Meningomyelocele: early detection using 3-dimensional ultrasound imaging in the family medicine center.

A young primigravida presented to the family medicine clinic 7 weeks pregnant. Standard 2-dimensional ultrasound at 9 weeks revealed a grossly abnormal posterior brain and 2 adjacent sonolucent structures: 2 yolk sacs versus a yolk sac and cyst. Imaging by 3-dimensional ultrasound distinguished these structures, revealing a caudal cyst with continuity of fetal tissue consistent with a meningomyelocele. To date there is no documentation in the literature of a meningomyelocele diagnosed during the first trimester of pregnancy. Identification of neural tube defects early in pregnancy offers increased options to the mother and may impact long-term fetal prognosis.