Normally, in human embryos, the closure of the<unk> <unk>  occurs around the 30th day after fertilization. However, if something interferes and the<unk>  fails to close properly, a<unk> will occur.
The incidence of<unk>  is 2.6 in 1,000 worldwide.
Neural tube defects
Craniofacial anomalies
Anorectal anomalies
Fetal distress
Intrauterine growth retardation
Growth failure
Small for gestational age
Hydrocephalus