Types of spina bifida

by Christine Haran

What is spina bifida?

Spina BifidaWhen a woman is pregnant, her thoughts tend to focus on the baby's name, the color of the nursery and preparing the home for the new arrival.

Most parents-to-be never have to worry about their child being born with a birth defect, but a little bit of planning can prevent some forms of these diseases.

Understanding your risk of having a child with a birth defect can help prepare you for the difficult decisions that come with the diagnosis.

Spina bifida is the most common form of a type of birth deformity called a neural tube defect. When these birth defects occur, the structure inside the embryo that develops into the brain and spinal cord, the neural tube, does not develop normally.

Spina bifida, for example, causes the backbone to develop irregularly and may even affect the spinal cord. This birth defect is one of the most common, affecting approximately 1,300 babies in the Unites States every year.

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Four main types of spina bifida

1. Occulta. This is the mildest form of spina bifida. In fact, occulta means without symptoms, so in this form of spina bifida, one or more vertebrae in the back are malformed but they rarely cause any disability.

2. Closed neural tube defect. In this type of spine bifida, there are no openings in the spine, which are the hallmarks of more serious forms of this defect. Closed neural tube defects, instead include small defects in which the spinal cord has an abnormal formation of fat, bone or membrane on its surface. The effects of these deformities range from few or no symptoms to incomplete paralysis.

3. Meningocele. With this type, the meninges, or the lining of the spinal cord, poke through openings in the spine and become fluid-filled cysts known as meningoceles. Symptoms can vary from none to partial paralysis, but these cysts can sometimes be removed with surgery, allowing the child to develop normally.

4. Myelomeningocele. This is the most severe form of spina bifida. It is caused when the actual nerves of the spinal cord (as opposed to just the lining) poke though openings in the spine. Surgery can repair some of this damage and prevent infection, but babies with this defect often have some degree of paralysis depending on the location of the problem.

Preventing spina bifida

It's not clear as to what causes spina bifida, but scientists believe a combination of genes, nutrition and environmental factors come into play.

The one clear link that has been discovered is folic acid intake. Consuming enough of this form of vitamin B may help to prevent birth defects including spina bifida. Prenatal vitamins that are prescribed by a doctor will almost always contain folic acid along with other vitamins essential for your baby's development.

Detecting a defect

Over the nine months of pregnancy, your doctor will likely perform various screening tests. Many of these are meant to check on the health of the embryo as well as look for potential birth defects. Keep in mind, however, that none of these tests can determine the severity of a birth defect.

Ultrasound can sometimes be used to detect the spinal cord and vertebrae abnormalities found in spina bifida. Also, a blood test can detect levels of a protein, called alpha-fetoprotein. Abnormally high levels of this protein in the mother's bloodstream can indicate a neural tube defect.

If your doctor has reason to suspect a birth defect, he or she will likely recommend an amniocentesis, in which a small amount of fluid is taken from the sac in which the baby floats, to confirm that high levels of alpha-fetoprotein are present. Amniocentesis raises the risk of some side effects for the embryo and mother, so make sure you discuss your risk with your doctor.

Living with spina bifida

Unfortunately, there is no cure for spina bifida, and treatment will vary depending on the severity of the defect. Many children with spina bifida will never have any symptoms of this defect and will need no treatment, while others will need various surgeries to help them function at the highest level possible.

Hydrocephalus, a condition in which fluid collects in the brain, is a condition often found in people with the myelomeningocele form of spina bifida. For these children, a shunt is surgically placed in the brain to help the fluid drain. Because of the paralysis, bladder and bowel problems are also common in children with this type of birth defect and both can be managed with treatment.

Assistive devices, such as braces, crutches, walkers or wheelchairs may be helpful for children with more severe forms of spina bifida.

New treatments

Doctors try to diagnose spina bifida early because many believe that the earlier treatment can begin, the better the child's body will develop over time. Along those lines, a new, experimental treatment is being studied to help children before they are even born.

If a serious neural tube defect, like myelomeningocele, is highly likely, some doctors perform surgery on the fetus while it is still in the uterus of the mother. During this surgery, doctors try to close the opening in the fetus's spinal cord to try to reduce the amount of neurological damage done.

In some cases it seems, this surgery allows the body to correct some defects, such as hydrocephalus, itself, lowering the need for additional surgeries after birth.

"The question is if repairing the damage earlier is going to stop other things from evolving," says Dr. Cathy Spong, chief for the pregnancy and perinatology branch of the National Institute of Child Health and Human Development.

However, the procedure carries with it many risks, including organ defects, brain hemorrhage and even death. The mother is also put at risk for infection, blood loss and gestational diabetes.

It is not yet known for sure if fetal surgery is beneficial for the mother and child, however a clinical trial is currently underway to determine if the risks of this surgery outweigh the benefits.

"When you have an intervention that can cause harm, it's important to determine if it is beneficial before exposing the mother and child to that risk," said Spong.

Christine Haran has been a health journalist for more than seven years, and her work has appeared in Woman's Day, MAMM Magazine, Bride's Magazine, Publishers Weekly and other publications. In 2003, she received an Excellence in Women's Health Research Journalism Award from the Society for Women's Health Research. Haran has a master's degree in journalism from New York University and a bachelor's degree in english from Skidmore College.

Copyright © Christine Haran. Permission to republish granted to Pregnancy.org.