Spina bifida is a birth defect that describes the condition when there is incomplete development of the spinal cord or its covering. The term is taken from the Latin for "split" or "open" spine.
The development of the condition of Spina bifida occurs at the end of the first month of pregnancy when during development, the two sides of the embryo's spine fail to join together, leaving an open area.

In some cases, the spinal cord or other membranes may push up and through this opening in the back. With regular scanning this condition is usually detected before a baby is born and treated right away.

The actual cause of spina bifida is largely unknown. There is some evidence to suggest that there may be a genetic connection, but in the majority of cases there is no familial connection. It does seem that a high fever during pregnancy might increase a woman's chances of having a baby with spina bifida. Women with epilepsy who have taken the drug valproic acid to control seizures apparently may also have an increased risk of having a baby with spina bifida.

There are two forms of spina bifida and they are called spina bifida occulta and spina bifida manifesta.

Spina bifida occulta is the mildest form of spina bifida and most children with this type of defect never have any health problems, and the spinal cord is often unaffected.

Spina bifida manifesta includes two types of spina bifida:

Meningocele involves the meninges, the membranes responsible for covering and protecting the brain and spinal cord.

Myelomeningocele is the most severe form of spina bifida. It occurs when the meninges push through the hole in the back, and the spinal cord also pushes though. Most babies who are born with this type of spina bifida also have an accumulation of fluid in and around the brain.

Because of the abnormal development of and damage to the spinal cord, a child with myelomeningocele will typically have some paralysis. The degree of paralysis largely depends on where the opening occurs in the spine. The higher the opening is on the back, the more severe the paralysis tends to be.

Having a child with spina bifida can often give rise of problems with bowel and bladder control, and some might have attention deficit hyperactivity disorder (ADHD) or a range of other learning difficulties, such as hand-eye coordination problems.

There are certain tests that can be done to find out if a baby has spina bifida and expectant parents can opt for certain kinds of prenatal tests.
The alpha-fetoprotein (AFP) test, performed between the 16th and 18th weeks of pregnancy, measures how much AFP, produced by the foetus passes into the mother's bloodstream. If the amount of AFP is high, the test will be repeated because many high AFP readings are false. If the second result is high, other tests will be done to double-check and confirm the diagnosis that will then allow the parents to consider whether or not they want to continue with the pregnancy

I know that doctors can also use ultrasound to see if a baby has spina bifida; and in some cases, the spinal defect can be seen on the ultrasound study. The amniocentesis test can also help determine whether a baby has spina bifida. A needle is inserted through the mother's belly and into the uterus to collect fluid that is tested for AFP.
Maternal folic acid deficiency has been linked to spina bifida, and researchers believe that many cases can be prevented if women of childbearing age consume 0.4 milligrams (400 micrograms) of folic acid every day, and continue to take it throughout the first three months of pregnancy.
It is important that folic acid consumption starts before the onset of pregnancy to provide the best possible protection. Good sources of folic acid include eggs, orange juice, and dark green leafy vegetables. Many multivitamins contain the recommended dose of folic acid, too and it can be bought on its won from the chemist or even supermarket!

After all that it does seem strange to know that often babies who are born with spina bifida occulta have no outward signs or symptoms. The spinal cord does not visibly protrude through the skin, although a patch of hair, a birthmark, or a dimple may be present on the skin over the lower spine.

Other forms of the disease have obvious signs. Babies who are born with the meningocele form have a fluid-filled sac visible on the back. The sac is often covered by a thin layer of skin and can be as small as a grape or as large as a grapefruit. Babies with myelomeningocele also have a sac-like mass that bulges from the back, but a layer of skin may not always cover it. In some cases, the nerves of the spinal cord may be exposed. A baby who also has hydrocephalus will have an enlarged head, the result of excess fluid and pressure inside the skull.