Ultrasound measurement of the fetal head to abdomen circumference ratio in the assessment of growth retardation

Fetal biometry in the Brachmann-de Lange syndrome

The Brachmann-de Lange syndrome (BDLS) is diagnosed in children on the basis of a distinctive clinical phenotype which includes retarded physical growth. Because there are no genetic or biochemical tests at present, the antenatal detection of the syndrome may depend upon identification of some aspect of the phenotype in the fetus using ultrasound imaging. We studied the growth of 23 subsequently diagnosed fetuses with the BDLS using standard biometric parameters defined by prenatal ultrasound imaging. Sonographic studies were obtained through a national parents' group, the Cornelia de Lange Syndrome Foundation. Assessment of fetal growth was made using four standardized measurements: the biparietal diameter, head circumference, femur length, and abdominal circumference. These values were compared to established tables of normal fetal growth and established ratios of fetal body proportions. The cross-sectional growth curve derived using all measurements collected as a composite group indicates that growth retardation would be first detected as early as 25 weeks. In five fetuses with measurements both before and after 25 weeks of gestation, longitudinal growth curves indicated that the diagnosis of "small for gestational age" would have been suggested between 20 and 25 weeks. The mean fetal weight estimates closely followed the fifth centile curve of normal fetuses both before and after 25 weeks. Cephalic indices in BDLS fetuses indicated either frank brachycephaly (25%), or were at the upper portion of the normal range. Femur lengths were relatively short (less than 90% of their expected length) ion 4 of the 11 fetuses where such information could be obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Routine ultrasound surveillance of the pregnant uterus

The routine ultrasound examination of the pregnant uterus is presented in this article. The approach is based on published guidelines, dividing the examination into studies of the first trimester and studies of the second and third trimesters. The discussion emphasizes the standard anatomical views and describes the normal sonographic appearances. The methods of obtaining important measurements are described, and tables are provided to analyze these measurements. A systematic approach to obstetric ultrasound is important in ensuring completeness and in maximizing the detection of fetal abnormality.

Fetal growth retardation: associated malformations and chromosomal abnormalities

OBJECTIVE

Our objective was to determine the incidence and pattern of chromosomal abnormalities in fetal growth retardation.

STUDY DESIGN

Blood karyotyping was performed in 458 fetuses referred to us for further assessment of growth retardation at 17 to 39 weeks' gestation.

RESULTS

The fetal karyotype was normal in 369 and abnormal in 89 (19%) of the cases. The most common chromosomal defect in the group referred at < 26 weeks' gestation was triploidy; in those referred at > or = 26 weeks, it was trisomy 18. The incidence of fetal autosomal chromosome aberrations increased, whereas the incidence of triploidy did not change, with maternal age. Ninety-six percent of chromosomally abnormal fetuses had multisystem fetal defects that were characteristic of the different types of chromosomal abnormalities. Compared with those fetuses with a normal karyotype, the chromosomally abnormal group had a higher mean head circumference/abdominal circumference ratio, a higher incidence of normal or increased amniotic fluid volume, and normal waveforms from the uterine or umbilical arteries or both.

CONCLUSION

The findings of the different types of chromosomal abnormalities and their ultrasonographically detectable phenotypic expression provide the background for prospective studies to determine the incidence of chromosomal abnormalities in unselected populations of small-for-gestational-age fetuses.

Effects of methyldopa on uteroplacental and fetal hemodynamics in pregnancy-induced hypertension

OBJECTIVE

Our purpose was to study the effect of methyldopa on uteroplacental and fetal hemodynamics in women with pregnancy-induced hypertension.

STUDY DESIGN

A prospective study of Doppler ultrasonographic blood flow data before and after 1 week of methyldopa treatment was conducted at the Department of Obstetrics and Gynecology, National University Hospital, Singapore, in 20 women (mean 35 weeks' gestation) with pregnancy-induced hypertension. The main outcome measures were maternal blood pressure, maternal and fetal heart rate, and blood velocity waveforms characterized by the pulsatility index in the fetal ascending aorta, middle cerebral artery, umbilical artery, and maternal uterine and arcuate arteries. Statistical evaluation was performed with t tests for paired observations.

RESULTS

Maternal mean arterial blood pressure was reduced 9.7 mm Hg (95% confidence interval -13.8 to -5.6), and mean heart rate decreased 6.3 beats/min (95% confidence interval -11.1 to -1.4). Mean pulsatility index in the uterine (0.93 to 0.92) and arcuate arteries (0.61 to 0.73) were unchanged after treatment. Fetal hemodynamic changes before and after treatment were not significant. Fetal and neonatal outcome was uneventful.

CONCLUSION

Short-term treatment with methyldopa in the last trimester in women with pregnancy-induced hypertension reduced maternal blood pressure and heart rate but had no adverse effects on uteroplacental and fetal hemodynamics.

Judging fetal growth from body proportions at birth

Fetal growth velocity from 27 weeks until birth was calculated in 378 infants born after high risk pregnancies from at least three ultrasound measurements of estimated fetal weight and the weight at birth. Anthropometric measurements at birth (weight, head circumference, length, ponderal index and skinfolds), after correction for differences in gestational age, were significantly related to fetal growth velocity. The relation between fetal growth velocity and ponderal index was significant (correlation coefficient = 0.34, P < 0.001). However, the correlations between fetal growth velocity and each of the anthropometric measures disappeared when birth weight relative to gestational age was accounted for. This means that given the birth weight and the gestational age of a newborn infant, body proportions, e.g. ponderal index or skinfold thickness, do not contribute further to the judgment about fetal growth rate.

Transvaginal sonography for fetal measurement in early pregnancy

OBJECTIVE

To establish reference ranges for fetal size by gestation in the first trimester as indicated by cephalic, abdominal and limb measurements using transvaginal sonography.

DESIGN

A prospective descriptive study.

SETTING

Two antenatal clinics in Milan, Italy.

SUBJECTS

270 women with normal singleton pregnancies at 42-108 days gestation. All had regular cycles and certain dates.

INTERVENTIONS

Vaginal ultrasound examination including inspection of fetal structures and lasting 5-15 min.

MAIN OUTCOME MEASURES

As many of the following fetal measurements as possible according to gestational age and ease: crown-rump length (CRL), biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur and foot lengths.

RESULTS

CRL was measured in 183 fetuses, BPD in 201, HC in 162, AC in 160, femur length in 133 and foot length in 62. The best description of the relation of CRL to gestational age was achieved by a quadratic function (y = -3.98 - 0.308x + 0.0117x2). Mean values thus derived were virtually identical to those obtained by Robinson & Fleming in 1975 with transabdominal static scanning. Fetal BPD, HC, AC and femur length correlated more closely with CRL than gestational age. Reference ranges (mean and 95% data intervals) were constructed for each biometrical measurement in relation to gestational age and CRL. The HC/AC and femur/foot length ratios did not show any significant variation with gestational age or CRL.

CONCLUSIONS

These data may be useful in the early detection of genetic disorders affecting the growth of fetal head, trunk and limbs. Genetic and/or environmental variables play an appreciable role in the modulation of early fetal growth.

Numeric analysis of heart rate variation in intrauterine growth-retarded fetuses: a longitudinal study

OBJECTIVE

We attempted to determine changes occurring with time in fetal heart rate and its variation in fetuses with intrauterine growth retardation in whom late antepartum fetal heart rate decelerations eventually develop.

STUDY DESIGN

Thirteen fetuses with intrauterine growth retardation were studied over a median period of 25 days. One-hour fetal heart rate records were made two to five times per week and were analyzed numerically. Fetal movements were recorded by the women.

RESULTS

On average long-term fetal heart rate variation decreased gradually with time and fell below the norm (30 milliseconds) at about the same time decelerations appeared. Mean heart rate showed a slight but statistically significant increase after the occurrence of decelerations. There were large interfetal differences in all parameters studied.

CONCLUSION

In fetuses with intrauterine growth retardation a decrease in long-term fetal heart rate variation is a rather late sign of impairment that coincides with the occurrence of late decelerations. In the surveillance of the fetus with intrauterine growth retardation it might be most appropriate to use each fetus as its own control.

Antenatal diagnosis of intrauterine growth retardation by ultrasound

Ultrasound estimation of fetal weight or ultrasound measurement of fetal abdomen alone enables identification of small-for-gestational-age fetuses. A prerequisite for this is a reliable dating of pregnancy, which is provided by a routine ultrasound screening in the first half of gestation. The fetal growth can be followed by serial fetometric measurements. As a standard, charts of intrauterine growth based on the ultrasonic measurement can be used. As a secondary diagnostic test for monitoring fetal health in pregnancies suspected of intrauterine growth retardation, Doppler ultrasound evaluation of fetal and uteroplacental hemodynamics provided useful for early detection of imminent fetal distress.

Transverse cerebellar diameter: a useful predictor of gestational age for fetuses with asymmetric growth retardation

There have been conflicting reports regarding the ability of cerebellar diameter to satisfactorily predict the gestational age of growth-retarded fetuses. Gestational age prediction intervals were derived from 270 normal fetuses between 14 and 40 weeks' gestation for biparietal diameter, head circumference, abdominal circumference, femur length, and transverse cerebellar diameter. We evaluated the ability of these parameters to predict gestational age for 19 small-for-gestational-age fetuses. The cerebellar diameter regression model led to the smallest differences between observed and predicted gestational age for all growth-retarded fetuses. Transverse cerebellar diameter satisfactorily predicted gestational age for all six fetuses with asymmetric intrauterine growth retardation and was associated with the least amount of underestimation bias when compared with other ultrasonographic parameters. However, transverse cerebellar diameter appeared to be no better than biparietal diameter, head circumference, or femur length for accurately predicting gestational age of fetuses with symmetric intrauterine growth retardation (n = 13) despite the finding that cerebellar growth was also relatively spared under these circumstances. We conclude that transverse cerebellar diameter can be used to reliably approximate gestational age in fetuses with asymmetric intrauterine growth retardation. However, caution is warranted when using it to predict the gestational age of fetuses affected by symmetric intrauterine growth retardation.

Absent or reversed end diastolic flow velocity in the umbilical artery and necrotising enterocolitis

Absent or reversed end diastolic flow (AREDF) velocities in the umbilical artery were identified in 25 high risk pregnancies. In six pregnancies the fetus was abnormal and all but one of these ended in perinatal death. Of the 19 morphologically normal fetuses, three died in utero and there were four neonatal or infant deaths. The mortality rate was 48% for all pregnancies and 37% for those with morphologically normal fetuses. There was a highly significant increased risk for the development of necrotising enterocolitis in these morphologically normal fetuses with AREDF (53%) compared with controls (6%) who did have umbilical artery end diastolic flow velocities in fetal life. There were no significant differences between the matched pairs for parameters of neonatal outcome chosen to reflect neonatal morbidity. These findings demonstrate the close association between AREDF and necrotising enterocolitis that appears to be independent of other variables such as degree of growth retardation, prematurity, and perinatal asphyxia.

Obstetrical management of patients with diabetes in pregnancy

The management of the woman with diabetes diagnosed before the onset of pregnancy, or who develops it during pregnancy, requires a team approach involving the woman and her partner, the diabetes nurse educator, the dietitian, the endocrinologist, the obstetrician, the ultrasonologist and the paediatrician. It should start before pregnancy so that normoglycaemia is achieved before conception and maintained throughout gestation and labour. Fetoplacental surveillance commences with an early ultrasound to confirm fetal viability, repeated around 20 weeks to exclude major fetal malformations and then later in the third trimester to monitor fetal growth. CTG and biophysical profile assessment are major adjuncts to ensuring fetal well-being. The pregnancy should be allowed to go to full term when maternal blood glucose control has been satisfactory, fetal growth is within the normal range and other obstetrical complications, e.g. pre-eclampsia, are absent. Such an approach will ensure that the caesarean section rate can be minimized. During labour, the progress of labour and fetal well-being should be closely monitored. The woman who has microvascular complications of her diabetes (including proliferative retinopathy and nephropathy) requires even closer surveillance and premature delivery is more likely to be needed. The principles of management of the woman who develops gestational diabetes are similar, with even greater emphasis being placed on not inducing labour before full term unless complications dictate otherwise.

Head circumference/abdominal circumference ratio, ponderal index and fetal malnutrition. Should head circumference/abdominal circumference ratio be abandoned?

Head circumference/abdominal circumference (HC/AC) ratios of the fetus are accepted as a means of distinguishing different patterns of growth retardation with a high ratio implying malnutrition of the fetus. Ponderal index (birthweight/length3) is used by paediatricians as a measure of neonatal wasting and would therefore be expected to correlate with HC/AC ratios at delivery. Anthropometric data on 999 newborn infants have been collected and analyzed by multiple regression. The results show a poor correlation between ponderal index and HC/AC ratio, worse than that between ponderal index and AC alone. The use of HC/AC ratios antenatally to identify subgroups of intrauterine malnutrition should be abandoned. The prediction of intrauterine malnutrition by weight/length ratios should be investigated further.

Proportionality of small for gestational age babies as a predictor of neonatal mortality and morbidity

Neonatal mortality and morbidity of 2609 babies who weighed less than the fifth centile for gestational age were studied in order to evaluate the relationship between the type of intrauterine growth retardation and the short-term prognosis after birth. Of these babies, 1175 had both a birthweight and head circumference below the fifth centile ('proportionately small'); the others, whose body weight was below but head circumference above the fifth centile, were defined as 'disproportionately small'. The former group showed a consistently higher risk of death during the neonatal period. Morbidity defined by birth asphyxia, respiratory distress and neonatal infections was higher in those proportionately small babies who were delivered at term. The picture reversed for hyperbilirubinaemia, which was more frequent among disproportionately small babies. Proportionality, defined on the basis of the correspondence between birthweight and head circumference centiles, appears to be a simple and non-invasive clinical method to identify babies who are at higher risk of adverse outcome.

Reliability of ultrasonographic formulary in the prediction of fetal weight and survival of very-low-birth-weight infants

Antenatal management of very-low-birth-weight infants often requires difficult obstetric decisions. This study was designed to evaluate the predictive value for neonatal outcome of antenatally acquired estimation of gestational age and ultrasonographically estimated fetal weight or a combination of both in very-low-birth-weight infants. Sixty-seven fetuses with estimated gestational ages between 22 0/7 and 28 6/7 weeks were studied ultrasonographically to estimate fetal weight. A comparison of accuracy of estimated fetal weight with actual birth weight showed good correlation (r = 0.93). Neonatal outcome of these infants was analyzed by estimated gestational age and estimated fetal weight. Estimated gestational age and estimated fetal weight greater than 25 weeks and greater than 750 gm were associated with 50% survival, respectively. However, when both of these conditions were met survival reached 85%. This information may be useful to guide antepartum management decisions in this very-low-birth-weight group.

Limited role of fetal blood sampling in prediction of outcome in intrauterine growth retardation

Fetal acid-base status was evaluated on 66 blood samples taken for rapid karyotyping from 58 growth-retarded fetuses. Before blood sampling, doppler blood flow studies of the umbilical artery showed end-diastolic frequencies to be absent in 32 fetuses (group 1) and present in 26 (group 2). Fetuses with chromosomal (n = 4) or structural (n = 8) abnormalities were excluded from subsequent analysis. Gestational age at blood sampling (27.8 [95% CI 26.5-29.1] vs 32.2 [30.4-34.1] weeks) and time from sampling to delivery (median 2 (range 0-35] vs 14 [0-77] days) were significantly lower in group 1 than group 2. There were no perinatal deaths in group 2 whereas mortality in group 1 was 65.4%. There were significant differences between the groups at blood sampling in pH, pO2, pCO2, base equivalents, and nucleated-red-cell count, but within group 1 these measurements were similar in surviving fetuses and those who died perinatally. Since acid-base determination does not predict perinatal outcome in growth-retarded fetuses, fetal blood sampling has a limited role in monitoring fetal wellbeing.

Early Doppler ultrasound screening in prediction of hypertensive disorders of pregnancy

1198 nulliparous women were screened in early pregnancy (median 18 weeks' gestation) by the recording of doppler ultrasound waveforms from the uteroplacental circulation. After exclusions, the results of 1014 women were available for analysis; 118 (12%) of them had persistently abnormal waveforms on repeat ultrasound scans at 24 weeks and were taken to have a positive test result. Hypertension was significantly more frequent among those women than among women with normal doppler waveforms (29/118 [25%] vs 45/896 [5%]). In addition, hypertension in women with abnormal waveforms was more likely to be severe; 12 (10%) had proteinuria and 15 (13%) intrauterine growth retardation compared with 7 (0.8%) and 0, respectively, of those with normal waveforms. Overall, the test did poorly when assessed by standard statistical means. However, the sensitivity was high for hypertension associated with either proteinuria (63%) or intrauterine growth retardation (100%). The test is cheap, easy to carry out, and non-invasive, and it can be done in early pregnancy; it is therefore a useful means of identifying a high-risk group of pregnant women suitable for therapeutic intervention to reduce the incidence of hypertensive disorders and their complications.

Screening tests for intrauterine growth retardation: a comparison of umbilical artery Doppler to real-time ultrasound

In a study designed to compare Doppler umbilical artery velocimetry to ultrasound morphometric measurements in the prediction of intrauterine growth retardation, 636 paired ultrasound and Doppler umbilical artery examinations were performed between 24 and 40 weeks gestational age. Intrauterine growth retardation was defined as birth weight less than the tenth percentile per gestational age and 25 (9.2%) of the infants born in our study met this criteria. In general, when the gestational age was limited to less than 30 weeks, none of the tests were highly predictive of intrauterine growth retardation. Doppler umbilical artery systolic-to-diastolic ratios of greater than 3 had the highest sensitivity. However, due to inclusion of a large number of false-positives, it was considered a poor test. After 30 weeks, fetal abdominal circumference less than the tenth percentile had a greater sensitivity (45%) and positive predictive value (28%) than Doppler systolic-to-diastolic ratios greater than 3 (36% and 18%, respectively). Doppler ultrasound umbilical artery systolic-to-diastolic ratios are not more predictive of intrauterine growth retardation than ultrasound morphometric measurements.

Ratios between growth parameters for the prenatal ultrasonographic diagnosis of skeletal dysplasias

The clinical applicability and usefulness of nine ratios that express the relation between particular fetal growth parameters were tested in ten fetuses affected by skeletal dysplasia. The results were compared with the ratios calculated from five growth-retarded fetuses without structural anomalies. Femur/foot, femur/head circumference, head circumference/thoracic circumference and abdominal circumference/thoracic circumference ratios are useful additional parameters for the prenatal ultrasonographic diagnosis of skeletal dysplasias. They reduce the problem of an unknown gestational age and help to distinguish between fetal skeletal dysplasia and intra-uterine growth-retardation caused by other factors.

Umbilical flow waveforms versus fetal biophysical profile in hypertensive pregnancies

The pulsatility index (PI) of the umbilical arteries was measured in 40 hypertensive pregnancies. Doppler-velocimetric data were kept unknown to the clinical staff. An abnormal PI was found in 79% of cases in which an abnormal fetal growth in utero had been diagnosed by ultrasonographic measurements. Serial PI findings showed worsening figures in most of the cases with an abnormal fetal growth, irrespective of the last absolute value. Amniotic fluid estimation and PI data were significantly correlated. PI values were markedly abnormal in fetuses with non-reactive heart-rate tracings. A high sensitivity and an optimal specificity were found for umbilical PI versus the diagnosis of fetal growth retardation made by the coexistence of different biophysical criteria. However, false normal results may occur. 62% of the newborns weighed below the 5th percentile. The sensitivity of abnormal PI values to detect these light fetuses resulted to be only 67%. However the prevalence of neonatal morbidity in fetuses with abnormal PI values was 74%, while morbidity occurred only in 14% of cases with normal PI values. In hypertensive pregnancies, this simple velocimetric parameter proved to correlate with abnormal biophysical monitoring and complicated neonatal outcomes.

Ultrasonographic measurement of fetal femur length in growth disturbances

Ultrasonographic measurement of fetal femur length is a recognized technique for determination of gestational age and fetal growth. A total of 280 pregnant women were studied, each of whom had pathologies with the potential to either accelerate or delay fetal growth. There were 1000 measurements of the fetal femur length performed on these 280 fetuses. A total of 125 fetuses were found to have a growth disturbance-91 with asymmetrical intrauterine growth retardation and 34 with macrosomia. Comparison of fetuses with either intrauterine growth retardation or macrosomia with appropriate-for-gestational-age fetuses showed that the femur length is not statistically affected by intrauterine growth abnormalities.

A comparison of three methods of assessing inter-observer variation applied to ultrasonic fetal measurement in the third trimester

The inter-observer variation of fetal biparietal diameter, head circumference, abdominal circumference, and femoral length measured in the third trimester by ultrasound was studied by three different methods--coefficient of variation, correlation coefficient, and the 95% limits of agreement. The coefficients of variation were 1.6 to 3.7%, the correlation coefficients were 0.89 to 0.98 with P values of less than 0.001, yet the limits of agreement when applied to centile charts were found to be too wide to separate reliably small fetuses from those that were not small. We conclude that the limits of agreement is the preferred method of assessing inter-observer variation, and we suggest that future research into growth retardation move away from ultrasonic measurements of the fetus.

A comparison of fetal abdominal circumference measurements and Doppler ultrasound in the prediction of small-for-dates babies and fetal compromise

A total of 145 pregnancies clinically suspected of being small-for-dates was studied at presentation with a single measurement of the fetal abdominal circumference and Doppler studies of the umbilical and arcuate arteries. The abdominal circumference measurement gave the best prediction of the small-for-gestational-age (SGA) baby (sensitivity 73%, umbilical artery sensitivity 47%, arcuate artery sensitivity 29%). The umbilical artery measurement gave the best prediction of antenatal fetal compromise; the performance of the tests was compared for a fixed sensitivity of 100% (i.e. all cases of antenatal compromise would be detected), the specificity of the umbilical artery measurement was 77%, abdominal circumference measurement 12% and arcuate artery measurement 2%. In our data, umbilical artery studies were not a sensitive predictor of the SGA baby but they did give an accurate prediction of the potentially compromised SGA fetus.

Cerebral Doppler ultrasound of the human fetus

Maximal flow velocity waveforms were recorded in the internal carotid artery (ICA), middle cerebral artery (MCA), posterior cerebral artery (PCA) and anterior cerebral artery (ACA) in 55 normal pregnancies and 14 complicated by intrauterine growth retardation between 25 and 41 weeks gestation. In normal pregnancy, acceptable flow velocity waveforms were obtained in the ICA in 89%, in the MCA in 91%, in the PCA in 58% and in the ACA in 64%. A decrease in pulsatility was observed in all four intracranial arteries during the latter weeks of gestation. In growth-retarded pregnancies, pulsatility in all vessels was significantly reduced compared with normal pregnancy, suggesting participation of all major intracranial arteries in a brain-sparing effect in the presence of chronic fetal hypoxia.

Bari district birthweight study: comparison with the Bristol perinatal growth chart

We studied the neonatal weight distribution of 15,298 newborns from the Bari District at various gestational ages by the 10th, 50th, and 90th percentiles. After analysis, we constructed a growth chart following the method of Dunn. By comparing our results with those of Dunn's Bristol Perinatal Growth Chart, we found a weight difference of +4.5% in our population. This difference may be related to ethnic as well as socioeconomic factors.

Evidence of redistribution of cardiac output in asymmetrical growth retardation

Thirty-one fetuses with growth retardation were studied by Doppler estimation of the cardiac output from each side of the fetal heart. Asymmetrical growth retardation was diagnosed in 16 fetuses by a head to abdominal circumference ratio above the 95th centile. In the 15 fetuses with symmetrical growth retardation, the distribution of cardiac output was normal. The mean and maximum velocity of blood flow in the pulmonary artery and aorta were similar to values in normal fetuses, and there was a greater calculated output from the right heart than from the left. The right heart flow expressed as a percentage of the combined cardiac output was not statistically significantly different from that in normal fetuses. In contrast, all 16 fetuses with asymmetrical growth retardation had a higher mean and maximum velocity in the aorta than in the pulmonary artery. The calculated volume flow from each side of the heart showed a greater output from the left than the right heart in 15. The right heart flow expressed as a percentage of the combined cardiac output was statistically different from the value in normal fetuses. These findings are consistent with theories of the redistribution of fetal blood flow, where cerebral blood flow is preferentially 'spared'.

Estimation of birth weight by use of ultrasonographic formulas targeted to large-, appropriate-, and small-for-gestational-age fetuses

This report sought to determine whether estimates of fetal weight are enhanced by using ultrasonographic formulas targeted to the large-, appropriate-, and small-for-gestational-age fetus in both preterm and term pregnancies. Ultrasonographic fetal measurements from 575 singleton pregnancies were obtained within 7 days of delivery. The first 194 fetuses were classified into three groups on the basis of the growth percentile rank of the abdominal circumference (greater than or equal to 90%, greater than 5% and less than 90%, and less than or equal to 5%). Regression analyses were performed to generate three formulas for estimating fetal weight on the basis of the following: Gestational age (weeks) + Head circumference (cm) + 2 x Abdominal circumference (cm) + Femur length (cm). This mathematic model allowed formulation of accurate and concise tables relating the sum of these measurements to estimated birth weight. The accuracy of these formulas was then prospectively compared, first, with the formula published by Hadlock et al. (in 32 large-, 279 appropriate-, and 70 small-for-gestational-age fetuses) and second, with the formula of Weiner et al. (in 82 preterm fetuses). The difference between actual and estimated birth weights generated by the three study formulas had no systemic error (t test, p greater than 0.05). Cumulatively, there was a statistically significant reduction of random error in the birth weight estimates by use of the three study formulas versus the best single formulas of Hadlock et al. (2 SD reduced from 21.6% to 19.8% and absolute 2 SD reduced from 15.6% to 12.2%). Additionally, the three study formulas resulted in a statistically significant reduction in the absolute 2 SD error compared with the best formula by Weiner et al. in fetuses less than or equal to 34 weeks' gestation (2 SD reduced from 19.1% to 13.6%).

Short-term effects of maternal oxygen administration on blood flow velocity waveforms in healthy and growth-retarded fetuses

To determine whether maternal oxygen administration affects fetal hemodynamics, we investigated 10 healthy fetuses and 10 growth-retarded fetuses near term by means of Doppler ultrasonography. The growth-retarded fetuses were characterized by abnormal blood flow velocity waveforms. Velocity waveforms were simultaneously recorded at 5-minute intervals from the fetal descending aorta and internal carotid artery before, during, and after maternal oxygen administered through a face mask that delivered 60% oxygen. The pulsatility index was calculated. During oxygen treatment growth-retarded fetuses showed significant temporary hemodynamic modifications as expressed by changes of pulsatility index values that increased in the internal carotid artery and decreased at the level of the descending aorta. On the other side no changes were found in healthy fetuses. These findings suggest that maternal oxygen administration can modify fetal hemodynamics in cases of growth retardation associated with abnormal blood flow velocity waveforms.

Ultrasound measurement of fetal abdominal circumference and the ratio of biparietal diameter to transverse abdominal diameter in a mixed Nigerian population

The fetal abdominal circumference (FAC) and biparietal diameter to transverse abdominal diameter ratio (BPD/TAD) were measured by ultrasound in 219 normal pregnant Nigerian women from 20 weeks until term using the cross-sectional method. There was a progressive linear growth of the FAC and a consistent standard deviation throughout the study period. When compared to caucasian growth curves, the curve shapes were identical but the FAC values were consistently less for each week of gestation in our Nigerian sample. The BPD/TAD ratio showed a progressive fall from 20 weeks until term similar to that previously noted for fetal head circumference to abdominal circumference ratio, indicating that this parameter may also be useful for predicting abnormal fetal growth.

The impact of diagnostic ultrasound on the prediction of intrauterine growth retardation in developing countries

The purpose of this report is to throw light on the problem of intrauterine growth retardation in our society, and to show how this situation could be affected by the introduction of diagnostic ultrasound in our antenatal service. A series of 828 pregnant women were serially examined by ultrasound during the course of pregnancy. Among the whole series (no. 828) there were 98 growth retarded neonates (11.8%). Antenatal ultrasonic evaluation could predict 89.7% of these cases, while only 34.7% of cases could have been predicted by fundal palpation. Among the different etiological factors, maternal anemia was the most common (25%).

Blood flow in obstetrics using Doppler ultrasound

We describe the history of obstetric blood flow research in the human fetal circulation (1978-1982) using both continuous wave (CW) Doppler and pulsed (PW) Doppler with linear array scanning. After the initial work (mainly in Ireland, Australia, Sweden, The Netherlands and the UK) it was recognized that CW Doppler velocity waveforms were of diagnostic significance and yielded as much useful clinical information as more complex PW duplex systems. PW duplex continues to be a useful research tool where accurate Doppler sampling or mean velocity measurement is required. The measurement of fetal Doppler velocity waveforms is clinically useful in the evaluation of the 'small-for-dates' fetus and abnormalities of cardiac anatomy or rhythm. Simple CW pencil probe study of the maternal utero-placental vasculature distinguishes normal from abnormal placentation and may be useful as a screening test to predict hypertensive disease of pregnancy.

Failure of ultrasonographic parameters to predict the severity of fetal anemia in rhesus isoimmunization

Ultrasonographic measurements of placental thickness, extrahepatic and intrahepatic umbilical vein diameters, abdominal circumference, head circumference, head/abdominal circumference ratio, and intraperitoneal volume were made in 50 rhesus-isoimmunized pregnancies at 18 to 26 weeks' gestation. The severity of fetal anemia was assessed by fetal blood sampling. Results in the isoimmunized group were compared with a control population of 410 normal pregnancies at 17 to 32 weeks' gestation. In the absence of fetal hydrops, none of the parameters studied could reliably distinguish mild from severe fetal hemolytic disease.

Fetal biparietal diameter and head circumference measurements: results of a longitudinal study in Zimbabwe

In a longitudinal study in Harare, Zimbabwe, 1233 biparietal diameter and 857 head circumference measurements were obtained from the fetuses of 190 women. Weekly mean values and the two standard deviations were calculated for both the biparietal diameter and head circumference from 12 to 40 weeks of pregnancy. There was little difference between these values and some Caucasian and African standards. Comparison was also made of the weekly biparietal diameter growth rate between our results and those from one study in West Africa. The possible reasons for the differences are explained.

Doppler echocardiographic assessment of atrioventricular velocity waveforms in normal and small-for-gestational-age fetuses

A prospective longitudinal study determined the physiological patterns of blood flow velocity waveforms in normal and in small-for-gestational-age (SGA) fetuses. Using a Pulsed Doppler Duplex system, 125 normally grown fetuses and 35 SGA fetuses were studied longitudinally at between 27 and 42 weeks gestation. In normal fetuses the ratio between the E velocity (early passive ventricular filling) and the A velocity (active ventricular filling during atrial contraction) increased progressively during pregnancy in both transmitral and transtricuspid waveforms, approaching 1 at term. In SGA fetuses, the E/A ratios did not increase during pregnancy and the values obtained were significantly lower than in normal fetuses. The ratio between the transtricuspid and transmitral mean temporal velocities remained almost constant throughout pregnancy in the normal fetuses with transtricuspid velocity slightly exceeding the transmitral velocity. On the other hand, in SGA fetuses the ratio between the mean temporal velocities was inversed with the transmitral velocity progressively greater than the transtricuspid velocity suggesting the existence of intracardiac haemodynamic changes in these fetuses.

Computerized analysis of behavioural states in asymmetrical growth retarded fetuses

The fetal behaviour of 15 asymmetrical intrauterine growth retarded (IUGR) fetuses was compared to that of a control group of healthy fetuses. Fetuses underwent simultaneous cardiotocographic and ultrasonographic examinations for 2 consecutive hours at 36-38 weeks' gestation. Behavioural states analysis was carried out by means of a computerized system (Digital PDP 11) that allowed the recording of several fetal variables including heart rate (FHR), gross body movements (FM), eye movements (FEM) and breathing movements (FBM). FHR was classified in four different patterns (FHRP) according to Nijhuis et al.; fetal movements were automatically synchronized with FHR and grouped for each FHRP. Several quantitative parameters (i.e. incidence, mean duration, lag time, % time spent moving) were then computed for each movement. There were no statistical differences in the distribution of FHRP between healthy and IUGR fetuses. On the other hand quantitative differences were found when the movements investigated were related to FHRP. In IUGR fetuses FEM were mainly represented by low frequency movements (IEM) during both low (FHRP A) and high variability (FHRP B) FHRP, whereas healthy fetuses exhibited mostly rapid eye movements (REM) during FHRP B and absent type of FEM during FHRP A. Moreover IUGR fetuses showed a reduction of state 1F (quiet sleep) and an increase of periods of no coincidence between behavioural state variable when compared to the control group fetuses. These findings, therefore suggest the existence of quantitative differences in fetal behaviour in asymmetrical IUGR fetuses when compared to healthy fetuses.

Longitudinal follow-up of 100 patients at risk of intrauterine growth retardation: comparison of diagnosis in two periods

The concept of low birth weight includes two different entities: prematurity and intrauterine growth retardation. Both of them are major public health problems, because they increase perinatal morbidity and mortality Early diagnosis of IUGR leads to adequate decisions, making possible a reduction in perinatal morbidity and mortality. In order to make an early diagnosis of IUGR, clinical methods have proven to be insufficient. Ultrasonography is an important aid to this diagnosis, introducing the measurement of fetal diameters and perimeters. This study, designed to compare both methods, was carried out in at the Antoine Béclère Hospital, Clamart, France. Data processing was done in CLAP-PAHO/WHO. In the first period, retrospective analyses of 116 clinical histories with IUGR were performed. In this study, only fetal diameters were used and the accuracy of clinical and ultrasonographic diagnosis was evaluated. In the second period a prospective longitudinal follow-up study of 100 pregnant women at risk of developing IUGR was carried out. Clinical diagnosis was also evaluated, and compared to the ultrasonographic approach. The parameters used were the fetal diameters and perimeters (head and abdominal perimeters, and their relationship). Sensitivity, specificity and predictive values of the ultrasonic parameters were calculated (table I). The clinical and ultrasonographic diagnosis of both periods were compared with the purpose to analyze the effect of the measurement of fetal perimeters in the diagnostic accuracy. Newborns of the 100 patients in the prospective study were classified into two groups according to birth weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Microcephaly: genetic counselling and antenatal diagnosis after the birth of an affected child

We describe the clinical and genetic details of a series of microcephalic patients who were referred to the Genetic Counselling Service for the West of Scotland. There were 29 isolated cases of microcephaly and 9 families with recurrent microcephaly. The sib recurrence risk was 19%, which reflects the high incidence of autosomal recessive microcephaly in this series. There was evidence for several varieties of recessive microcephaly. The most frequent, affecting 5 sib pairs, was associated with spastic quadriplegia, seizures, and profound mental handicap. In 15 families with one microcephalic child, prenatal diagnosis by serial ultrasound scans was undertaken in 21 subsequent pregnancies. Four recurrences of microcephaly were detected in the third trimester and one recurrence was missed because no scans were performed after 24 wk gestation when the ultrasound measurements indicated satisfactory head growth. The main reason for late diagnosis of affected fetuses was that head growth did not slow appreciably until the last trimester. The high recurrence risk in this prospective series emphasizes the contribution of autosomal recessive inheritance of microcephaly amongst patients of our Genetic Counselling Service.

The Neu-Laxova syndrome in female sibs: clinical and pathological features with prenatal diagnosis in the second sib

We report on affected sisters with the Neu-Laxova syndrome. Prenatal diagnosis of the condition was achieved by serial ultrasound examinations which demonstrated abnormal fetal growth in the second affected fetus before 24 weeks gestation.

Diagnostic ultrasonography

The use of diagnostic ultrasound has contributed to the evaluation of the fetal condition in two ways--the detection of fetal abnormality and the assessment of fetal growth and development. Routine early pregnancy scanning enables most major structural anomalies to be detected and provides accurate gestational dating. Maternal serum alphafetoprotein screening complements ultrasound in identifying abnormalities, and may also be an indicator of a growth problem in later pregnancy. In high-risk pregnancies, or when growth retardation or acceleration is suspected, abnormalities should always be considered and investigations should include karyotyping. Fetal growth may be assessed by multiple parameters, including measurement of fetal head, trunk, limbs, and amniotic fluid volume, in addition to grading of the placenta. Fetal responses to stimulation can be visualized and quantified. No single parameter may be used alone to predict fetal outcome, but by using this multiple-parameter approach, contributing to a biophysical profile of the fetus, the outcome of pregnancy may be predicted with greater accuracy.

A new method for fetal weight estimation using real-time ultrasound

A method for estimating fetal weight by calculating an approximate fetal volume from abdominal area, head area and femur length has been developed. Birthweights were calculated within 48 h before delivery for 434 patients, using this method and two other methods already in widespread use. Statistical analysis of the three sets of predictions gave standard deviations of 297 g for the new method, compared with 323 g and 342 g for the other methods. Further analysis of the data showed that estimates closest to the true birthweight were obtained in 41% of cases by using the new method, and in 33% and 26% of cases using the other methods.

Doppler studies in the growth retarded fetus and prediction of neonatal necrotising enterocolitis, haemorrhage, and neonatal morbidity

In 82 consecutive cases of intrauterine growth retardation managed by established criteria fetal Doppler studies identified 29 fetuses with absence of end diastolic frequencies in the fetal aorta. These same fetuses were significantly more growth retarded (p less than 0.001) and had an earlier gestational age at delivery (p less than 0.001) than those with end diastolic frequencies present. A subgroup of these cases was analysed in more detail to examine the prognostic value of this phenomenon for the neonate. Two groups of neonates of equivalent gestational age and with a birth weight below 2000 g were compared. There were 26 neonates with absent end diastolic frequencies (group 1) and 20 with end diastolic frequencies (group 2) in the fetal aorta. Those in group 1 were more likely to suffer perinatal death (p less than 0.05), necrotising enterocolitis (p less than 0.01), and haemorrhage (p less than 0.05). Only 4 (15%) of the babies in group 1 had an uncomplicated neonatal period compared with 15 (75%) in group 2 (p less than 0.001). The circulatory changes identified in these cases may provide a more sensitive measure of critical fetal compromise than current techniques and thus allow the clinician to deliver the fetus before irreversible tissue damage has occurred.

Fetal echocardiography. VI. Assessment of cardiothoracic disproportion--a new technique for the diagnosis of thoracic hypoplasia

Fifty-eight fetuses were studied with use of diagnostic real-time and M-mode ultrasound between 15 and 40 weeks of gestation in which the chest circumference, biventricular outer dimension of the heart, biparietal diameter, head circumference, abdominal circumference, and femur length were measured. The chest circumference correlated with the biparietal diameter (r = 0.978), head circumference (r = 0.977), abdominal circumference (r = 0.989), femur length (r = 0.983), and biventricular outer dimension (r = 0.972). Regression analysis with predicted mean and 95% and 5% confidence limits demonstrated a linear relationship between the chest circumference and the following: biparietal diameter, head circumference, abdominal circumference, femur length, and biventricular outer dimension. Four representative cases (triploidy [69,XXX], osteogenesis imperfecta, intrauterine growth retardation, and renal agenesis) illustrate the usefulness of the data when thoracic hypoplasia is suspected.

Prolonged pregnancy: the management debate

A prospective trial was conducted to compare the effects of conservative management of prolonged pregnancy (conservative group) with routine induction of labour at 42 weeks' gestation (active group) in otherwise uncomplicated pregnancies. Of the 402 pregnancies studied, 207 (51%) were allocated to conservative management and 195 (49%) were allocated to have labour induced. The groups were well matched for age, parity, and smoking habits. One hundred and sixty six (80%) of the patients in the conservative group went into spontaneous labour. Of the remainder, two underwent elective caesarean section, 19 had labour induced because of clinical concern, and the remaining 20 had labour induced at the patient's own request. One hundred and twenty five (64%) of the patients in the planned active group underwent induction of labour. Of the remaining 70, 49 went into spontaneous labour and 21 (11%) asked that they should not have labour induced. Comparison of the two groups showed no difference in the length of the first stage of labour but a trend towards an increased need for intervention for fetal distress (p less than 0.06) in the active group. There were no differences in the length of the second stage, the need for intervention, or the mode of delivery. In terms of Apgar scores the neonatal outcome was not significantly different between the two groups, but a greater proportion of the babies (15% v 8%) in the active group required intubation. Umbilical cord venous pH estimated in the last 183 consecutive deliveries in the study showed a significantly lower mean value in the active group (p less than 0.05). There was no difference in birth weight between the two groups. Two deaths occurred in the study. There was a stillbirth in the conservative group at 292 days after massive abruption, and one neonatal death in the active group owing to multiple congenital abnormalities. The outcome for mother and baby in patients from both groups who went into spontaneous labour was generally good. The outcome for patients for whom conservative management was planned but induction became necessary was no different from that of patients who underwent planned induction at term. Thus from our results we can find no evidence to support the view that women with normal prolonged pregnancy should undergo routine induction of labour at 42 weeks' gestation.

Proportionality of small-for-gestational age babies at birth: perinatal associations and postnatal sequelae

Head and chest circumference and crown-rump length measurements were obtained for 413 small-for-gestational age (SGA) infants at birth; and head-chest, head-crown-rump and chest-crown rump ratios derived. There was an inverse correlation between head-chest ratios and gestational age, and boys had higher ratios than girls. First-born infants, and those whose mothers had pre-eclampsia had higher ratios than the rest, and higher ratios were associated with instrumental delivery. Higher ratios were also found for girls (but not boys) born to women of above average weight, and those who suffered birth asphyxia or other problems in the neonatal period. When adjustment was made for confounding between variables gestational age and sex were the only factors making a significant contribution to the variance in head-chest ratios at birth. SGA babies with relatively high head-chest ratios at birth grew faster than those with lower ratios during the first 6 mth of life. Girls with above-average ratios were heavier and had larger heads at the age of 7 yr, but no differences were found for either sex in any aspect of developmental ability at 7 yr associated with head-chest ratios at birth.