Fetal cerebral blood flow redistribution in late gestation: identification of compromise in small fetuses with normal umbilical artery Doppler

Early Versus Late Minimal Enteral Feeding in Weeks Preterm Growth-Restricted neonates with Abnormal Antenatal Doppler Studies

Abstract Background: Preterm and growth-restricted babies are at high risk of milk intolerance and necrotising enterocolitis, as well as post-natal growth failure. Objective: To evaluate the effects of an "early" enteral feeding regimen, starting on day 2 after birth compared to late enteral feeding, starting on day 6 after birth in preterm growth restricted babies with abnormal antenatal Doppler studies regarding the incidence of NEC and feeding intolerance. Patients and Methods: Babies with gestational age below 37 weeks, and with birth weight below 10th centile for gestational age, will be randomly allocated to an "early" or "late" enteral feeding regimen. Results: Hundred-thirty three infants enrolled in the study: 66 received early feeding and 67 received delayed feeding. The incidence of NEC and feeding intolerance was not significantly different between the two groups. Conclusion: Early minimal enteral feeding (MEF) of preterm infants with IUGR and abnormal antenatal Doppler results may not have a significant effect on the incidence of NEC or feeding intolerance.

Two-dimensional and three-dimensional Doppler assessment of fetal growth restriction with different severity and onset

OBJECTIVES

To investigate the role of three-dimensional (3D) power Doppler ultrasonography in the assessment of fetal growth-restriction (FGR) with various degrees of severity and onset, and compare the results with the analysis of two-dimensional (2D) Doppler.

STUDY DESIGN

Vascular indices extracted from 3D Doppler measurements of the placenta were compared with indices of flow-velocity waveforms extracted from 2D Doppler measurements of the major sites of the fetal circulation between FGR (study group) and uncomplicated pregnancies (control group) from 25 to 38 weeks' gestation.

RESULTS

Three-dimensional indices were significantly lower in pregnancies complicated by FGR compared with uncomplicated pregnancies. When measured in placental periphery, vascularization index was 9.4 ± 9.6 in FGR pregnancies compared with 16 ± 14.7, P = 0.04. Flow index was 33.9 ± 6.9 compared with 38.7 ± 4.9, P = 0.03 and the vascularization-flow index was 3.8 ± 4.3 compared with 6.5 ± 6, respectively, P = 0.03. Among the conventional 2D indices, umbilical artery and middle cerebral artery pulsatility indices were not significantly different between the FGR and control groups. Higher rate of maternal or fetal compartment vascular lesions were detected in the FGR group.

CONCLUSIONS

Three-dimensional Doppler was found to be more strongly associated with placental vascular compromise than conventional 2D Doppler, regardless of severity and onset of fetal growth restriction.

Umbilical venous blood flow and its measurement in the human fetus

In this review, we evaluate the published methodologies to describe a noninvasive technique for the quantitative assessment of umbilical venous blood flow in the human fetus. We identify a number of variations in the reported methodologies and address some of the common errors associated with Doppler assessment of umbilical venous flow volume. The potential role of umbilical venous flow volumetry in the management of intrauterine growth restriction is briefly evaluated including its utility and reliability in everyday clinical practice.

Systematic review and meta-analysis of middle cerebral artery Doppler to predict perinatal wellbeing

OBJECTIVE

Identification of the fetus at risk of compromise is crucial to judicious allocation of monitoring resources and use of preventative treatment with the prospect of improving perinatal outcome. The accuracy of middle cerebral artery (MCA) Doppler for prediction of the fetus at risk of compromise of wellbeing is not known. The objective of this systematic review with bivariate meta-analysis was to evaluate the accuracy of middle cerebral artery Doppler for prediction of compromise of fetal/neonatal wellbeing.

STUDY DESIGN

Systematic review and bivariate meta-analysis with searches of Medline, Embase, Cochrane library, Medion (inception to October 2011), hand searching of journal and reference lists, contact with experts. Two reviewers independently selected articles in which the results of middle cerebral artery Doppler were associated with the occurrence of compromise of fetal/neonatal wellbeing. There were no language restrictions applied.

RESULTS

Thirty-five studies, testing 4025 fetuses, met the selection criteria. Data were extracted on study characteristics, quality and results to construct 2×2 tables. Likelihood ratios for positive and negative test results, sensitivity, specificity and their 95% confidence intervals were generated for the different indices and thresholds. Meta-analysis showed low predictive accuracy. For prediction of adverse perinatal outcome and perinatal mortality the results were positive likelihood ratios 2.77 (1.93, 3.96) and 1.36 (1.10, 1.67) and negative likelihood ratios 0.58 (0.48, 0.69) and 0.51 (0.29, 0.89) respectively.

CONCLUSION

Abnormal middle cerebral artery Doppler showed limited predictive accuracy for compromise of fetal/neonatal wellbeing. High quality primary research or individual patient data meta-analysis looking at this test in combination with other tests is required.

Doppler in obstetrics: beyond the umbilical artery

Doppler analysis of the umbilical and uterine arteries has long been performed in perinatal medicine to assess fetal health and maternal risk for preeclampsia. Several other vessels can be interrogated to obtain additional, vital information. Velocimetry in the fetal middle cerebral artery can yield evidence of the presence or absence of anemia and, in cases of delayed growth, of the risk of hypoxic damage. Ductus venosus waveforms are a very good indicator of impeding fetal jeopardy and should be used when umbilical artery waveforms become abnormal. Early pregnancy uterine artery Doppler reflects the status of the placental vasculature and, as such, is an excellent tool for predicting the risk of preeclampsia or intrauterine growth restriction.

The placenta in preeclampsia

The root cause of preeclampsia is the placenta. Preeclampsia begins to abate with the delivery of the placenta and can occur in the absence of a fetus but with the presence of trophoblast tissue with hydatidiform moles. In view of this, study of the placenta should provide insight into the pathophysiology of preeclampsia. In this presentation we examine placental pathological and pathophysiological changes with preeclampsia and fetal growth restriction (FGR). It would seem that this comparison should be illuminating as both conditions are associated with similarly abnormal placentation yet only in preeclampsia is there a maternal pathophysiological syndrome. Similar insights about early and late onset preeclampsia should also be provided by such information.We report that the placental abnormalities in preeclampsia are what would be predicted in a setting of reduced perfusion and oxidative stress. However, the differences from FGR are inconsistent. The most striking differences between the two conditions are found in areas that have been the least studied. There are differences between the placental findings in early and late onset preeclampsia but whether these are qualitative, indicating different diseases, or simply quantitative differences within the same disease is difficult to determine.We attempt to decipher the true differences, seek an explanation for the disparate results and provide recommendations that we hope may help resolve these issues in future studies.

Estimated weight centile as a predictor of perinatal outcome in small-for-gestational-age pregnancies with normal fetal and maternal Doppler indices

OBJECTIVE

To evaluate the risk of adverse perinatal outcome according to estimated fetal weight (EFW) in a cohort of term small-for-gestational-age (SGA) pregnancies with normal umbilical, fetal middle cerebral and maternal uterine artery Doppler indices.

METHODS

A cohort of 132 term SGA fetuses with normal umbilical artery pulsatility index (PI), mean uterine artery PI and cerebroplacental ratio was compared to a control group of 132 appropriate-for-gestational-age babies, matched by gestational age at delivery. The capacity of the EFW percentile to predict Cesarean delivery, Cesarean delivery for non-reassuring fetal status (NRFS), neonatal acidosis and days of neonatal hospitalization was analyzed.

RESULTS

As a whole, SGA fetuses with normal Doppler findings did not show a statistically significant difference for intrapartum Cesarean delivery (22.0 vs. 15.9%; P = 0.21) and neonatal acidosis (3.3 vs. 1.5%; P = 0.30), but had significantly higher risk for Cesarean delivery for NRFS (15.9 vs. 5.3%; P < 0.01) and longer neonatal hospitalization (1.39 vs. 0.87 days; P < 0.05) than did controls. SGA fetuses with EFW < 3(rd) centile had a significantly higher incidence of intrapartum Cesarean delivery (30.0 vs. 15.3%; P = 0.04), Cesarean delivery for NRFS (25.0 vs. 8.3%; P < 0.01) and longer neonatal hospitalization (2.0 vs. 0.9 days; P < 0.01) than those with EFW ≥ 3(rd) centile. SGA cases with EFW ≥ 3(rd) centile had perinatal outcomes similar to those of controls with normal EFW.

CONCLUSION

Among SGA fetuses with normal placental and cerebral Doppler ultrasound findings, EFW < 3(rd) centile discriminates between those with a higher risk for adverse perinatal outcome and those with outcomes similar to those of normally grown fetuses.

Changes in myocardial performance index and aortic isthmus and ductus venosus Doppler in term, small-for-gestational age fetuses with normal umbilical artery pulsatility index

OBJECTIVE

To evaluate the changes in myocardial performance index (MPI) and aortic isthmus (AoI) and ductus venosus (DV) Doppler in term, small-for-gestational age (SGA) fetuses with normal umbilical artery (UA) Doppler.

METHODS

MPI, AoI and DV pulsatility indices (PI) were measured within 1 week prior to delivery in a cohort of 178 term singleton consecutive SGA fetuses with normal UA-PI (< 95(th) percentile) and 178 controls matched by gestational age. Cardiovascular parameters were converted into Z-scores and values above the 95(th) centile defined as abnormal.

RESULTS

Median gestational age at inclusion and at delivery was 35.7 and 38.6 weeks, respectively. Compared to controls, SGA fetuses showed significantly higher values in MPI and AoI-PI and similar values in DV-PI. SGA fetuses showed a significantly higher proportion of increased MPI (28.1 vs. 6.7%; P < 0.01) and abnormal AoI-PI (14.6 vs. 5.1%; P < 0.01) than controls. The proportion of cases with abnormal DV-PI was similar between SGA cases and controls. Retrograde net blood flow in the AoI was observed in 7.3% of the SGA cases and in none of the controls.

CONCLUSION

A proportion of SGA fetuses show cardiovascular Doppler abnormalities. This information might be of clinical relevance in improving the detection and management of late-onset intrauterine growth restriction.

Tissue Doppler echocardiographic markers of cardiac dysfunction in small-for-gestational age fetuses

OBJECTIVE

The objective of the study was to evaluate echocardiographic markers of cardiac dysfunction in small-for-gestational age (SGA) fetuses with normal umbilical artery Doppler.

STUDY DESIGN

Cardiac function was evaluated in 58 SGA (mean gestational age, 38 weeks) and 58 gestational-age matched normally grown fetuses by conventional echocardiography (peak early [E] and late [A] ratios and myocardial performance index [MPI]), and tissue Doppler imaging (TDI) (annular peak velocities and MPI').

RESULTS

With conventional echocardiography, SGA fetuses had a nonsignificant trend to increased E/A ratios and left MPI compared with controls. TDI demonstrated that SGA fetuses had significantly lower right E' and A' peak velocities and higher MPI' values.

CONCLUSION

These findings further support that a proportion of SGA fetuses have true late-onset intrauterine growth restriction, which is associated with subclinical cardiac dysfunction, as previously described for early-onset intrauterine growth restriction.

Intrauterine growth restriction: new concepts in antenatal surveillance, diagnosis, and management

Intrauterine growth restriction (IUGR) remains one of the main challenges in maternity care. Improvements have to start from a better definition of IUGR, applying the concept of the fetal growth potential. Customized standards for fetal growth and birthweight improve the detection of IUGR by better distinction between physiological and pathological smallness and have led to internationally applicable norms. Such developments have resulted in new insights in the assessment of risk and surveillance during pregnancy. Serial fundal height measurement plotted on customized charts is a useful screening tool, whereas fetal biometry and Doppler flow are the mainstay for investigation and diagnosis of IUGR. Appropriate protocols based on available evidence as well as individualized clinical assessment are essential to ensure good management and timely delivery.

Delayed introduction of progressive enteral feeds to prevent necrotising enterocolitis in very low birth weight infants

BACKGROUND

The introduction of progressive enteral feeds for very low birth weight (VLBW) infants is often delayed for several days or longer after birth due to concern that earlier introduction may not be tolerated and may increase the risk of necrotising enterocolitis (NEC). However, delaying enteral feeding could diminish the functional adaptation of the gastrointestinal tract and prolong the need for parenteral nutrition with its attendant infectious and metabolic risks.

OBJECTIVES

To determine the effect of delayed introduction of progressive enteral feeds on the incidence of NEC, mortality and other morbidities in VLBW infants.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2010, Issue 4), MEDLINE (1966 to December 2010), EMBASE (1980 to December 2010), CINAHL (1982 to December 2010), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that assessed the effect of delayed (more than four days' postnatal age) versus earlier introduction of progressive enteral feeds on the incidence of NEC, mortality and other morbidities in VLBW infants.

DATA COLLECTION AND ANALYSIS

Data collection and analysis were performed in accordance with the standard methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

We identified five randomised controlled trials (RCT) in which a total of 600 infants participated. The trials defined delayed introduction as later than five to seven days after birth and early introduction as less than four days after birth. Two of the trials, in which a total of 488 infants participated, only recruited growth-restricted infants with Doppler ultrasound evidence of abnormal fetal circulatory distribution or flow. Meta-analyses did not detect statistically significant effects on the risk of NEC [typical relative risk 0.89, 95% confidence interval (CI) 0.58 to 1.37] or all cause mortality (typical relative risk 0.93, 95% CI 0.53 to 1.64). Infants who had delayed introduction of enteral feeds took significantly longer to establish full enteral feeding (reported median difference three days).

AUTHORS' CONCLUSIONS

Current trial data do not provide evidence that delayed introduction of progressive enteral feeds reduces the risk of NEC in VLBW infants. Delaying the introducing of progressive enteral feeds results in several days delay in establishing full enteral feeds but the clinical importance of this effect is unclear. Further RCTs are needed to give more precise estimates of the effect of delaying the introduction of enteral feeds on clinical outcomes in VLBW infants.

Longitudinal changes in uterine, umbilical and fetal cerebral Doppler indices in late-onset small-for-gestational age fetuses

OBJECTIVES

To determine the longitudinal trends and rates of conversion of normal to abnormal uterine (UtA), umbilical (UA) and middle cerebral artery (MCA) Doppler velocimetry throughout the third trimester in late-onset small-for-gestational-age (SGA) fetuses.

METHODS

UtA, UA and MCA Doppler velocimetry was serially performed in a cohort of singleton consecutive late-onset SGA fetuses with normal Doppler values at diagnosis. The rate of conversion of normal to abnormal Doppler values was evaluated by survival analysis. Longitudinal trends were modeled by means of multilevel analysis.

RESULTS

A total of 616 scans were performed on 171 SGA fetuses. Mean gestational age at inclusion and at delivery was 34.1 (SD 1.6) and 38.7 (SD 1.7) weeks, respectively. The proportions of abnormal UtA (2.3 vs. 4.1%) and UA (2.3 vs. 2.9%) pulsatility index (PI) were not significantly different between 37 weeks and before delivery. On the other hand, the proportions of abnormal MCA-PI (4.1 vs. 13.5%) and cerebroplacental ratio (CPR) (7 vs. 22.8%) were significantly different between these two examinations. The remaining proportion of cases with normal UtA-, UA- and MCA-PIs and CPR at 40 weeks were 98.6, 94.5, 85 and 49.6%, respectively. Whereas a slight increasing trend was observed for the UtA-PI (β = 0.002) and UA-PI (β = 0.01), MCA-PI (β = 0.044) and CPR (β = 0.124) showed a progressive decrease until delivery.

CONCLUSIONS

Late-onset SGA fetuses with normal Doppler velocimetry upon diagnosis show progression from 37 weeks' gestation with worsening CPR followed by a decrease in MCA-PI.

Relations between fetal brain-sparing circulation, oxytocin challenge test, mode of delivery and fetal outcome in growth-restricted term fetuses

OBJECTIVE

The study was designed as a prospective non-interventional, observational study to elucidate the potential value of fetal middle cerebral artery Doppler velocimetry to identify brain-sparing flow in a surveillance program for suspected intrauterine growth restriction (IUGR).

MATERIAL AND METHODS

The study was carried out at Skåne University Hospital, Malmö, Sweden. One hundred and twenty-six single pregnancies suspected of IUGR at ≥36 gestational weeks were assessed. The main outcome measures were positive/negative oxytocin challenge test (OCT) and cesarean/vaginal delivery. The pregnancies were managed with ultrasound fetometry, uterine and umbilical artery Doppler flow velocimetry, nonstress test, and an OCT to decide the optimal time and mode of delivery. Cases with a positive OCT were promptly delivered by cesarean section, whereas negative cases were allowed a trial of labor. Middle cerebral artery Doppler flow velocimetry results were blinded to the managing obstetricians. Brain-sparing flow was defined as a middle cerebral artery-to-umbilical artery pulsatility index ratio of <1.08. Nonparametric statistics with significance set at p < 0.05 were used, and Cohen's kappa coefficient was calculated for congruence of brain-sparing flow with OCT and mode of delivery, respectively.

RESULTS

The positive predictive value and sensitivity figures of brain-sparing flow to indicate a positive OCT and cesarean delivery were 33-63%. The inter-rater reliability of brain-sparing flow vs. positive OCT showed a kappa coefficient of 0.19, and brain-sparing flow vs. cesarean section among OCT-negative cases a kappa coefficient of 0.23.

CONCLUSION

Fetal brain-sparing flow is a poor predictor of a positive OCT, and of cesarean section in OCT-negative cases.

Can adverse neonatal outcome be predicted in late preterm or term fetal growth restriction?

OBJECTIVE

To identify independent predictors of adverse neonatal outcome in cases of fetal growth restriction (FGR) at > or = 34 weeks.

METHODS

From a cohort of 481 FGR cases delivered at > or = 34 weeks, demographic and obstetric variables, fetal biometry and Doppler indices of the uterine, umbilical and fetal middle cerebral arteries available within 2 weeks of delivery, were related to adverse neonatal outcome, defined as admission to the neonatal intensive care unit for indications other than low birth weight alone.

RESULTS

Logistic regression analysis showed that gestational age (GA) at delivery (odds ratio (OR) = 0.59; 95% CI, 0.50-0.70), abdominal circumference (AC) centile (OR = 0.69; 95% CI, 0.59-0.81) and umbilical artery (UA) pulsatility index (PI) centile (OR = 1.02; 95% CI, 1.01-1.04) significantly correlated with adverse neonatal outcome. From this model we calculated a score of adverse neonatal outcome expressed by the formula: (UA-PI centile/3) - (10 x AC centile) + (10 x (40 - GA at delivery in weeks)). Receiver-operating characteristics curve analysis demonstrated that a score of > or = 25 optimally predicted adverse neonatal outcome (sensitivity of 75%, false-positive rate of 18%). Beyond 37.5 weeks, gestational age no longer had an independent impact on outcome.

CONCLUSIONS

In late preterm or term FGR, GA at delivery is the most important predictor of adverse neonatal outcome. At > 37.5 weeks, delivery may be the best option to minimize adverse outcome in all FGR cases. At 34-37 weeks, a score based on GA at delivery, UA-PI centile and AC centile optimally predicts adverse neonatal outcome.

Longitudinal brain perfusion changes in near-term small-for-gestational-age fetuses as measured by spectral Doppler indices or by fractional moving blood volume

OBJECTIVE

The objective of this study was to compare the temporal sequence of fetal brain hemodynamic changes in near-term small-for-gestational-age fetuses as measured by spectral Doppler indices or by fractional moving blood volume.

STUDY DESIGN

Cerebral tissue perfusion measured by fractional moving blood volume, cerebroplacental ratio, anterior cerebral artery, and middle cerebral artery pulsatility indices were weekly performed in a cohort of singleton consecutive small-for-gestational-age fetuses with normal umbilical artery delivered after 37 weeks of gestation.

RESULTS

A total of 307 scans were performed on 110 small-for-gestational-age fetuses. Mean gestational age at diagnosis and at delivery was 35.7 and 38.6 weeks, respectively. The proportion of fetuses with abnormal fractional moving blood volume, cerebroplacental ratio, anterior cerebral artery-pulsatility index, and middle cerebral artery-pulsatility index values was 31.3%, 16.8%, 17.2%, and 10.8% at 37 weeks of gestation and 42.7%, 23.6%, 20.9%, and 16.4% before delivery.

CONCLUSION

The presence of brain redistribution in small-for-gestational-age fetuses was detected earlier and in a higher proportion of fetuses using cerebral tissue perfusion rather than spectral Doppler indices.

Middle versus anterior cerebral artery Doppler for the prediction of perinatal outcome and neonatal neurobehavior in term small-for-gestational-age fetuses with normal umbilical artery Doppler

OBJECTIVE

To evaluate whether anterior cerebral artery (ACA) Doppler ultrasonography is superior to middle cerebral artery (MCA) Doppler in the prediction of perinatal outcome and neonatal neurobehavior in term small-for-gestational-age (SGA) fetuses with normal umbilical artery (UA) Doppler.

METHODS

MCA and ACA Doppler ultrasonography was performed in a cohort of SGA term fetuses with normal UA Doppler. Perinatal outcome and neonatal neurobehavioral performance were compared with a group of term appropriate-for-gestational age (AGA) infants. Neurobehavior was evaluated at 40 ( +/- 1) weeks of corrected age with the Neonatal Behavioral Assessment Scale. Differences between the study groups were adjusted for potential confounding variables by multiple linear or logistic regression analyis.

RESULTS

A total of 199 newborns (98 SGA and 101 AGA) were included. Among the SGA fetuses, 28.6 and 17% had MCA and ACA redistribution, respectively. Cases with either type of redistribution had an increased risk for adverse outcome, with no differences in predictive performance between the two parameters. SGA fetuses with MCA redistribution compared with controls had an increased risk for abnormal neurobehavioral performance in motor (36 vs. 20%; adjusted P = 0.02) and state organization (25 vs. 17.5%; adjusted P = 0.03) areas. SGA fetuses with ACA redistribution had only an increased risk for abnormal neurobehavioral performance area in state organization compared with controls (30 vs. 17.5%; adjusted P = 0.021).

CONCLUSION

In term SGA newborns with no signs of brain-sparing, ACA Doppler investigation does not provide any benefit over MCA in terms of the prediction of adverse perinatal outcome.

Cerebral blood perfusion and neurobehavioral performance in full-term small-for-gestational-age fetuses

OBJECTIVE

The purpose of this study was to evaluate changes in cerebral blood perfusion and middle cerebral artery (MCA) Doppler in full-term small-for-gestational-age fetuses (SGA) and to explore their association with neonatal neurobehavioral performance.

STUDY DESIGN

Frontal brain perfusion that was measured by fractional moving blood volume (FMBV) and MCA Doppler pulsatility index were assessed in 60 SGA fetuses with normal umbilical artery Doppler results that were matched with adequate-for-gestational-age fetuses. Neonates were evaluated with the Neonatal-Behavioral-Assessment-Scale (NBAS).

RESULTS

The proportion of SGA fetuses with increased FMBV (35% vs 5%; P < .001) and decreased MCA Doppler pulsatility index (15% vs 1.7%; P < .01) was significantly higher. SGA fetuses showed poorer NBAS scores in all areas. Increased FMBV identified SGA fetuses with the highest risks of abnormal NBAS in social-interactive (odds ratio, 7.8), attention (odds ratio, 22.8), and state-organization (odds ratio, 25.0). Abnormal MCA Doppler identified SGA with abnormal scores in motor area (odds ratio, 10.7).

CONCLUSION

Increased brain blood perfusion discriminates SGA fetuses that are at risk for abnormal neurobehavior.

Neurobehavior in term, small-for-gestational age infants with normal placental function

OBJECTIVE

The goal was to evaluate the neurobehavioral outcomes of term, small-for-gestational age (SGA) newborns with normal placental function.

METHODS

A cohort of consecutive term SGA newborns with normal prenatal umbilical artery Doppler ultrasound findings was created and compared with a group of term infants with size appropriate for gestational age, who were sampled from our general neonatal population. Neonatal behavior was evaluated at corrected age of 40 +/- 1 weeks with the Neonatal Behavioral Assessment Scale. The effect of the study group on each Neonatal Behavioral Assessment Scale area was adjusted, through multivariate analysis of covariance, for smoking during pregnancy, maternal BMI, socioeconomic level, onset of labor, mode of delivery, use of epidural anesthetic medication, gestational age at delivery, postnatal age (in days) at evaluation, and gender.

RESULTS

A total of 202 newborns (102 SGA and 100 appropriate for gestational age) were included. All of the neurobehavioral areas studied were poorer in the SGA group, with significance for attention, habituation, motor, social-interactive, and regulation of state. The average mean differences in scores between the study groups were 0.77 (95% confidence interval: 0.38-1. 14) for attention, 0.64 (95% confidence interval: 0.13-1.14) for habituation, 0.52 (95% confidence interval: 0.31-0.74) for motor, 0.95 (95% confidence interval: 0.54-1.37) for social-interactive, and 0.68 (95% confidence interval: 0.23-1.13) for regulation of state. These differences remained significant after adjustment for potential confounders.

CONCLUSION

Term SGA newborns with no signs of placental insufficiency had poorer neurobehavioral competencies, which suggests delayed neurologic maturation.

ADEPT - Abnormal Doppler Enteral Prescription Trial

BACKGROUND

Pregnancies complicated by abnormal umbilical artery Doppler blood flow patterns often result in the baby being born both preterm and growth-restricted. These babies are at high risk of milk intolerance and necrotising enterocolitis, as well as post-natal growth failure, and there is no clinical consensus about how best to feed them. Policies of both early milk feeding and late milk feeding are widely used. This randomised controlled trial aims to determine whether a policy of early initiation of milk feeds is beneficial compared with late initiation. Optimising neonatal feeding for this group of babies may have long-term health implications and if either of these policies is shown to be beneficial it can be immediately adopted into clinical practice.

METHODS AND DESIGN

Babies with gestational age below 35 weeks, and with birth weight below 10th centile for gestational age, will be randomly allocated to an "early" or "late" enteral feeding regimen, commencing milk feeds on day 2 and day 6 after birth, respectively. Feeds will be gradually increased over 9-13 days (depending on gestational age) using a schedule derived from those used in hospitals in the Eastern and South Western Regions of England, based on surveys of feeding practice. Primary outcome measures are time to establish full enteral feeding and necrotising enterocolitis; secondary outcomes include sepsis and growth. The target sample size is 400 babies. This sample size is large enough to detect a clinically meaningful difference of 3 days in time to establish full enteral feeds between the two feeding policies, with 90% power and a 5% 2-sided significance level. Initial recruitment period was 24 months, subsequently extended to 38 months.

DISCUSSION

There is limited evidence from randomised controlled trials on which to base decisions regarding feeding policy in high risk preterm infants. This multicentre trial will help to guide clinical practice and may also provide pointers for future research.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN: 87351483.

The role of Doppler and placental screening

Placental-associated diseases account for most cases of adverse perinatal outcome in developing countries. Uterine Doppler evaluation predicts most instances of early-onset preeclampsia and intrauterine growth restriction, but there is no evidence in favour of any prophylactic strategy in cases of an abnormal screening result. Umbilical artery Doppler investigation allows identifying those small-for-gestational-age foetuses at higher risk, and its use in these pregnancies improves a number of perinatal outcomes. Middle cerebral artery Doppler investigation reflects brain redistribution, and its use in combination with the umbilical artery in a cerebroplacental ratio seems to improve prediction of adverse outcome, mainly in near-term pregnancies, where most instances of adverse outcome occur in foetuses with normal umbilical artery. Ductus venosus Doppler waveform is a surrogate parameter of the foetal acid-base status. However, the benefits of its use in the management of early-onset growth restriction needs further evidence.

Evaluation of the use of umbilical artery Doppler flow studies and outcome of pregnancies at a secondary hospital

OBJECTIVE

To investigate the use of a personal computer (PC)-based, continuous-wave Doppler machine by a trained midwife at a secondary hospital to assess umbilical artery flow velocity waveforms (FVW) in referred women.

METHODS

Pregnant women referred for suspected poor fetal growth were evaluated from June 2002 through December 2004. The Umbiflow apparatus, consisting of a Pentium 3 PC with an ultrasound transducer plugged into the USB port and software, was used to analyze the FVW of the umbilical artery. Pregnancies in which the resistance index (RI) was <75(th) percentile (P75) were not further evaluated for fetal well-being unless the clinical condition of the mother changed. Pregnancies with an RI >or=P75 were followed up according to a specific protocol. Primary end points were intrauterine death and intrauterine growth restriction.

RESULTS

A total of 572 singleton pregnancies were followed up. Significantly more infants were small-for-gestational-age when the RI was >P95 (55.6%) than those between P75 and P95 (41.2%) or <P75 (27.2%). Perinatal mortality rates were 13.2, 39.1 and 41.7 for women with RIs <P75, P75-95 and >P95, respectively.

CONCLUSIONS

A normal Doppler FVW of the umbilical artery is less likely to be followed by perinatal death.

Fetal cerebrovascular response to chronic hypoxia—implications for the prevention of brain damage

Fetal hypoxia is one of the leading causes of perinatal morbidity and mortality. One of the most severe sequels of fetal hypoxic insult is the development of perinatal brain lesions resulting in a spectrum of neurological disabilities, from minor cerebral disorders to cerebral palsy. One of the most important fetal adaptive responses to hypoxia is redistribution of blood flow towards the fetal brain, known as the 'brain sparing effect'. The fetal blood flow redistribution in favor of the fetal brain can be detected and quantified by the Doppler cerebral/umbilical ratio (C/U ratio = cerebral resistance index (CRI)/umbilical resistance index (URI)). Our studies on animal models and human fetuses have demonstrated clearly that this phenomenon cannot prevent the development of perinatal brain lesions in the case of severe or prolonged hypoxia. Fetal deterioration in chronic and severe hypoxia is characterized by the disappearance of the physiological cerebral vascular variability (vasoconstriction and vasodilatation), followed by an increase in cerebral vascular resistance. However, our latest study on growth-restricted and hypoxic human fetuses has shown that perinatal brain lesions can develop even before the loss of cerebrovascular variability. The fetal exposure to hypoxia can be quantified by using a new vascular score, the hypoxia index. This parameter, which takes into account the degree as well as duration of fetal hypoxia, can be calculated by summing the daily % C/U ratio reduction from the cut-off value 1 over the period of observation. According to our results, the use of this parameter, which calculates the cumulative, relative oxygen deficit, could allow for the first time the sensitive and reliable prediction and even prevention of adverse neurological outcome in pregnancies complicated by fetal hypoxia.

Fetal growth restriction is associated with prioritization of umbilical blood flow to the left hepatic lobe at the expense of the right lobe

Eighty to 85% of the venous perfusion to the fetal liver is from the umbilical vein, the rest from the portal vein. Umbilical venous flow to the liver is essential for intrauterine growth, and is impaired in placental insufficiency. We hypothesized that in growth-restricted fetuses portal blood flow compensates for insufficient umbilical blood flow to the liver. In 29 fetuses with fetal growth restriction (estimated fetal weight < or =5th percentile), we used ultrasound to measure blood flows in the umbilical vein, ductus venosus, left portal vein, and main portal stem. Compared with normal fetuses, both absolute and normalized total venous liver blood flows were reduced in growth-restricted fetuses, related to the degree of placental compromise and equally affecting both liver lobes. However, portal replaced umbilical flow to the right lobe, in a manner graded according to placental vascular resistance; in extreme cases, the right lobe received no umbilical perfusion. In fetal growth restriction, the liver suffers from venous hypoperfusion, and portal blood partially replaces umbilical flow to the right lobe; this will result in right liver lobe hypoxemia. This striking prioritization in nutrient delivery of left over right lobes suggests an adaptive response to poor placental perfusion that may have functional consequences.

Growth deficit in term small-for-gestational fetuses with normal umbilical artery Doppler is associated with adverse outcome

AIM

The association between the growth deficit and the occurrence of adverse outcome was analyzed in a cohort of small-for-gestational age fetuses delivered at term.

METHODS

A cohort of consecutive singleton fetuses suspected of being SGA during the late third trimester and delivered beyond 37 weeks was selected. Growth deficit area was calculated as that between the individual 10(th) centile curve of the customized optimal fetal weight and the individual fetal growth curve.

RESULTS

A total of 55 women were included. Of these, 16 had 28 adverse events: eight cases of umbilical artery pH<7.15, 9 cases of caesarean section for fetal distress and 11 cases of admission to neonatal intensive care unit. Whereas the mean area of growth deficit was 8.8 kg x week units (SD 7.6) for cases with normal outcomes, it was 13.9 (SD 8.04) for cases with adverse outcomes (P=0.03). A growth area deficit >10 units, predicted the occurrence of adverse outcome with a sensitivity and specificity of 62% and 68%, respectively.

CONCLUSION

In term growth restricted fetuses the degree of growth deficit from the optimal customized growth may be used to identify a subgroup of fetuses at high-risk for adverse outcomes.

Prediction of adverse perinatal outcome at term in small-for-gestational age fetuses: comparison of growth velocity vs. customized assessment

OBJECTIVE

To explore the ability of growth velocity and customized standards of fetal weight to predict adverse outcomes in small fetuses delivered at term.

METHODS

We evaluated a cohort of 86 consecutive singletons suspected to be small for gestational age during the third trimester (estimated fetal weight <10(th) centile), who had normal umbilical artery Doppler and ultimately delivered at term. Conditional growth velocity and customized fetal growth were compared for the prediction of adverse outcome.

RESULTS

Overall, customized growth assessment showed better sensitivity than growth velocity assessment (57.1% vs. 42.9% for a 10(th) centile cut-off) for the prediction of adverse outcome, but with comparable specificity. The odds of having an adverse outcome for women with a positive test compared with women with a negative test were 1.54 and 3.22 for the 10(th) centile growth velocity and customized definitions, respectively. The area under the curve for the prediction of adverse outcome was larger for customized than for growth velocity standards (0.65 vs. 0.59), albeit without statistical significance.

CONCLUSIONS

Our study suggests that customized growth assessment may have better accuracy in predicting adverse perinatal outcome than growth velocity in small fetuses with normal umbilical Doppler delivered at term.

Neurodevelopmental outcome in 2-year-old infants who were small-for-gestational age term fetuses with cerebral blood flow redistribution

OBJECTIVE

To assess the neurodevelopmental outcome at 2 years of age of children who had been small-for-gestational-age (SGA) term babies with cerebral blood flow redistribution.

METHODS

Perinatal outcome was assessed in a cohort of 97 term singleton appropriate-for-gestational-age and 125 term singleton SGA fetuses with normal umbilical artery Doppler, stratified according to the presence of cerebral blood flow redistribution. Neurodevelopmental outcome was assessed prospectively at 2 years of age by means of the 24-month Age & Stage Questionnaire (ASQ).

RESULTS

Of the 125 SGA fetuses, 25 had redistribution of the cerebral blood flow, and 100 did not. There were no significant differences in perinatal outcome between these two SGA groups. At 2 years of age, children who had been SGA fetuses with middle cerebral artery (MCA) pulsatility index (PI) < 5(th) centile had a higher incidence of suboptimal neurodevelopmental outcome compared with those with normal MCA-PI (52% vs. 31%; P = 0.049) and a lower mean centile in communication (53.1 vs. 67.4; P = 0.006) and problem-solving (39.7 vs. 47.4; P = 0.04) areas.

CONCLUSION

SGA fetuses with cerebral blood flow redistribution have a higher risk of subtle neurodevelopmental deficits at 2 years of age. This challenges the concept that fetal cerebral redistribution is an entirely protective mechanism and suggests MCA-PI as a risk stratifying factor for adverse neurodevelopmental outcome.

Nomograms of Iranian fetal middle cerebral artery Doppler waveforms and uniformity of their pattern with other populations' nomograms

BACKGROUND

Doppler flow velocity waveform analysis of fetal vessels is one of the main methods for evaluating fetus health before labor. Doppler waves of middle cerebral artery (MCA) can predict most of the at risk fetuses in high risk pregnancies. In this study, we tried to obtain normal values and their nomograms during pregnancy for Doppler flow velocity indices of MCA in 20-40 weeks of normal pregnancies in Iranian population and compare their pattern with other countries' nomograms.

METHODS

During present descriptive cross-sectional study, 1037 normal pregnant women with 20th-40th week gestational age were underwent MCA Doppler study. All cases were studied by gray scale ultrasonography initially and Doppler of MCA afterward. Resistive Index (RI), Pulsative Index (PI), Systolic/Diastolic ratio (S/D ratio), and Peak Systolic Velocity (PSV) values of MCA were determined for all of the subjects.

RESULTS

Results of present study showed that RI, PI, S/D ratio values of MCA decreased with parabolic pattern and PSV value increased with simple pattern, as gestational age progressed. These changes were statistically significant (P=0.000 for all of indices) and more characteristic during late weeks of pregnancy.

CONCLUSION

Values of RI, PI and S/D ratio indices reduced toward the end of pregnancy, but PSV increased. Despite the trivial difference, nomograms of various Doppler indices in present study have similar pattern with other studies.

Progression of Doppler abnormalities in intrauterine growth restriction

OBJECTIVE

To identify the sequence of progression of arterial and venous Doppler abnormalities from the onset of placental insufficiency in intrauterine growth restriction (IUGR).

METHODS

Prospective observational study of singletons with IUGR (abdominal circumference < 5(th) percentile) who underwent serial standardized umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV) and umbilical vein (UV) Doppler surveillance. Time intervals between progressive Doppler abnormalities and patterns of deterioration were related to UA Doppler status and gestational age.

RESULTS

Six hundred and sixty-eight longitudinal examinations were performed in 104 fetuses, identifying three patterns of progression: (1) Mild placental dysfunction (n = 34) that remained confined to the UA/MCA. The UA became abnormal at a median of 32 weeks' gestation but the pulsatility index never exceeded 3 SD above normal. Progression took a median of 33 days, requiring delivery at a median of 35 weeks. (2) Progressive placental dysfunction (n = 49). Initially normal UA Doppler PI at 29 weeks' gestation increased beyond 3 SD, progressing to abnormal MCA, absent/reversed UA diastolic flow, abnormal DV, UV pulsations in 9-day intervals requiring delivery by 33 weeks. (3) Severe early-onset placental dysfunction (n = 21). Markedly elevated UA PI established by 27 weeks' gestation was associated with rapid (7-day intervals) progression to abnormal venous Doppler with median delivery at 30.6 weeks. Gestational age at onset, time to delivery and progression intervals were different between patterns (all P < 0.05).

CONCLUSION

The characteristics of cardiovascular manifestations in IUGR are determined by the gestational age at onset and the severity of placental disease. Recognition of these factors is critical for planning fetal surveillance in IUGR.

Predictiveness of antenatal umbilical artery Doppler for adverse pregnancy outcome in small-for-gestational-age babies according to customised birthweight centiles: population-based study

OBJECTIVE

To examine the relationship between smallness at birth and the predictive value of umbilical artery Doppler.

DESIGN

Retrospective cohort.

SETTING

Tertiary referral university hospital, Barcelona.

POPULATION

A total of 7645 singleton pregnancies delivered between January 2002 and June 2004.

METHODS

The associations with adverse outcome were assessed for small-for-gestational-age (SGA) babies according to customised standards who had normal and abnormal umbilical artery Doppler.

MAIN OUTCOME MEASURES

Neonatal morbidity and perinatal mortality.

RESULTS

Of the 369 SGA fetuses that had been identified antenatally, 70 (19%) had an abnormal umbilical artery Doppler and the babies from these pregnancies had a higher risk for neonatal morbidity when compared with babies with normal birthweight (OR 3.99, 95% CI 1.04-11.03). However, the remaining 299 (81%) fetuses with normal umbilical artery Doppler also had an elevated risk of neonatal morbidity (OR 2.26, 95% CI 1.04-4.39). Overall, many of the instances of adverse outcome associated with smallness for gestational age were attributable to the group with normal Doppler than to the group with abnormal Doppler.

CONCLUSION

Normal antenatal umbilical artery Doppler cannot be taken as an indicator of low risk in pregnancies where the fetus is SGA according to customised percentiles.

Elevated asymmetric dimethylarginine concentrations precede clinical preeclampsia, but not pregnancies with small-for-gestational-age infants

OBJECTIVE

The purpose of this study was to investigate maternal plasma concentrations of asymmetric dimethylarginine (ADMA) in mid pregnancy and at the time of disease in women who experience preeclampsia, compared with women with uncomplicated pregnancies and women with small-for-gestational-age infants.

STUDY DESIGN

Plasma samples were collected at mid-pregnancy and at the time of delivery from 31 women with uncomplicated pregnancies, from 12 women with small-for-gestational-age infants, and from 15 women with preeclampsia. ADMA and L-arginine concentrations were measured using high-pressure liquid chromatography.

RESULTS

Maternal ADMA concentrations were elevated at mid pregnancy and remained elevated at delivery in women who later experienced preeclampsia (0.45 +/- 0.09 micromol/L) compared with women with uncomplicated pregnancies (0.34 +/- 0.08 micromol/L; P < .01) and with women with small-for-gestational-age infants (0.33 +/- 0.06 micromol/L; P < .01).

CONCLUSION

Maternal ADMA concentrations are higher in mid pregnancy in women who experience preeclampsia, compared with women with uncomplicated pregnancies and small-for-gestational-age infants. Elevated ADMA concentration before clinical onset of preeclampsia suggests a role of this nitric oxide synthase inhibitor in the pathophysiologic condition of preeclampsia.

Differential gene expression of somatotrophic and growth factors in response to in vivo hypoxia in human placenta

OBJECTIVE

Hypoxia-inducible transcription factors (HIFs) have been characterized as the most important regulators of O(2)-dependent gene transcription. We investigated expression of HIF-dependent growth factors and HIF-independent somatotrophic factors in term placenta in response to hypoxic ischemia.

STUDY DESIGN

Our cross-sectional in vivo analysis included term placentas of gestations complicated by the following: (1) birth asphyxia (n = 22); (2) chronic hypoxic ischemia (n = 22); and (3) controls (n = 28). Gene expression of leptin, insulin-like growth factor (IGF)-1, IGF-2, ghrelin, and human placental growth hormone (hPGH) were measured by TaqMan reverse transcriptase-polymerase chain reaction.

RESULTS

Acute and chronic hypoxia significantly increased leptin messenger ribonucleic acid (mRNA) levels, compared with controls (P < .001). Augmented IGF-2 mRNA levels were present in chronic hypoxia (P < .001) but not in birth asphyxia. IGF-1, ghrelin, and hPGH mRNA levels did not change in relation to hypoxia.

CONCLUSION

IGF-2 and leptin are suggested to be involved in adaptive response to hypoxic ischemia in term placenta with differential transcriptional regulation related to the duration of hypoxia.

Outcome of antenatally diagnosed abdominal wall defects

OBJECTIVE

To examine the natural history and detailed outcome of antenatally diagnosed abdominal wall defects.

METHODS

This was a retrospective review of the antenatal reports, pediatric surgery records and subsequent follow-up information of all cases of omphalocele and gastroschisis diagnosed in a 10-year period in our tertiary referral center.

RESULTS

There were 109 cases of abdominal wall defects, including omphalocele in 67 cases and gastroschisis in 42 cases. Of the 67 cases of omphalocele there were 26 (39%) with chromosomal abnormalities and 22 (33%) underwent termination of pregnancy, mainly for associated structural abnormalities. Of the ongoing 19 cases there were five (26%) in-utero deaths, 12 (63%) survivors and two (11%) neonatal deaths, both associated with prematurity. Excluding chromosomal abnormalities, the survival rate in isolated omphalocele was 7/16 (44%) whilst it was 5/25 (20%) in those with associated abnormalities. Gastroschisis was isolated in 40 (95%) cases. Among these 40 isolated cases there were two (5%) terminations. Of the 38 ongoing cases, there were two (5%) in-utero deaths, and 36 (95%) live births. Four of the 36 liveborn infants (11%) died in the postoperative period owing to complications of small bowel atresia.

CONCLUSIONS

Although only 18% of infants with antenatally diagnosed omphalocele were alive in the neonatal period, postoperative morbidity was low. The majority (90%) of fetuses with antenatally diagnosed gastroschisis survived to delivery, but the mortality in affected newborns was 11%.

Middle cerebral artery blood flow velocities and pulsatility index and the cerebroplacental pulsatility ratio: longitudinal reference ranges and terms for serial measurements

OBJECTIVES

To establish reference ranges suitable for serial assessments of the fetal middle cerebral (MCA) and umbilical (UA) artery blood flow velocities, pulsatility index (PI) and cerebroplacental pulsatility ratio and to provide terms for calculating conditional reference intervals suitable for individual serial measurements.

METHODS

This was a longitudinal study of 161 singleton pregnancies. Using Doppler ultrasound, MCA and UA blood velocities and PI were determined three to five times at 3-5-week intervals over a gestational age range of 19-41 weeks. Polynomial regression lines for the 95th, 50th and 5th percentiles were calculated for the peak systolic velocity (PSV), time-averaged maximum velocity (TAMXV), PI and cerebroplacental ratio. Terms for calculating conditional reference intervals were established.

RESULTS

Based on 566 observations our new longitudinal reference ranges for fetal middle cerebral PSV, TAMXV and PI provided terms for calculating conditional reference intervals (i.e. predicting expected 95% confidence limits based on a previous measurement), and correspondingly for the cerebroplacental ratio (n = 550). The reference ranges were at some variance with those of previous cross-sectional studies. The narrow 95% confidence limits for the 5(th) and 95(th) percentiles ensured reliable ranges.

CONCLUSIONS

We have established longitudinal reference ranges appropriate for the serial assessment of MCA blood velocities and PI and cerebroplacental ratio. Particularly the terms for calculating conditional ranges based on a previous observation make this system more appropriate for longitudinal monitoring than are cross-sectional data.

Fetal middle cerebral to uterine artery pulsatility index ratios in normal and pre-eclamptic pregnancies

OBJECTIVES

To calculate the normal range for the fetal middle cerebral artery (MCA)/uterine artery pulsatility index (PI) ratio in the third trimester of pregnancy and to assess its value, compared with that of the MCA/umbilical artery PI ratio, in predicting an unfavorable outcome of pregnancies complicated by pre-eclampsia.

METHODS

Doppler blood flow velocimetry of the uterine and umbilical arteries and fetal MCA was performed. We calculated the ratios between 1) the PI of the MCA and the mean PI value of both uterine arteries and 2) the PI of the MCA and the PI of the umbilical artery. All women were examined at or beyond 26 weeks of gestation. A cross-sectional study of 231 normal pregnancies was conducted to construct the reference range. Values below the 5th percentile or an MCA/umbilical artery PI ratio lower than 1.08 were defined as brain-sparing. A further 115 pregnancies with pre-eclampsia (50 mild and 65 severe) were assessed prospectively and the results were related to perinatal outcome. The accuracy of MCA/uterine artery and MCA/umbilical artery PI ratios for prediction of unfavorable pregnancy outcome was compared.

RESULTS

Normal MCA/uterine artery PI ratios decreased with advancing gestational age. Redistribution of the fetal circulation indicated by a low MCA/uterine artery PI ratio was seen in 30% of the mild (n=15) and 46% of the severe (n=30) pre-eclamptic cases. There was a significant difference between those without and those with signs of brain-sparing, respectively, in mean birth weight (2456.0 vs. 1424.5 g), gestational age at delivery (35.6 vs. 31.3 weeks) and gestational age at the time of examination (34.9 vs. 30.9 weeks). Furthermore, there was a significantly higher rate of small-for-gestational-age (SGA) neonates (57.8% vs. 25.7%), preterm delivery (100% vs. 81.8%) and Cesarean section (90.7% vs. 66.7%) in cases with an MCA/uterine artery PI ratio below the 5th percentile. However, there was no difference between the groups in the rate of low 5-min Apgar scores, admission to the neonatal intensive care unit, or deliveries before 34 weeks. The MCA/uterine artery and MCA/umbilical artery PI ratios were similar in the prediction of adverse perinatal outcome. Both ratios were better at predicting the outcome of pregnancy than were signs of increased vascular impedance in either the umbilical or uterine arteries.

CONCLUSIONS

Normal MCA/uterine artery PI ratio decreases with gestational age. Abnormally low MCA/ uterine artery PI ratios are related to unfavorable pregnancy outcome. The predictive value of the MCA/uterine artery PI ratio is similar to that of the MCA/umbilical artery PI ratio.

Maternal serum activin A and the prediction of intrauterine growth restriction

BACKGROUND

Differentiating between the small healthy fetus and the high risk growth restricted fetus remains a significant obstetric challenge. It has been previously shown that maternal activin A levels are increased in association with fetal growth restriction.

AIM

To evaluate maternal serum activin A as a marker of fetal growth restriction.

METHODS

Prospective cohort study of 62 women referred for fetal assessment because of a clinical suspicion of a small for gestation fetus. Maternal serum levels of activin A were measured with an ELISA.

RESULTS

Activin A levels, expressed as median (95% CI) MoMs, were similar in the women with a normal-sized fetus and in those with a healthy small for gestational age fetus, 1.14 (95% CI 1.0-1.5) and 1.31 (95% CI 0.8-2.1), respectively (P = 0.97). Compared to the women with a normal-sized fetus or a healthy small fetus, activin A levels were significantly elevated in the women who had an intrauterine fetal growth restriction fetus 2.37 (95% CI 1.6-3.7; P = 0.01 compared to normal and P = 0.04 compared to healthy small).

CONCLUSIONS

These data confirm that circulating activin A is increased in association with fetal growth restriction. However, a single blood sample for activin A will not efficiently discern between healthy and compromised small fetuses.

The pathogenesis of gastrointestinal bacterial overgrowth

The normal indigenous intestinal microflora consists of about 10(15) bacteria that under physiological conditions reside mainly in the lower gastrointestinal tract. Bacterial overgrowth implies abnormal bacterial colonization of the upper gut, resulting from failure of specific defense mechanisms restricting colonization under physiological conditions. At present two types of bacterial overgrowth with defined pathogenesis can be distinguished: (1) gastric overgrowth with upper respiratory tract microflora resulting from selective failure of the gastric acid barrier, and (2) gastrointestinal overgrowth with Gram-negative bacilli (enteric bacteria) resulting from failure of intestinal clearance. Helicobacter pylori-induced gastritis of the oxyntic mucosa is the main cause of acquired failure of the gastric acid barrier, which is common among the healthy elderly. Intestinal clearance may fail as the result of impaired intestinal peristalsis or anatomical abnormalities that alter luminal flow. Impaired peristalsis is associated with conditions interfering with intestinal neuromuscular function including myopathic, neuropathic, autoimmune, infectious, inflammatory, metabolic, endocrine, and neoplastic diseases. Anatomical abnormalities are mainly the result of gastrointestinal surgery, intestinal diverticula or fistula. Combined failure of intestinal clearance and the gastric acid barrier results in more severe colonization with Gram-negative bacilli. Gram-negative bacilli are uncommon in the upper gut of otherwise healthy individuals with gastric hypochlorhydria, being acquired (H. pylori) or drug-induced. Significant bacterial overgrowth with Gram-negative bacilli is a rational in the search for an explanation to optimize clinical management. The clinical significance of colonization with upper respiratory tract microflora remains unclear. Translocation of live bacteria, their metabolic products, or antigens from a small bowel colonized by Gram-negative bacilli play a role in the pathogenesis of spontaneous bacterial peritonitis in hepatic disease and in certain types of sepsis, indicating that further studies can point to new patient populations with potential benefit from medical treatment.