Early prenatal diagnosis of neural-tube defects by ultrasound-guided fetoscopy.

In three fetuses with neural-tube defects (N.T.D.s) the lesions were clearly seen by fetoscopy in the second trimester. In a fourth fetus, in which the diagnosis of N.T.D. was suspected because of raised amniotic-fluid alpha-fetoprotein, spina bifida was excluded by fetoscopic examination and a normal baby was delivered at term. Ultrasound-guided fetoscopy has a place in the diagnosis of N.T.D.s when the results of other investigations are conflicting or inconclusive, and may be useful in assessing the severity of a lesion.