Abdominal Circumference Ratio Research Articles

Accuracy of Ultrasonic Fetal Weight Estimation and Detection of Small for Gestational Age Fetuses

One hundred and eight-six pregnant women were studied with ultrasound for clinical suspicion of poor fetal growth. Fetal weight was estimated using biparietal diameter and mean abdominal diameter with a special nomogram. The fetal femur length (FL) to abdominal circumference (AC) ratio was also calculated. The mean interval between the last ultrasound examination and delivery was 9 days (range, 0 to 14 days). Eighty-three women had their last ultrasonic examination 0 to 4 days (mean, 2 days) before delivery. In this group the arithmetic mean of weight estimation errors was -1 gm (SD, 159 gm). The signed mean percent error was +0.6% (SD, 6.6%). Neither systematic nor random errors were found between different growth percentile groups. When small for gestational age (SGA) was defined as birthweight below 2.5 percentile, the sensitivity, specificity, and positive predictive value of the weight estimations were 82%, 92%, and 84%, respectively, in 186 cases. Significant differences were found in FL to AC ratios between growth pattern groups but fetal weight estimation was found to be superior in the detection of SGA fetuses.

A prospective trial of the femur length to abdominal circumference ratio to predict the outcome of preterm labor.

Femur length to abdominal circumference ratio was used to predict the adequacy of fetal growth for patients undergoing treatment for preterm labor. When quantitated in this way, no correlation could be found between fetal growth and effectiveness of tocolytic therapy. Despite its correlation in retrospective studies, poor fetal growth was not correlated with preterm delivery to any measurable extent in this prospective trial.

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'.

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

The fetal adbominal 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.

Etiological factors and perinatal risks in symmetrical and asymmetrical intrauterine growth retardation.

Fetuses with intrauterine growth retardation (IUGR) are of two types—symmetrical and asymmetrical, and it is important to differentiate between the two types antenatally. Ultrasound studies on 22 patients with IUGR were done after 28 weeks of gestation. The fetuses were distinguished as symmetrical and asymmetrical on the basis of ratio of head to abdominal circumference. It was found that the ratio of head to abdominal circumference differentiated well between the two types of IUGR after 36 weeks of gestation. The etiology and perinatal behaviour in the two groups were also different. A single head: abdominal circumference ratio may be useful in differentiating between symmetrical and asymmetrical IUGR after 36 weeks.

Ultrasonic ratio of fetal thoracic to abdominal circumference: An association with fetal pulmonary hypoplasia

Real time ultrasound was used in pregnant women who were considered to be at risk for development of pulmonary hypoplasia (n = 26). The population consisted of women who had either premature rupture of membranes (n = 16) or oligohydramnios (n = 10). The ratio calculated by comparing the fetal thoracic circumference to abdominal circumference was obtained in all cases within 10 days of delivery. This ratio correlated strongly with neonatal outcome. Multivariate regression models of neonatal outcome were developed to analyze the relationship of gestational age at which premature membrane rupture occurred, the duration of premature rupture, date of birth, and prenatal diagnosis. The addition of the thoracic circumference to the abdominal circumference ratio increased significantly the proportion of explained variability. Application of this ratio should be considered in evaluating fetal status in oligohydramnios and in the expectant management of premature rupture of membranes.

Symmetrical and asymmetrical intra-uterine growth retardation

SummaryIntra-uterine growth retardation may be classified by ultrasonography into symmetrical and asymmetrical. In the symmetrical type the biparietal diameter increases in parallel with, but below, the normal growth curve and the head to abdominal circumference ratio is normal. In the asymmetrical group the biparietal diameter is either normal or flattened, and deviates from the normal curve, whilst the head to abdomen circumference ratio is above normal in both situations. We have reviewed 34 cases of intra–uterine growth retarded fetuses. Ten of these were symmetrical of which five had malformations. Twenty-four were asymmetrical and in eighteen of them the mother had hypertensive disease. The course and outcome of pregnancy and labour were different in these two groups. This classification can be useful in planning the clinical management of pregnancies with fetal growth retardation.

Fetal Femur Length and Abdominal Circumference Ratio in Bangladesh

Objective: The ratio of fetal femur length and abdominal circumference is one of the important ratios. But we do not have any study on it in our country so far. Therefore a study was conducted to prepare a table based on Bangladeshi population. Method: Well dated pregnancies were included in a cross-sectional prospective study. By fitting Polynomial regression model a table and a graph were prepared. Nomograms of Caucasian population which were established before, were compared with this study. Results: A chart of the raw data of 1223 subjects with superimposed fitted percentiles was produced. The quadratic model showed a good fit to the data. 3rd, 10th, 50th, 90th and 97th percentiles, means and two standard deviations of the data were derived. Conclusion: These table and charts can be useful for accurate assessment of fetal femur length/abdominal circumference ratio to detect the type of fetal growth abnormality, symmetrical or asymmetrical. This study shows that there is similarity of this ratio with the western ratio unlike the individual fetal parameters. Key words: Femur length/abdominal circumference ratio; Bangladesh. Bangladesh J Obstet Gynaecol, 2009; Vol. 24(2) : 52-55 DOI: http://dx.doi.org/10.3329/bjog.v24i2.8528

Fetal Biparietal Diameter and Abdominal Circumference Ratio in Bangladesh

This study was conducted to determine fetal biparietal diameter and abdominal circumference ratio in Bangladesh. There is still no table of this ratio in our country. A prospective, cross-sectional study was conducted on well dated, singleton fetuses of healthy pregnant women. One table and two graphs were prepared by fitting Polynomial regression model. Percentiles, mean and two standard deviations were derived of the ratio. Fetal charts of the raw data with superimposed fitted curves were constructed. The model showed a good fit to the data of 1223 subjects. It covered 95% of the population and gave 3rd, 10th, 50th, 90th and 97th percentiles. This chart can be useful for accurate assessment of fetal biparietal diameter and abdominal circumference ratio to determine the type of fetal growth abnormality, symmetrical or asymmetrical. This is the first time that this ratio has been studied in Bangladesh. Key words: Biparietal diameter; abdominal circumference. DOI: 10.3329/bmj.v39i1.6229 Bangladesh Medical Journal 2010; 39(1): 24-27