Contribution of prenatal imaging to the anatomical assessment of fetal hydrocolpos

Hydrocolpos may be associated with a lower urinary tract obstruction in a spectrum of urorectal malformations ranging from persistent urogenital sinus to cloacal dysgenesis. As cloacal dysgenesis carries the worst postnatal prognosis, detailed prenatal ultrasound should focus on the fetal pelvic anatomy to provide the parents with appropriate prenatal counseling. We report three cases of fetal hydrocolpos associated with low urinary tract obstructions, including two with a normal appearance of the anal canal and rectum on prenatal ultrasound and one with a complex cloacal malformation which contributed to the precise prenatal assignment of the malformation in each case within the spectrum of urogenital sequence malformations.

[Contribution of three dimensional imaging techniques in the visualization of the fetal uterus]

The prenatal diagnosis of ambiguous genitalia requires a complete examination of the fetal anatomy to rule out any other congenital defects and the analysis of the fetal genotype. In addition any additional information on the anatomy of the internal genitalia, i.e. the presence or absence of fetal uterus, may be relevant to the prenatal evaluation of female pseudo-hermaphroditism. The recent development of 3D and 4D ultrasound technology may be relevant to a more clearly identification of the fetal uterus. Volume contrast imaging (VCI) provides high contrast images by the realization of thick slices of the region of interest (ROI) thereby providing a clearer picture of the fetal uterus. The multiplanar mode may also facilitate the differentiation of the fetal uterus from the other intra-pelvic organs by offering images in three perpendicular planes. Finally, the tomographic ultrasound imaging (TUI) mode offers the ability to display on a single panel numerous 2-dimensional sections, as obtained using computed tomography imaging.

French fetal biometry: reference equations and comparison with other charts

OBJECTIVES

To construct new reference charts and equations for fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL), using a large sample of fetuses examined at 15-40 weeks in France, and to compare them with previous references.

METHODS

The study data were obtained over a continuous 1-year period from a population of pregnant women undergoing ultrasound examination. Excluded were those with a known abnormal karyotype or congenital malformation, multiple pregnancies, and those with no first-trimester dating based on crown-rump length. No fetuses were excluded on the basis of abnormal biometry or birth weight. For each measurement, separate regression models were fitted to estimate both the mean and the SD at each gestational age.

RESULTS

Full biometric measurements were obtained for 19 647 fetuses. New charts and reference equations are reported for BPD, HC, AC and FL. Prediction intervals for the new reference charts were similar to those of previous ones, whereas there were some differences in predicted centiles.

CONCLUSION

We present new French reference charts and equations for fetal biometry. They can be used easily to compute centiles and Z-scores to control the quality of biometric assessments and to evaluate their performance relative to other references.

[Contribution of fetal middle cerebral artery peak systolic velocity in the management of non-immune hydrops]

Hydrops fetalis is associated with a wide variety of fetal and maternal disorders. Among these disorders, cases with anemia may benefit from a specific treatment. The authors report on two cases of hydrops fetalis with increased middle cerebral artery peak systolic velocity and discussed the contribution of this finding in the management of fetuses with hydrops.

[An update on the fetal circulation]

The fetal circulation has been an exciting area of study for centuries. The principles which grew from the period of hypotheses have been demonstrated in several animal models. These experiments have shaped the major concept of fetal circulation. More recently, the improvement in ultrasound technology has allowed a non invasive study of the fetal circulation in humans. Although the general schema of the fetal circulation has been confirmed in humans, in some aspects some substantial differences have been demonstrated. They may not only reflect some inter-species differences, but also underscore the limitation of chronically instrumented animal studies.

[Biometry 2000. Fetal growth charts by the French College of fetal ultrasonography and the Inserm U 155]

OBJECTIVE

The aim of Biometry 2000 was to establish reliable sonographic fetal auxology reference charts for biparietal diameter, head circumference, abdominal diameter, abdominal circumference and femur length.

DESIGN

A prospective multicentric longitudinal and transversal study was carried out.

SUBJECTS

The data of this study were obtained from 35,456 scans recorded in 10,043 women for a period of one year.

METHODS

Sonographic measurements were performed using a single method for each parameter. Twins and unknown gestational ages were not included. No exclusions were made for small-for-age, congenital malformations or any event during pregnancy. Assuming measurements have a normal distribution, centiles were calculated after polynomial regression models from mean and standard deviation according to gestational age in exact weeks from last menstrual period.

RESULTS

A total of 32,584 fetal biparietal diameters, 20,400 direct cephalic circumferences, 31,790 transverse abdominal diameters, 21,562 direct abdominal circumferences and 30,960 femur lengths were obtained. Fetal growth charts with means, standard deviations and centiles are presented.

CONCLUSION

The multicentric study, Biometry 2000, has established sonographic fetal charts derived from a large sample of scans and unselected pregnant women assuming a normal distribution.

[Diagnosis of ectopic pregnancy]

The diagnosis of ectopic pregnancy rests on the results of plasma beta-HCG hormone assays and on those of ultrasonography. If the plasma level of beta-HCG is lower than 10 m IU/ml, the woman is not pregnant; if it is higher than 10 IU/ml, ectopic pregnancy is excluded when ultrasounds show a gestation sac within the uterine cavity from the 5th week of amenorrhoea onward. The diagnosis of ectopic pregnancy is certain when ultrasounds show a gestation sac outside the uterine cavity; it is highly probable when they show an inhomogeneous masson the side of the uterus or a collection of blood in Douglas' pouch.