A pregnant mother went to hospital after two weeks of having an abnormal vaginal discharge. At 26 weeks, she had not taken any folic acid nor had any antenatal care visits. Upon examination, all the amniotic fluid had drained out. Elisha Atuhairwe, a radiographer at Remnant Diagnostic Centre, who did a scan discovered the baby had severe defects.
“Although there was a heartbeat, there was no amniotic fluid around the baby. Upon examination of the foetus, since we use the head, abdomen and femur to determine its gestation, I discovered that the head was missing and because of this, the mother was advised to terminate the pregnancy,” Atuhairwe says, adding that mothers who do not go for antenatal care risk giving birth to children with neurological defects.
Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the first month of pregnancy, often before a woman even knows that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In spina bifida, the fetal spinal column does not close completely.
In simpler terminology, spina bifida is a birth defect where the baby’s spine does not form completely and may be exposed and damaged. This could cause infections, trauma, and death. Low levels of folic acid consumed during and before pregnancy may be one of the causes along with genetic causes. It is a high risk disorder which may result in the infant’s death in the first few days of life.
According to Dr Nandini Gokulchadran, a consultant neurosurgeon and head of medical services at NeuroGen Brain and Spine Institute in Mumbai, India, spina bifida can happen anywhere along the spine if the neural tube does not close all the way. When this happens, the backbone that protects the spinal cord does not form and close as it should. This often results in damage to the spinal cord and nerves.
Anencephaly is when the baby is born without parts of the brain and skull. This could be genetic or caused by other factors such as nutritional, and environmental factors. An insufficient intake of folic acid in the mother’s diet is a key factor in causing spina bifida and other neural tube defects.
The neural tube is a narrow channel that folds and closes between the third and fourth weeks of pregnancy to form the brain and spinal cord of the embryo. Anencephaly occurs when the “cephalic” or head end of the neural tube fails to close, resulting in the absence of a major portion of the brain, skull, and scalp.
“Infants with this disorder are born without a forebrain (the front part of the brain) and a cerebrum (the thinking and coordinating part of the brain). The remaining brain tissue is often exposed (not covered by bone or skin). Children born with spina bifida often have a fluid-filled sac on their back that is covered by skin, called a meningocele,” Dr Nandini says.
The signs and symptoms of these abnormalities range from mild to severe, depending on where the opening in the spinal column is located and how much of the spinal cord is contained in the sac. Related problems can include a loss of feeling below the level of the opening, weakness or paralysis of the legs, and problems with the bladder as well as bowel control.
Some affected individuals have additional complications, including a buildup of excess fluid around the brain (hydrocephalus) and learning problems. With surgery and other forms of treatment, many people with spina bifida live into adulthood.
Scans to detect NTDs
Dr Joseph Nsengiyumva, a general physician, says when you go for an antenatal visit, your gynaecologist will ask you to do an AFP test to determine the amount of alpha-fetoprotein (AFP) in the blood between 16 and 18 weeks of pregnancy. The higher the levels, the higher the chances that your baby has a neural tube defect.
This is confirmed using an ultrasound scan according to Atuhairwe. “The role of a scan during pregnancy is to examine the whole baby. In most cases, anencephaly and spina bifida aperta, can be detected on a prenatal ultrasound. Anencephaly can be detected between 10 to 15 weeks and spina bifida at 18 to 22 weeks,” he says.
These neural tube defects are characterised by absence of the brain, cranial vault (acrania) and foetal head in the uterus. Also, failure to identify the normal bony structure and brain tissue cephalad to the bony orbits is the most reliable feature of this anomaly.
He adds that anencephaly is more prevalent in females and that 50 per cent of such babies die in the uterus while others die immediately after birth. “Go for an ultrasound scan during pregnancy to ensure that your baby is in good condition (in utero) during pregnancy,” he advises.
There is no cure or standard treatment for anencephaly according to Dr Nandini. Treatment is supportive and may include the help of neurosurgeons, urologists, and orthopedic surgeons, physical and occupational therapists, and social workers.
“For spina bifida, surgical options are to close the defect and minimise the risk of infection or further trauma within the first few days of life. Foetal surgery (performed in utero) is an option for some forms of spina bifida. The nerve damage in NTDs is irreversible,” he says.
The key early priorities for treating myelomeningoceles (a neural tube defect in which the bones of the spine do not completely form) are to prevent infection from developing through the exposed nerves and tissue through the spine defect and to protect the exposed nerves and structures from additional trauma.
The likely outcome of the disease, activity, and participation depend on the number and severity of abnormalities and associated personal and environmental factors. A comprehensive follow up is required with all healthcare providers.
Dr Nandini says: “Surgical treatment during pregnancy also called prenatal repair of myelomeningocele is a delicate surgical procedure where foetal surgeons open the uterus and close the opening in the baby’s back while they are still in the womb in cases of severe spina bifida.”
Some surgeries after birth can also reduce the severity of the disorder but symptoms may persist. Through supportive treatments and physical as well as functional rehabilitation, children with NTDs can achieve independence to some level.