Maternal and fetal plasma endothelin levels in intrauterine growth restriction: relation to umbilical artery Doppler flow velocimetry

The objective of this study was to examine maternal and fetal endothelin-1 (ET-1) in pregnancies complicated with intrauterine growth restriction (IUGR) and to correlate these data with umbilical artery Doppler flow velocity waveforms (FVW). Higher mean maternal (13.8 +/- 6.4 vs 9.2 +/- 3.4 pmol/L, p < 0.05) and fetal (18.5 +/- 9.6 vs 11.7 +/- 6.9 pmol/L, p < 0.05) ET-1 levels were found in pregnancies complicated with IUGR than in controls. Fetal ET-1 level was related to birth weight percentile for gestational week. Maternal and fetal ET-1 concentrations were not related to umbilical artery Doppler flow S/D ratio, PI and RI. Maternal or fetal ET-1 concentrations were also not related to umbilical artery pH, PO2 and PCO2. Pregnancy-induced hypertension was significantly associated with an elevated fetal and maternal ET-1 concentration. In conclusion, increased production and secretion of ET-1 may play a role in the pathophysiology of idiopathic IUGR. Over-production of ET-1 in IUGR is not associated with increased placental resistance as reflected in abnormal umbilical artery Doppler FVW.     

Doppler velocimetry in patients with preeclampsia

Doppler velocimetry is a fast and convenient method for monitoring of fetal well being in high risk pregnancies. Doppler velocimetry is more specific and sensitive method of fetal surveillance than cardiotocography. The study's objective is to prove Doppler's effectiveness in predicting perinatal outcome in preeclamptic pregnancies. A retrospective study is designed, including pregnant women, diagnosed with preeclampsia, admitted to Maternity hospital "Majchin dom" for ten years. Doppler study was made and results were correlated to Apgar score, umbilical artery pH and base excess of the neonate at delivery. A correlation between RI of umbilical artery, uterine arteries and Apgar score at 5th minute was demonstrated. In severe cases correlation between RI of umbilical artery and neonatal pH was found. CONCLUSION: Doppler velocimetry is an effective method of fetal surveillance in pregnancies, complicated by preeclampsia     

Placental Doppler velocimetry in gestational diabetes mellitus

OBJECTIVE: To evaluate if maternal glucose level and growth of the fetus were related to placental vascular impedance in pregnancy complicated by gestational diabetes mellitus. MATERIAL AND METHODS: A retrospective study of 146 gestational diabetic women of which 117 needed insulin therapy. Glycosylated hemoglobin (HbA1c) was evaluated as well as umbilical and uterine artery Doppler velocimetry. The results were related to adverse outcome of pregnancy including newborn birthweight. RESULTS: Abnormal umbilical artery blood flow velocity was seen in 5% of the cases and abnormal uterine artery flow in 16%. Uterine and umbilical artery vascular impedance was significantly lower in macrosomic newborns. There was a poor correlation between HbA1c, vascular impedance and birthweight. There were 11 cases that developed preeclampsia, all having abnormal uterine artery Doppler and two abnormal umbilical artery Doppler. CONCLUSION: Uterine and umbilical artery vascular impedance in pregnancies complicated by gestational diabetes is related to birthweight and placental weight, but not to maternal HbA1c levels. Placental Doppler ultrasound does not seem to be of clinical value for fetal surveillance in these pregnancies unless the pregnancy is complicated by preeclampsia and/or intrauterine fetal growth restriction.     

Doppler examinations of fetal and uteroplacental blood flow in AGA and IUGR fetuses before and after maternal physical exercise with the bicycle ergometer

OBJECTIVE: To study changes in uteroplacental and fetal circulation after maternal exercise in appropriate-for-gestational-age fetuses (AGA) and intrauterine-growth-retarded fetuses (IUGR). MATERIALS AND METHOD: 33 women with an uncomplicated course of pregnancy and ten women with IUGR were examined. Physical stress was caused through a bicycle ergometer with 1.25 W/kg maternal weight. Doppler examinations were performed in the umbilical artery, fetal aorta, middle cerebral and in the uterine artery. Fetal heart rate was documented by monitoring. Maternal lactate and glucose levels as well as maternal blood pressure and heart rate were recorded. RESULTS: No significant changes after cycling could be observed in umbilical and uterine vessels either in the normal pregnancies or in pregnancies with IUGR. In contrast, in the fetal aorta an increase of the RI was recorded in both groups (an increase of 16% [P<0.01] and 18% [P<0.05], respectively for AGA and IUGR cases). In cerebral arteries a decrease of the RI was observed after cycling in both groups (a decrease of 24% [P<0.01] and 13% [P<0.05], respectively for AGA and IUGR cases). In AGA fetuses the RI of the aorta and middle cerebral artery returned to pre-test level by the 18th minute of examination. In IUGR fetuses the RI of the aorta and middle cerebral artery did not return to pre-test levels at the end of the test. Fetal heart rate remained unchanged in both groups. Maternal blood pressure and heart rate increased during the exertion phase but returned to initial values at the end of the test. A 21% and 24% (for AGA and IUGR groups respectively) reduction of maternal glucose values after exercise was observed (P<0.001). Lactate values doubled in both groups after exercise (P<0.001). CONCLUSION: From the results obtained we conclude that maternal exercise does not significantly alter uterine and umbilical perfusion in AGA and IUGR pregnancies, suggesting an absence of change in the uterine vascular bed resistance. However, submaximal maternal exercise was followed by fetal cerebral vasodilatation and an increase of resistance in the fetal aorta that was more evident in IUGR fetuses. This might be due to slight fetal hemoglobin desaturation in those cases.     

Doppler sonography of the uterine and the cubital arteries in normal pregnancies, preeclampsia and intrauterine growth restriction: evidence for a systemic vessel involvement

AIMS: The decrease in uterine resistance during normal pregnancy is known to be related to invading trophoblast cells which derive from placental tissue. Uterine and peripheral resistance is elevated in preeclampsia. The aim of the present study was to prospectively examine uterine and peripheral resistance in pregnancies complicated by preeclampsia (PE), fetal intrauterine growth restriction (IUGR) and pregnancy induced hypertension (PIH). METHODS: Sixty-seven women with normal pregnancies, 17 with PE, 12 with IUGR underwent Doppler sonographic investigation of the uterine and the cubital arteries. The Pulsatility Index (PI) was calculated for each vessel. Statistical analysis was performed and a P-value <0.05 was considered significant. RESULTS: Patients with preeclampsia and IUGR showed a significant higher resistance at the placental (mean PI 1.267 and 1.063), nonplacental (mean PI 1.631 and 1.124) and cubital artery (mean PI 3,777 and 3.995) compared to the normal pregnancy group (mean PI 0.678; 0.859 and 2.95 respectively). Mean birth weight in the PE group was 1409 g, in the IUGR group 1649 g and 3419 g in the normal pregnancy group. CONCLUSIONS: Pregnancies with IUGR are associated with elevated peripheral resistance in the maternal arterial system as seen in pregnancies with preeclampsia. Our findings encourage to further investigate the maternal vascular system in high risk pregnancies.     

Umbilical artery velocimetry in insulin dependent diabetes mellitus (IDDM) pregnancies

Seven hundred and sixty seven Doppler umbilical artery velocity waveform analyses were performed in 108 pregnant insulin-dependent diabetes mellitus (IDDM) women. No significant correlation between mean third trimester systolic to diastolic (S/D) ratio and either mean blood glucose (r = 0.19) or glycosylated hemoglobin levels (r = 0.28) was found. Mean second and third trimester S/D ratios differed significantly in patients with or without vascular disease (P less than 0.05). Furthermore, women without vasculopathy who demonstrated an elevated S/D developed preeclampsia and delivered appropriate for gestational age infants while patients with vascular disease or chronic hypertension and elevated third trimester S/D (greater than 3) delivered intra uterine growth retarded (IUGR) infants. Moreover, in most of the latter group elevated S/D ratios were recorded in the second trimester prior to ultrasound documentation of IUGR. Our data suggest that in the absence of vasculopathy normal fetal placental resistance can be expected in most pregnancies complicated by diabetes. Patients with vasculopathy are at higher risk for fetal IUGR, which may be identified by early umbilical artery velocimetry.     

Uterine artery Doppler and prediction of preeclampsia

Identifying patients at risk for preeclampsia would allow an increase in perinatal surveillance and possibly decrease the inherent maternal and fetal morbidity and mortality associated with severe preeclampsia and eclampsia. First and second trimester uterine artery Doppler velocimetry is a sensitive screening tool for the detection of preeclampsia and intrauterine growth retardation (IUGR) requiring delivery before 34 weeks. The performance of uterine artery Doppler velocimetry as a screening test depends on the prevalence of the adverse outcome in the studied population and whether the adverse outcomes are assessed individually or collectively as a group. Future research in this area should focus on identification of additional markers that may be incorporated into a prediction model for early identification of patients at risk for adverse outcomes.     

Histomorphology of the placenta and the placental bed of growth restricted foetuses and correlation with the Doppler velocimetries of the uterine and umbilical arteries

The aim of the present study was to evaluate the histomorphology of the placenta and the placental bed and to correlate this with the Doppler study of the uterine and umbilical arteries of intrauterine growth restricted pregnancies. The study group consisted of 47 women with intrauterine growth restricted foetuses. Twenty-five uneventful pregnancies with appropriate for gestational age foetuses were selected as controls. Doppler studies of umbilical and uterine arteries were performed within the last week before delivery. Placental bed biopsies were obtained at Caesarean section with direct visualization of the placental site. The incidence of pathologic bed biopsies in control, IUGR with normal uterine artery Doppler velocimetry and IUGR with abnormal uterine artery Doppler velocimetry was 0 per cent, 16.6 per cent and 79.3 per cent respectively (P< 0.001). Placentae from IUGR cases with abnormal umbilical artery Doppler velocimetries had a significantly increased number of villous infarcts, cytotrophoblast proliferation and thickening of the villous trophoblastic basal membrane (P=0.001, P=0.038 and P=0.02 respectively). Abnormal placental bed biopsy pathology was significantly associated with abnormal uterine artery velocimetry (OR 33.7, 6.5-173.6; P< 0.001). Abnormal placental pathology was significantly associated with abnormal umbilical artery Doppler velocimetry (OR 21.04, 3.8-115.9;P< 0.001). Women with both abnormal uterine and umbilical artery Doppler velocimetries were delivered earlier and their babies had lower mean birth and placental weight (P< 0.001). In conclusion, placental bed biopsy and placental pathologies are best reflected by abnormal uterine and umbilical artery velocity waveforms, respectively. The most severe clinical outcomes and perinatal mortality are present when both uterine and umbilical districts are altered.     

Evaluation of maternal and umbilical serum TNFalpha levels in preeclamptic pregnancies in the intrauterine normal and growth-restricted fetus.

OBJECTIVE: The aim of this study was to carry out a comparative analysis of the maternal and umbilical cord TNFalpha serum levels in pregnancies complicated by severe preeclampsia with normal intrauterine fetal growth, in preeclamptic pregnancies with intrauterine growth restriction (IUGR), and in normotensive pregnant patients. PATIENTS AND METHODS: The study was carried out on eight patients with severe preeclampsia complicated by IUGR and 18 preeclamptic patients with normal intrauterine fetal growth. The control group consisted of 18 healthy normotensive patients with singleton uncomplicated pregnancies. Maternal and umbilical serum TNFalpha concentrations were estimated using a sandwich ELISA assay. RESULTS AND CONCLUSIONS: Pregnant women with severe preeclampsia had significantly higher maternal and umbilical serum TNFalpha levels than those in the normotensive controls. Our findings and other reports indicate that TNFalpha may participate in the pathogenesis and sequelae of preeclampsia with and without IUGR. The results of excessive umbilical serum activity of tumor necrosis factor alpha (TNFalpha) in preeclamptic pregnancy complicated by intrauterine growth restriction (IUGR) may suggest additional changes and dysfunction of the placental-fetal unit and deterioration of placental function, leading to fetal hypotrophia in the course of preeclampsia.     

Uterine Doppler velocimetry and placental hypoxic-ischemic lesion in pregnancies with fetal intrauterine growth restriction.

We tested the hypothesis that Doppler velocimetry of the ascending uterine arteries (Ut.DV) in cases of fetal intrauterine growth restriction (IUGR) can reflect the presence of hypoxic-ischaemic lesions of the placenta, and whether this prediction is affected by the maternal blood pressure status.Ut.DV was obtained within 7 days of delivery in 90 consecutive pregnancies with IUGR and in 37 uneventful control pregnancies. Abnormal Ut.DV was defined as an average of a (left and right systolic)/diastolic ratio >2.6 and diastolic notching. After delivery, pathological studies were performed with attention paid to macroscopic and microscopic evidence of hypoxic or ischaemic placental lesions related to uteroplacental vascular pathological features.In patients with IUGR, the total rate of placental lesions was significantly higher in the presence of abnormal Ut.DV compared to the presence of normal Ut.DV (relative risk, 6.35; 95 per cent confidence interval=5.2-7.3). The rate and the severity of these lesions was not significantly different between normotensive and hypertensive pregnancies (87 versus 93 per cent;P =0.2). When Ut.DV was normal, the rate of placental lesions was similar between IUGR cases and control pregnancies (14 versus 8 per cent;P =0.69). The perinatal outcome was not significantly different in any of the normotensive and the hypertensive pregnancies with growth-restricted fetuses and abnormal Ut.DV.The presence of abnormal Doppler velocimetry of the uterine arteries in pregnancies with fetal intrauterine growth restriction is may be in fact an important indicator of hypoxic or ischaemic placental lesions. This abnormal Doppler velocimetry is independent of the maternal blood pressure status.     

Angiogenin and vascular endothelial growth factor in pregnancies complicated by preeclampsia.

OBJECTIVE: To investigate the role of the angiogenic factors, vascular endothelial growth factor (VEGF) and angiogenin in the pathophysiology of preeclampsia and how their concentrations correlate with the severity of the disease and fetal outcome. PATIENTS AND METHODS: A prospective study was carried out on 71 pregnant patients with preeclampsia and 20 pregnant normotensive controls. Maternal serum levels of VEGF and angiogenin were determined in all cases by enzyme immunoassay. Assessment of fetal well-being using the Biophysical Profile Score (BPS), umbilical and uterine artery Doppler velocimetry, and infant birthweight were carried out. RESULTS: Maternal serum VEGF and angiogenin levels were significantly increased in cases of mild and severe preeclampsia compared to controls. Their increase was positively correlated with elevated systolic and diastolic blood pressure, as well as poor BPS, abnormal Doppler velocimetry, and low birthweight. CONCLUSION: Elevated levels of both VEGF and angiogenin could confirm the existence of vascular reactivity and endothelial disturbance in preeclampsia. Measurement of these angiogenic factors in maternal serum may be a useful as biomarkers for the assessment of the severity of the disease and of fetal outcome.     

Minimal alteration in the ratio of circulatory fetal DNA to fetal corticotropin-releasing hormone mRNA level in preeclampsia

OBJECTIVES: We have recently observed that fetal DNA and fetal corticotropin-releasing hormone (CRH) mRNA are associated with in vitro generated syncytiotrophoblast-derived microparticles, and that the ratio of fetal DNA to mRNA (CRH) varied according to whether the particles were derived by predominantly apoptotic, apo-necrotic or necrotic pathways. Hence, we examined whether these ratios varied in maternal plasma samples taken from normotensive and preeclamptic pregnancies in vivo. METHODS: Maternal plasma samples were collected from 18 cases with preeclampsia and 29 normotensive term controls. Circulatory fetal CRH mRNA and DNA levels were quantified by real-time PCR and RT-PCR. RESULTS: Circulatory fetal mRNA and fetal DNA levels were significantly elevated in the preeclampsia study group when compared to normotensive controls. Alterations in the fetal mRNA to DNA ratio between the study and control groups were minimal, even when stratified into early (<34 weeks of gestation) and late (>34 weeks of gestation) onset preeclampsia. CONCLUSIONS: Our data suggest that although circulatory fetal DNA and mRNA levels are significantly elevated in preeclampsia, the ratios in maternal plasma are not dramatically altered.     

Fetal and maternal Doppler velocimetry and cytokines in high-risk pregnancy

OBJECTIVE: Fetal hypoxia and preterm delivery are reported to be strongly associated with brain damage and neurodevelopmental delay. Doppler signs of fetal brain sparing have been described during chronic hypoxia, but whether they are related to brain damage is unknown. The aim of this study was to evaluate if markers of tissue injury, i.e., tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) are related to signs of increased perinatal vascular impedance and/or fetal brain sparing in high-risk pregnancies. STUDY DESIGN: TNF-alpha and IL-6 levels were evaluated in maternal blood serum of 67 high-risk pregnancies. Serum samples were taken at the time of umbilical, middle cerebral artery and uterine artery Doppler velocimetry examination. The values for TNF-a and IL-6 were correlated with reference median values obtained with gestational age in the form of a Z-score. RESULTS: TNF-alpha levels showed values within the normal range in only four cases. IL-6 values were found normal in 14 cases. The Z-score for mean middle cerebral artery pulsatility index (PI) showed a significant correlation to TNF-alpha and IL-6 levels, P < 0.0001 and P < 0.003, respectively. This might suggest a strong correlation between signs of fetal brain sparing and increased maternal serum TNF-alpha and IL-6 levels. Abnormal uterine artery PI and the presence of a "notch" were also highly significantly related to TNF-alpha and IL-6 levels, which were nearly two-fold higher compared to normal uterine artery blood flow and the absence of a "notch". Abnormal cerebro/placental ratios showed significant correlations to TNF-alpha and IL-6 levels. CONCLUSION: The present results suggest a strong correlation between levels of TNF-alpha and IL-6 not only for signs of fetal brain sparing, but also for uteroplacental blood flow. This finding supports the role of tissue injury in cases of fetal brain sparing, but whether this is a reflection of brain damage or secondary to placental pathology needs further evaluation.     

Intrauterine growth restriction with abnormal umbilical artery Dopplers: a harbinger for preeclampsia?

Objective: To determine whether abnormal umbilical artery Doppler velocimetry in the setting of unexplained intrauterine growth restriction (IUGR) is predictive of preeclampsia. Methods: This was a retrospective cohort study of singleton pregnancies diagnosed with unexplained IUGR between 2005 and 2008. Subjects were classified based on the presence or absence of abnormal Dopplers. The proportions of preeclampsia in the two groups were compared. Results: A total of 268 cases were included in the study. There were 57 cases with abnormal umbilical artery Dopplers. Of those, preeclampsia was diagnosed in 8 (14.0%) cases. In turn, there were 211 cases with normal Dopplers. Of those, preeclampsia was diagnosed in 9 (4.3%) cases. After controlling for age and parity, patients with abnormal Dopplers were 2.9 times more likely to be diagnosed with preeclampsia. Conclusions: Cases of unexplained IUGR with abnormal umbilical artery Dopplers appear to be at increased risk of preeclampsia compared to those with normal Dopplers.     

Uterine and umbilical artery Doppler velocimetry in postterm pregnancy

Uterine and umbilical artery Doppler velocimetry was carried out on 149 women whose pregnancies went to 41 weeks or beyond. Flow velocity was not altered even in the presence of other signs suggestive of fetal compromise. It appears that the postdate syndrome is not associated with significant alterations in the maternal or umbilical blood flow prior to the onset of labor.     

Maternal and umbilical sTNF-R1 in preeclamptic pregnancies with intrauterine normal and growth retarded fetus.

OBJECTIVE: The aim of this study was to determine the maternal and umbilical cord sTNF R1 serum levels in pregnancies complicated by severe preeclampsia with normal intrauterine fetal growth and in preeclamptic pregnancies with intrauterine growth retardation (IUGR). PATIENTS AND METHODS: The study was carried out on 8 patients with preeclampsia complicated by intrauterine growth retardation (group PI) and 18 preeclamptic patients with appropriate-for-gestational-age weight infants (group P). The control group consisted of 18 healthy normotensive delivering patients with singleton uncomplicated pregnancies (group C). Maternal and umbilical serum sTNF-R1 concentrations were estimated using a sandwich enzyme-linked immunosorbent assay (ELISA). RESULTS AND CONCLUSIONS: Pregnant women with severe preeclampsia had higher maternal and umbilical serum sTNF-R1 levels than did normotensive controls. Furthermore significantly higher umbilical levels of sTNF-R1 were observed in the group of patients with preeclampisa complicated by IUGR, compared with preeclamptic patients with appropriate-for-gestational-age weight infants. The umbilical sTNF-R1 levels in preeclamptic groups tended to be higher in comparison with the maternal levels. Our results and those of other reports seem to suggest that TNFalpha and sTNFR1 play a crucial role in pathogenesis and sequelae of preeclampsia with and without intrauterine growth retardation.     

Placental ischemia and changes in umbilical and uteroplacental arterial and venous hemodynamics

Objective: To relate Doppler velocimetry findings in fetoplacental and uteroplacental circulation to placental histomorphology. Material and methods: In 14 uncomplicated and 31 high-risk pregnancies Doppler velocimetry was performed in umbilical artery and vein, and in maternal uterine veins and arteries during the second half of gestation. Histopathology of the placentas was examined, especially for signs of ischemia and inflammation. Results: All fetuses in uncomplicated pregnancies had normal flow velocity waveforms in umbilical artery; in the high-risk group, 18 fetuses had abnormal flow (increased PI or absent/reverse end-diastolic flow). The latter group had more often high ischemic score and infarctions in the placenta than found in pregnancies with normal umbilical artery flow (p?<?0.001 and p?=?0.02, respectively). Similarly, the abnormal uterine artery flow pattern (uterine artery score 3–4) occurred more often with high ischemic score and placenta infarctions (p?<?0.001 and p?<?0.001, respectively). No significant associations were found between the uterine venous flow type and placental ischemia. Conclusion: Placental ischemic morphological changes were associated with Doppler ultrasound signs of increased resistance to arterial blood flow, both on the fetal and maternal sides of the placenta. No significant relation to the uterine venous flow velocities was found.     

Evaluation of maternal and umbilical serum TNFα levels in preeclamptic pregnancies in the intrauterine normal and growth-restricted fetus

Objective.?The aim of this study was to carry out a comparative analysis of the maternal and umbilical cord TNFα serum levels in pregnancies complicated by severe preeclampsia with normal intrauterine fetal growth, in preeclamptic pregnancies with intrauterine growth restriction (IUGR), and in normotensive pregnant patients.

Patients and methods.?The study was carried out on eight patients with severe preeclampsia complicated by IUGR and 18 preeclamptic patients with normal intrauterine fetal growth. The control group consisted of 18 healthy normotensive patients with singleton uncomplicated pregnancies. Maternal and umbilical serum TNFα concentrations were estimated using a sandwich ELISA assay.

Results and conclusions.?Pregnant women with severe preeclampsia had significantly higher maternal and umbilical serum TNFα levels than those in the normotensive controls. Our findings and other reports indicate that TNFα may participate in the pathogenesis and sequelae of preeclampsia with and without IUGR. The results of excessive umbilical serum activity of tumor necrosis factor α (TNFα) in preeclamptic pregnancy complicated by intrauterine growth restriction (IUGR) may suggest additional changes and dysfunction of the placental–fetal unit and deterioration of placental function, leading to fetal hypotrophia in the course of preeclampsia.     

Sonographic measurements with umbilical and uterine artery Doppler analysis in suspected intrauterine growth retardation

A retrospective analysis was performed to evaluate the role of sonographic measurement with umbilical and uterine artery Doppler studies in cases of suspected intrauterine growth retardation (IUGR). The sonogram was more sensitive (72%), but the umbilical artery Doppler scan was more specific (90%), for the diagnosis of IUGR. Abnormal uterine artery Doppler measurements in cases of IUGR diagnosed with a sonogram and umbilical artery Doppler scan were associated with chronic maternal hypertension. Those fetuses fared worse than those in which the uterine artery Doppler scans were normal. In contrast, small infants from pregnancies in which all three studies were normal performed well overall. Complementary use of these three studies to evaluate suspected IUGR fetuses may help us distinguish the small, troubled fetus from the small but healthy one.     

Doppler velocimetry and fetal heart rate studies in nephropathic diabetics.

OBJECTIVES: Our objectives were to determine in pregnancies complicated by diabetic nephropathy (1) if impedance to flow in the uterine and umbilical arteries is normal and (2) if these fetuses are hypoxemic and acidemic and if they have decreased fetal heart rate variation and Doppler blood flow redistribution. STUDY DESIGN: In a cross-sectional study at the Harris Birthright Research Centre for Fetal Medicine, London, serial assessment of fetal heart rate variation and Doppler velocimetry of the placental and fetal circulations was undertaken in six pregnancies complicated by diabetic nephropathy. In all cases cordocentesis was performed within 24 hours before delivery for the measurement of umbilical venous blood gases. RESULTS: Cordocentesis demonstrated these fetuses to be hypoxemic and acidemic. The fetal heart rate variation was decreased; however, impedance to flow in the uterine artery was normal, and increased impedance to flow in the umbilical artery with evidence of blood flow redistribution was observed in only one case. CONCLUSIONS: Fetal hypoxemia and acidemia in pregnancies complicated by diabetic nephropathy is not a consequence of impaired placental perfusion, and the degree of metabolic derangement may be obscured by the apparent normal growth and failure of these fetuses to demonstrate blood flow redistribution.