in maternal plasma to evaluate fetal tobacco exposure. The pregnancies were between 37 and 40 weeks' gestation, were uncomplicated, and were delivered vaginally. RESULTS: Fetal weight was significantly (P <.01) lower in the smokers than in controls. A positive significant (P <.001) correlation was found between maternal and umbilical venous cotinine concentrations. Significantly lower concentrations of aspartic acid (P <.01), hydroxyproline (P <.05), threonine (P <.005), alanine (P <.05), alpha-aminobutyric acid (P <.001), methionine (P <.05), tyrosine (P <.001), phenylalanine (P <.01), and lysine (P <.05) were found in the venous cord plasma of the smokers compared with nonsmokers. The fetomaternal ratios were similar in both groups. The umbilical plasma alkaline phosphatase activity was significantly (P <.01) lower in the smokers than in the controls. CONCLUSION: Chronic maternal smoking is associated with alterations of protein metabolism and enzyme activity in fetal cord blood. These may be secondary to irreversible changes in the cellular functions of the trophoblast and may contribute to fetal growth restriction.     

Beneficial impact of term labor: nonenzymatic antioxidant reserve in the human fetus

OBJECTIVE: Oxidative stress occurs when the production of damaging free radicals and other oxidative molecules exceeds the capacity of the body's antioxidant defenses. Oxidative stress is implicated in diseases that are associated with prematurity (such as retinopathy, cerebral palsy, intraventricular hemorrhage, and necrotizing enterocolitis). Nonenzymatic antioxidant reserve is the first line of defense against free radicals. We hypothesized that an in utero redox imbalance because of stress would diminish the fetal antioxidant reserve. We tested aspects of this hypothesis by investigating whether the presence of labor or gestational age at delivery (term vs preterm) alters the maternal/fetal nonenzymatic antioxidant reserve peripartum. STUDY DESIGN: Fetal redox consumption was calculated from the difference in the nonenzymatic antioxidant reserve that was measured in umbilical venous and arterial blood that was collected prospectively at delivery from 39 newborn infants. Eight women were delivered at term by elective cesarean delivery in the absence of labor; 31 women labored either at term (n = 20) or preterm (<37 weeks, n = 11). Maternal venous blood was collected on admission and within 1 hour of delivery. Nonenzymatic antioxidant reserve was measured in the plasma and red blood cells of each specimen by the quantitation of glutathione content (glutathione in red blood cell lysate) and the plasma total free radical-trapping antioxidant potential. Glutathione was measured with the use of a colorimetric assay and expressed in nanomoles per milligram of hemoglobin. The plasma total radical-trapping antioxidant potential was estimated with the use of a controlled, kinetic assay based on the time that was required to inhibit peroxyl-free radical generated under controlled conditions. The differences between both umbilical venous and umbilical arterial total radical-trapping antioxidant potential and glutathione were computed to estimate fetal nonenzymatic antioxidant reserve consumption. The differences between maternal total radical-trapping antioxidant potential and glutathione before and after delivery were computed to estimate maternal peripartal nonenzymatic antioxidant reserve consumption. RESULTS: Fetal red blood cell glutathione content was significantly greater than maternal red blood cell glutathione content, independent of delivery route. The calculation of the fetal nonenzymatic antioxidant reserve consumption and maternal peripartal nonenzymatic antioxidant reserve consumption revealed that women who labored at term experienced an up-regulation in red blood cell glutathione content, while their fetuses had significantly lower red blood cell glutathione consumption. In contrast, there was consumption of plasma antioxidants in preterm fetuses, as illustrated by a doubling of the fetal nonenzymatic antioxidant reserve consumption (elective cesarean delivery in the absence of labor, 0.9 +/- 0.5 min/microL; term labor, 1.0 +/- 0.1 min/microL; preterm labor, 2.0 +/- 0.4 min/microL; one-way analysis of variance; P =.04). This was mostly due to a lower umbilical arterial total radical-trapping antioxidant potential in preterm versus term fetuses (umbilical arterial, 3.3 min/microL versus umbilical venous 5.4 min/microL; paired t test; P =.001; power, 0.98). Generally, maternal total radical-trapping antioxidant potential remained unchanged peripartum. CONCLUSION: Term labor triggers a compensatory up-regulation of nonenzymatic antioxidant reserve in the fetal red blood cell compartment that may act to protect against the relative hyperoxia that is experienced by the newborn infant at birth. In contrast, the decreased nonenzymatic antioxidant reserve in the fetal red blood cell and plasma compartments after preterm labor and delivery would enhance the vulnerability to free radical damage of the preterm neonate. These findings suggest that the two compartments of nonenzymatic antioxidant reserve have distinct physiologic roles in the peripartal defense against free radicals and that their development is, in some fashion, ontogenes, in some fashion, ontogenetically regulated.     

Maternal and fetal alphafetoprotein (AFP) levels at term. Relation to sex, weight and gestation of the infant

Serum alpha-fetoprotein (AFP) was measured in maternal, cord arterial and venous blood. Samples were collected at the time of vaginal delivery from 105 women at 36-42 weeks' gestation. There was a significant correlation between maternal, cord arterial and venous AFP. Umbilical cord arterial and venous AFP levels were considerably higher in male infants than in females. Umbilical AFP levels declined with lengthening gestation and increasing birthweight for both male and female infants and a similar pattern was seen in the mother. Fetal AFP levels were significantly higher in subjects giving birth at 40 weeks whose infants had a birthweight below the population mean vis-à-vis those above the mean. It is concluded that the absolute size of the fetus as well as gestational age may play a significant role in determining maternal and fetal AFP concentration.     

Folate, vitamin B12, and homocysteine levels in South Asian women with growth-retarded fetuses

OBJECTIVE. To investigate whether intrauterine growth retardation (IUGR) and preterm delivery in a poor population of South Asia was associated with altered maternal and fetal levels of folate, vitamin B12, and homocysteine. SUBJECTS AND METHODS. Hundred and twenty-eight pregnant women from a low socio-economic strata in the city of Lahore, Pakistan were followed with ultrasound of fetal growth from the 12th week of pregnancy. Blood samples were drawn from the woman and the cord at delivery. Serum was analyzed by a chemiluminescent immunoassay for folate and vitamin B12 and by fluorescence polarization immunoassay for total homocysteine (tHcy). RESULTS. Fourty-six infants showed IUGR. In term, but not preterm, deliveries with IUGR, maternal and cord blood folate levels were half of those in deliveries of normal birth weight infants (P=0.004 and P=0.005). The risk of IUGR was reduced among women with folate levels in the highest quartile (OR 0.31, 95% CI 0.10--0.84). There was no association between vitamin B12 and IUGR. Total homocysteine levels were higher in women delivering IUGR infants (P=0.02). There was an inverse correlation between cord blood folate and tHcy levels (r=-0.26, P=0.006). We also found increased risks for hypertensive illness (OR 3.5, 95% CI 1.4--8.6) and premature delivery (OR 2.5, 95% CI 1.1--6.2) in women in the highest quartile of tHcy. CONCLUSIONS. The occurrence of IUGR increased with low maternal and cord concentrations of folate and high maternal levels of tHcy. Further studies on the effects of vitamin B supplementation through pregnancy are warranted.     

The role of calcium, copper, iron and zinc in preterm delivery and premature rupture of fetal membranes

Maternal and cord blood samples were collected in 60 cases with or without rupture of membranes before and at term. Serum concentrations of calcium, copper, iron and zinc were determined by proton-induced X-ray emission. Maternal and cord serum ceruloplasmin and maternal hemoglobin were also determined. Mothers with preterm delivery showed significantly lower hemoglobin values than those with delivery at term. Concentrations of calcium, iron and zinc were higher in cord than in maternal serum whereas maternal copper levels were higher than respective cord levels in all groups. The cord copper and ceruloplasmin and also their fetal/maternal ratios were significantly lower in the group with preterm premature rupture of fetal membranes (PROM) than in other groups. Maternal serum zinc and calcium were lower in preterm groups than in term groups. The study suggests a possible role of copper in preterm PROM and of zinc in the initiation of preterm labor, whereas calcium and iron do not seem to be involved in the etiology of prematurity or PROM.     

The effect of preterm birth on umbilical cord blood gases.

Apgar scores are used routinely to assess early neonatal status, but are less accurate in the preterm neonate because of developmental immaturity. Attention has been directed to umbilical cord gases as a method of neonatal evaluation. Using a retrospective chart review of all viable preterm births (24-36 weeks' gestation) between January 1986 and December 1989, we tabulated the umbilical cord gas indices of these infants. Fetuses with lethal congenital anomalies and those with abnormal heart rate tracings on admission were excluded from the data base, leaving 1872 infants. Cord arterial blood gas values were available for analysis in 74.4% of cases and cord venous gas values in 81.8%. The mean (+/- standard deviation [SD]) arterial and venous umbilical cord blood gas values for the preterm infants, were, respectively: pH, 7.26 +/- 0.08 and 7.33 +/- 0.07; oxygen pressure, 19.0 +/- 7.9 and 29.2 +/- 9.7 mmHg; carbon dioxide pressure, 53.0 +/- 10.0 and 43.4 +/- 8.3 mmHg; bicarbonate, 24.0 +/- 2.3 and 22.8 +/- 2.1 mEq/L; and base excess, -3.2 +/- 2.9 and -2.6 +/- 2.5 mEq/L. Acidemia was defined statistically as 2 SDs or more below the population mean. The incidence of 5-minute Apgar scores below 7 in the preterm infants was 8.5% and within this group, 17.8% were acidemic (arterial pH 7.10 or lower). More than 82% of neonates with 5-minute Apgar scores less than 7 had normal umbilical cord blood gases. There was no significant difference in umbilical arterial blood gas values between preterm infants and 1924 term deliveries at our institution between 1986-1988.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fetal and maternal levels of lipid peroxides in term pregnancies

OBJECTIVE: To examine the relationships between maternal and fetal concentrations of lipid peroxides in term pregnancies before the onset of labor. METHODS: Umbilical cord arterial and venous blood samples were collected from 114 singleton term pregnancies delivered by elective cesarean section. Base excess, oxygen, carbon dioxide and pH were measured in both samples and compared to identify double venous samples. Maternal venous and umbilical cord arterial and venous concentrations of organic hydroperoxides and malondialdehyde were assayed. RESULTS: Maternal plasma malondialdehyde was, on average, double that of cord blood, whereas maternal organic hydroperoxide was only 18% higher. Maternal organic hydroperoxide was correlated with cord arterial and venous levels of organic hydroperoxide but not with pH, carbon dioxide, oxygen or base excess. Maternal malondialdehyde concentration was significantly correlated with both umbilical arterial and venous values of malondialdehyde and with arterial oxygen. Multiple regression shows that 70% of the variation in maternal malondialdehyde can be accounted for by variation in arterial and venous malondialdehyde, and arterial oxygen and base excess. A similar regression analysis with maternal organic hydroperoxide as dependant variable incorporated only umbilical arterial organic hydroperoxide concentration. CONCLUSION: These findings suggest that there is significant trans-placental transport of malondialdehyde from the fetal circulation.     

Placental release of corticotrophin-releasing hormone across the umbilical circulation of the human newborn

This study attempted to determine the placental release of corticotrophin-releasing hormone (CRH) into the umbilical circulation, and the factors which affect it, by measuring venous and arterial levels for CRH across the umbilical circulation in labouring as well as non-labouring elective caesarean section patients. The relationship with measures of fetal oxygenation and acid-base status at birth was investigated also. Forty-eight patients were studied (term labour n = 30, term elective caesarean section n = 12, and preterm labour n = 6) with blood sampling from a clamped segment of cord after delivery of the fetus and from the cord at its insertion into the placenta after delivery of the placenta, with subsequent measurement of blood gases, pH, base excess, and CRH. For all patients, mean plasma CRH levels in the umbilical and placental vein (115+/-13 and 145+/-18 pg/ml) were higher than those from the corresponding artery (85+/-7 and 102+/-8 pg/ml, P<0.01 and P<0.05, respectively), indicating placental release of CRH into the fetal compartment. In addition, placental venous and arterial cord CRH levels were higher than those from the corresponding umbilical levels (P<0.01 and P<0.02, respectively) indicating continued placental release of CRH into blood within the placenta after clamping of the umbilical circulation and delivery of the fetus. While plasma CRH levels from respective cord vessels were all significantly higher in labouring patients at term versus elective caesarean section patients, there were no differences compared with preterm labouring patients. For all patients, CRH as measured in both the umbilical and placental vein showed a modest inverse correlation to base excess as measured in the umbilical artery, -0.31 and -0.33, respectively, both P<0.05. It is concluded that CRH is released by the placenta into the fetal compartment and is increased with both term and preterm labour, and with metabolic acidosis during labour, supporting a role in the endocrine events of labour and/or compensatory changes in uteroplacental blood flow.     

Maternal venous procalcitonin levels do not correlate with umbilical cord blood and venous blood concentrations in the neonate

BACKGROUND: To compare procalcitonin (PCT) concentrations between maternal blood and levels in umbilical cord or venous blood of neonates who were born with or without infection. METHODS: Forty-six women with singleton pregnancies, complicated by premature rupture of membranes, preterm delivery and/or chorioamnionitis, were enrolled in this study. The study group comprised 15 patients and their infected newborns. The control group consisted of 31 women and their healthy newborns. We compared PCT concentrations between maternal, umbilical cord and neonatal serum, in both study and control groups. Additionally, PCT levels were compared between the corresponding compartments. RESULTS: PCT concentrations in the umbilical cord and venous blood in infected newborns, but not in non-infected neonates, were significantly higher than maternal serum PCT levels. PCT concentrations of mothers who delivered infected newborns were comparable to those in the controls. However, PCT concentrations in the umbilical cord and in the venous blood of the infected newborns were higher than in healthy newborns. CONCLUSION: Measurement of maternal PCT concentration during labor does not contribute to early prediction of infection in the neonate. However, umbilical cord PCT concentrations, as well as its neonatal venous levels on the second day of life, seem to be related to intrauterine infection, and may be a useful tool in the diagnosis of early neonatal infection.     

Trace elements’ concentrations in maternal and umbilical cord plasma at term gestation: a comparison between active labor and elective cesarean delivery

Objective.?Trace elements are minerals required in minute quantities to maintain proper physical functioning. The role of trace elements in the process of parturition is poorly understood. This study was aimed to determine levels of trace elements’ concentration in maternal plasma and umbilical venous and arterial plasma at term during active labor vs elective cesarean delivery (CD).

Study design.?A prospective case–control study was conducted. Forty healthy parturients in active labor at term with their newborns were compared to 40 healthy parturients matched for maternal age, parity, and gestational age, who delivered by elective CD (before commencement of labor). Samples of maternal venous blood and umbilical cord arterial and venous blood were drawn immediately following delivery. Trace elements’ concentrations were measured using the inductively coupled plasma mass spectrometer (ICP-MS).

Results.?Significant higher levels of manganese (Mn) and selenium were found in maternal venous plasma during active labor vs elective CD. Magnesium (Mg) levels were significantly higher in maternal venous blood during elective CD compared to active labor. Umbilical cord artery levels of Mg, Mn, and zinc (Zn) were significantly higher in active term labor vs elective CD. Also, significant higher levels of copper and Zn were found in umbilical cord vein between active labor and elective CD.

Conclusion.?Trace elements’ concentrations differ significantly in fetal blood during active labor vs elective CD. Hence, trace elements may play a crucial role in the process of human parturition.     

Glucocorticoid receptor expression and cortisol level in cord blood of term infants

Objective.?To examine the expression levels of glucocorticoid receptor (GR) isoforms in peripheral blood mononuclear cells (PBMCs) and serum cortisol levels in cord blood from term infants.

Methods.?The study population consisted of 172 term infants who were delivered from healthy pregnant women. GRalpha and GRbeta expression levels, and serum cortisol level in cord blood were determined by real-time PCR and ELISA, respectively.

Results.?Detection rates of GRalpha, GRbeta, and GAPDH were 100%, 63.4%, and 100%, respectively. The expression level of GRalpha was about 200 times that of GRbeta. There were no associations between GR expression level and clinical variables. There were significant associations of low UmApH, maternal gravidity or parity, and vaginal delivery with a high cortisol level; however, there were no correlations between GR expression levels and cortisol level.

Conclusions.?It is considered that glucocorticoid effects could be expected from the fetal period to the neonatal period, because GRalpha expression level was not related to perinatal factors, GRbeta expression level, and cortisol level in term infants. Further studies of larger populations including very preterm and small for gestational age infants are necessary to determine the balance of expression between GRalpha and GRbeta, and cortisol level.     

Influence of breast-feeding on the restoration of the low serum concentration of vitamin E and beta-carotene in the newborn infant

Vitamin E and beta-carotene are two important natural antioxidants. However, the mean (+/- SD) serum concentrations of beta-carotene in the cord blood of term (17.9 +/- 4.4 micrograms/dl) and preterm (14.04 +/- 4.7 micrograms/dl) infants are one eighth the concentration in the maternal serum (131 +/- 43 micrograms/dl). Likewise the serum concentrations of vitamin E in the term (0.31 +/- 0.09 mg/dl) and preterm (0.29 +/- 0.08 mg/dl) infants are one-third the concentration in the maternal serum (0.97 +/- 0.16 mg/dl). Human breast milk, particularly colostrum, contains very high concentrations of both vitamin E (3.28 +/- 2.93 mg/dl) and beta-carotene (213 +/- 166 micrograms/dl). Thus the breast-fed, term infant attains serum levels of both vitamin E and beta-carotene comparable to those in the adult within 4 to 6 days of breast-feeding. This study shows that the seeming barrier in the fetus to access to the antioxidants vitamin E and beta-carotene, in rapidly corrected and the substances are replenished postnatally through breast-feeding. This study therefore alludes to the possible role of breast-feeding in providing for the infant's defense against oxygen toxicity.     

Oxytocin induction of labour: hyponatraemia and neonatal jaundice

To determine the effects of fluid restriction in induced labour with oxytocin in 5% dextrose solution, maternal venous blood and fetal cord venous blood were examined in 164 mothers in induced labour and 29 mothers with a spontaneous onset of labour. After satisfactory uterine activity was induced either the oxytocin infusion was managed according to routine delivery unit practice (n = 36), or infusion rates were halved (n = 45), or quartered (n = 43), or discontinued (n = 40). Despite fluid restriction during labour the mean sodium concentration in maternal blood or cord blood had fallen to a similar extent in all four induced groups at delivery. Potassium, urea, creatinine, total protein, and albumin in maternal blood or cord blood were affected differently by induced labour as compared with sodium. The fall in sodium concentration in maternal blood was a more consistent reflection of the total volume of fluid received, mean infusion rates and cord blood sodium after infusion rates were quartered or discontinued. The incidence of hyponatraemia was 5% in mothers and 8% in infants. A comparison of hyponatraemic and normonatraemic cord blood showed no significant differences in serum bilirubin levels or red cell counts, but more hyponatraemic infants developed neonatal jaundice. It is suggested that in induced labour fluid restriction alone does not prevent hyponatraemia and neonatal jaundice.     

Umbilical cord pH, PCO2, and bicarbonate following uncomplicated term vaginal deliveries

Normal values for umbilical arterial and venous pH, PCO2, PO2, and bicarbonate must be known before these parameters can be used for assistance in clinical decisions. We evaluated the cord blood from 146 infants born after uncomplicated labor and vaginal deliveries at 37 to 42 weeks' gestation. All infants had a normal baseline fetal heart rate and normal beat-to-beat variability for at least 10 minutes preceding expulsion. The cord blood of infants born to women with pregnancy complications such as diabetes mellitus, preeclampsia, twins, meconium-stained amniotic fluid, or fetal growth retardation was not included. Mean umbilical arterial values +/- 1 SD for the parameters studied were: pH, 7.28 +/- 0.05; PCO2, 49.2 +/- 8.4 mm Hg; PO2, 18.0 +/- 6.2 mm Hg; bicarbonate, 22.3 +/- 2.5 mEq/L. Umbilical venous values were: pH, 7.35 +/- 0.05; PCO2, 38.2 +/- 5.6 mm Hg; PO2, 29.2 +/- 5.9 mm Hg; bicarbonate, 20.4 +/- 4.1 mEq/L.