Preterm Growth-restricted Fetuses Research Articles

Labor Induction in Case of Fetal Growth Restriction (FGR)

Clinicians consider a range of variables when formulating decisions regarding the diagnosis, monitoring plan, and ultimately the decision to recommend the delivery of a growth-restricted fetus. The differential diagnosis of a pathological fetal growth pattern is initially considered via the history, a physical and laboratory examination of the pregnant person, as well as a comprehensive fetal ultrasound examination. These factors allow a broad distinction between pre-existing disease in the pregnant person, constitutionally small normal growth, placenta-mediated Fetal Growth Restriction (FGR), and intrinsic fetal disease. Most commonly, pathological growth restriction is mediated by underlying placental diseases, of which maternal vascular malperfusion is the most common, and often results in co-existent hypertension. A program of combined monitoring of the pregnant person and fetus, comprising hypertension assessment, and serial fetal ultrasound, including Doppler studies is then instituted, and may be combined with biochemical markers, such as Placental Growth Factor, for greater clinical precision. Recommendations on timing to deliver the growth-restricted fetus worldwide are converging, with similar guidance from clinical practice guidelines informed by high-quality Randomized Controlled Trials (RCTs) and large cohort studies. In most instances, it is reasonable to recommend delivery of all growth-restricted fetuses by approximately 38 weeks. Timing of delivery should take into consideration both short-term neonatal outcomes and long-term outcomes at school age. Mode of delivery is based on many factors, and induction of labor is a safe approach, especially after 34 weeks. Mechanical methods of induction may be preferred to pharmacologic methods, although both have a role and the choice of method is based on individualized assessment. Elective Cesarean birth thereby bypassing fetal stress during labor, is recommended in preterm growth-restricted fetuses with signs of adaptive fetal compromise, especially when ductus venosus flow is abnormal, or a contraction stress test is positive.

How and when to recommend delivery of a growth-restricted fetus: A review.

Clinicians consider a range of variables when formulating decisions regarding the diagnosis, monitoring plan, and ultimately the decision to recommend the delivery of a growth-restricted fetus. The differential diagnosis of a pathological fetal growth pattern is initially considered via the history, a physical and laboratory examination of the pregnant person, as well as a comprehensive fetal ultrasound examination. These factors allow a broad distinction between pre-existing disease in the pregnant person, constitutionally small normal growth, placenta-mediated Fetal Growth Restriction (FGR), and intrinsic fetal disease. Most commonly, pathological growth restriction is mediated by underlying placental diseases, of which maternal vascular malperfusion is the most common, and often results in co-existent hypertension. A program of combined monitoring of the pregnant person and fetus, comprising hypertension assessment, and serial fetal ultrasound, including Doppler studies is then instituted, and may be combined with biochemical markers, such as Placental Growth Factor, for greater clinical precision. Recommendations on timing to deliver the growth-restricted fetus worldwide are converging, with similar guidance from clinical practice guidelines informed by high-quality Randomized Controlled Trials (RCTs) and large cohort studies. In most instances, it is reasonable to recommend delivery of all growth-restricted fetuses by approximately 38 weeks. Timing of delivery should take into consideration both short-term neonatal outcomes and long-term outcomes at school age. Mode of delivery is based on many factors, and induction of labor is a safe approach, especially after 34 weeks. Mechanical methods of induction may be preferred to pharmacologic methods, although both have a role and the choice of method is based on individualized assessment. Elective Cesarean birth thereby bypassing fetal stress during labor, is recommended in preterm growth-restricted fetuses with signs of adaptive fetal compromise, especially when ductus venosus flow is abnormal, or a contraction stress test is positive.

Extent of absent end-diastolic flow in umbilical artery andoutcome of pregnancy.

To investigate if the extent of absent end-diastolic flow (AEDF) on umbilical artery (UA) Doppler velocimetry predicts pregnancy outcome. This was a retrospective observational study based on data from 25 000 Doppler examinations of UA flow performed between 1998 and 2017 at the Blood Flow Laboratory, Level III Perinatal Center, Lund, Sweden. All pregnancies with AEDF in the UA were identified, and the duration of AEDF as a proportion of the total duration of the cardiac cycle (Ta /Ttot ratio) was measured in digital images of the Doppler spectrum recorded at the last examination showing AEDF before delivery. Clinical data on pregnancies and neonatal outcomes were extracted from the regional perinatal database and the hospital patient records. The predictive performance of the Ta /Ttot ratio for intrauterine death and any (intrauterine or postnatal) death was assessed. A total of 170 fetuses (122 (72%) singletons and 48 (28%) twins) were included in the study. Median gestational age at birth was 189.5 days (range, 163-279 days) (i.e. 27 + 0 weeks (range, 23 + 2 to 39 + 6 weeks)), birth weight was 650 g (range, 320-3326 g) and deviation from expected birth weight (standard deviation score) was -2.975 (range, -6.38 to 0.69). There were 15 (9%) intrauterine and 26 (15%) postnatal deaths. The principal outcome variables and their relationship with Doppler velocimetry results did not differ significantly between singletons and twins, giving a rationale for using the Ta /Ttot ratio in the total study group. Mean Ta /Ttot ratio was 0.42 ± 0.08 and 0.34 ± 0.08 in stillborn and liveborn fetuses, respectively (P = 0.002). For fetuses examined before 30 weeks' gestation, a Ta /Ttot ratio cut-off of 0.30 predicted intrauterine death with 92% sensitivity and a negative predictive value (NPV) of 98% (area under receiver-operating-characteristics curve (AUC), 0.74) and predicted any death with 83% sensitivity and a NPV of 85% (AUC, 0.66). In fetuses with AEDF in the UA, duration of absent flow for at least 30% of the total cardiac cycle length might predict the risk of fetal demise, even when assessed before 30 weeks' gestation. This finding is particularly relevant to growth-restricted fetuses. After evaluation in further studies, the extent of AEDF might facilitate obstetric decision-making in very preterm growth-restricted fetuses. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

483: Antenatal corticosteroids in preterm growth-restricted fetuses: A systematic review and meta- analysis

Prior studies evaluating antenatal corticosteroids (ACS) and preterm birth outcomes have largely excluded patients with fetal growth restriction (FGR), resulting in limited evidence to guide ACS use in these pregnancies. Because growth-restricted fetuses are exposed to higher levels of endogenous steroids, exogenous ACS may not offer additional benefit. We conducted a systematic review and meta-analysis to evaluate the effect of ACS on neonatal outcomes in patients with preterm FGR. We conducted a predefined, systematic search in MEDLINE using relevant search terms. Selected studies were cohort or case-control studies comparing neonatal mortality and morbidity among FGR pregnancies delivered preterm that received ACS to those that did not. The primary outcome was neonatal mortality. Secondary outcomes were composite neonatal morbidity, respiratory distress syndrome (RDS), necrotizing enterocolitis (NEC), intraventricular hemorrhage and/or periventricular leukomalacia (IVH/PVL), bronchopulmonary dysplasia or chronic lung disease of prematurity (BPD/CLD), or neonatal sepsis. We assessed heterogeneity via Higgins I2, and calculated pooled odds ratios (OR) with 95% confidence intervals (CI) using random effects models. Thirteen studies published 1995-2018 met selection criteria including 6,387 FGR pregnancies delivered from 22-35 weeks’ gestational age. Of these, 3,554 (55.6%) received ACS and 2457 (44.4%) did not. Neonatal mortality was significantly lower in patients who received ACS compared to those who did not (12 studies: 12.8% vs. 15.1%, OR 0.63 [95% CI 0.46, 0.86]), with significant heterogeneity between studies (I2=55.1%). There was no significant difference in composite neonatal morbidity (4 studies: OR 0.73 [95% CI 0.53, 1.00]), RDS (12 studies: OR 0.89 [95% CI 0.69, 1.15]), NEC (7 studies: OR 0.93 [95% CI 0.70, 1.22]), IVH/PVL (10 studies: OR 0.82 [95% CI 0.56, 1.19]), BPD/CLD (8 studies: OR 1.11 [95% CI 0.88, 1.41]), or neonatal sepsis (6 studies: OR 1.23 [95% CI 0.94, 1.62]). These data show that ACS reduces neonatal mortality in pregnancies with FGR delivered preterm, with no apparent effect on measures of neonatal morbidity. This supports continued use of ACS for reduction of neonatal mortality in pregnancies with FGR at risk for preterm birth.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Impact of Intended Mode of Delivery on Outcomes in Preterm Growth-Restricted Fetuses.

Scheduled cesarean is frequently performed for fetal growth restriction due to concerns for fetal intolerance of labor. We compared neonatal outcomes in preterm growth-restricted fetuses by intended mode of delivery. We performed a retrospective cohort study of indicated preterm births with prenatally diagnosed growth restriction from 2011 to 2014 at a single institution. Patients were classified by intended mode of delivery. The primary outcome was a composite of adverse neonatal outcomes, including perinatal death, cord blood acidemia, chest compressions during neonatal resuscitation, seizures, culture-proven sepsis, necrotizing enterocolitis, and grade III-IV intraventricular hemorrhage. Secondary analysis was performed examining the impact of umbilical artery Dopplers. Of 101 fetuses with growth restriction, 75 underwent planned cesarean deliveries. Of those induced, 46.2% delivered vaginally. Delivery by scheduled cesarean was not associated with a decreased risk of the composite outcome (adjusted odds ratio [aOR], 1.61; 95% confidence interval [CI], 0.45-5.78), even when only those with abnormal umbilical artery Dopplers were considered (aOR, 2.8; 95% CI, 0.40-20.2). In this cohort, planned cesarean was not associated with a reduction in neonatal morbidity, even when considering only those with abnormal umbilical artery Dopplers. In otherwise appropriate candidates for vaginal delivery, fetal growth restriction should not be considered a contraindication to trial of labor.

219: Neonatal morbidity in preterm growth-restricted fetuses: does mode of delivery matter?

219: Neonatal morbidity in preterm growth-restricted fetuses: does mode of delivery matter?

550: Relationship between umbilical vein volume flow, umbilical artery and MCA doppler in late preterm growth restricted fetuses

550: Relationship between umbilical vein volume flow, umbilical artery and MCA doppler in late preterm growth restricted fetuses

425: Multi-vessel Doppler parameters for the prediction of adverse neonatal outcome in the preterm growth-restricted fetus: does gestational age matter?

with a birthweight less than the 10th percentile without malformations were included. Group A (study group); GRF delivered at term without other clinical signs of PI. Group B, (1st control group); GRF accompanied with clinical signs of PI and delivered at term. Group C, (2nd control group), GRF accompanied with early severe preeclampsia, placental abruption or abnormal Doppler and delivered before 34 weeks. Group D, (3rd control group); term placentas from healthy women who delivered fetuses appropriate for age. Placental lesions examined included maternal and fetal vascular obstructive lesions, villitis and perivillous fibrinoid deposition. Primary outcome was the incidences of placental lesions among the study group compared to the controls. RESULTS: The most frequent placental lesions found among all groups were maternal obstructive lesions (Table). For women in group A, the odds of having any maternal obstruction lesion was 3.3 times higher than women in group D (p 0.0006). There were no differences between groups A and B (p 0.98). The incidence of any obstructive maternal lesion was significantly higher among group C compared to group A (p 0.0004) and B (p 0.0003). The incidence of any placental lesion was significantly higher among all the groups with GRF (A, B and C) compared to group D. The incidence of any lesion among group A (69.4%) was 7.9 times higher than women in group D (22.3%) (p 0.0001) and comparable to group B (61.7%), (p 0.3). CONCLUSION: The incidence of placental lesions among GRF delivered at term was comparable regardless of whether clinical signs of PI exist or not. Antepartum management of GRF at term probably needs to be similar regardless of other signs of PI.

387: Delivery timing of the preterm growth-restricted fetus (FGR): lessons from a prospective study

387: Delivery timing of the preterm growth-restricted fetus (FGR): lessons from a prospective study

Early adverse perinatal complications in preterm growth-restricted fetuses

Growth-restricted fetuses are at increased risk of adverse perinatal outcome when compared to their normally grown counterparts. The additional risks associated with growth restriction in preterm fetuses are not well quantified, and this meta-analysis serves to address this uncertainty. This is a meta-analysis and meta-regression of all relevant studies published since 1997 investigating perinatal outcome in preterm growth-restricted fetuses. Growth-restricted fetuses across all gestational ages were found to be at significant risk of having low Apgar scores at 5 min, sepsis, intracranial haemorrhage, intrauterine and neonatal death, necrotising enterocolitis and respiratory complications. Although this risk reduced as gestation increased, it remained amplified in growth-restricted fetuses when compared to normally grown fetuses. This large meta-analysis for the first time quantifies the additional perinatal risks associated with preterm fetal growth restriction and may help counsel parents about the complications these fetuses face following birth.

Long-term Neurologic Outcome for the Very Preterm Growth-Restricted Fetus

The very preterm (VPT) ( 19th centile, but only in the subgroup of those born at 29 to 32 weeks' gestation. In a Swedish study,7 34 children who survived … Address correspondence to Lex W. Doyle, MD, FRACP, Department of Obstetrics and Gynaecology, Royal Women's Hospital, 20 Flemington Rd Parkville, Victoria 3052, Australia. E-mail: lwd{at}unimelb.edu.au

Predictors of outcome at 2 years of age after early intrauterine growth restriction

To examine the relative importance of antenatal and perinatal variables on short- and long-term outcome of preterm growth restricted fetuses with umbilical artery (UA) Doppler abnormalities. This was a cohort study of 180 neonates with birth weight < 10(th) percentile, gestational age at delivery < 34 weeks and abnormal Doppler ultrasound examination of the UA. Various antenatal and perinatal variables were studied in relation to short- and long-term outcome. Neonatal and overall mortality (up to 2 years of age) were predicted by low gestational age at delivery. Neonatal mortality was additionally predicted by absent or reversed UA end-diastolic flow, while the presence of severe neonatal complications and placental villitis were additional predictors of both infant (between 28 days and 1 year of postnatal life) and overall mortality. Placental villitis was found to be the only predictor of necrotizing enterocolitis. Low gestational age at delivery, male sex, abnormal cardiotocography, absent or reversed UA end-diastolic flow and the HELLP syndrome predicted respiratory distress syndrome. Abnormal neurodevelopmental outcome at 2 years was predicted by low birth weight (< 2.3(rd) percentile), fetal acidosis (UA pH < 7.00), and placental villitis. Less advanced gestation at delivery remains an important predictor of short-term outcome in growth-restricted fetuses. In addition, the presence of placental villitis may aid neonatologists in the early identification of infants at increased risk of necrotizing enterocolitis, death and abnormal neurodevelopment at 2 years of age. Abnormal neurodevelopment was related to low weight and acidosis at birth, indicating that the severity of malnutrition and fetal acidosis affect long-term outcome.

Is antenatal steroid treatment effective in preterm IUGR fetuses?

There are no randomized studies on the effect of antenatal corticosteroids in preterm intrauterine growth restricted (IUGR) fetuses. Fetal lung maturation has been postulated to be enhanced in these fetuses, which may result in little benefit of steroid treatment. Furthermore, corticosteroid treatment may be detrimental, as has been shown in IUGR animal models. The objective of this study was to review the available literature on antenatal steroid treatment of the IUGR fetus. All available reports on antenatal steroid treatment of IUGR and small for gestational age (SGA) fetuses published prior to October 2007 were included in this review. IUGR fetuses are a subgroup of SGA fetuses that are small due to placental insufficiency, which is reflected in abnormal Doppler examination of the umbilical artery. The main outcome measures were respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), and neonatal mortality. No difference in neonatal mortality was seen in any of the reviewed studies and RDS, IVH, and NEC incidence did not differ between treated and untreated IUGR fetuses. In SGA fetuses, results on RDS incidence and intracranial outcome were inconclusive. Antenatal steroid treatment does not seem to have an effect on neonatal mortality or morbidity in IUGR fetuses. In SGA fetuses, it remains unclear if antenatal steroid treatment is beneficial due to heterogeneous populations and treatment regimes. A randomized controlled trial should be performed to confirm prior results and answer further questions regarding antenatal steroid treatment of these fetuses.

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

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. 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. 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%. 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.

Early intervention in management of very preterm growth‐restricted fetuses: 2‐year outcome of infants delivered on fetal indication before 30 gestational weeks

To describe the outcome of growth-restricted fetuses with absent or reversed end-diastolic flow (ARED) in the umbilical artery delivered on fetal indication before 30 gestational weeks. Between 1998 and 2004, 42 fetuses with intrauterine growth restriction (IUGR) and ARED in the umbilical artery were delivered liveborn by Cesarean section on fetal indication before 30 gestational weeks. The median gestational age at delivery was 27 + 1 (range, 24 + 4 to 29 + 5) weeks. An additional four fetuses died in utero at a median gestational age of 24 + 2 (range, 23 + 5 to 25 + 4) weeks. Neonatal morbidity, infant mortality and major neurological morbidity of liveborn infants were compared with those in two control groups: all 371 liveborn infants delivered at < 30 weeks during the corresponding time period (Group A) and a subset of these, 42 matched infants without IUGR (Group B). Thirty-two fetuses (76%) [corrected] were delivered within 48 h of the occurrence of ARED (25 absent, seven reversed end-diastolic flow). The remaining 10 fetuses (five absent, five reversed end-diastolic flow) were monitored for a median of 6.5 (range, 3-18) days before delivery. One infant died in the neonatal period and three during the first year of postnatal life (2-year survival 90%). The incidence of chronic lung disease was higher in the ARED Group than in Control Groups A and B (P = 0.001 and P = 0.03, respectively). There were no differences between the groups in the occurrence of necrotizing enterocolitis, cerebral hemorrhage or retinopathy of prematurity. Cerebral palsy was diagnosed in 14% of the index group compared with 11% and 17% of Control Groups A and B (P > 0.05). Very preterm growth-restricted fetuses with umbilical artery ARED delivered on fetal indication, in most cases before the occurrence of severe changes in the ductus venosus velocity waveforms and/or fetal heart rate tracings, showed high 2-year survival and low morbidity.

Monitoring of fetuses with intrauterine growth restriction: longitudinal changes in ductus venosus and aortic isthmus flow

To explore in growth-restricted fetuses the sequence of changes in aortic isthmus and ductus venosus blood flow in relation to other arterial Doppler parameters commonly used to evaluate fetal wellbeing. Umbilical and middle cerebral arteries, ductus venosus and aortic isthmus were explored serially by means of pulsed Doppler in a cohort of singleton small-for-gestational age fetuses requiring delivery before 34 weeks. Longitudinal changes in the last 30 days before delivery were modeled by multilevel analysis. Individual regression lines for each variable were calculated for each fetus and from these the regression lines for the whole group were derived, in order to estimate the mean time point at which each Doppler parameter became abnormal (outside the 5th-95th centile range). A survival analysis was performed during the monitoring period, in which the endpoint was an abnormal Doppler pulsatility index. A total of 162 observations were performed on 46 fetuses (median, 3; range, 2-10). The median gestational age at inclusion was 28.9 (range, 23.6-33.4) weeks and delivery occurred at a median gestational age of 30.5 (range, 25.9-33.9) weeks. Six (13%) cases of perinatal mortality occurred. Umbilical and middle cerebral artery Doppler showed an almost linear deterioration throughout monitoring, becoming abnormal on average 24 days and 20 days before delivery, respectively. Aortic isthmus Doppler became abnormal on average 13 days before delivery, while ductus venosus Doppler did so within the last week before delivery. In preterm growth-restricted fetuses, aortic isthmus blood flow becomes abnormal on average 1 week earlier than does that in the ductus venosus. This could provide a sound basis to better define management protocols aimed to improve intact fetal survival.

No short-term benefits of antenatal corticosteroid treatment in severely preterm growth restricted fetuses: A case–control study

Background Antenatal corticosteroid administration to premature, growth restricted fetuses may not be beneficial and even have adverse effects on neonatal outcome. Aims To determine if preterm growth restricted fetuses benefit from antenatal corticosteroids. Study design Retrospective cohort study. Methods All singleton pregnancies with growth restricted fetuses delivered at our department before 34 weeks' gestation or weighing less than 1500 g, between January 2001 and December 2005, were retrospectively reviewed. Neonatal outcome was compared between growth restricted fetuses (defined as abnormal flow patterns in umbilical and middle cerebral arteries) that received antenatal CST (CST group) and those who did not receive antenatal CST (no CST group). The administration of CST appeared to be quasi randomized. Results A total of 88 pregnancies fulfilled the inclusion criteria (CST group, n = 54; no CST group, n = 34). The incidence of neonatal respiratory distress syndrome in the CST and no CST group was 42% (22/54) and 50% (17/34), respectively ( p = 0.44). Neonatal mortality in the CST and no CST group was 9% (5/54) and 12% (4/34), respectively ( p = 0.73). The prevalence of adverse neonatal outcome (neonatal mortality, major neonatal morbidity or severe cerebral lesions) in the CST and no CST group was 28% (15/54) versus 24% (8/34), ( p = 0.62). Conclusions Administration of CST to growth restricted preterm fetuses does not appear to be beneficial with respect to short term neonatal outcome.

Doppler assessment of the aortic isthmus and perinatal outcome in preterm fetuses with severe intrauterine growth restriction

To evaluate the characteristics and association with perinatal outcome of the aortic isthmus (AoI) circulation as assessed by Doppler imaging in preterm growth-restricted fetuses with placental insufficiency. This was a prospective cross-sectional study. Fifty-one fetuses with intrauterine growth restriction (IUGR) and either an umbilical artery (UA) pulsatility index (PI) > 95(th) centile or a cerebroplacental ratio < 5(th) centile were examined at 24-36 weeks' gestation. AoI impedance indices (PI and resistance index) and absolute velocities (peak systolic (PSV), end-diastolic and time-averaged maximum (TAMXV) velocities), were measured in all cases and compared with reference ranges by gestational age. Furthermore, fetuses were stratified into two groups according to the direction of the diastolic blood flow in the AoI: those with antegrade flow (n = 41) and those with retrograde flow (n = 10). Clinical surveillance was based on gestational age and Doppler assessment of the UA, middle cerebral artery and ductus venosus (DV). Adverse perinatal outcome was defined as stillbirth, neonatal death and severe morbidity (respiratory distress syndrome, bronchopulmonary dysplasia, Grade III/IV intraventricular hemorrhage, necrotizing enterocolitis and a neonatal intensive care unit stay > 14 days). Adverse perinatal outcome was significantly associated with an increased AoI-PI (area under the curve 0.77; 95% CI, 0.63-0.92; P < 0.005). A significant correlation (P < 0.001) was found between retrograde blood flow in the AoI and adverse perinatal outcome, the overall perinatal mortality being higher in the retrograde group (70% vs. 4.8%, P < 0.001). In 4/5 (80%) fetuses the reversal of flow in the AoI preceded that in the DV by 24-48 h. AoI-PSV and AoI-TAMXV were < 5(th) centile in 40/51 (78%) and 48/51 (94%) cases, respectively, whereas AoI-PI was > 95(th) centile in 21/51 (41%) cases. Retrograde flow in the AoI in growth-restricted fetuses correlates strongly with adverse perinatal outcome. Absolute velocities in the AoI are decreased in growth-restricted fetuses. The data suggest a potential role for Doppler imaging of the AoI in the clinical surveillance of fetuses with severe IUGR, which should be confirmed in larger prospective studies.

OP07.16: Regional cerebral blood flow perfusion as measured with fractional moving blood volume at different hemodynamic stages in severe IUGR fetuses

Objective: To study the aortic isthmus (AoI) circulation in preterm growth-restricted fetuses (IUGR). Methods: Fifty one IUGR fetuses with either an umbilical artery (UA) pulsatility index (PI)>95th centile or a cerebroplacental ratio 95th centile was shown in 21/51 cases (41%). No adverse perinatal outcome was significantly associated with neither a high PI or low absolute velocities. Comparing group 1 (anterograde) and group 2 (retrograde) significant differences were found in birth weight (p < 0.01), gestational age at delivery (p < 0.001), UA pH values (p < 0.001) and need of mechanical ventilation (p < 0.01). Perinatal mortality was higher in group 2 than group 1 (5.7% vs 60%; p < 0.001). A significant correlation (p < 0.001) was found between retrograde flow in the AoI and adverse perinatal outcome. Conclusions: The decrease in AoI absolute velocities is likely to reflect a decrease in AoI blood flow. Retrograde blood flow in the AoI is clearly related to adverse perinatal outcome.

OP07.17: Identification of fetuses at risk of perinatal mortality by the combination of ductus venosus, myocardial performance index and aortic isthmus Doppler waveforms

Objective: To study the aortic isthmus (AoI) circulation in preterm growth-restricted fetuses (IUGR). Methods: Fifty one IUGR fetuses with either an umbilical artery (UA) pulsatility index (PI)>95th centile or a cerebroplacental ratio 95th centile was shown in 21/51 cases (41%). No adverse perinatal outcome was significantly associated with neither a high PI or low absolute velocities. Comparing group 1 (anterograde) and group 2 (retrograde) significant differences were found in birth weight (p < 0.01), gestational age at delivery (p < 0.001), UA pH values (p < 0.001) and need of mechanical ventilation (p < 0.01). Perinatal mortality was higher in group 2 than group 1 (5.7% vs 60%; p < 0.001). A significant correlation (p < 0.001) was found between retrograde flow in the AoI and adverse perinatal outcome. Conclusions: The decrease in AoI absolute velocities is likely to reflect a decrease in AoI blood flow. Retrograde blood flow in the AoI is clearly related to adverse perinatal outcome.