Folic acid deficiency in pregnancy increases the risk of which neural tube defect?

Folic acid deficiency during pregnancy significantly increases the risk of spina bifida, which is the correct answer. Folic acid, also known as vitamin B9, plays a crucial role in the neural tube's proper closure during the early stages of fetal development. Inadequate levels of folic acid can lead to improper closure of the neural tube, resulting in spina bifida, where the spinal cord does not close completely, leading to various degrees of paralysis and other complications.

While other conditions listed, such as anencephaly and encephalocele, are also neural tube defects associated with folate deficiency, spina bifida is the one most commonly highlighted in relation to folic acid deficiency. Hydrocephalus, although it can occur alongside neural tube defects, is not a direct outcome of folic acid deficiency itself but is rather a condition resulting from various etiologies.

The emphasis on spina bifida in public health recommendations regarding folic acid supplementation during pregnancy is due to its prevalence and the potential for prevention with adequate folate intake.