What is Anencephaly?

Anencephaly is a type of neural tube malformation. Anencephaly: The brain is completely missing, and the scalp and skull are also missing. Only the basal nucleus is covered by fibrous connective tissue, and the baby cannot survive after birth.

Basic Information

English name

anencephalus

Visiting department

Obstetrics and Gynecology

Common causes

Genetic factors, environmental factors

Common symptoms

Polyhydramnios

Causes of anencephaly

Neural tube malformations occur because of the influence of many factors in the heredity and environment during the embryonic period, resulting in incomplete closure of the neural tube, which results in anencephaly and spina bifida. Environmental factors directly or indirectly affect the embryo, especially in the third and fourth weeks of the embryo, which have a great impact on the nervous system and easily cause fetal malformations.

Clinical manifestations of anencephaly

Anencephaly children are often deformed and have excessive amniotic fluid. The patient's abdominal circumference is larger than that of the month of pregnancy, the fetal head is unclear, the fetal position is unclear, and the fetal heart sound is distant.

No brain examination

Physical examination

(1) Examination during pregnancy. Abnormal cerebral deformities are often associated with polyhydramnios. The abdominal circumference of pregnant women is larger than that of the gestation month.

(2) Anus examination and vaginal examination may be uneven at the time of labor. If the blood vessels on the top of the fetus rupture, the amniotic fluid can be bloody.

2. Auxiliary inspection

(1) Ultrasound examination of amniotic fluid depth> 8cm indicates that there is too much amniotic fluid, and no double parietal diameter can be measured. The aura of the fetal head is not seen in the B-mode ultrasound image.

(2) X-ray film shows that the fetus has no parietal bone, and some have skull base bone. Spina bifida is often associated with a defect in which the vertebral body is interrupted or flattened.

(3) The AFP value measured by alpha -fetoprotein (AFP) is 4 to 10 times higher than the same gestational week or higher than the upper limit of the normal threshold. Especially before 20 weeks of pregnancy, the diagnostic significance is even greater.

(4) Amniotic sac angiography and fetal angiography can further understand whether the fetus is deformed, because it is harmful to the mother and child, it should be used with caution.

No brain child treatment

Induction of labor should be performed after diagnosis. If there is too much amniotic fluid, a high rupture membrane should be performed to promote natural birth.

Anencephaly prevention

1. Cold and fever in early pregnancy

In the early stages of pregnancy, a woman with a common cold will not cause spina bifida or anencephaly, but it is possible in high fever. Fever has an impact on the fetus, especially with a history of high fever from 13 to 26 days of pregnancy, prone to spina bifida or anencephaly. Therefore, pregnant women who have had a history of fever in the early stages of pregnancy should undergo an antenatal B-ultrasound to confirm the diagnosis.

2. Exposure to radiation in early pregnancy

In the early stages of pregnancy, women have been exposed to radiological examinations due to diagnosis, which does not cause fetal neural tube defects. However, high-dose radiation can have adverse effects on embryo development and can cause embryo death or various types of birth defects, including anencephaly. Different developmental stages of the placenta have different sensations of radiation. X-ray exposure on the 18th to 20th days after conception can cause death of pregnant eggs. On the 20th to 50th day after conception, severe malformations can be caused if exposed to large doses; although the malformation is not induced on the 50th day after pregnancy, it will also delay fetal development. X-rays should be avoided in the early pregnancy.

3. Take certain medicines early in pregnancy

Women who have taken medicine in the early stages of pregnancy do not cause fetal neural tube defects, but if they take a large amount of antitumor drugs (methotrexate, thiopurine), hormones (prednisone), anticonvulsants (phenytoin ), Etc., may cause fetal spina bifida and anencephaly.

4. Exposure to harmful toxicants in early pregnancy

Women's exposure to a small amount of harmful poisons in early pregnancy will not cause fetal malformation, but harmful poisons can directly affect the embryo or fetus, and can also adversely affect the fetus through the adverse effects of the mother, which damage the health of the mother. Whether or not the exposure to harmful poisons in the early pregnancy can cause adverse effects on the fetus depends mainly on the size of the toxicity of the harmful poisons, the length of exposure, and the amount.

5. Precautions for Folic Acid Supplement

(1) Folic acid should be added 3 months before pregnancy and 3 months in advance. During pregnancy, the content of folic acid in the body will reach an ideal level. It should be taken until 3 months after pregnancy to ensure the baby's development. need.

(2) Some scholars have suggested that men also need to supplement folic acid. This is because folic acid can help DNA synthesis. If men lack folate, it will increase the probability of chromosomal defects in babies.

(3) Pay attention to the dose of folic acid supplement. The best supplemental dose to prevent neural tube defects is 400 micrograms per day.

(4) Folic acid can be supplemented through diet. Folic acid is widely distributed in animal and plant foods. Foods rich in folic acid include green vegetables, fresh fruits, animal livers and kidneys, eggs, beans, nuts, and cereals. However, if you take folic acid in food, you need to pay attention to that: because folic acid is a water-soluble vitamin, it is unstable to heat and light and easily loses its activity. This requires you to change some cooking habits in your daily life. The dishes are kept for too long to minimize the loss of folic acid.

(5) Do not overuse folic acid Take folic acid preparations under the guidance of a doctor. Do not take it for a long time. Long-term use will interfere with zinc metabolism in the body. Insufficient zinc intake will also affect your baby's development. If you take the contraceptive for a long time before pregnancy, it is best to stop using it 6 months before pregnancy, because the contraceptive may interfere with the metabolism of vitamins such as folic acid.