Filed under: Brain & Nervous System
Spina bifida is part of a group of birth defects called neural tube defects. The neural tube is the embryonic structure that eventually develops into the baby's brain and spinal cord and the tissues that enclose them.
Normally, the neural tube forms early in the pregnancy and closes by the 28th day after conception. In babies with spina bifida, a portion of the neural tube fails to develop or close properly, causing defects in the spinal cord and in the bones of the backbone.
Spina bifida occurs in various forms of severity. When treatment for spina bifida is necessary, it's done through surgery, although such treatment doesn't always completely resolve the problem.
Spina bifida occurs in three forms, each varying in severity:
Spina bifida occulta
This mildest form results in a small separation or gap in one or more of the bones (vertebrae) of the spine. Because the spinal nerves usually aren't involved, most children with this form of spina bifida have no signs or symptoms and experience no neurological problems. Visible indications of spina bifida occulta can sometimes be seen on the newborn's skin above the spinal defect, including:
Many people who have spina bifida occulta don't even know it, unless the condition is discovered during an X-ray or other imaging test done for unrelated reasons.
In this rare form, the protective membranes around the spinal cord (meninges) push out through the opening in the vertebrae. Because the spinal cord develops normally, these membranes can be removed by surgery with little or no damage to nerve pathways.
Also known as open spina bifida, myelomeningocele is the most severe form — and the form people usually mean when they use the term "spina bifida."
In myelomeningocele, the baby's spinal canal remains open along several vertebrae in the lower or middle back. Because of this opening, both the membranes and the spinal cord protrude at birth, forming a sac on the baby's back. In some cases, skin covers the sac. Usually, however, tissues and nerves are exposed, making the baby prone to life-threatening infections.
Neurological impairment is common, including:
Doctors aren't certain what causes spina bifida. As with many other problems, it appears to result from a combination of genetic and environmental risk factors, such as a family history of neural tube defects and folic acid deficiency.
Although doctors and researchers don't know for sure why spina bifida occurs, they have identified a few risk factors:
If you have known risk factors for spina bifida, talk with your doctor to determine if you need a larger dose or prescription dose of folic acid, even before a pregnancy begins. If you take medications, tell your doctor. Some medications can be adjusted to diminish the potential risk of spina bifida, if plans are made ahead of time.
Spina bifida may cause no symptoms or only minor physical disabilities. Frequently, it leads to severe physical and mental disabilities.
Factors that affect severity
The severity of the condition is affected by:
Range of complications
Complications may include:
Your health care provider will likely suspect or diagnose your baby's condition during your pregnancy. In addition to the health care provider you've selected to care for you during your pregnancy, you'll also likely consult with a multidisciplinary team of physicians, surgeons and physical therapists at a center that specializes in spina bifida treatment. Children with myelomeningocele require ongoing medical attention throughout their lives to monitor their condition and treat complications.
Because appointments can be brief, and there's often a lot of ground to cover, it's a good idea to be well prepared. Here's some information to help you get ready for your appointment, and what to expect from your health care providers if there are suspicions that your baby may have spina bifida.
What you can do
Preparing questions ahead of time will help you make the most of your time with your health care providers. List your questions from most important to least important in case time runs out. For spina bifida, some basic questions to ask include:
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
If you're pregnant, you'll be offered prenatal screening tests to check for spina bifida and other birth defects. The tests aren't perfect. Most mothers who have positive blood tests have normal babies. Also, even if the results are negative, there's still a small chance that spina bifida is present. Talk to your doctor about prenatal testing, its risks and how you might handle the results.
Your doctor will most likely check for spina bifida by first performing the following:
Maternal serum alpha-fetoprotein (MSAFP) test. A common test used to check for myelomeningocele is the maternal serum alpha-fetoprotein (MSAFP) test. To perform this test, your doctor draws a blood sample and sends it to a laboratory, where it's tested for alpha-fetoprotein (AFP) — a protein that's produced by the baby. It's normal for a small amount of AFP to cross the placenta and enter the mother's bloodstream, but abnormally high levels of AFP suggest that the baby has a neural tube defect, most commonly spina bifida or anencephaly, a condition characterized by an underdeveloped brain and an incomplete skull.
Some spina bifida cases don't produce a high level of AFP. On the other hand, when a high level of AFP is found, a neural tube defect is present only a small percentage of the time. Varying levels of AFP can be caused by other factors — including a miscalculation in fetal age or multiple babies — so your doctor may order a follow-up blood test for confirmation. If the results are still high, you'll need further evaluation, including an ultrasound examination.
Many obstetricians rely on ultrasonography to screen for spina bifida. If blood tests indicate high AFP levels, your doctor will suggest an ultrasound exam to help determine why. The most common ultrasound exams bounce high-frequency sound waves off tissues in your body to form black-and-white images on a video monitor.
The information these images provide can help establish whether there's more than one baby and can help confirm gestational age, two factors that can affect AFP levels. An advanced ultrasound can also detect signs of spina bifida, such as an open spine or particular features in your baby's brain that indicate spina bifida.
In expert hands, ultrasound today is quite effective in detecting spina bifida and assessing its severity. Ultrasound is safe for both mother and baby.
If a blood test shows high levels of AFP in your blood but the ultrasound is normal, your doctor may offer amniocentesis. During amniocentesis, your doctor uses a needle to remove a sample of fluid from the amniotic sac that surrounds the baby. An analysis indicates the level of AFP present in the amniotic fluid.
A small amount of AFP is normally found in amniotic fluid. However, when an open neural tube defect is present, the amniotic fluid contains an elevated amount of AFP because the skin surrounding the baby's spine is gone and AFP leaks into the amniotic sac. A second test can be done on the same sample to reliably confirm that a neural tube defect is present.
Discuss the risks of this test, including a slight risk of loss of the pregnancy, with your doctor.
Spina bifida treatment depends on the severity of the condition. Spina bifida occulta often doesn't require treatment at all, but other types of spina bifida do.
Meningocele involves surgery to put the meninges back in place and close the opening in the vertebrae. Myelomeningocele also requires surgery, usually within 24 to 48 hours after birth. Performing the surgery early can help minimize risk of infection that's associated with the exposed nerves and may also help protect the spinal cord from additional trauma. During the procedure, a neurosurgeon places the spinal cord and exposed tissue inside the baby's body and covers them with muscle and skin. Sometimes a shunt to control hydrocephalus in the baby's brain is placed during the operation on the spinal cord.
In this procedure — which takes place before the 26th week of pregnancy — surgeons expose a pregnant mother's uterus surgically, open the uterus and repair the baby's spinal cord.
Proponents of fetal surgery believe that nerve function in babies with spina bifida seems to worsen rapidly after birth, so it may be better to repair spina bifida defects while you're still pregnant and the baby is still in your uterus (in utero). So far, children who received the fetal surgery need fewer shunts, and are less likely to need crutches or other walking devices. But the operation poses risks to the mother and greatly increases the risk of premature delivery.
Discuss with your doctor whether this procedure may be right for you.
Treatment doesn't end with the initial surgery, though. In babies with myelomeningocele, irreparable nerve damage has already occurred, and ongoing care from a multidisciplinary team of surgeons, physicians and therapists is usually needed. Paralysis and bladder and bowel problems often remain, and treatment for these conditions typically begins soon after birth. Babies with myelomeningocele may also start exercises that will prepare their legs for walking with braces or crutches when they're older.
In addition, babies with myelomeningocele may need further operations for a variety of complications. Many have a tethered spinal cord — a condition in which the spinal cord is bound to the scar of the closure and is less able to properly grow in length as the child grows. This progressive "tethering" can cause loss of muscle function to the legs, bowel or bladder. Surgery can limit the degree of disability and may also restore some function.
Cesarean birth also may be part of the treatment for spina bifida. Many babies with myelomeningocele tend to be in a feet-first (breech) position. If your baby is in this position or if your doctor has detected a large cyst, cesarean birth may be a safer way to deliver your baby.
News that your newborn child has a condition such as spina bifida can naturally cause you as a parent to feel grief, anger, frustration, fear and sadness. There's good reason to hope, however, because most people with spina bifida live active, productive and full lives — especially with encouragement and support from loved ones.
Even with severe spina bifida, most children can walk for at least short distances, usually with the assistance of braces, canes or crutches, although they may require wheelchairs for longer distances. Using these devices can help a child compensate for his or her condition and gain more independence.
Many children with spina bifida have normal intelligence, but they may need early educational intervention for learning problems. They may also need extra help from teachers and counselors to adapt to school. A physical disability like spina bifida can also cause emotional and social problems. Children with spina bifida need encouragement to participate in activities with their peers and to lead independent lives, within their physical limitations and capabilities. It may be helpful to remember that these children have never known what's accepted as normal function and often adapt to their condition in remarkable ways.
If your child has spina bifida, you may benefit from finding a support group of other parents who are dealing with the condition. Talking with others who understand the challenges — and rewards — of living with spina bifida can be helpful.
Folic acid, taken in supplement form at least one month before conception and during the first trimester of pregnancy, greatly reduces the risk of spina bifida and other neural tube defects.
Get folic acid first
It's critical to have enough folic acid in your system by the early weeks of pregnancy to prevent spina bifida. Because many women don't discover that they're pregnant until this time, experts recommend that all women of childbearing age take a daily supplement of 400 micrograms (mcg) of folic acid. Several foods, including bread, pasta, rice and breakfast cereals, are fortified with 400 mcg of folic acid per serving. Folic acid may be listed on food packages as folate, which is the natural form of folic acid found in food.
If you're actively trying to conceive, most pregnancy experts believe supplementation of at least 400 mcg of folic acid a day is the best approach for women planning pregnancy. Your body doesn't absorb folate as easily as it absorbs synthetic folic acid, and most people don't get the recommended amount of folate through diet alone, so vitamin supplements are necessary to prevent spina bifida. And, it's possible that folic acid will also help reduce the risk of other birth defects, including cleft lip, cleft palate and some congenital heart defects.
It's also a good idea to eat a healthy diet, including foods rich in folate or enriched with folic acid. This vitamin is present naturally in many foods, including:
When higher doses are needed
If you have spina bifida or if you've given birth to a child with spina bifida, you'll need extra folic acid before you become pregnant. If you're taking anti-seizure medications or you have diabetes, you may also benefit from a higher dose of this B vitamin. In these cases, the recommended dose of folic acid may be up to 4,000 mcg (4 mg) beginning one month prior to conception and during the first few months of pregnancy. However, check with your doctor before taking additional folic acid supplements.