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Anencephaly is a malformation that can occur due to infections, drug use or exposure to radiation during pregnancy and which is characterized by the partial absence of the brain, skullcap, cerebellum and meninges, which are important structures of the central nervous system. As a consequence of this change, it is possible that babies born with anencephaly tend to have a shorter life expectancy, which may represent hours or a few months of life.
Anencephaly has no treatment or cure, and it is important that the diagnosis is made during pregnancy so that the woman and her family members have the proper psychological support. The diagnosis of anencephaly can be made by means of an ultrasound examination during prenatal care or by measuring alpha-fetoprotein in maternal serum or amniotic fluid from the 13th week of pregnancy.
Main causes of anencephaly
Anencephaly is an alteration that occurs due to the non-closure of the neural tube between the third and fourth week of gestation, that is, between days 23 and 28 of gestation. The main factors that can cause the neural tube to close are:
- Lack of folic acid during pregnancy;
- Use of drugs during pregnancy;
- Infections during pregnancy;
- Radiation exposure;
- Very young or older women;
- Previous pregnancy with anencephaly baby.
In some cases, the neural tube also presents malformation in the cervical region, resulting in spina bifida, which is characterized by incomplete formation of the spinal cord and the structures that protect it. Learn more about spina bifida.
It is important to remember that this condition is not hereditary, that is, it is not transmitted from parents to children. However, having a child with neural tube changes may increase the chances of having a baby with anencephaly.
Difference between anencephaly, hydranencephaly and microcephaly
Hydranencephaly is a malformation where the baby lacks the right and left parts of the brain and these spaces are filled with the fluid that protects the brain and spinal cord. Some of the causes of this condition include stroke from the mother during pregnancy and infection of the uterus, which hinder the development of the baby's nervous system, causing seizures, hydrocephalus, poor eyesight, deafness, and failure to thrive. Many babies die before the first year of life, but in some rare cases, children with this condition live for many years.
Microcephaly is a condition where the child's head and brain do not develop properly, being smaller than expected for their age.According to the degree of microcephaly, it can lead to situations such as loss of vision and hearing, and intellectual disability of the child. Understand what microcephaly is and how it is treated.
In anencephaly, the baby is born without some important parts for the development of the nervous system, such as meninges, skull and scalp. With this condition, most babies die before birth or within a few hours or days after birth.
How the diagnosis is made
The diagnosis of anencephaly can be made during prenatal care through an ultrasound examination, in which the doctor can observe changes in the closure of the neural tube. In addition, alpha-fetoprotein can be measured in serum or amniotic fluid from the 13th week of pregnancy, with high concentrations of this protein being verified.
If the diagnosis is not made during pregnancy and there has been no miscarriage, the diagnosis is made after the baby is born, in which the partial absence of the skullcap, brain and other nervous system structures is observed.
Consequences of anencephaly
Anencephaly can lead, in some cases, to the occurrence of spontaneous abortion or complications for the woman during childbirth. Furthermore, in the case of babies who were born alive, their life expectancy is very low, ranging from hours to a few months.
In addition, due to neural tube changes, it is possible for the baby to develop blindness, deafness or changes in pain perception, for example, depending on the degree of anencephaly. Thus, it is important that babies with anencephaly are regularly monitored by the medical team so that it is possible to promote the extension of their life expectancy.