Anencephaly and spina bifida are common congenital malformations, and both are collectively referred to as open neural tube defects. Anencephaly is a fatal condition that is approximately 1.5 times more common in females than in males. These children have a lack of skull and brain tissue, with occasional brain tissue remnants, and are often associated with adrenal hypoplasia and excessive amniotic fluid. Approximately 75% die during labor and delivery, while others die hours or days after delivery. The anencephalic child has prominent eyes, a large and wide nose, a large tongue, and no neck, resembling a toad. This malformation has a high incidence in China, especially in the north. So, how does anencephaly develop? Under normal circumstances, the neural plate formed by the thickening of the neural ectoderm gradually evolves into a neural sulcus in the 3-4 week embryo, which then becomes a neural tube with head and tail openings, and then the openings at both ends close and further evolve into the brain and spinal cord. If, for some reason, the head of the neural tube does not close, anencephaly results. Anencephaly can occur in combination with spina bifida. Spina bifida is a partial failure of closure of the spinal canal with a defect mostly on the posterior side; occult spina bifida is a defect of the lumbosacral spinal canal with a skin-covered surface. Spina bifida can cause abnormal nerve root development and growth outward from the bifida, which can result in lower body dysfunction.