Autosomal dominant cataracts of the fetus: Early detection by transvaginal ultrasound

Cataracts are lens opacities that account for approximately 10% of blindness in children. We report on four consecutive pregnancies in a woman at risk for recurrent autosomal dominant cataracts in which extensive ultrasound studies were helpful in establishing the correct diagnosis. The normal appearance of the fetal lens is that of a ring with a central sonolucency, but in cases of cataracts the lens appears hyperechogenic to various degrees. In the first pregnancy, normal lenses were seen at 15 postmenstrual weeks and, at birth, the baby girl had normal lenses. In the second pregnancy, the male fetus was affected by a left-sided cataract and a right-sided anophthalmia which were diagnosed at 16 postmenstrual weeks. The histological examination of the specimen from the aborted fetus correlated with the sonographic diagnosis. The third pregnancy, also a male fetus, had bilateral cataracts suspected at 14 weeks, but the final diagnosis was made at 19 weeks and confirmed at 21 weeks. The couple opted to terminate the pregnancy and the histology confirmed the presence of congenital cataracts. In the fourth pregnancy, we diagnosed asymmetry of the orbital sizes and bilateral cataracts at 15 weeks. In conclusion, the diagnosis of fetal cataract from the second trimester of pregnancy is possible and imaging of the fetal lenses should be part of the routine anatomical survey. Since the exact onset of fetal cataracts is uncertain at present, in cases at risk, serial sonograms may be indicated.