Fetal MCA Research Articles

The effect of middle cerebral artery peak systolic velocity on prognosis in early and late-onset fetal growth restriction.

We aim to investigate the utility of middle cerebral artery peak systolic velocity (MCA PSV) Doppler in determining the perinatal mortality and morbidity in serial Doppler measurements from the time of diagnosis to the delivery of complicated cases with fetal growth restriction (FGR). At 24-38weeks of gestation, 65 pregnant women diagnosed with FGR were included in the study. The fetal biometry measurements, MCA pulsatility index (PI), and MCA PSV Doppler evaluation of the cases formed at the diagnosis and the delivery were recorded. Gestational weeks, birth weights, APGAR scores, cord pH values, NICU (neonatal intensive care unit) admission, NICU duration of stay, and perinatal morbidity parameters such as RDS (respiratory distress syndrome), BPD (bronchopulmonary dysplasia), NEC (necrotizing enterocolitis), sepsis and perinatal mortality were compared. The patients were divided into two groups: early and late-onset fetal growth restriction. Perinatal morbidity and mortality were accepted as adverse perinatal outcomes. MCA PSV above the 95th percentile at the diagnosis and delivery time was seen at a significantly higher rate with adverse perinatal outcomes. This study shows that evaluating MCA PSV with Doppler can be a helpful diagnostic method for early diagnosis of restriction and hypoxic fetuses. Also, it may be used in clinics as a noninvasive method to predict neonatal prognosis.

Retrospective study for correlation of fetal middle cerebral artery PSV and fetal anemia using newborn hemoglobin and blood indices

To establish relation between fetal MCA’s PSV in 3rd trimester and fetal anemia as non-invasive method. The study was done retrospectively, including 40 pregnant women who had raised PSV of MCA (Multiple of Median(MoM) >1.5) blood flow in third trimester and was correlated with the new born’s Hemoglobin and Blood indices (MCV and MCH). Forty fetuses who had MCA’s PSV more than 1.5 MoM(coming out to be around 66.50 ± 12.35 cm/seconds), after delivery, blood samples of these 40 neonate were taken, of which 37 were anemic based on hemoglobin and blood indices using reference range from study done by kumar et al8. Sensitivity was 92.5% and specificity around 88 %. Doppler spectral analysis of PSV of MCA is very reliable for predicting fetal anemia. MoM of PSV of Fetal MCA correlates very well with MoM of Neonatal Hemoglobin . Thus, fetal MCA’s PSV is very potential to replace invasive method for diagnosis of fetal anemia.

Effect of Color Doppler Indices on the Diagnosis of Intrauterine Growth Restriction in High-Risk Pregnancies: A Cross-Sectional Study

Aim: To assess the effect of Color Doppler indices on intrauterine growth restriction diagnosis in high-risk pregnancies Study design: Across-sectional study Place and duration: This study was conducted at Al Shifa Hospital Quetta, Pakistan. from January 2020 to July 2020. Methodology: In this study, 100 patients with suspected intrauterine growth restriction (IUGR) in their 31 to 41 weeks of pregnancy have participated. The patients were studied till the babies were delivered. The Doppler indices and the grayscale results were correlated to the baby's weight. Result: The HC/AC ratio was found to be sensitive (84.4%). Whereas the most specific was oligohydramnios and C/U ratio that was 100% and 68.8% respectively. The lowest sensitivity was of the fetal MCA, which was 7.7%. Conclusion: For the diagnosis of IUGR, the highest specific parameter is oligohydramnios and the HC/AC ratio is very sensitive. However, the MCA PI should not be utilized for screening purposes in IUGR because it has very low sensitivity alone. C/U ratio is notably more specific than HC/AC ratio and more sensitive than oligohydramnios. It is the most appropriate parameter to use for the diagnosis of IUGR in the 3rd trimester. Keywords: IUGR,Fetal Doppler, Placentation and IUGR, C/U pulsatility ratio, Small for gestational age

Role of Antenatal Dexamethasone Administration on Fetal Doppler Velocimetry

Aim: The aim of this study was assess the change in fetal and uteroplacental circulation followingantenatal dexamethasone administration to high-risk of preterm labor pregnant women.Patients and Methods: Prospective study was conducted between January and May 2021 in Tikrit cityat Salahadeen General Hospital /genecology and obstetrics department The study included 30 pregnantwomen with high risk of preterm labor with gestational age from 24 to 34 weeks. Doppler Study wereperformed just before dexamethasone administration and will be repeated 24 h after completion of thedexamethasone course.Results: The study showed the highest means of Fetal MCA pulsitility index. levels were recordedin women who at risk of preterm uterine contractions, placenta previa and pre-eclampsia respectivelybefore dexamethasone administration as compared with the same groups at 24 hour after dexamethasoneadministration (P<0.05). The study showed the highest means of Fetal MCA resistive index levels wererecorded in women with preterm uterine contractions, placenta previa and pre-eclampsia respectivelybefore dexamethasone administration as compared with the same groups 24 hour after dexamethasoneadministration (P<0.05). The study showed the highest means of Uterine artery pulsitility index.levels were observed in women with preterm uterine contractions, placenta previa and pre-eclampsiarespectively before dexamethasone administration as compared with the same groups 24 hour afterdexamethasone administration.

Colour Doppler study of Fetomaternal and uteroplacental circulation in pregnancy induced hypertension and/or oligohydramnios

Purpose: To study the fetoplacental and uteroplacental circulation by evaluating uterine artery, umbilical artery and fetal MCA using color Doppler in hypertensive disorders of pregnancy and oligohydramnios in second and third trimester with comparing different parameters.Methodology: Total 62 antenatal patients in their second or third trimester, who were clinically diagnosed as having pregnancy-induced hypertension or oligohydramnios by department of obstetrics had been recruited. Color Doppler study of umbilical artery, uterine artery and fetal MCA was performed with measurement of umbilical artery PI and SV/DV ratio, MCA PI and SV/DV ratio, uterine artery RI and SV/DV ratio and CPR.At last, color Doppler prediction was correlated with fetal outcome.Results: Out of 62 patients, 27 had PIH, 14 had associated oligohydramnios with PIH and 21 had oligohydramnios. 56% patients with PIH and 47% patients with oligohydramnios had adverse fetal outcome. The percentages of abnormal parameters of uterine artery, umbilical artery and MCA in PIH patients were 61%, 46% and 51% respectively. The sensitivity and specificity for detecting fetal distress was 70% and 81%, 70% and 87% and 67% and 86% for uterine artery, umbilical artery and fetal MCA respectively. CPR was 100% sensitive and 92.3% specific in detecting severe fetal distress.Conclusion: Chances of fetal compromise inutero are high in PIH patients, also significant number of oligohydramnios patients show adverse fetal outcome. Color Doppler study of fetoplacental and uteroplacental circulation proved a useful and noninvasive technique in determining hypoxic fetus and planning timely management of delivery before severe hypoxic injury to fetus occurs. Uterine artery and umbilical artery are more sensitive followed by MCA in diagnosing fetal distress.

Clinical implications of dexamethasone administration on Doppler indices of umbilical and middle cerebral arteries in preterm fetuses

BackgroundMaternal administration of dexamethasone is essential to improve fetal lung surfactant production and hasten the fetal lung maturity in women at risk for preterm birth. Umbilical and fetal middle cerebral arteries' (MCAs) Doppler indices are important to evaluate the effects of dexamethason on fetal and uteroplacental circulation in pregnancies at risk for preterm birth.ObjectiveThe aim was to evaluate the effects of maternal dexamethasone administration on umbilical and fetal MCAs Doppler indices (Resistance index (RI), Pulsalitility index (PI), and S/D ratio) in singleton pregnancies considered at risk for preterm delivery.Patients and methodsA total of 100 women were included in this study. They were at risk of preterm labor and were divided in two groups: 50 participants who took dexamethasone as a study group and 50 participants did not take dexamethasone as a control group. Doppler examination of umbilical and MCAs was performed, and comparisons between values of study group and control group were done after 0, 1, 4, and 7 weeks of dexamethasone administration.ResultsThe authors found a significant change in the mean values of the pulsatility and resistive indices and systolic-diastolic ratios of study group in umbilical artery and fetal MCA after 1 week after dexamethasone administration.ConclusionAdministration of dexamethasone improves Doppler indices and biophysical profile and decreases NICU admission. In healthy fetuses, a transient, significant, and unexplained decrease in fetal MCA impedance occurs on the fourth day following maternal dexamethasone administration.

Magnesium Sulfate Effect on Fetal Umbilical Artery and Middle Cerebral Artery Doppler Indicies in Women with Severe Preeclampsia and Eclampsia

Objective: To study MgSO4 effect on fetal MCA and UA blood flow changes using Doppler ultrasound in cases of severe PET and eclampsia. Materials and Methods: A total of 40 patients with severe PET admitted to El-Shatby Maternity University Hospital, Alexandria (Egypt) were examined before and after administration of MgSO4 using Doppler study to measure fetal MCA and UA blood flow changes. Results: After administration of MgSO4, the mean RI of UA, PI of UA showed a statistically significant decrease (P The C/U (cerebroumblical) ratio increased after the treatment (P Conclusions: Infusion of MgSO4 significantly decreases the fetal RI, PI, SDR umbilical and increases the fetal RI, PI, SDR MCA and increases cerebroumblical ratio indices obtained by Doppler examinations.

Is fetal middle cerebral artery peak systolic velocity correlated with hemoglobin levels in cases of nonimmune fetal anemia?

Objectives To establish whether a correlation exists between the fetal middle cerebral artery peak systolic velocity (MCA PSV) and fetal hemoglobin levels before intrauterine transfusion (IUT) in cases of severe fetal anemia. Methods This was a single-center, retrospective study of data from 49 fetuses treated with IUT for fetal anemia between 2003 and 2018. Severe fetal anemia was suspected when MCA PSV was or exceeded 1.55 multiples of the median. Results The causes of anemia were largely idiopathic, and the overall survival rate was 57%. MCA PSV and hemoglobin were correlated in all 34 fetuses with alloimmune fetal anemia, whereas the 15 fetuses with nonimmune causes showed no correlation. Of the 15 noncorrelated cases, twin pregnancy was most common, followed by idiopathic causes. All the twin pregnancies involved monochorionic twins. Fetal hydrops, especially ascites, was significantly associated with severe anemia. Conclusions Fetal MCA PSV may not be a reliable independent factor for the diagnosis of severe fetal anemia in nonimmune cases, and the presence of associated hydrops implies that the fetus is more likely to have severe fetal anemia than in a fetus without hydrops.

Cerebro-Umbilical Ratio at 30-34 weeks Gestation as A Prognostic Parameter for Pregnancy and Adverse Neonatal Outcomes

Fetal cerebral dissemination normally shows a high opposition example of stream in the MCA. There is a typical physiologic reaction of MCA enlargement in babies presented to intense or ceaseless hypoxia, bringing about a reductionin fetal MCA PI. Umbilical corridor and center cerebral conduit Doppler ultrasound unmistakably delineate the data about placental obstruction and the adjustments in the fetal hemodynamics in light of it. The cerebral-umbilical proportion stays steady during the most recent 10 weeks of incubation and gives preferred symptomatic precision over either vessels pulsatility list (PI) alone. The current examination is forthcoming associate investigation which was completed at Benha University Hospital (outpatient center). The investigation included 90 pregnant ladies at 30-multi week incubation introduced for antenatal consideration and afterward followed till conveyance. There are factually huge relations between CUR level and gestational age, nearness of comorbid diabetes and hypertension, method of conveyance, APGAR score and NICU affirmation. There is measurably critical positive relationship among's CUR and both maternal age and APGAR score. The best cutoff of CUR in expectation of nonattendance of requirement for crisis CS is ≥ 0.94. Additionally, the best cutoff of CUR in expectation of nonappearance of requirement for NICU affirmation is ≥1.0075. Mutt is prescient of expanded obstetric intercession rates and unfriendly perinatal and neonatal results and might be helpful in certain high danger gatherings. Cerebro_umbilical proportion shows high exactness in contrast with center cerebral supply route and umbilical conduit Doppler alone so it is proficient test for anticipation and mediation.

An effect of maternal nifedipine therapy on fetoplacental blood flow: a prospective study.

The aim of this study is to assess the effects of maternal nifedipine administration on placental and fetal blood flow. A total of 29 patients with preterm labor diagnosis admitted to the tertiary care center, Zeynep Kamil Hospital, were evaluated. Before and 24-48h after administration of oral nifedipine, Doppler ultrasound scan was carried out to measure fetal middle cerebral artery, ductus venosus, umbilical artery, and maternal uterine artery blood flow. After 24 and 48h of therapy, there were no changes in mean PI and RI in the umbilical arteries and ductus venosus (p > 0.05). Fetal middle cerebral artery and maternal uterine artery PI and RI values showed a significant reduction 24-48h after oral nifedipine therapy (p < 0.05). Our study showed that 24 and 48h after oral nifedipine therapy, there is a significant increase in fetal MCA and maternal uterine artery blood flow, while fetal umbilical artery and ductus venosus Doppler values do not change.

EP20.04: Diagnostic indices of MCA PSV for fetal severe anemia in MCDA twin pregnancy

To examine the diagnostic indices of fetal middle cerebral artery peak systolic velocity (MCA PSV) above 1.55 multiples of the median(MoM) Doppler velocimetry for the identification of fetal severe anemia in monochorionic diamniotic (MCDA) twin pregnancies. Study population consisted of 178 MCDA twin fetuses who underwent MCA PSV Doppler velocimetry within 7 days of delivery between gestational age (GA) of 24 and 38 weeks at Seoul National University Hospital between 2005 and February 2017. Fetuses with chromosomal abnormalities, major congenital anomalies or intrauterine demise were excluded. We examined the frequency of severe fetal anemia according to the presence of an increased fetal MCA PSV (≥1.55 MoM). Severe anemia was defined in the presence of hemoglobin concentration < 0.55 MoM in umbilical cord blood at the time of delivery. An increased MCA PSV (≥1.55 MoM) was present in 8.4% of study population and severe anemia was present in 2.2%. Diagnostic indices of an increased MCA PSV (≥1.55 MoM) for the identification of severe anemia were as follows: sensitivity 100% (4/4), specificity 93.7% (163/14), positive predictive value (PPV) 26.7% (4/15) and negative predictive value 100% (163/163). However, PPV at GA 30 weeks or more was only 12.5%, while that at GA less than 30 weeks was 42.9%. The sensitivity and specificity of an increased MCA PSV (≥1.55 MoM) for the identification of severe anemia in MCDA twin pregnancies are very high. However, PPV of that is much lower in cases with GA 30 weeks or more than in those with GA less than less than 30 weeks among MCDA twin pregnancies. EP20.04: Table 1. Middle cerebral artery peak systolic velocity (MCA PSV) Doppler velocimetry in the prediction of fetal severe anemia

Can middle cerebral artery peak systolic velocity predict polycythemia in monochorionic-diamniotic twins? Evidence from a prospective cohort study.

The antenatal diagnosis of twin anemia-polycythemia sequence (TAPS) in monochorionic-diamniotic (MCDA) twin pregnancies is based on elevated peak systolic velocity in the middle cerebral artery (MCA-PSV) in the donor twin and decreased MCA-PSV in the recipient twin. However, the association between these parameters and polycythemia has not yet been established. The aim of this study was to determine whether MCA-PSV can predict polycythemia in MCDA pregnancies. This was a prospective cohort study of MCDA pregnancies recruited at 14-18 weeks' gestation from a single tertiary care center between January 2011 and June 2014. Fetal MCA Doppler waveforms were recorded every 2 weeks from 18 weeks' gestation until delivery. Only those with an MCA-PSV measurement within 1 week of delivery were included in the analysis. Neonatal hematocrit level was determined in all twins from venous blood obtained within 4 h of delivery. Polycythemia was defined as a hematocrit of > 65%, and anemia as a hematocrit of < 45%. TAPS was diagnosed when an intertwin hemoglobin difference of > 8 g/dL and reticulocyte count ratio of > 1.7 were observed. Of 162 MCDA pregnancies followed during the study period, 69 had an MCA-PSV measurement within 1 week of delivery and were included in the study. Twenty-five neonates were diagnosed with polycythemia and nine twin pairs met the criteria for TAPS. In a pooled analysis, MCA-PSV was negatively correlated with neonatal hematocrit (P = 0.017, r = -0.215) and was significantly higher in anemic fetuses than in normal controls (1.15 multiples of the median (MoM) vs 1.02 MoM, respectively; P = 0.001). However, MCA-PSV was similar among polycythemic and normal fetuses (0.95 MoM vs 1.02 MoM, respectively; P = 0.47). Intertwin difference in MCA-PSV (delta MCA-PSV) was positively correlated with intertwin hematocrit difference (P = 0.002, r = 0.394). Moreover, twin pregnancies with an intertwin hematocrit difference of > 24% had a significantly greater delta MCA-PSV than did those with an intertwin hematocrit difference of ≤ 24% (delta MCA-PSV, 19 vs 5 cm/s; P < 0.001). MCA-PSV is not significantly decreased in polycythemic MCDA twins. However, delta MCA-PSV is associated with a large intertwin difference in hematocrit, and its use may be better than conventional methods for the risk assessment of TAPS. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Doppler velocimetry and adverse outcome in labor induction for late IUGR

Background: Late onset intrauterine growth restriction (IUGR) represents one of the main causes of perinatal morbidity/mortality. No guidelines are available on labor induction in IUGRs, even if delivery at 37/38 weeks is suggested. This study aims to assess maternal–fetal variables related to adverse outcome in labor induction for late IUGR.Methods: One hundred cases of induction for late IUGR were retrospectively revised on fetal weight, MCA, UA, CPR and uterine artery (utA) Doppler, oligohydramnios, Bishop score, start of induction, augmentation. The variables were matched with the following adverse outcomes: CS or vacuum extractor delivery (IVD); NICU admission; low Apgar score; UA pH < 7.10.Results: Regular vaginal delivery occurred in 65% of cases; the rate of CS and IVD was 32% and 5%. UA, MCA and CPR abnormalities were all significantly related to a higher risk of CS. Bishop score < 3 and start of induction by oxitocin resulted statistically associated to CS, while prostaglandins were related to vaginal delivery. No augmentation and oxitocin in labor were positively related to vaginal delivery. Maternal morbidity and Bishop score < 3 showed a significant association with NICU admission.Discussion: Doppler velocimetry of UA, MCA and CPR are useful tools for the identification and management of the late term IUGRs.

The Impact of Type, Dosage and Time of Prenatal Steroid Administration on Neonatal Outcome

Background: In 1972, Liggins and Howie demonstrated that antenatal steroid administration reduced the incidence of respiratory distress syndrome and perinatal mortality in neonates. Since the publication of these findings, perinatal and long-term results of steroid therapy have been evaluated in numerous studies. The aim of the study was to compare the impact of prenatal steroid dosage on perinatal outcomes in neonates and in mothers. Summary: Although the results of the studies are ambiguous, one should consider the potential benefits of dexamethasone in cases of risk of preterm delivery due to abnormalities in fetal health assessments. Dexamethasone may also lead to better results when preterm neonates are burdened with cardiovascular defects or diseases. The opposite holds true for abnormal flows within UA or fetal MCA, i.e., one should consider whether betamethasone is the appropriate drug of choice. Steroid treatment after 34 weeks of gestation is not beneficial. Administration of the full course of steroid treatment (24 mg) in lower single doses is probably more favorable for the mother. On the other hand, a shorter time interval between the doses may allow more women in preterm birth to receive the full course of steroids. Further studies are required to answer these questions, and better methods for predicting preterm birth should be determined.

OP06.04: Minor bleeding events during fetoscopic surgery for spina bifida aperta result in small but hemodynamically not significant increases of fetal MCA peak velocity

OP06.04: Minor bleeding events during fetoscopic surgery for spina bifida aperta result in small but hemodynamically not significant increases of fetal MCA peak velocity

Inter-observer variability in assessment of fetal MCA PSV doppler in a tertiary imaging unit

Inter-observer variability in assessment of fetal MCA PSV doppler in a tertiary imaging unit

Discordant Fetal Infection for Parvovirus B19 in a Dichorionic Twin Pregnancy

There are only a few reports of fetal parvovirus infection in the circumstance of a twin pregnancy. We report a case of differential fetal infection following maternal parvovirus B19 infection in a dichorionic twin pregnancy culminating in a dual live-birth. A 32-year-old woman was diagnosed with parvovirus infection following exposure to her infected child at 19 weeks' gestation in a dichorionic twin gestation. Maternal IgG seroconversion was documented and maternal blood parvovirus B19 DNA was detected by PCR testing. Fetal monitoring with serial ultrasound assessment was instituted. At 25 weeks' gestation Twin I (male) displayed minor ascites, small pericardial effusion, placentomegaly and oligohydramnios. Middle cerebral artery peak systolic velocity (MCA PSV) studies were abnormal. Twin II (female) was sonographically unremarkable. A single fetal intravascular transfusion for Twin I was performed (pretransfusion Hb 80 g/L). Twin I fetal blood parvovirus B19 DNA was detected by polymerase chain reaction (PCR) and serum demonstrated both B19 IgG and IgM. Following fetal transfusion the hydrops resolved, although the placentomegaly persisted. Two live infants were delivered at 37 weeks' gestation. Individual neonatal venepuncture detected B19 DNA by PCR in Twin I but not in Twin II. B19 IgM was present in Twin I but not Twin II. Both neonates had B19 IgG antibodies. Placental histopathology demonstrated mild edema for Twin I but no inclusion cells. The placenta of Twin II was unremarkable. This case demonstrates the ability for differential transplacental infection of this virus and the assistance of fetal MCA flow studies to guide therapy in a multiple pregnancy at risk of parvovirus infection.

Discordant Fetal Infection for Parvovirus B19 in a Dichorionic Twin Pregnancy

AbstractThere are only a few reports of fetal parvovirus infection in the circumstance of a twin pregnancy. We report a case of differential fetal infection following maternal parvovirus B19 infection in a dichorionic twin pregnancy culminating in a dual live-birth. A 32-year-old woman was diagnosed with parvovirus infection following exposure to her infected child at 19 weeks' gestation in a dichorionic twin gestation. Maternal IgG seroconversion was documented and maternal blood parvovirus B19 DNA was detected by PCR testing. Fetal monitoring with serial ultrasound assessment was instituted. At 25 weeks' gestation Twin I (male) displayed minor ascites, small pericardial effusion, placentomegaly and oligohydramnios. Middle cerebral artery peak systolic velocity (MCA PSV) studies were abnormal. Twin II (female) was sonographically unremarkable. A single fetal intravascular transfusion for Twin I was performed (pretransfusion Hb 80 g/L). Twin I fetal blood parvovirus B19 DNA was detected by polymerase chain reaction (PCR) and serum demonstrated both B19 IgG and IgM. Following fetal transfusion the hydrops resolved, although the placentomegaly persisted. Two live infants were delivered at 37 weeks' gestation. Individual neonatal venepuncture detected B19 DNA by PCR in Twin I but not in Twin II. B19 IgM was present in Twin I but not Twin II. Both neonates had B19 IgG antibodies. Placental histopathology demonstrated mild edema for Twin I but no inclusion cells. The placenta of Twin II was unremarkable. This case demonstrates the ability for differential transplacental infection of this virus and the assistance of fetal MCA flow studies to guide therapy in a multiple pregnancy at risk of parvovirus infection.

P05.18: Doppler velocimetry in M1 and M2 segments of middle cerebral artery in pregnancies complicated by intrauterine growth restriction

The aim of the study was to evaluate the prognostic value of the examination of PI of two segments of MCA in the prediction of hypoxia in normal and growth-restricted fetuses. Doppler examination was performed in 98 normal and 64 growth-restricted fetuses between 26 and 42 weeks of gestation. The standard curves of PI in different sections of fetal MCA: initial segment (M1) and subcortical segment (M2) were established. Prognostic values of abnormal PI were calculated. There are significant differences in PI values in normal pregnancy and pregnancy complicated by intrauterine growth restriction with hypoxia, especially in M2 segment. The prognostic values of abnormal M2 PI in prediction of fetal hypoxia were: sensitivity and positive predictive value of birthweight below 10 centile, 60 and 89%, respectively; sensitivity and negative predictive value of admission to NICU, 78 and 85%, respectively; and sensitivity and negative predictive value of artificial ventilation, 89 and93%, respectively. There were found low sensitivity and positive predictive value of pH and BE in umbilical artery, with high specificity and negative predictive value, 82 and 85%, 82 and 95%, respectively. Specificity and negative predictive value of pH and BE in umbilical vein, also were high, 85 and 89%, 84 and 100%, respectively. PI of M2 segments of the MCA seems to be a good predictor of fetal hypoxia during the second half of pregnancy complicated by growth restriction.

Fetal cerebral Doppler in the recognition of fetal compromise.

To establish reference ranges for the human fetal middle cerebral artery pulsatility index (MCA PI) for the local obstetric population, and to compare computerised antenatal fetal heart rate (FHR) analysis with the MCA PI as indicators of fetal compromise. Prospective data collection for selected patients. High risk pregnancy unit of a teaching hospital. Group 1 consisted of 18 healthy women with uncomplicated singleton pregnancies. Group 2 consisted of 27 women admitted to the high risk pregnancy unit over a 9 month period with intrauterine growth retardation and other related problems; all these women were delivered by prelabour caesarean section. Serial Duplex sonography to determine fetal MCA PI in Groups 1 and 2. Serial FHR analysis using computerised numerical techniques in Group 2 only. Serial MCA PI values from 24 to 39 completed weeks of gestation in Group 1. Comparison of serial MCA PI values with FHR analysis in relation to fetal outcome in Group 2. In Group 1 the MCA PI diminished significantly as gestation advanced from 1.73 (SD 0.25) at 24 weeks to 1.38 (SD 0.26) at 39 weeks (P < 0.01). In Group 2 eleven babies were hypoxaemic at delivery: all had low MCA PI values while only nine had an abnormal FHR prior to delivery. In normal pregnancy, there is a fall in the fetal MCA PI with advancing gestation which probably reflects a decreasing vascular resistance to fetal cerebral blood flow. Hypoxaemia at delivery appeared to be better recognised by the fetal MCA flow velocity waveform than the FHR analysis. This increased sensitivity, however, was achieved at the expense of a reduced specificity. Larger studies are needed to confirm the findings of this preliminary investigation.