Arterial and venous Doppler in the diagnosis and management of early onset fetal growth restriction

Maternal rest improves growth in small-for-gestational-age fetuses (<10th percentile)

BACKGROUND

Optimal management of fetuses diagnosed as small for gestational age based on an estimated fetal weight of <10th percentile represents a major clinical problem. The standard approach is to increase fetal surveillance with serial biometry and antepartum testing to assess fetal well-being and timing of delivery. Observational studies have indicated that maternal rest in the left lateral position improves maternal cardiac output and uterine blood flow. However, maternal bed rest has not been recommended based on the results of a randomized clinical trial that showed that maternal rest does not improve fetal growth in small-for-gestational-age fetuses. This study was conducted to revisit this question.

OBJECTIVE

This study aimed to determine whether maternal bed rest was associated with an increase in the fetal biometric parameters that reflect growth after the diagnosis of a small-for-gestational-age fetus.

STUDY DESIGN

A retrospective study was conducted on fetuses who were diagnosed as small for gestational age because of an estimated fetal weight of <10th percentile for gestational age. The mothers were asked to rest in the left lateral recumbent position. Fetal biometry was performed 2 weeks after the diagnosis. All fetuses before entry into the study had a previous ultrasound that demonstrated an estimated fetal weight of >10th percentile. To assess the response to bed rest, the change in fetal biometric parameters (estimated fetal weight, head circumference, abdominal circumference, and femur length) after the recommendation of bed rest was computed for 2 periods: (1) before the diagnosis of a weight of <10th percentile vs at the time of diagnosis of a weight of <10th percentile and (2) at the time of diagnosis of a weight of <10th percentile vs 2 weeks after maternal bed rest. For repeated measures, proportions were compared using the McNemar test, and percentile values were compared using the Bonferroni Multiple Comparison Test. A P value of <.05 was considered significant. To describe changes in the estimated fetal weight without bed rest, 2 control groups in which the mothers were not placed on bed rest after the diagnosis of a small-for-gestational-age fetus were included.

RESULTS

A total of 265 fetuses were observed before and after maternal bed rest. The following were observed in this study: (1) after 2 weeks of maternal rest, 199 of 265 fetuses (75%) had a fetal weight of >10th percentile; (2) the median fetal weight percentile increased from 6.8 (interquartile range, 4.4-8.4) to 18.0 (interquartile range, 9.5-29.5) after 2 weeks of bed rest; (3) similar trends were noted for the head circumference, abdominal circumference, and femur length. In the groups of patients who were not asked to be on bed rest, a reassignment to a weight of >10th percentile at a follow-up examination only occurred in 7 of 37 patients (19%) in the Texas-Michigan group and 13 of 111 patients (12%) in the Colorado group compared with the bed rest group (199/265 [75%]) (P<.001).

CONCLUSION

Patients who were prescribed 2 weeks of bed rest after the diagnosis of a fetal weight of <10th percentile had an increase in weight of >10th percentile in 199 of 265 fetuses (75%). This increase in fetal weight was significantly higher than that in the 2 control groups in which bed rest was not prescribed. This observation suggests that bed rest improves fetal growth in a subset of patients.

Arterial and Venous Doppler in Evaluation of the "At-risk" Fetus

Our practice utilizes Doppler ultrasound as one of the most objective and effective methods to assess at-risk pregnancies. This review will discuss the application of arterial and venous Doppler techniques in assessing and managing various diseases and conditions for high-risk fetuses.

Chromosomal Abnormalities Detected by Chromosomal Microarray Analysis and Karyotype in Fetuses with Ultrasound Abnormalities

Objective

Chromosomal microarray analysis (CMA) is a first-line test to assess the genetic etiology of fetal ultrasound abnormalities. The aim of this study was to evaluate the effectiveness of CMA in detecting chromosomal abnormalities in fetuses with ultrasound abnormalities, including structural abnormalities and non-structural abnormalities.

Methods

A retrospective study was conducted on 368 fetuses with abnormal ultrasound who received interventional prenatal diagnosis at Meizhou People's Hospital from October 2022 to December 2023. Samples of villi, amniotic fluid, and umbilical cord blood were collected according to different gestational weeks, and karyotype and CMA analyses were performed. The detection rate of chromosomal abnormalities in different ultrasonic abnormalities was analyzed.

Results

There were 368 fetuses with abnormal ultrasound, including 114 (31.0%) with structural abnormalities, 225 (61.1%) with non-structural abnormalities, and 29 (7.9%) with structural combined with non-structural abnormalities. The detection rate of aneuploidy and pathogenic (P)/likely pathogenic (LP) copy number variations (CNVs) of CMA in fetuses with structural abnormalities was 5.26% (6/114), the detection rate of karyotype was 2.63% (3/114), and the additional diagnosis rate of CMA was 2.63%. In the fetuses with ultrasonic non-structural abnormalities, the detection rate of karyotype was 6.22% (14/225), the detection rate of aneuploidy and P/LP CNVs in fetuses with ultrasonic structural abnormalities was 9.33% (21/225), and the additional diagnosis rate of CMA was 3.11%. There was no significant difference in chromosome abnormality detection rate of CMA among structural abnormality, non-structural abnormality, and structural abnormality combined with non-structural abnormality groups (5.3%, 9.3%, and 13.8%, p = 0.241), also among multiple ultrasonic abnormality and single ultrasonic abnormality groups (14.8%, and 7.3%, p = 0.105).

Conclusion

CMA can significantly improve the detection rate of genetic abnormalities in prenatal diagnosis of ultrasonic abnormal fetuses compared with karyotype analysis. CMA is a more effective tool than karyotyping alone in detecting chromosomal abnormalities in fetuses with ultrasound abnormalities.

Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors

Under intrauterine growth restriction (IUGR), abnormal attainment of the nutrients and oxygen by the fetus restricts the normal evolution of the prenatal causing in many cases high morbidity being one of the top-ten causes of neonatal death. The current gold standards in hospitals to detect this relevant problem is the clinical observation by echography, cardiotocography and Doppler. These qualitative techniques are not conclusive and requires risky invasive fetal scalp blood testing and/or amniocentesis. We developed micro-implantable multiparametric electrochemical sensors for measuring ischemia in real time in fetal tissue and vascular. This implantable technology is designed to continuous monitoring for an early detection of ischemia to avoid potential fetal injury. Two miniaturized electrochemical sensors were developed based on oxygen and pH detection. The sensors were optimized in vitro under controlled concentration, to assess the selectivity and sensitivity required. The sensors were then validated in vivo in the ewe fetus model, by means of their insertion in the muscle leg and inside the iliac artery of the fetus. Ischemia was achieved by gradually obstructing the umbilical cord to regulate the amount of blood reaching the fetus. An important challenge in fetal monitoring is the detection of low levels of oxygen and pH changes under ischemic conditions, requiring high sensitivity sensors. Significant differences were observed in both; pH and pO₂ sensors under changes from normoxia to hypoxia states in the fetus tissue and vascular with both sensors. Herein, we demonstrate the feasibility of the developed sensors for future fetal monitoring in medical applications.

Doppler Ultrasonography of the Fetal Tibial Artery in High-Risk Pregnancy and Its Value in Predicting and Monitoring Fetal Hypoxia in IUGR Fetuses

Background and Objectives: Intrauterine growth restriction (IUGR) is the term used to describe a fetus whose estimated weight is less than the 10th percentile of its age growth curve. IUGR is the second most common cause of perinatal death. In many cases there is a deficiency in the standardization of optimal management, prenatal follow-up and timing of delivery. Doppler examination is the most sensitive test that can assess the condition of the fetus and indicate fetal intrauterine hypoxia. Numerous studies of the fetal intrauterine state focus on the umbilical artery and the fetal cerebral blood vessels, while the peripheral arteries have so far received insufficient attention. Materials and Methods: We present a case of an IUGR fetus monitored with a non-stress test (NST) and a Doppler examination of the fetal arteries (tibial, umbilical, middle cerebral and uterine) and the ductus venosus. In this case the first early sign of fetal hypoxia was revealed by blood flow changes in the tibial artery. Results: We hypothesize that peripheral vascular changes (in the tibial artery) may more accurately reflect the onset of deterioration in the condition of the IUGR fetus, such that peripheral blood flow monitoring ought to be employed along with other techniques already in use. Conclusion: This paper describes the clinical presentation of an early detection of late IUGR hypoxia and claims that blood flow changes in the tibial artery signal the worsening of the fetus’s condition.

Miniaturized Electrochemical Sensors to Monitor Fetal Hypoxia and Acidosis in a Pregnant Sheep Model

Perinatal asphyxia is a major cause of severe brain damage and death. For its prenatal identification, Doppler ultrasound has been used as a surrogate marker of fetal hypoxia. However, Doppler evaluation cannot be performed continuously. We have evaluated the performance of a miniaturized multiparametric sensor aiming to evaluate tissular oxygen and pH changes continuously in an umbilical cord occlusion (UCO) sheep model. The electrochemical sensors were inserted in fetal hindlimb skeletal muscle and electrochemical signals were recorded. Fetal hemodynamic changes and metabolic status were also monitored during the experiment. Additionally, histological assessment of the tissue surrounding the sensors was performed. Both electrochemical sensors detected the pO₂ and pH changes induced by the UCO and these changes were correlated with hemodynamic parameters as well as with pH and oxygen content in the blood. Finally, histological assessment revealed no signs of alteration on the same day of insertion. This study provides the first evidence showing the application of miniaturized multiparametric electrochemical sensors detecting changes in oxygen and pH in skeletal muscular tissue in a fetal sheep model.

Non-invasive monitoring of pH and oxygen using miniaturized electrochemical sensors in an animal model of acute hypoxia

Background

One of the most prevalent causes of fetal hypoxia leading to stillbirth is placental insufficiency. Hemodynamic changes evaluated with Doppler ultrasound have been used as a surrogate marker of fetal hypoxia. However, Doppler evaluation cannot be performed continuously. As a first step, the present work aimed to evaluate the performance of miniaturized electrochemical sensors in the continuous monitoring of oxygen and pH changes in a model of acute hypoxia-acidosis.

Methods

pH and oxygen electrochemical sensors were evaluated in a ventilatory hypoxia rabbit model. The ventilator hypoxia protocol included 3 differential phases: basal (100% FiO₂), the hypoxia-acidosis period (10% FiO₂) and recovery (100% FiO₂). Sensors were tested in blood tissue (ex vivo sensing) and in muscular tissue (in vivo sensing). pH electrochemical and oxygen sensors were evaluated on the day of insertion (short-term evaluation) and pH electrochemical sensors were also tested after 5 days of insertion (long-term evaluation). pH and oxygen sensing were registered throughout the ventilatory hypoxia protocol (basal, hypoxia-acidosis, and recovery) and were compared with blood gas metabolites results from carotid artery catheterization (obtained with the EPOC blood analyzer). Finally, histological assessment was performed on the sensor insertion site. One-way ANOVA was used for the analysis of the evolution of acid-based metabolites and electrochemical sensor signaling results; a t-test was used for pre- and post-calibration analyses; and chi-square analyses for categorical variables.

Results

At the short-term evaluation, both the pH and oxygen electrochemical sensors distinguished the basal and hypoxia-acidosis periods in both the in vivo and ex vivo sensing. However, only the ex vivo sensing detected the recovery period. In the long-term evaluation, the pH electrochemical sensor signal seemed to lose sensibility. Finally, histological assessment revealed no signs of alteration on the day of evaluation (short-term), whereas in the long-term evaluation a sub-acute inflammatory reaction adjacent to the implantation site was detected.

Conclusions

Miniaturized electrochemical sensors represent a new generation of tools for the continuous monitoring of hypoxia-acidosis, which is especially indicated in high-risk pregnancies. Further studies including more tissue-compatible material would be required in order to improve long-term electrochemical sensing.

Quantification of Wave Reflection in the Human Umbilical Artery From Asynchronous Doppler Ultrasound Measurements

Elevated umbilical artery pulsatility is a widely used biomarker for placental pathology leading to intra-uterine growth restriction and, in severe cases, still-birth. It has been hypothesized that placental pathology modifies umbilical artery pulsatility by altering the degree to which the pulse pressure wave, which originates from the fetal heart, is reflected from the placental vasculature to interfere with the incident wave. Here we present a method for estimating the reflected pulse wave in the umbilical artery of human fetuses using asynchronously acquired Doppler ultrasound measurements from the two ends of the umbilical cord. This approach assumes non-dispersive and loss-less propagation of the waves along the artery and models the reflection process as a linear system with a parameterized impulse response. Model parameters are determined from the measured Doppler waveforms by constrained optimization. Velocity waveforms were obtained from 142 pregnant volunteers where 123 met data quality criteria in at least one umbilical artery. The reflection model was consistent with the measured waveforms in 183 of 212 arteries that were analyzed. The analysis method was validated by applying it to simulated datasets and comparing solutions to ground-truth. With measurement noise levels typical of clinical ultrasound, parameters describing the reflected wave were accurately determined.

Society for Maternal-Fetal Medicine Consult Series #52: Diagnosis and management of fetal growth restriction: (Replaces Clinical Guideline Number 3, April 2012)

Fetal growth restriction can result from a variety of maternal, fetal, and placental conditions. It occurs in up to 10% of pregnancies and is a leading cause of infant morbidity and mortality. This complex obstetrical problem has disparate published diagnostic criteria, relatively low detection rates, and limited preventative and treatment options. The purpose of this Consult is to outline an evidence-based, standardized approach for the prenatal diagnosis and management of fetal growth restriction. The recommendations of the Society for Maternal-Fetal Medicine are as follows: (1) we recommend that fetal growth restriction be defined as an ultrasonographic estimated fetal weight or abdominal circumference below the 10th percentile for gestational age (GRADE 1B); (2) we recommend the use of population-based fetal growth references (such as Hadlock) in determining fetal weight percentiles (GRADE 1B); (3) we recommend against the use of low-molecular-weight heparin for the sole indication of prevention of recurrent fetal growth restriction (GRADE 1B); (4) we recommend against the use of sildenafil or activity restriction for in utero treatment of fetal growth restriction (GRADE 1B); (5) we recommend that a detailed obstetrical ultrasound examination (current procedural terminology code 76811) be performed with early-onset fetal growth restriction (<32 weeks of gestation) (GRADE 1B); (6) we recommend that women be offered fetal diagnostic testing, including chromosomal microarray analysis, when fetal growth restriction is detected and a fetal malformation, polyhydramnios, or both are also present regardless of gestational age (GRADE 1B); (7) we recommend that pregnant women be offered prenatal diagnostic testing with chromosomal microarray analysis when unexplained isolated fetal growth restriction is diagnosed at <32 weeks of gestation (GRADE 1C); (8) we recommend against screening for toxoplasmosis, rubella, or herpes in pregnancies with fetal growth restriction in the absence of other risk factors and recommend polymerase chain reaction for cytomegalovirus in women with unexplained fetal growth restriction who elect diagnostic testing with amniocentesis (GRADE 1C); (9) we recommend that once fetal growth restriction is diagnosed, serial umbilical artery Doppler assessment should be performed to assess for deterioration (GRADE 1C); (10) with decreased end-diastolic velocity (ie, flow ratios greater than the 95th percentile) or in pregnancies with severe fetal growth restriction (estimated fetal weight less than the third percentile), we suggest weekly umbilical artery Doppler evaluation (GRADE 2C); (11) we recommend Doppler assessment up to 2-3 times per week when umbilical artery absent end-diastolic velocity is detected (GRADE 1C); (12) in the setting of reversed end-diastolic velocity, we suggest hospitalization, administration of antenatal corticosteroids, heightened surveillance with cardiotocography at least 1-2 times per day, and consideration of delivery depending on the entire clinical picture and results of additional evaluation of fetal well-being (GRADE 2C); (13) we suggest that Doppler assessment of the ductus venosus, middle cerebral artery, or uterine artery not be used for routine clinical management of early- or late-onset fetal growth restriction (GRADE 2B); (14) we suggest weekly cardiotocography testing after viability for fetal growth restriction without absent/reversed end-diastolic velocity and that the frequency be increased when fetal growth restriction is complicated by absent/reversed end-diastolic velocity or other comorbidities or risk factors (GRADE 2C); (15) we recommend delivery at 37 weeks of gestation in pregnancies with fetal growth restriction and an umbilical artery Doppler waveform with decreased diastolic flow but without absent/reversed end-diastolic velocity or with severe fetal growth restriction with estimated fetal weight less than the third percentile (GRADE 1B); (16) we recommend delivery at 33-34 weeks of gestation for pregnancies with fetal growth restriction and absent end-diastolic velocity (GRADE 1B); (17) we recommend delivery at 30-32 weeks of gestation for pregnancies with fetal growth restriction and reversed end-diastolic velocity (GRADE 1B); (18) we suggest delivery at 38-39 weeks of gestation with fetal growth restriction when the estimated fetal weight is between the 3rd and 10th percentile and the umbilical artery Doppler is normal (GRADE 2C); (19) we suggest that for pregnancies with fetal growth restriction complicated by absent/reversed end-diastolic velocity, cesarean delivery should be considered based on the entire clinical scenario (GRADE 2C); (20) we recommend the use of antenatal corticosteroids if delivery is anticipated before 33 6/7 weeks of gestation or for pregnancies between 34 0/7 and 36 6/7 weeks of gestation in women without contraindications who are at risk of preterm delivery within 7 days and who have not received a prior course of antenatal corticosteroids (GRADE 1A); and (21) we recommend intrapartum magnesium sulfate for fetal and neonatal neuroprotection for women with pregnancies that are <32 weeks of gestation (GRADE 1A).

Normative references and clinical correlates of fetal umbilical artery Doppler indices in southwestern Nigeria

OBJECTIVE

To derive normative references for umbilical artery (UA) Doppler indices, including pulsatility index (PI), resistance index (RI), and systolic/diastolic (SD) ratio, for singleton pregnancies in Ile-Ife, Nigeria, and compare them with reference values from other populations.

METHODS

A longitudinal study involving 415 women with a singleton fetus at 26-40 gestational weeks attending Obafemi Awolowo University Hospital, Ile-Ife, between July 2015 and March 2019. Fetal UA PI, RI, and SD ratio were measured every 4 weeks until delivery. Reference values from the 2.5th to the 97.5th centiles were derived from 1375 measurements. Correlations between indices and bio-demographic characteristics were assessed; regression equations were generated.

RESULTS

The RI, PI, and SD ratio decreased by 0.013, 0.027, and 0.71, respectively, for each additional week of pregnancy. There was a negative correlation between the three indices and birthweight (P<0.001), but not maternal parity, age, or fetal gender. Regression equations for RI, PI, and SD ratio were, respectively, 1.004 - 0.013x, 1.78 - 0.027x, and 4.77 - 0.71x, where x is gestational age (weeks).

CONCLUSION

The derived normative references for fetal UA Doppler indices are recommended for monitoring high-risk pregnancies in Nigeria. The indices are comparable to those derived from Norwegian, Thai, and British cohorts.

Arterial and Venous Doppler in Evaluation of the "At-Risk" Fetus

Our practice utilizes Doppler ultrasound as one of the most objective and effective methods to assess at-risk pregnancies. This review will discuss the application of arterial and venous Doppler techniques in assessing and managing various diseases and conditions for high-risk fetuses.

Evaluation of the predictive value of fetal Doppler ultrasound for neonatal outcome from the 36th week of pregnancy

Background

Early prediction of adverse neonatal outcome would be possible by Doppler impedance indices of middle cerebral artery (MCA), umbilical artery (UmA), and descending aortal artery (AO) that result in decrease neonatal morbidity and mortality rate. The aim of the present study was a determination of optimal value for the ratio of MCA to descending aorta blood flow (MCA/AO) impedance indices and its comparison with the ratio of MCA to UmA (MCA/UmA) impedance indices and their relationship with neonatal outcome.

Materials and Methods

This was a prospective cohort study on 212 pregnant women with gestational age 36 weeks or more, in three hospitals in Tehran, from April 2012 to April 2013. We investigated AO, MCA, and UmA impedance indices Doppler ultrasound every 2 weeks till delivery. The mother was monitored for adverse pregnancy outcome (hypertension [HTN], fetal growth retardation, and other maternal complications) then infant birth weight, cord blood of pH, and Neonatal Intensive Care Unit (NICU) admission during the first 24 h after delivery were assessed. Finally, we investigated relationships between Doppler indices and neonatal outcomes include neonatal body weight (NBW), cord blood of pH, and NICU admission.

Results

MCA/AO resistance index (RI) and MCA/AO pulsatile index (PI) showed an area under the receiver operating characteristics curve (area under the curve) of 0.905 (95% confidence interval (CI): 0.850, 0.959) and 0.818 (95% CI: 0.679, 0.956), respectively. The cutoff values for pH (≥7.2 vs. <7.2) based on MCA/AO RI and MCA/AO PI indices were 0.951 (sensitivity, 80% and specificity, 86%) and 0.853 (sensitivity, 91% and specificity, 83%), respectively. The cutoff value for NBW (≥2500 vs. <2500 g) based on MCA/UmA PI index was 1.467 (sensitivity, 73% and specificity, 63%). The cutoff value of NICU admission of child based on MCA/AO PI index was 1.114 (sensitivity, 73% and specificity, 54%).

Conclusion

In the end of third-trimester pregnancies with the assessment of MCA and AO artery Doppler ultrasonography, it is possible to prevent many cases of neonatal acidosis caused by prenatal asphyxia as well as inappropriate interventions which are applied on mother. If MCA/AO PI was <0.85, the fetus needs to be evaluated further because it is at risk for acidosis.

"Does short-term variation in fetal heart rate predict fetal acidaemia?" A systematic review and meta-analysis

OBJECTIVE

To evaluate the association of short-term variation (STV) of the fetal heart rate in predicting fetal acidaemia at birth.

METHODS

The search strategy employed searching of electronic databases (MEDLINE, Web of Science, Scopus, and Google Scholar) and reference lists of relevant studies. Data were extracted from studies, adhering strictly to the following criteria: singleton pregnancy at ≥24 weeks' gestation, computerized CTG (index test) and calculation of STV before delivery. The outcome measure was arterial pH assessed in cord blood obtained at birth.

RESULTS

Meta-analysis showed moderate accuracy of STV in predicting fetal acidaemia with a sensitivity of 0.57 (95% CI: 0.45-0.68), specificity of 0.81 (95% CI: 0.69-0.89), positive likelihood ratio of 3.14 (95% CI: 2.13-4.63) and negative likelihood ratio of 0.58, (95% CI: 0.46-0.72). However, in intra-uterine growth restricted fetuses, a small improvement in detecting acidaemia was observed; with a sensitivity of 0.63 (95% CI: 0.49-0.75) and negative likelihood ratio of 0.50 (95% CI: 0.31-0.80).

CONCLUSION

STV appears to be a moderate predictor for fetal acidaemia. However, its usefulness as a stand-alone test in predicting acidaemia in clinical setting remains to be determined.

Umbilical Artery Half-Peak Systolic Velocity Deceleration Time in Fetal Growth Restriction

Objective: To study the umbilical artery (UA) half-peak systolic velocity deceleration time (hPSV-DT) in pregnancies complicated by fetal growth restriction (FGR). Methods: The study included 266 singleton, high-risk pregnancies with an estimated fetal weight <10th percentile, which were examined between 24 and 40 weeks' gestation and delivered within a week from the last ultrasound evaluation. UA hPSV-DT was measured with Doppler ultrasound in the same wave used to measure the pulsatility index. UA hPSV-DT values were correlated with perinatal outcome. Results: UA hPSV-DT <5th percentile was found in 87 and 98% of fetuses with moderate and severe FGR, respectively. 94% of fetuses with a UA hPSV-DT <90 ms had poor perinatal outcome including perinatal death or prolonged admission to the neonatal intensive care unit. None of the fetuses had a UA hPSV-DT <70 ms. Perinatal death occurred in 39 fetuses; UA hPSV-DT was abnormal in all of them, with 95% of these fetuses having values of ≤120 ms. In the group of fetuses with absent/reverse end-diastolic velocity in the UA, the perinatal mortality rate was 51% for those with a UA hPSV-DT ≤90 ms and only 23% for those having a UA hPSV-DT >90 ms (p < 0.01). Conclusions: UA hPSV-DT seems to be a useful technique in the evaluation of pregnancies at risk for FGR and perinatal death. Additionally, hPSV-DT was shown to be a good predictor of perinatal death, with values of <90 ms corresponding to imminent risk of intrauterine demise and values of <70 ms being likely to be incompatible with intrauterine life.

Placental oxygen transport estimated by the hyperoxic placental BOLD MRI response

Estimating placental oxygen transport capacity is highly desirable, as impaired placental function is associated with fetal growth restriction (FGR) and poor neonatal outcome. In clinical obstetrics, a noninvasive method to estimate the placental oxygen transport is not available, and the current methods focus on fetal well-being rather than on direct assessment of placental function. In this article, we aim to estimate the placental oxygen transport using the hyperoxic placental blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) response. In 21 normal pregnancies and in four cases of severe early onset FGR, placental BOLD MRI was performed in a 1.5 Tesla MRI system (TR:8000 msec, TE:50 msec, Flip angle:90). Placental histological examination was performed in the FGR cases. In normal pregnancies, the average hyperoxic placental BOLD response was 12.6 ± 5.4% (mean ± SD). In the FGR cases, the hyperoxic BOLD response was abnormal only in cases with histological signs of maternal hypoperfusion of the placenta. The hyperoxic placental BOLD response is mainly derived from an increase in the saturation of maternal venous blood. In the normal placenta, the pO₂ of the umbilical vein is closely related to the pO₂ of the uterine vein. Therefore, the hyperoxic placental BOLD response may reflect the placental oxygen supply to the fetus. In early onset FGR, the placental oxygen transport is reduced mainly because of the maternal hypoperfusion, and in these cases the placental BOLD response might be altered. Thus, the placental BOLD MRI might provide direct noninvasive assessment of placental oxygen transport.

Doppler for growth restriction: the association between the cerebroplacental ratio and a reduced interval to delivery

OBJECTIVE

Evaluation of the cerebroplacental ratio (CPR) as an adjunct to umbilical artery Doppler (UA) to assess risk of delivery before 32 weeks and/or delivery within 2 weeks from diagnosis of fetal growth restriction (FGR).

STUDY DESIGN

In a cohort of fetuses with suspected FGR, UA Doppler was performed, and when abnormal the CPR was calculated (middle cerebral pulsatility index/umbilical artery pulsatility index). Doppler characteristics were used to determine three study groups: (1) normal UA, (2) abnormal UA with normal CPR and (3) abnormal UA with abnormal CPR. The primary outcomes were delivery before 32 weeks and delivery within 2 weeks. Adjusted odds ratio (aOR) with 95% confidence intervals (CIs) were calculated controlling for maternal age, chronic hypertension and tobacco use. We performed a linear regression analysis comparing the value of the CPR with the gestational age at delivery. Kaplan-Meier survival curve analysis with log-rank tests for probability was performed.

RESULTS

We included 154 patients: 91, 31 and 32 in Group 1, 2 and 3, respectively. Subjects in Group 3 had higher rates of the two primary outcomes: there was a fivefold increased risk (aOR=5.2 (95% CI=2.85-9.48)) for delivery before 32 weeks and over a fourfold increased risk for delivery within 2 weeks (aOR=4.76 (95% CI=2.32-9.76)) compared with those with a normal CPR (Group 1). In contrast, subjects in Group 2 (abnormal UA Doppler but normal CPR) had a similar rate of delivery before 32 weeks (aOR=1.16 (95% CI=0.55-2.48)) and within 2 weeks (aOR=1.07 (95% CI=0.43-2.69)). The median gestational age at delivery was 36, 36 and 29 weeks in Groups 1, 2 and 3, respectively (P<0.001). Linear regression analysis revealed a strong correlation between the value of the CPR and gestational age at delivery: R(2)=0.56, correlation coefficient=0.75. Kaplan-Meier analysis revealed a significantly decreased latency to delivery in Group 3, as opposed to Groups 1 and 2 (Cox-Mantel hazard ratio (HR) of Group 2 versus Group 1 HR=1.20 (95% CI=0.78-1.83) and Group 3 versus Group 1 HR=5.00 (95% CI=2.4-10.21)).

CONCLUSION

The CPR differentiates those fetuses with suspected growth restriction most at risk for delivery before 32 weeks and delivery within 2 weeks from those likely to have a more prolonged latency until delivery is required. In patients with suspected FGR and an abnormal UA, the CPR can be used to guide management decisions, such as maternal hospitalization and/or transport, aggressive fetal monitoring and antenatal corticosteroid administration.

Estimation of the growth rate in fetuses with an abnormal cerebroplacental ratio compared to those with suspected growth restriction without evidence of centralization of blood flow

OBJECTIVES

To evaluate the growth rate in fetuses with suspected growth restriction according to their Doppler characteristics.

METHODS

A retrospective cohort of fetuses with suspected growth restriction was identified. We reviewed umbilical artery and middle cerebral Doppler pulsatility indices and calculated the cerebroplacental ratio. Three study groups were determined: (1) normal umbilical artery Doppler findings; (2) abnormal umbilical artery findings with a normal cerebroplacental ratio; and (3) abnormal umbilical artery findings with an abnormal cerebroplacental ratio. The primary outcome was the growth rate as estimated by fetal biometry from serial sonographic evaluations. Analysis of the mean growth rate in each study group was performed by analysis of variance. In addition, linear regression analysis comparing the cerebroplacental ratio to the growth rate was performed.

RESULTS

Fetal growth restriction was suspected in 416 patients; 176 patients were included in this analysis: 113, 38, and 25 in groups 1, 2, and 3 respectively. The estimated mean (SD) growth rate in group 3 was significantly lower than in groups 1 and 2: 8.3 (4.4) versus 19.6 (6.0) and 18.6 (7.7) g/d, respectively (P < .001). Linear regression analysis revealed a strong correlation between the growth rate and cerebroplacental ratio (r = 0.76; R(2) = 0.58) as well as the birth weight and cerebroplacental ratio (r = 0.78; R(2) = 0.61).

CONCLUSIONS

In fetuses with suspected growth restriction and abnormal umbilical artery Doppler findings, an abnormal cerebroplacental ratio is strongly associated with reduced fetal growth. In contrast, if the cerebroplacental ratio is normal, even in the setting of abnormal umbilical artery Doppler findings, fetuses grow similarly to those with normal umbilical artery findings.

Association between an abnormal cerebroplacental ratio and the development of severe pre-eclampsia

OBJECTIVE

To study the association between the cerebroplacental ratio (CPR) and the development of pre-eclampsia.

STUDY DESIGN

Three study groups were determined: Group 1-normal umbilical artery (UA; referent), Group 2-abnormal UA and normal CPR and Group 3-abnormal UA and an abnormal CPR. The primary outcome was the development of severe pre-eclampsia.

RESULTS

We included 270 women. Women in Group 3 had significantly elevated rates of severe pre-eclampsia versus those in Group 1 and Group 2, 52.5% versus 5.1% and 15.4%, respectively, (P<0.01), adjusted odds ratio 4.14 (95% confidence interval, 2.59 to 6.61). Kaplan-Meier analysis revealed earlier delivery in women with pre-eclampsia in Group 3 versus Group 1, Cox-Mantel hazard ratio 2.39 (1.17 to 4.88), log rank P=0.01.

CONCLUSION

An abnormal CPR is associated with a higher rate severe pre-eclampsia with delivery at earlier gestational ages than with a normal UA or an abnormal UA, but normal CPR.

Clinical characteristics and perinatal outcome of fetal hydrops

Objective

To investigate the clinical characteristics of fetal hydrops and to find the antenatal ultrasound findings predictive of adverse perinatal outcome.

Methods

This is a retrospective study of 42 women with fetal hydrops who delivered in a tertiary-referral center from 2005 to 2013. Fetal hydrops was defined as the presence of fluid collection in ≥2 body cavities: ascites, pleural effusion, pericardial effusion, and skin edema. Predictor variables recorded included: maternal characteristics, gestational age at diagnosis, ultrasound findings, and identifiable causes. Primary outcome variables analyzed were fetal death and neonatal death.

Results

The mean gestational age at diagnosis was 29.3±5.4 weeks (range, 18 to 39 weeks). The most common identifiable causes were cardiac abnormality (10), followed by syndrome (4), aneuploidy (3), congenital infection (3), twin-to-twin transfusion syndrome (3), non-cardiac anormaly (2), chorioangioma (2), inborn errors of metabolism (1), and immune hydrops by anti-E antibody isoimmunization (1). Thirteen cases had no definite identifiable causes. Three women elected termination of pregnancy. Fetal death occurred in 4 cases. Among the 35 live-born babies, only 16 survived (54.0% neonatal mortality rate). Fetal death and neonatal mortality rate was not significantly associated with Doppler velocimetry indices or location of fluid collection, but increasing numbers of fluid collection site was significantly associated with a higher risk of neonatal death.

Conclusion

The incidence of fetal hydrops in our retrospective study was 24.4 per 10,000 deliveries and the perinatal mortality rate was 61.9% (26/42). The number of fluid collection sites was the significant antenatal risk factor to predict neonatal death.

Poor neonatal acid-base status in term fetuses with low cerebroplacental ratio

OBJECTIVE

To determine whether small- and appropriate-for-gestational-age (SGA and AGA) term fetuses with a low cerebroplacental ratio (CPR) have worse neonatal acid-base status than those with normal CPR.

METHODS

This was a retrospective study of 2927 term fetuses divided into groups according to birth-weight centile and CPR multiple of the median. The acid-base status at birth as determined by arterial and venous umbilical cord blood pH was compared between weight-centile groups with and without low CPR.

RESULTS

CPR was better correlated with umbilical cord blood pH (arterial pH, r(2)  = 0.008, P < 0.0001 and venous pH, r(2)  = 0.01, P < 0.0001) than was birth weight (arterial pH, r(2)  = 0.001, P =0.180 and venous pH, r(2)  = 0.005, P < 0.001). AGA fetuses with low CPR were more academic than were those with normal CPR (P = 0.0359 and 0.0006, respectively, for arterial and venous pH).

CONCLUSIONS

The findings of this study demonstrate that low CPR in AGA fetuses is an equally important marker of low neonatal pH secondary to placental underperfusion as is being SGA. Although the relative importance of low CPR and birth weight in identifying pregnancies at risk of placental hypoxemia and adverse fetal and neonatal outcome remains to be determined, this finding may be of particular value in the prediction and prevention of stillbirth and long-term neurodevelopmental disability.

DALI: Vitamin D and lifestyle intervention for gestational diabetes mellitus (GDM) prevention: an European multicentre, randomised trial - study protocol

Background

Gestational diabetes mellitus (GDM) is an increasing problem world-wide. Lifestyle interventions and/or vitamin D supplementation might help prevent GDM in some women.

Methods/design

Pregnant women at risk of GDM (BMI≥29 (kg/m²)) from 9 European countries will be invited to participate and consent obtained before 19+6 weeks of gestation. After giving informed consent, women without GDM will be included (based on IADPSG criteria: fasting glucose<5.1mmol; 1 hour glucose <10.0 mmol; 2 hour glucose <8.5 mmol) and randomized to one of the 8 intervention arms using a 2×(2×2) factorial design: (1) healthy eating (HE), 2) physical activity (PA), 3) HE+PA, 4) control, 5) HE+PA+vitamin D, 6) HE+PA+placebo, 7) vitamin D alone, 8) placebo alone), pre-stratified for each site. In total, 880 women will be included with 110 women allocated to each arm. Between entry and 35 weeks of gestation, women allocated to a lifestyle intervention will receive 5 face-to-face, and 4 telephone coaching sessions, based on the principles of motivational interviewing. The lifestyle intervention includes a discussion about the risks of GDM, a weight gain target <5kg and either 7 healthy eating ‘messages’ and/or 5 physical activity ‘messages’ depending on randomization. Fidelity is monitored by the use of a personal digital assistance (PDA) system. Participants randomized to the vitamin D intervention receive either 1600 IU vitamin D or placebo for daily intake until delivery. Data is collected at baseline measurement, at 24–28 weeks, 35–37 weeks of gestation and after delivery. Primary outcome measures are gestational weight gain, fasting glucose and insulin sensitivity, with a range of obstetric secondary outcome measures including birth weight.

Discussion

DALI is a unique Europe-wide randomised controlled trial, which will gain insight into preventive measures against the development of GDM in overweight and obese women.

Trial registration

ISRCTN70595832

Regimens of fetal surveillance for impaired fetal growth

BACKGROUND

Policies and protocols for fetal surveillance in the pregnancy where impaired fetal growth is suspected vary widely, with numerous combinations of different surveillance methods.

OBJECTIVES

To assess the effects of antenatal fetal surveillance regimens on important perinatal and maternal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (29 February 2012).

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing the effects of described antenatal fetal surveillance regimens.

DATA COLLECTION AND ANALYSIS

Review authors R Grivell and L Wong independently assessed trial eligibility and quality and extracted data.

MAIN RESULTS

We included one trial of 167 women and their babies. This trial was a pilot study recruiting alongside another study, therefore, a separate sample size was not calculated. The trial compared a twice-weekly surveillance regimen (biophysical profile, nonstress tests, umbilical artery and middle cerebral artery Doppler and uterine artery Doppler) with the same regimen applied fortnightly (both groups had growth assessed fortnightly). There were insufficient data to assess this review's primary infant outcome of composite perinatal mortality and serious morbidity (although there were no perinatal deaths) and no difference was seen in the primary maternal outcome of emergency caesarean section for fetal distress (risk ratio (RR) 0.96; 95% confidence interval (CI) 0.35 to 2.63). In keeping with the more frequent monitoring, mean gestational age at birth was four days less for the twice-weekly surveillance group compared with the fortnightly surveillance group (mean difference (MD) -4.00; 95% CI -7.79 to -0.21). Women in the twice-weekly surveillance group were 25% more likely to have induction of labour than those in the fortnightly surveillance group (RR 1.25; 95% CI 1.04 to 1.50).

AUTHORS' CONCLUSIONS

There is limited evidence from randomised controlled trials to inform best practice for fetal surveillance regimens when caring for women with pregnancies affected by impaired fetal growth. More studies are needed to evaluate the effects of currently used fetal surveillance regimens in impaired fetal growth.

Reactivity of blood vessels in response to prostaglandin E2 in placentas from pregnancies complicated by fetal growth restriction

OBJECTIVE

The authors aimed to study the contractility responses of normal and fetal growth restriction (FGR) placentas to prostaglandin E(2) (PGE(2) ) and to correlate the results to subsequent placental histological analysis.

METHOD

A dual-perfused single cotyledon model was used. Placentas from pregnancies complicated by FGR and from normal pregnancies were obtained. Selected cotyledons were cannulated and dually perfused. Following stabilization, three concentrations of PGE(2) (0.05, 0.1, and 0.15 mg/mL) were administered to the fetal arterial side causing contraction/relaxation response. Fetal perfusion pressure was measured continuously during these contraction and relaxation phases. Following the perfusion experiments, the placentas were analyzed for fetal or maternal origin vascular lesions.

RESULTS

A total of 21 complete experiments were performed (16 normal, 5 FGR). In response to PGE(2) , FGR placentas exhibited lower change in the perfusion pressure and lower relaxation time constant. Basal perfusion pressure did not differ significantly between the two groups. Placental histopathology lesions, fetal or maternal origin, were more common in the FGR compared with the controls placentas, 80% versus 25%, respectively, P=  0.047.

CONCLUSIONS

The lower vascular reactivity in response to PGE(2) and the presence of fetal and maternal vascular placental lesions suggest a mechanism explaining the altered vascular supply in FGR.

Doppler assessment of the fetus with intrauterine growth restriction

OBJECTIVE

We sought to provide evidence-based guidelines for utilization of Doppler studies for fetuses with intrauterine growth restriction (IUGR).

METHODS

Relevant documents were identified using PubMed (US National Library of Medicine, 1983 through 2011) publications, written in English, which describe the peripartum outcomes of IUGR according to Doppler assessment of umbilical arterial, middle cerebral artery, and ductus venosus. Additionally, the Cochrane Library, organizational guidelines, and studies identified through review of the above were utilized to identify relevant articles. Consistent with US Preventive Task Force suggestions, references were evaluated for quality based on the highest level of evidence, and recommendations were graded.

RESULTS AND RECOMMENDATIONS

Summary of randomized and quasirandomized studies indicates that, among high-risk pregnancies with suspected IUGR, the use of umbilical arterial Doppler assessment significantly decreases the likelihood of labor induction, cesarean delivery, and perinatal deaths (1.2% vs 1.7%; relative risk, 0.71; 95% confidence interval, 0.52-0.98). Antepartum surveillance with Doppler of the umbilical artery should be started when the fetus is viable and IUGR is suspected. Although Doppler studies of the ductus venous, middle cerebral artery, and other vessels have some prognostic value for IUGR fetuses, currently there is a lack of randomized trials showing benefit. Thus, Doppler studies of vessels other than the umbilical artery, as part of assessment of fetal well-being in pregnancies complicated by IUGR, should be reserved for research protocols.

Behavioural problems at the age of eleven years in preterm-born children with or without fetal brain sparing: a prospective cohort study

BACKGROUND

In severe intrauterine growth restriction (IUGR) due to placental insufficiency a haemodynamic adaptation occurs, resulting in preferential blood flow to the fetal brain (brain sparing). With Doppler ultrasound an increased ratio between the umbilical and the cerebral artery pulsatility index (U/C ratio) can be demonstrated. IUGR is associated with impaired neurodevelopmental outcome.

OBJECTIVE

Evaluation of the effect of fetal brain sparing on behavioural problems at eleven years in premature born children.

METHODS

Prospective cohort study in premature children born in 1989, with a gestational age of 26 0/7 to 33 0/7 weeks. An U/C ratio>0.72 was defined as brain sparing. Behavioural problems were assessed with the parent-reported Child Behaviour Check List (CBCL) and the Teacher's Report Form (TRF). T scores >60 for total problem score and subscales of internalizing and externalizing behaviour, were considered abnormal.

RESULTS

Ninety-eight of the 116 survivors were assessed, of which 31 with antenatally established fetal brain sparing. According to the CBCL-total problem score 23.3% of the premature born babies in the brain sparing group had behavioural problems compared with 22.8% of those without brain sparing. According to the TRF-total problem score the percentages were 21.4% and 20.0%, respectively. Logistic regression analysis failed to show a significant association of U/C ratio with behavioural problems. In this model oxygen dependency at 28 days, IQ<85 at five years, cranial ultrasound abnormalities, fetal growth ratio<0.80, Apgar scores<7 after 5 min and birth weight<p10 contributed significantly.

CONCLUSION

In this cohort brain sparing itself has no significant association with behavioural problems at eleven years.

Contribution of the myocardial performance index and aortic isthmus blood flow index to predicting mortality in preterm growth-restricted fetuses

OBJECTIVES

To evaluate the predictive value for perinatal death of the myocardial performance index (MPI) and aortic isthmus flow index (IFI), as isolated parameters and in a combined model including currently used Doppler indices, in preterm growth restricted (IUGR) fetuses.

METHODS

Umbilical artery, fetal middle cerebral artery (MCA) and ductus venosus (DV) pulsatility indices (PIs) were recorded, along with IFI and MPI, in a cohort of 97 preterm (delivered at between 24 and 34 weeks) IUGR fetuses. Logistic regression analysis was performed to identify those variables that were independently associated with perinatal mortality, and an algorithm to estimate probability of death was constructed including the best combination of parameters.

RESULTS

With the exception of MCA, all Doppler indices were significantly associated with perinatal death as isolated parameters, but only DV-PI and MPI were found to be independent predictors on multivariate analysis. An algorithm combining DV atrial flow (positive or absent/reversed) and MPI (normal or above 95(th) percentile) had a better predictive accuracy than did any single parameter. The risk for death in IUGR fetuses below 28 weeks' gestation with present atrial flow in the DV and normal MPI was 18%, with either characteristic abnormal it was 70-73%, and with both abnormal it was 97%. The risk for death in IUGR fetuses above 28 weeks with present atrial flow in the DV and normal MPI was 0.1%, with either abnormal it was 6-7%, and with both abnormal it was 45%.

CONCLUSIONS

MPI is an independent predictor of perinatal death in preterm IUGR fetuses with accuracy similar to that of DV flow. A combination of DV flow with MPI may better stratify the estimated probability of death. IFI does not add to the prediction of perinatal death when used in combination with DV flow.

Regimens of fetal surveillance for impaired fetal growth

BACKGROUND

Policies and protocols for fetal surveillance in the pregnancy where impaired fetal growth is suspected vary widely, with numerous combinations of different surveillance methods.

OBJECTIVES

To assess the effects of antenatal fetal surveillance regimens on important perinatal and maternal outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (April 2008).

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing the effects of described antenatal fetal surveillance regimens.

DATA COLLECTION AND ANALYSIS

R Grivell and L Wong independently assessed trial eligibility and quality and extracted data.

MAIN RESULTS

One trial of 167 women and their babies was included. This trial was a pilot study recruiting alongside another study, therefore a separate sample size was not calculated. The trial compared a twice-weekly surveillance regimen (biophysical profile, nonstress tests, umbilical artery and middle cerebral artery Doppler and uterine artery Doppler) with the same regimen applied fortnightly (both groups had growth assessed fortnightly). There were insufficient data to assess this review's primary infant outcome of composite perinatal mortality and serious morbidity (although there were no perinatal deaths) and no difference was seen in the primary maternal outcome of emergency caesarean section for fetal distress. In keeping with the more frequent monitoring, mean gestational age at birth was four days less for the twice-weekly surveillance group compared with the fortnightly surveillance group. Women in the twice-weekly surveillance group were 25% more likely to have induction of labour than those in the fortnightly surveillance group. The risk ratio was 1.25 (95% confidence interval 1.04 to 1.50).

AUTHORS' CONCLUSIONS

There is limited evidence from randomised controlled trials to inform best practice for fetal surveillance. regimens when caring for women with pregnancies affected by impaired fetal growth. More studies are needed to evaluate the effects of currently used fetal surveillance regimens in impaired fetal growth.

Ultrasound of the placenta: a systematic approach. Part II: functional assessment (Doppler)

Doppler velocimetry is the ideal clinical tool to assess placental performance in high-risk pregnancies. It also has value in predicting later complications and outcome in pregnancies which appear uncomplicated. All three circulations (fetal, placental and maternal) may be interrogated by Doppler technology. In the following review, we present basic physics aspects of Doppler and discuss mainly Doppler investigation of the fetal-placental circulation (umbilical artery, intraplacental circulation) as well as the uterine arteries. The assessment of umbilical blood flow provides information on blood perfusion of the fetal-placental unit. The diastolic blood flow velocity component in umbilical artery increases with advancing gestation. In pregnancies complicated by placental dysfunction, there may be a reduction in the number of functional villi and/or small blood vessels with, as a result, increased impedance, reflected, mainly, by a decrease in end-diastolic velocity. When the resistance increases even more, there is no diastolic forward velocity (absent end-diastolic velocity). Further increase in the resistance causes reversed end-diastolic velocity, which is considered a late step in the cascade of events leading to intrauterine fetal demise. Doppler assessment of the umbilical arteries was found to improve outcome of high-risk pregnancies, and reduce hospital admissions. On the contrary, routine Doppler ultrasound in low risk or unselected populations does not seem to confer benefit on mother or newborn. Uterine artery Doppler is a useful test in predicting pregnancies at high risk of developing complications related to uteroplacental insufficiency. It identifies women who may benefit from increased antenatal surveillance or prophylactic therapy. Three-dimensional power Doppler sonography can provide new insights into placental pathophysiology.

Altered gene expression and methylation of the human chromosome 11 imprinted region in small for gestational age (SGA) placentae

Imprinted genes are known to be crucial for placental development and fetal growth in mammals, but no primary epigenetic abnormality in placenta has been documented to compromise human fetal growth. Imprinted genes demonstrate parent-of-origin-specific allelic expression that is epigenetically regulated i.e. extrinsic to the primary DNA sequence. To undertake an epigenetic analysis of poor fetal growth in placentae and cord blood tissues, we first established the tissue-specific patterns of methylation and imprinted gene expression for two imprinting clusters (KvDMR and H19 DMR) on chromosome 11p15 in placentae and neonatal blood for 20 control cases and 24 Small for Gestational Age (SGA) cases. We confirmed that, in normal human placenta, the H19 promoter is unmethylated. In contrast, most other human tissues show paternal methylation. In addition, we showed that the IGF2 DMR2, also paternally methylated in most human tissues, exhibits hypomethylation in placentae. However, in neonatal blood DNA, these two regions maintain the differential methylation status seen in most other tissues. Significantly, we have been able to demonstrate that placenta does maintain differential methylation at the imprinting control regions H19 DMR and KvDMR. Of note, in one SGA placenta, we found a methylation alteration at the H19 DMR and concomitant biallelic expression of the H19 gene, suggesting that loss of imprinting at H19 is one cause of poor fetal growth in humans. Of particular interest, we demonstrated also a decrease in IGF2 mRNA levels in all SGA placentae and showed that the decrease is, in most cases, independent of H19 regulation.

Indices of oxidative stress in pregnancy with fetal growth restriction

Intrauterine fetal growth restriction (IUGR), the main cause of premature delivery and fetal mortality, has been suggested to involve oxidative stress. We found elevated values of indices of oxidative stress in the blood serum of pregnant women with IUGR: increased levels of malondialdehyde and 4-hydroxyalkenals, decreased activity of alpha-1-antitrypsin and decreased total antioxidant capacity of the serum, with respect to healthy pregnancy. Twenty day treatment with 3 g of l-arginine and 75 mg of acetylsalicylic acid daily resulted in a decrease of the level of lipid peroxidation products and augmentation of alpha-1-antitrypsin activity. This study confirms the occurrence of oxidative stress in IUGR and demonstrates the beneficial effect of arginine/acetylsalicylic acid therapy in reducing oxidative stress in IUGR.

Longitudinal reference ranges for ductus venosus flow velocities and waveform indices

OBJECTIVES

Serial Doppler measurements of the ductus venosus are used increasingly for monitoring fetuses at risk of hemodynamic compromise, but existing reference ranges are based on cross-sectional studies and thus are less suitable for comparison with serial measurements. We aimed to establish longitudinal reference ranges for ductus venosus flow velocities and waveform indices and to provide the necessary terms for calculating conditional reference ranges for serial measurements.

METHODS

This was a longitudinal study of 160 low-risk pregnancies. Pulsed Doppler ultrasound was used to record ductus venosus blood flow velocities at 4-week intervals from 20-22 weeks of gestation onwards.

RESULTS

With a success rate of 93%, 547 measurements (four or five in each fetus) were used to establish reference ranges. The time-averaged maximum velocity was 50 cm/s at 21 weeks of gestation, increased to 60 cm/s at 32 weeks, and remained so until term. Similarly, the peak systolic velocity increased from 59 cm/s at 21 weeks to 71 cm/s at 31 weeks and remained so until term. The end-diastolic velocity showed a continuous increase from 31 cm/s at 21 weeks to 43 cm/s at 40 weeks. The pulsatility index for veins decreased from 0.57 at 21 weeks to 0.44 at 40 weeks. When conditioned by a previous measurement, the reference ranges for the next observation became narrower and commonly shifted compared with those of the entire population.

CONCLUSION

The new longitudinal reference ranges presented here reflect the development of the ductus venosus flow velocities and velocity indices and are thus appropriate for serial measurements, particularly if conditional terms are included.