Management of ventriculomegaly in the fetus

With recent improvements on obstetrical ultrasound, abnormal enlargement of the human fetal cerebral ventricles (ventriculomegaly) is being detected more frequently. Several problems, however, remain unsolved. The relationship between ventriculomegaly detected in utero and hydrocephalus (communicating and noncommunicating), detected in the neonatal period, is only speculative. Another problem is the accuracy of prenatal ultrasound in distinguishing hydrocephalus from ventricular enlargement associated with other brain malformations. Finally, there is the question of how confidently other congenital malformations can be excluded.The present authors evaluated the prenatal management and neonatal outcome in 24 fetuses with ventriculomegaly, reviewing the serial obstetrical sonograms of these fetuses to assess the ability of ultrasound to detect normal and abnormal fetal ventricular development at different gestational ages. They correlated the prenatal and postnatal histories of the fetus with ventriculomegaly to see how serial ultrasound findings can be used to select a therapeutic strategy that offers the best hope for improving outcome and prognosis of the salvageable fetus and avoids unnecessary intervention when the outlook is hopeless. It appears that most fetuses with ventriculomegaly do not require intervention in utero The 24 cases were divided retrospectively into three categories: 1) ventriculomegaly associated with other severe anomalies thought to be incompatible with life (10 cases): 2) ventriculomegaly detected fortuitously late in gestation (three cases); and 3) isolated ventriculomegaly, without detectable associated lethal anomalies (11 cases).In cases of ventriculomegaly with severe associated anomalies, most families requested termination of pregnancy, and vaginal delivery was induced. Three cases required ultrasound-guided transabdominal cephalocen-tesis to prevent dystocia. Eight fetuses were stillborn, and one survived for approximately 24 hours. In the three fetuses found during ultrasound examination for obstetrical indications near term, the extent of the ventriculomegaly or associated anomalies was so severe that obstetrical management was biased to decrease maternal morbidity at the expense of the fetus. Two fetuses were stillborn, and one survived for only 30 minutes.In 10 of the 11 fetuses with isolated ventriculomegaly, serial ultrasound showed stable ventriculomegaly without significant enlargement of the ventricles or of the head with advancing gestation. Ten of these babies survived. Only three of the survivors had signs of increased intracranial pressure at birth and required ventriculoperitoneal shunts in the first 2 weeks of life. Only one of these had obstructive hydrocephalus secondary to aqueductal stenosis. Two of the seven survivors who showed no evidence of increased intracranial pressure at birth subsequently developed signs of increased pressure and of progressive ventricular enlargement. Ventriculoperitoneal shunts were placed in these at 2 and 3 months of age, respectively.Only one fetus showed mild progresive ventricular en largement in utero. In one fetus ventriculomegaly resolved spontaneously. This fetus had normal intracranial anatomy at 13 weeks of gestation, with consistently dilated ventri- cles from 19 to 24 weeks and normal-sized ventricles at 28 weeks. The baby was normal at birth. In most cases (22 of 24), the fetal abnormality was detected fortuitously during ultrasound performed for rou- tine obstetrical or maternal indications. In two cases, the initial ultrasound was performed because a previous child had hydrocephalus. The diagnostic accuracy of ultrasound for ventriculomegaly was 100 per cent, and there were no false-positive studies. Ultrasound also was able to detect associated central nervous system anomalies (myelome- ningocele, occipital encephalocele, and holoprosence- phaly) ana anomalies not of the central nervous system (intrauterine growth retardation, cyclopia, monochorionic- monoamniotic placentation, and bilateral hydronephrosis), but failed to recognize a porencephalic cyst associated with massive hydrocephalus, and two small flat 2-cm my- elomeningoceles. Of greater clinical significance is the inability of ultra- sound to distinguish hydrocephalus from ventricular en- largement associated with other congenital central nervous system malformations. In three fetuses ventricular enlarge- ment was associated with midline defects that could not have been detected by ultrasound before birth, even in retrospect. These three were born with agenesis of the corpus callosum, two of them had absence of the septum pellucidum, and one had septo-optic dysplasia.