context: Spina bifida is a relatively common birth defect in the U. S. The words literally mean "split spine" in Latin. If a baby has the condition, during development, the neural tube (a group of cells that form the brain and the spinal cord of a baby) doesn't close all the way, so the backbone that protects the spine doesn't form completely. This can cause physical and mental issues. About 1,500 to 2,000 babies of the 4 million born in the U. S. every year have spina bifida. Thanks to advances in medicine, 90% of babies who have this defect live to be adults, and most go on to lead full lives. There are three main types of spina bifida: Spina bifida occulta ( SBO): This is the most common and mildest form of the defect. Many people don't even know they have it. (" Occulta" means "hidden" in Latin.) Here, the spinal cord and nerves are usually fine, but there might be a small gap in the spine. People often find out they have SBO when they get an X-ray for some other reason. This type of spina bifida doesn't typically cause any type of disability. Meningocele: This rare type of spina bifida happens when a sac of spinal fluid (but not the spinal cord) pushes through an opening in the baby's back. Some people have few or no symptoms, while others have problems with their bladder and bowels. Myelomeningocele: This is the most severe type of spina bifida. Here, the baby's spinal canal is open in one or several places in the lower or middle back, and a sac of fluid pokes out. This sac also holds part of the spinal cord and the nerves, and those parts get damaged. With spina bifida occulta, the most obvious sign might be a tuft of hair or a birthmark at the site of the defect. With meningocele and myelomeningocele, you can see the sac poking through the infant's back. In the case of meningocele, there may be a thin layer of skin over the sac. With myelomeningocele, there's usually no skin covering, and the spinal cord tissue is out in the open. Other symptoms of myelomeningocele include: Weak leg muscles (in some cases, the infant can't move them at all) Unusually shaped feet, uneven hips, or a curved spine (scoliosis) Seizures Bowel or bladder problems Children also might have trouble breathing, swallowing, or moving their upper arms. They also might be overweight. The symptoms depend a lot on where the problem is in the spine and which spinal nerves are involved. No one knows for sure what causes spina bifida. Scientists think it may be a combination of the environment and family history, or a lack of folic acid (a type of vitamin B) in the mother's body. But we do know that the condition is more common among white and Hispanic babies and in girls. Also, women who have diabetes that isn't managed well or who are obese may be more likely to have a child with spina bifida. Three tests can check for spina bifida and other birth defects while the baby is still in the womb: Blood test: A sample of the mother's blood is tested to see if it has a certain protein the baby makes called AFP. If the level of AFP is very high, it could mean the baby has spina bifida or another neural tube defect. Ultrasound: High-frequency sound waves bounce off tissues in your body to make black-and-white pictures of the baby on a computer monitor. If your baby has spina bifida, you may see an open spine or a sac poking out of the spine. Amniocentesis: If the blood test shows a high level of AFP but the ultrasound looks normal, your doctor may recommend amniocentesis. This is when your doctor uses a needle to take a small amount of fluid from the amniotic sac around the baby. If there's a high level of AFP in that fluid, that means the skin around the baby's sac is missing and AFP has leaked into the amniotic sac. Sometimes, spina bifida is diagnosed after a baby is born -- usually if the mother didn't get prenatal care or the ultrasound didn't show anything wrong. The doctor probably will want to get X-rays of the baby's body and do a magnetic resonance imaging ( MRI) scan, which uses strong magnets and radio waves to get more detailed images. Doctors can operate on babies when they're just a few days old or even while they're still in the womb. If the baby has meningocele, about 24 to 48 hours after birth, the surgeon will put the membrane around the spinal cord back in place and close the opening. If the baby has myelomeningocele, the surgeon will put the tissue and spinal cord back inside the baby's body and cover it with skin. Sometimes the surgeon will also put a hollow tube into the baby's brain called a shunt to keep water from collecting on the brain (called hydrocephalus). This is also done 24 to 48 hours after the baby's born. Surgery sometimes can be done while the baby is still in the womb. Before the 26th week of pregnancy, the surgeon goes into the mother's womb and sews shut the opening over the baby's spinal cord. Children who have this type of surgery seem to have fewer birth defects. But it's risky to the mother and makes it more likely that the baby will be born too early. After these surgeries, others may be needed to correct problems with feet, hips, or the spine or to replace the shunt in the brain. Between 20% and 50% of children with myelomeningocele may also have something called progressive tethering, which is when their spinal cords get fastened to the spinal canal. ( Normally, the bottom of the spinal cord floats freely in the spinal canal.) As the child grows, the spinal cord stretches, and that causes a loss of muscle and bowel or bladder problems. Surgery may be needed to fix that as well. Some people with spina bifida need crutches, braces, or wheelchairs to move around, and others need a catheter to help with their bladder issues. Studies have shown that taking a multivitamin with folic acid can prevent spina bifida and lower your baby's odds of having this and other birth defects. Any woman who's pregnant or trying to get pregnant should get 400 micrograms a day. If you have spina bifida, or have a child with spina bifida, you should get 4,000 micrograms per day at least 1 month before you get pregnant through the first few months. Folic acid is also in dark green vegetables, egg yolks, and some fortified breads, pastas, rice, and breakfast cereals.