Fetal Structural Defects Research Articles

The role of ultrasound in the early diagnosis of fetal structural defects following maternal anticonvulsant therapy

A total of 162 pregnant subjects using anticonvulsant drugs were examined for fetal congenital defects over a period of five years. In 138 of these subjects, alpha-feto-protein (AFP) levels were determined in amniotic fluid at 16 weeks of gestation to rule out spina bifida. In all instances, a fetal anomaly scan was performed between 18 and 20 weeks of gestation. AFP levels were always within the normal range; neonatal examination revealed no spina bifida; however, in seven newborns, a single, or multiple structural defect was established. Apart from cases of severe hydrocephaly, hypospadia, and radius aplasia, the anomalies were too small to be detected by present-day ultrasound equipment. Couples should be informed of the limitations of ultrasound in the early detection of structural defects previously associated with the use of anticonvulsant drugs.

First-trimester diagnosis of recurrence of cystic hygroma using a vaginal ultrasound transducer

The possibilities and limitations of first-trimester diagnosis of fetal structural defects using vaginal transducers are currently not well established. For couples at risk for cystic hygroma early transvaginal ultrasound examination at a gestational age of 10 weeks can be offered to rule out or confirm the presence of cystic hygroma, as described in this case report.

Color flow mapping in obstetrics.

Blood flow studies are now used extensively in evaluating fetal peripheral circulation. By using continuous and pulsed Doppler ultrasonic equipment the raw Doppler shifts caused by blood moving in the vessels can be analyzed in different ways. Spectral data can be used to estimate blood velocity and volume in the vessel, and pulsatility characteristics and turbulence. All these data are obtained from very restricted areas within the body so that aiming of the probe is critical, and obtaining data from an area requires long and tedious effort. Color flow mapping which has recently been introduced into clinical practice provides an overview of flow velocities and directions within an area. Color coded flow can be displayed by applying the moving target identification principle (as in radar) to an ultrasonic diagnostic instrument where sound waves are used instead of radio waves. The value of flow mapping has already been recognized in the diagnosis of congenital and acquired heart disease in adults and children. Direct visualization of intracardiac flow provides for a fast and accurate diagnosis of various cardiac defects, such as the ventricular septal defect, without cardiac catheterization. In the present study we have investigated the potential of color flow mapping in obstetrics. 211 pregnant women were examined between the 15th and 40th weeks of pregnancy. 193 of them had normal pregnancies; 18 were abnormal, including 11 cases of insulin dependent diabetes, 2 cases of Rh-immunization, 2 cases of nonimmunologic fetal hydrops, 2 cases of fetal cardiac structural defects and 1 case of intrauterine growth retardation. Intracardiac flow was clearly seen in 78% (35/45) of cases at the gestational age between the 20th and 24th weeks. After the 24th week the heart flow visualization rate gradually decreased to 31% (11/36) before term. In 2 cases of congenital heart abnormality flow mapping enabled clear visualization of reverse flow through the tricuspid valve and diagnosis of valvular insufficiency. The best results in studies of flow in peripheral vessels were obtained from umbilical vessels which were seen in all cases after the 15th week. The flow visualization rate was much lower when the fetal aorta, intrahepatic umbilical vein and internal carotid artery were studied. The comparison between the diameter of the umbilical vein measured on the B-scan and flow width in the same vessel showed no significant difference (t = 0.26; p less than 0.01; N = 209).(ABSTRACT TRUNCATED AT 400 WORDS)