Fetal plasma leptin concentrations: relationship with different intrauterine growth patterns from 19 weeks to term

The relationship between in utero fetal growth and fetal leptin concentrations was investigated between 19 and 41 wk in 40 normal (appropriate for gestational age, AGA) fetuses, in 25 intrauterine growth-restricted (IUGR) fetuses, and in 18 fetuses from gestational diabetic mothers (GDM), representing different intrauterine growth patterns. Umbilical venous plasma leptin concentrations were determined at the time of either in utero fetal blood sampling or delivery. Plasma leptin was measurable as early as 19 wk of gestation. A significant difference was observed between umbilical venous and arterial plasma leptin concentrations (0.6+/-0.6 ng/mL; p<0.01). In AGA and in IUGR fetuses, significant positive relationships were found between fetal leptin concentrations and both gestational age (p<0.001) and fetal weight (p<0.001). Leptin concentrations were significantly higher in AGA than IUGR only after 34 wk (p<0.05), but leptin per kilogram fetal weight (leptin/kg) was not significantly different. In IUGR with abnormal umbilical arterial Doppler velocimetry and fetal heart rate, leptin/kg significantly higher than in IUGR with normal biophysical and biochemical parameters was found (p<0.05). Both circulating plasma leptin and leptin/kg were significantly higher in GDM than in normal fetuses (p<0.001) and correlated with abdominal fat mass measured by ultrasound. No gender differences were observed in any group of fetuses. These findings indicate a clear relationship between fetal leptin concentrations and fetal fat mass. Data in severe IUGR suggest the presence of increased leptin concentrations associated with in utero signs of fetal distress.

Activity and expression of the Na(+)/H(+) exchanger in the microvillous plasma membrane of the syncytiotrophoblast in relation to gestation and small for gestational age birth

The effect of gestational age, low birth weight, and umbilical plasma pH on the activity and expression of the Na(+)/H(+) exchanger in the microvillous plasma membrane (MVM) of the placental syncytiotrophoblast was investigated. MVM were isolated from placentas of fetuses delivered in the first and second trimesters and from appropriately grown for gestational age (AGA) and small for gestational age (SGA) babies born at term. Na(+)/H(+) exchange activity (amiloride-sensitive Na(+) uptake) was higher (p<0.05) in second trimester and term AGA MVM versus first trimester MVM (median [range]: 1.80 [1.01-3.03], 1.72 [1.16-3.15] versus 1.48 [0.92-1.66] nmol/mg protein/30s, respectively, n = 6, 12, and 9). As regards exchanger isoforms, Western blotting showed that NHE1 expression did not change across gestation, but NHE2 and NHE3 expression were lower (p<0.01) in the first and second trimesters than in term AGA MVM. There were no differences in Na(+)/H(+) exchanger activity or in NHE1-3 expression in term AGA MVM versus SGA (n = 11) MVM. There was no correlation between exchanger activity and umbilical artery or vein plasma pH, although with a relatively small number of samples (n = 12 and 15, respectively). We conclude that there is differential regulation of the activity and expression of Na(+)/H(+) exchanger isoforms in the MVM over the course of gestation in normal pregnancy; this is not affected in pregnancies resulting in SGA babies at term.

High concentrations of serum inhibin in pre-eclampsia

OBJECTIVE

To evaluate maternal serum immunoreactive inhibin (ir-inhibin) concentrations in women with pre-eclampsia, and assess the correlation between serum ir-inhibin and HCG.

METHODS

The subjects comprised 28 pregnant women with suspected intrauterine growth retardation (IUGR) during the third trimester. Serum concentrations of ir-inhibin and HCG were measured in 13 women with pre-eclampsia and 15 pregnant women as control subjects. Serum ir-inhibin was determined by a double antibody radioimmunoassay, and HCG by a solid-phase immunoradiometric assay.

RESULTS

There were no significant differences in maternal characteristics between the pre-eclamptic group and control group. The pre-eclamptic group had significantly higher concentrations of serum ir-inhibin and HCG compared with the control group. The serum concentrations of ir-inhibin correlated positively with those of HCG.

CONCLUSION

The pre-eclamptic patients displayed high serum levels of ir-inhibin and HCG, and this might reflect hyperplasia of trophoblastic cells.

Plasma fibrinogen and factor VII concentrations in adults after prenatal exposure to famine

To assess the effect of maternal malnutrition during different stages of gestation on plasma concentrations of fibrinogen and factor VII, we investigated 725 people, aged 50 years, born around the time of the Dutch famine 1944-5. After adjustment for sex, plasma fibrinogen concentrations differed by -0.01 g/l (95% confidence interval, -0.14-0.11) in those exposed in late gestation, by -0.03 g/l (-0.16-0.11) in those exposed in mid gestation, and by 0.13 g/l (-0.03-0.30) in those exposed in early gestation, compared with non-exposed people (those born before and those conceived after the famine pooled together). Plasma factor VII concentrations differed by 0.4% (-5.4% to 6.6%) in those exposed to famine in late gestation, by 1.5% (-4.6% to 8.1%) in those exposed in mid gestation. and by -11.8% (-18.4 to -4.8%) in those exposed in early gestation, compared with nonexposed people. Size at birth was not associated with plasma concentrations of fibrinogen or factor VII. Our finding that factor VII concentrations were significantly lower in people whose mothers had been exposed to famine in early pregnancy suggests that liver function may be affected by undernutrition in early gestation.

Second-trimester plasma homocysteine levels and pregnancy-induced hypertension, preeclampsia, and intrauterine growth restriction

OBJECTIVE

The purpose of this study was to determine whether second-trimester plasma homocysteine levels are elevated among women whose pregnancies are subsequently complicated by pregnancy-induced hypertension, preeclampsia, or intrauterine growth restriction.

STUDY DESIGN

Women with normal but relatively low plasma zinc levels were randomly assigned to receive zinc supplementation or placebo from 19 weeks' gestation until delivery. Plasma homocysteine concentration and plasma and erythrocyte folate levels were determined for all available stored samples (zinc group, 231/294; placebo group, 206/286) at 26 and 37 weeks' gestation. Among all women with available samples, pregnancy-induced hypertension (n = 12) or preeclampsia (n = 4) developed in 16 women, and 22 pregnancies were complicated by intrauterine growth restriction.

RESULTS

Mean homocysteine levels in women with pregnancy-induced hypertension and preeclampsia were similar to those of control subjects at 26 weeks' gestation but were significantly higher at 37 weeks' gestation. Homocysteine levels were similar between women with pregnancies complicated by intrauterine growth restriction and control subjects at both time points.

CONCLUSION

Second-trimester plasma homocysteine concentrations do not predict the subsequent development of pregnancy-induced hypertension, preeclampsia, and intrauterine growth restriction.

[Usefulness of quantitative assessment of Toxoplasma gondii genome using PCR-TaqMan in amniotic fluid, maternal and neonatal blood in selected complications in pregnancy]

Routine serological diagnosis of Toxoplasmosis provides high sensitivity, but not high specificity. The high sensitivity combined with high specificity offered by PCR-TaqMan as well as the degree of infection led us to investigate the presence and levels of Toxoplasma gondii genome in amniotic fluid, maternal and neonatal blood in cases of pregnancy where infection with this agent was suspected.

MATERIALS AND METHODS

Samples of amniotic fluid and blood were taken from 28 women between the 16th and 40th week of gestational age. Postnatal blood samples were also taken from their infants. Included in the study group were women with IUGR, PROM, preterm delivery imminent, Toxoplasmosis in previous pregnancies, raised IgG or IgM anti-Toxoplasma antibody titers and with amniotic fluid disturbances (oligohydramnios and polyhydramnios). Presence and levels of Toxoplasma genome was investigated using PCR-TaqMan. PCR products were detected by electrophoresis on polyacrylamide gel.

RESULTS

Toxoplasma gondii genome was detected in blood from 13 women, 3 newborns and in amniotic fluid from one other women. Toxoplasma genome was detected in blood from one newborn, but was not detected in sample from its mother.

CONCLUSIONS

The PCR-TaqMan test is highly sensitive and specific method allowing detection of the parasite genome and assessment of its level. Limitations of this method are its relatively high cost and poor access to ABI PRISM 7700 (TaqMan) sequence detector. The PCR TaqMan is useful in cases, where serological tests for the presence of infections are ambiguous.

Increased fetal erythroblasts in women who subsequently develop pre-eclampsia

In pregnancies complicated by pre-eclampsia (PET) and/or intrauterine growth restriction (IUGR) there is an increased number of fetal cells in the maternal circulation. The aim of this study was to investigate whether this increase in fetal cells precedes the onset of these pregnancy complications. Doppler ultrasound studies at 24 weeks gestation have shown that increased impedance to flow in the uterine arteries identifies pregnancies with impaired placental perfusion that subsequently develop PET and/or IUGR. We obtained maternal blood from 18 pregnancies with abnormal Doppler results at 22-24 weeks gestation and from 10 normal controls. Fetal erythroblasts were enriched from maternal blood by triple density gradient centrifugation and magnetic cell sorting with CD71 antibody, and the percentage of these erythroblasts was determined. The median proportion of fetal erythroblasts in the group with abnormal Doppler results was 4.5% (range 1-12%), which was significantly higher than in the control group [median 1% (range 0-3%; P < 0.001)]. Furthermore, within the group with abnormal Doppler the median proportion of fetal erythroblasts was higher in the 10 cases which subsequently developed PET and/or IUGR [median 5.5% (range 3-12%)], than in those with normal pregnancy outcome [median 2% (range 1-5%; P < 0.01)]. These findings suggest that impaired placental perfusion is associated with an increase in feto-maternal cell traffic, which precedes the onset of PET and/or IUGR by several weeks.

[Lipid profile in newborns with intrauterine growth retardation]

BACKGROUND

The X syndrome, related to coronary disease in adults, could be possibly programmed priory to delivery, in children with intrauterine growth retardation.

AIM

To measure serum lipids in newborns with symmetrical or asymmetrical intrauterine growth retardation.

PATIENTS AND METHODS

One hundred thirty-five newborns with intrauterine growth retardation and 116 normal term newborns, with 38 to 41 gestational weeks, were studied. Total, HDL, and LDL cholesterol, triglycerides and apoproteins. A1 and B were measured in umbilical cord blood samples.

RESULTS

No differences in total, HDL, LDL cholesterol, apoproteins A1 and B were observed between the study groups. Triglycerides were higher in newborns with intrauterine growth retardation, compared to normal term newborns (45 +/- 27 and 36 +/- 19 mg/dl respectively, p < 0.001). Differences in serum triglyceride levels respect to controls were observed in both male and female newborns with asymmetrical growth retardation. Likewise the differences respect to controls were observed in newborns with mild or severe but not with moderate growth retardation.

CONCLUSIONS

Newborns with intrauterine growth retardation have higher triglyceride levels than normal term newborns.

Elevated circulating homocyst(e)ine levels in placental vascular disease and associated pre-eclampsia

We examined the hypothesis that hyperhomocyst(e)inaemia in the maternal or fetal circulation is associated with placental vascular disease with either the maternal syndrome of pre-eclampsia and/or fetal syndrome of growth restriction. Maternal plasma homocyst(e)ine levels were significantly higher in pregnancies complicated by pre-eclampsia, pregnancies with evidence of umbilical placental vascular disease, and pregnancies with both complications compared with the normal pregnancy group. In the fetal circulation mean plasma homocyst(e)ine concentration was significantly higher in the pre-eclampsia group compared with the normal group. The results suggest that hyperhomocyst(e)inaemia may be a risk marker for placental vascular disease and maternal pre-eclampsia. The elevated fetal plasma homocyst(e)ine concentrations, found only in the group of pregnancies with pre-eclampsia in the absence of umbilical placental vascular disease, may be due to an effect of placental vascular disease on homocyst(e)ine transfer from the maternal to fetal circulation.

Increased leptin concentration in preterm infants of pre-eclamptic mothers

AIM

To study the effect of maternal pre-eclampsia on cord plasma leptin concentrations in preterm infants.

METHODS

Leptin concentration was analysed in cord plasma of 74 preterm infants, gestational age 24 to 32 weeks. Of these, 14 were born to pre-eclamptic mothers, in 10 intrauterine growth retardation (IUGR) was present, and 59 had been exposed antenatally to corticosteroids.

RESULTS

The mean (SD) concentration of cord plasma leptin was 1.31 (0.88) microg/l. A significant correlation was found between leptin concentration and gestational age (r = 0.336; p = 0.0037). Leptin levels were higher in infants of pre-eclamptic mothers (p = 0.0007), in those with IUGR (p = 0.0005), and in infants exposed antenatally to corticosteroids (p = 0.02). In multiple regression analysis, leptin was associated with gestational age and maternal pre-eclampsia (both p < 0.05), but not with antenatal corticosteroids.

CONCLUSIONS

Increased fetal leptin in maternal pre-eclampsia may reflect a physiological adaptation to fetal stress such as hypoxia.

[The spectrum of lipids in the intrauterine growth retarded fetus and in the parents]

OBJECTIVE

The aim of this study was to determine the relationship between the parameters of individual serum lipids and the degree of intrauterine growth retardation (IUGR) of the fetus. The lipid levels were compared in fetuses with IUGR and in eutrophic fetuses and it was determined in which studied variable IUGR newborns differ from healthy newborns.

METHODS

The group under study consisted of 53 pregnant women in whom IUGR of the fetus was diagnosed by ultrasound during pregnancy. The control group consisted of 26 women who gave birth to eutrophic newborns. The cases in the control group were chosen by the method of matched control so that the results could be statistically evaluated in both groups at the same gestational age and at the same maternal age. In both groups blood samples from the umbilical cord were taken after delivery and the whole spectrum of lipid levels were evaluated (cholesterol-CH, triglycerides-TGA, high-density lipoprotein--HDL, low-density lipoprotein--LDL, Lp(a) lipoprotein, and apolipoproteins-ApoB, ApoAI, ApoE). The same parameters were evaluated in maternal and paternal blood samples. In several cases, intrauterine lipid levels of the fetus were determined by cordocentesis. The incidence of hyperlipoproteinemia in the families of both groups was surveyed.

SETTING

Department of Obstetrics and Gynaecology, 1st medical Faculty, Charles University, Prague.

RESULTS

There was a significant incidence of hyperlipoproteinemia in the families of the mothers in the group studied (chi-square test: p < 0.001). In the mothers of the groups studied, there were statistically significant higher levels of HDL, LDL, and Lp(a) in comparison to the mothers in the control group. A significant dependence was determined between the levels of ApoAI and Lp(a) of the mothers and newborns. In the regression analysis of the dependence of lipid levels on the birth weight of the newborns, a statistical correlation was determined for the values of ApoB and Lp(a).

CONCLUSION

The more increased the intrauterine growth retardation of the fetus and the lower its birth weight in relation to its gestational age, the higher its lipid levels, specifically apolipoproteins. Apolipoproteins are under genetic control and present a genetic risk for changes in the metabolism of cholesterol, hemocoagulation, and cardiovascular disease in adulthood.

Nucleated red blood cells in growth-restricted fetuses: associations with short-term neonatal outcome

OBJECTIVE

To determine the utility of the neonatal nucleated red blood cell (NRBC) count as an independent predictor of short-term perinatal outcome in growth-restricted fetuses.

METHODS

Hospital charts of neonates with a discharge diagnosis indicating a birth weight <10th percentile were reviewed for perinatal outcome. We studied all eligible neonates who had a complete blood count on the first day of life. After multiple gestations, anomalous fetuses and diabetic pregnancies were excluded; 73 neonates comprised the study group. Statistical analysis included ANOVA, simple and stepwise regression.

RESULTS

Elevated NRBC counts were significantly associated with cesarean section for non-reassuring fetal status, neonatal intensive care unit admission and duration of neonatal intensive care unit stay, respiratory distress and intubation, thrombocytopenia, hyperbilirubinemia, intraventricular hemorrhage and neonatal death. Stepwise regression analysis including gestational age at birth, birth weight and NRBC count demonstrated that in growth-restricted fetuses, NRBC count was the strongest predictor of neonatal intraventricular hemorrhage, neonatal respiratory distress and neonatal death.

CONCLUSION

An elevated NRBC count independently predicts adverse perinatal outcome in growth-restricted fetuses.

Nucleated red blood cell count in the differentiation of fetuses with pathologic growth restriction from healthy small-for-gestational-age fetuses

OBJECTIVE

The purpose of this study was to evaluate the utility of the neonatal nucleated red blood cell count in differentiating the fetus with growth restriction from the small but otherwise healthy fetus.

STUDY DESIGN

Perinatal outcomes were evaluated prospectively for all neonates admitted to the neonatal intensive care unit in 1997. Nonanomalous neonates with normal phenotype and a complete blood cell count performed within the first 6 hours after birth were included in the study. All neonates with birth weights lower than the 10th percentile for gestational age were considered small for gestational age. Neonates were divided into four groups: small-for-gestational-age neonates with elevated nucleated red blood cell counts, appropriately grown neonates with elevated nucleated red blood cell counts, small-for-gestational-age neonates with normal nucleated red blood cell counts, and appropriately grown neonates with normal nucleated red blood cell counts. Analysis of variance, chi(2) tests, and stepwise regression were used for statistical analysis.

RESULTS

Two hundred thirty-seven neonates met the inclusion criteria. Forty-three were small for gestational age. Small-for-gestational-age neonates with high nucleated red blood cell counts had significantly lower umbilical artery pH and were more likely to require mechanical ventilation or blood pressure support agents. Subgroup analysis demonstrated that small-for-gestational-age neonates with elevated nucleated red blood cell counts had significantly more adverse outcomes than did small-for-gestational-age neonates with normal nucleated red blood cell counts. Outcomes of small-for-gestational-age neonates with normal nucleated red blood cell counts were essentially identical to those of appropriately grown neonates.

CONCLUSION

An elevated nucleated red blood cell count may distinguish the fetus with growth restriction from the small but healthy fetus.

Coagulation and fibrinolysis in viable mid-trimester pregnancies of normal, intrauterine growth retardation, chromosomal anomalies and hydrops fetalis and their eventual obstetric outcome

A total of 71 pregnant women diagnosed by ultrasound to have viable fetus in late mid- trimester pregnancies of normal, IUGR, hydrops fetalis and chromosomal anomalies were studied for their coagulation, fibrinolytic and inhibitor levels with association on eventual obstetrics outcome. A hypercoagulable state was observed in all the pregnancies studied. However, higher hypercoagulation evidenced by significantly raised prothrombin formation and clot elasticity together with higher levels of D-dimer, uPA antigen and PAI-1 than observed in normal pregnancy suggests a hyperfibrinolytic/inhibitor state in hydrops fetalis pregnancy associated with bad obstetric outcome. In IUGR pregnancy associated with good outcome further enhanced clot elasticity was seen whilst no significant differences were observed in pregnancy with chromosomal anomalies when compared to uncomplicated normal pregnancy. Our study suggests that in hydrops fetalis pregnancy, further enhanced prothrombin formation and hyperfibrinolysis/inhibitor at late mid-trimester is associated with a poor obstetric outcome.

Increased maternal serum activin A but not follistatin levels in pregnant women with hypertensive disorders

Activin A levels are elevated in maternal serum of pregnant women with hypertensive disturbances. Because follistatin is a circulating binding protein for activin A, the present study was designed to evaluate whether serum follistatin and activin A levels also change in patients with hypertensive disorders in the last gestational trimester. The study design was a controlled survey performed in the setting of an academic prenatal care unit. Healthy pregnant women (controls, n=38) were compared with patients suffering from pregnancy-induced hypertension (PIH, n=18) or pre-eclampsia (n=16). In addition, the study included a subset of patients with pre-eclampsia associated with intrauterine growth restriction (IUGR, n=5). Maternal blood samples were withdrawn at the time of diagnosis (patients) or in a random prenatal visit (controls), and serum was assayed for follistatin and activin A levels using specific enzyme immunoassays. Hormone concentrations were corrected for gestational age by conversion to multiples of median (MoM) of the healthy controls of the same gestational age. Follistatin levels were not different between controls and patients, while activin A levels were significantly increased in patients with PIH (1.8 MoM), pre-eclampsia (4.6 MoM), and pre-eclampsia+IUGR (3.2 MoM, P<0.01, ANOVA). The ratio between activin A and follistatin was significantly increased in patients with PIH (1.5 MoM) and was further increased in patients with pre-eclampsia (4.5 MoM) and in the group with pre-eclampsia+IUGR (2.6 MoM). Follistatin levels were positively correlated with gestational age in control subjects (r=0. 36, P<0.05) and in patients with PIH (r=0.46, P<0.05) or pre-eclampsia (r=0.61, P<0.01), while activin A correlated with gestational age only in the healthy control group (r=0.69, P<0.0001). The finding of apparently normal follistatin and high activin A levels in patients with PIH and pre-eclampsia suggests that unbound, biologically active, activin A is increased in women with these gestational diseases.

Plasma total homocysteine, pregnancy complications, and adverse pregnancy outcomes: the Hordaland Homocysteine study

BACKGROUND

Total homocysteine (tHcy) measured in serum or plasma is a marker of folate status and a risk factor for cardiovascular disease.

OBJECTIVE

Our objective was to investigate associations between tHcy and complications and adverse outcomes of pregnancy.

DESIGN

Plasma tHcy values measured in 1992-1993 in 5883 women aged 40-42 y were compared with outcomes and complications of 14492 pregnancies in the same women that were reported to the Medical Birth Registry of Norway from 1967 to 1996.

RESULTS

When we compared the upper with the lower quartile of plasma tHcy, the adjusted risk for preeclampsia was 32% higher [odds ratio (OR): 1. 32; 95% CI: 0.98, 1.77; P for trend = 0.02], that for prematurity was 38% higher (OR: 1.38; 95% CI: 1.09, 1.75; P for trend = 0.005), and that for very low birth weight was 101% higher (OR: 2.01; 95% CI: 1.23, 3.27; P for trend = 0.003). These associations were stronger during the years closest to the tHcy determination (1980-1996), when there was also a significant relation between tHcy concentration and stillbirth (OR: 2.03; 95% CI: 0.98, 4.21; P for trend = 0.02). Neural tube defects and clubfoot had significant associations with plasma tHcy. Placental abruption had no relation with tHcy quartile, but the adjusted OR when tHcy concentrations >15 micromol/L were compared with lower values was 3.13 (95% CI: 1.63, 6. 03; P = 0.001).

CONCLUSION

Elevated tHcy concentration is associated with common pregnancy complications and adverse pregnancy outcomes.

Adrenomedullin is increased in the fetoplacental circulation in intrauterine growth restriction with abnormal umbilical artery waveforms

OBJECTIVE

To examine whether adrenomedullin, a novel vasoactive peptide produced by the placenta, participates in the uteroplacental hemodynamic alterations in intrauterine growth restriction, we studied the correlation between adrenomedullin levels and fetoplacental blood flow.

STUDY DESIGN

Maternal and umbilical blood samples were collected in pregnancies complicated by intrauterine growth restriction with abnormal umbilical artery Doppler findings and in control pregnancies. Adrenomedullin levels were measured by means of a specific radioimmunoassay, and flow velocimetry waveforms were recorded from uterine, umbilical, and fetal middle cerebral arteries.

RESULTS

Mean adrenomedullin values in umbilical plasma were higher (P <.05) in patients with intrauterine growth restriction (63.7 +/- 34.2 pg/mL; n = 16) than in control subjects (38.1 +/- 14.8 pg/mL; n = 16). A significant correlation was found between maternal adrenomedullin levels and umbilical artery pulsatility index. Moreover, fetal adrenomedullin concentrations correlated negatively with middle cerebral artery pulsatility index and positively with umbilical artery pulsatility index/middle cerebral artery pulsatility index ratio.

CONCLUSION

This study provides evidence that adrenomedullin is increased in fetuses with intrauterine growth restriction in response to reduced uteroplacental blood flow and suggests that it may participate in the fetal hemodynamic modifications.

Increased risk of preterm delivery with elevated maternal alpha-fetoprotein and plasma zinc levels in African-American women

BACKGROUND

This study evaluated the relationship of maternal serum alpha-fetoprotein (MSAFP) and plasma zinc levels (PZn) to pregnancy outcome.

METHODS

The subjects for this investigation consisted of 917 African-American women, who on registration for prenatal care between 7-22 weeks gestational age (GA), had PZn levels determined and also had MSAFP recorded in their charts.

RESULTS

MSAFP levels greater than the 90th percentile significantly increased the risk of PTD (adjusted odds ratio or AOR=2.5, 95% C.I.=1.5-4.2) but not of IUGR. There was no significant relationship between maternal PZn level and PTD or IUGR. When subjects were stratified by MSAFP levels, in women with MSAFP greater than the 90th percentile, the AOR for PTD was 4.0 (95% C.I.=1.2-13.5) for women with PZn levels greater than the median vs. those with PZn equal to or less than the median. In women with MSAFP equal to or less than the 90th percentile, there was no such difference. Multiple regression analyses, using GA at birth as the dependent variable, indicated an interaction between MSAFP and PZn levels.

CONCLUSION

In this population, the adverse pregnancy outcome associated with elevated MSAFP was seen only in women with PZn levels greater than the median. The reason for this association is not currently apparent.

Uteroplacental hemostasis in intrauterine fetal growth retardation

During pregnancy, extensive hemostatic changes occur in the uteroplacental circulation. Invading endovascular trophoblast cells induce physiological adaptations of uterine spiral arteries, required to accommodate the increased maternal blood flow to the intervillous space of the placenta as pregnancy advances. Much of the vascular endothelium and the underlying medial smooth muscle is replaced by trophoblasts, and fibrin or fibrinoid forms a major morphological feature of the arterial walls. Compared with endothelial cells, the trophoblast lining decidual spiral arteries have a reduced capacity to lyse fibrin, and recent studies have shown this to be caused by high levels of plasminogen activator inhibitors (PAI-1 and PAI-2). In pregnancies complicated by intrauterine fetal growth retardation (IUGR), with or without superimposed preeclampsia, a restricted physiological adaptation of uteroplacental spiral arteries is coupled with vascular lesions containing increased fibrin deposition. Significantly higher levels of PAI-1 are found in blood from the uterine vein at delivery and in tissue extracts of the placenta in these pregnancies than are found in normal pregnancy. Recent tissue culture studies have provided new information on the role of trophoblast cells in maintaining hemostatic control in the uteroplacental circulation in pregnancy. Cytotrophoblast cells isolated from the placenta and placental bed from IUGR pregnancies express significantly higher levels of PAI-1, coupled with a significant decrease in plasminogen activator activity, compared with trophoblast cells from normal pregnancy maintained in culture. This localized increased production of PAI-1 may play an important part in restricting endovascular trophoblast invasion in early pregnancy and increasing fibrin deposition and reducing uteroplacental blood flow in pregnancies complicated by IUGR.

Customized fetal weight limits for antenatal detection of fetal growth restriction

OBJECTIVE

To define cut-off limits for individually adjustable fetal weight standards for the detection of intrauterine growth restriction.

DESIGN

Retrospective study, with the outcome measures small-for-gestational age (SGA) birth weight, operative delivery for fetal distress, umbilical artery pH < 7.15, and admission to the neonatal intensive care unit.

SUBJECTS AND METHODS

Two hundred and fifteen women considered to be at increased risk of uteroplacental insufficiency were recruited to a study of serial ultrasound scans. Fetal weights were derived using standard formulae and, retrospectively, weight percentiles were calculated after individual adjustment for maternal height, weight in early pregnancy, ethnic group, parity and fetal sex.

INTRODUCTION

One or more antenatal scans indicative of fetal weight below the 10th customized percentile were predictive for a SGA neonate at birth (P < 0.001), operative delivery for fetal distress (P < 0.01) and admission to neonatal intensive care (P < 0.01) but not for a low umbilical artery pH (P = 0.6). Receiver-operator curves showed the optimal customized fetal weight percentile limit for predicting an SGA neonate to be the 18th percentile (sensitivity 83%, specificity 79%, positive predictive value 63% and negative predictive value 92%). For the prediction of operative delivery for fetal distress and admission to neonatal intensive care, the optional customized cut-off value was the 8th percentile.

CONCLUSIONS

The assessment of fetal weight using ultrasound and an individually-adjusted standard is predictive of growth restriction and perinatal events associated with hypoxia or diminished reserve. The optimal cut-off value for predicting operative delivery for fetal distress or admission to the neonatal intensive care unit suggests that the 10th customized percentile is a good limit for clinical use.

Plasma apolipoprotein A-I and B concentrations in growth-retarded fetuses: a link between low birth weight and adult atherosclerosis

Apolipoprotein B is elevated in growth-retarded compared with normally grown fetuses, demonstrating a link between low birth weight and risk of subsequent atherosclerosis. Increased apolipoprotein B levels and an elevated apolipoprotein B to A-I ratio are predictors of atherogenesis. Elevated apolipoprotein B levels in young adults have been linked to atherosclerosis in later life, whereas impaired fetal growth has been linked to higher than normal apolipoprotein B levels in adulthood. We conducted this research to test the hypothesis that circulating apolipoprotein A-I and B concentrations differ in growth-retarded compared with normal fetuses. Fetal umbilical plasma samples were obtained at diagnostic cordocenteses in 18 growth-retarded and 23 normally grown fetuses. Levels of apolipoprotein A-I and B were measured by turbidimetric assay. There were no differences in median (range) plasma apolipoprotein A-I concentrations between growth-retarded and normal fetuses [0.61 (0.30-1.42) vs. 0.60 (0.30-1.63) g/L, respectively; P = 0.94]. In contrast, we found significantly higher plasma apolipoprotein B levels in growth-retarded vs. normal fetuses [0.62 (0.37-1.84) vs. 0.40 (0.16-1.47) g/L, respectively; P<0.001]. Moreover, the ratio of apolipoprotein B to A-I was significantly higher in growth-retarded than in normal fetuses [1.00 (0.38-2.42) vs. 0.53 (0.31-1.80); P = 0.005]. Levels of apolipoprotein B are elevated in growth-retarded fetuses, suggesting a linkage between low birth weight and adult-onset atherosclerosis.

Gonadotropins, prolactin, inhibin A, inhibin B, and activin A in human fetal serum from midpregnancy and term pregnancy

Using specific enzyme-linked immunosorbent assays we measured inhibin A, inhibin B, and activin A in relation to LH, FSH, and PRL in normal human fetal midpregnancy serum obtained by in utero cord venipuncture (n = 25) and compared these results to those in fetal serum from term pregnancies (n = 23). We also tested serum from fetuses with intrauterine growth retardation (n = 6) or trisomy 21 (n = 6). We found no measurable inhibin A, except in three midpregnancy males (3 of 14). Inhibin B, however, was detected in midpregnancy male fetuses (167+/-67 pg/mL) and was higher than that in females (16+/-12 pg/mL). It was present in male term fetuses (125+/-32 pg/mL), but not in females. The activin A levels did not significantly differ between term and midpregnancy males and females. LH and FSH were detected in midpregnancy male fetuses (4.4+/-3.3 and 0.77+/-0.49 mIU/mL, respectively), with higher levels in females (33.0+/-23.2 and 54.4+/-27.7 mIU/mL, respectively), and were suppressed at term. PRL did not exhibit sexual difference, but showed a higher level at term (322.4+/-113.8 ng/mL) than at midpregnancy (33.0+/-26.1 ng/mL). Comparison of inhibin B with FSH levels showed correlation coefficients of -0.565 at midpregnancy vs. +0.445 at term. Serum from fetuses with intrauterine growth retardation or trisomy 21 did not show any different hormonal profiles. These data suggest that inhibin B is probably an additional factor in FSH inhibition at midpregnancy, whereas activin A is not associated with any change in the different studied populations. We speculate that inhibin A could be a method to detect maternal blood contamination in cord venipuncture.

[Correlation of intrauterine growth retardation with endocrine parameters]

OBJECTIVE

To investigate the relationship between intrauterine growth retardation (IUGR)and endocrine parameters and to assess the effects of the main endocrine factors on IUGR.

METHODS

The concentrations of growth hormone (GH), insulin, triiodothyronine (T(3)), tetraiodothyronine (T(4)), and thyroid-stimulating hormone (TSH) were measured in maternal serum, umbilical blood and amniotic fluid. The samples were collected from 23 term pregnancies with IUGR, and 42 normal pregnancies served as control. Growth hormone and insulin were measured by radioimmunoassay, and T(3), T(4) and TSH by microradioimmunoassay.

RESULTS

The concentrations of GH, insulin and T(4) in umbilical blood were lower in IUGR group than that in the normal group (IUGR: GH 4.63 microg/L vs 7.01 microg/L, insulin 10.68 mIU/L vs 31.44 mIU/L, T(4) 0.68 mg/L vs 1.07 mg/L. P < 0.05, 0.05, 0.05), the TSH level in umbilical blood was higher in IUGR than that in the control group (10.84 mIU/L vs 5.74 mIU/L. P < 0.01). The concentration of GH in maternal serum and insulin in amniotic fluid in IUGR group were also lower than that in normal group (GH 1.77 microg/L vs 2.74 microg/L, P < 0.01; insulin 5.84 mIU/L vs 15.64 mIU/L, P < 0.01).

CONCLUSIONS

This study confirms previous observation that insufficiency of GH might be a pathogenesis of IUGR. The decrease of GH and insulin might compromise the basic metabolism of the fetus. Besides, the change of early hypothyrosis of fetus with IUGR might benefit them to live in unfavorable environment.

Fetal cells in maternal blood of pregnancies with severe fetal growth restriction

The aim of this study was to examine whether, in pregnancies with severe early onset fetal growth restriction, the number of fetal erythroblasts in maternal blood is increased. The percentage of fetal erythroblasts in maternal blood, enriched by triple density gradient centrifugation and anti-CD71 magnetic cell sorting, was determined in 10 singleton pregnancies with severe intrauterine growth restriction in which there was Doppler ultrasound evidence of impaired placental perfusion. The values were compared to those of 10 normal pregnancies at the same gestational range of 22-26 weeks. In the growth restricted pregnancies the median number of fetal erythroblasts per 100 nucleated cells in maternal blood enriched for fetal cells was significantly higher than the median value in the control pregnancies (8.5% compared with 1%; P < 0.001). These data suggest that impaired uteroplacental perfusion and severe fetal growth restriction may be associated with placental damage leading to increased feto-maternal cell traffic. Alternatively the rate of transfer of fetal cells into the maternal circulation is not altered but in growth restriction the proportion of fetal erythroblasts in fetal blood is increased.

Maternal hypothyroxinemia influences glucose transporter expression in fetal brain and placenta

The influence of maternal hypothyroxinemia on the expression of the glucose transporters, GLUT1 and GLUT3, in rat fetal brain and placenta was investigated. Fetal growth was retarded in hypothyroxinemic pregnancies, but only before the onset of fetal thyroid hormone synthesis. Placental weights were normal, but placental total protein concentration was reduced at 19 days gestation (dg). Immunoblotting revealed a decreased abundance of GLUT1 in placental microsomes at 16 dg, whereas GLUT3 was increased. Fetal serum glucose levels were reduced at 16 dg. In fetal brain, the concentration of microsomal protein was deficient at 16 dg and the abundance of parenchymal forms of GLUT1 was further depressed, whereas GLUT3 was unaffected. Northern hybridization analysis demonstrated normal GLUT1 mRNA levels in placenta and fetal brain. In conclusion, maternal hypothyroxinemia results in fetal growth retardation and impaired brain development before the onset of fetal thyroid function. Glucose uptake in fetal brain parenchyma may be compromised directly, due to deficient GLUT1 expression in this tissue, and indirectly, as a result of reduced placental GLUT1 expression. Though corrected by the onset of fetal thyroid hormone synthesis, these deficits are present during the critical period of neuroblast proliferation and may contribute to long term changes in brain development and function seen in this model and in the progeny of hypothyroxinemic women.