BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuAnencephalyAprosencephaly with open craniumAnencephaly is the absence of a large part of the brain and the skull. Causes Anencephaly is one of the most common neural tube defects. Neural tube defects are birth defects that affect the tissue that becomes the spinal cord and brain.Anencephaly occurs early in the development of an unborn baby. It results when the upper part of the neural tube fails to close. The exact cause is not known. Possible causes include:Environmental toxins ToxinsToxins are substances created by plants and animals that are poisonous (toxic) to humans. Toxins may also include some medicines that are helpful in...ImageRead Article Now Book Mark Article Low intake of folic acid by the mother during pregnancyFolic acidFolic acid and folate are both terms for a type of B vitamin (vitamin B9). Folate is a B vitamin that occurs naturally in foods such as green leafy v...ImageRead Article Now Book Mark Article The exact number of cases of anencephaly is unknown. Many of these pregnancies result in miscarriage. Having one infant with this condition increases the risk of having another child with neural tube defects. Symptoms Symptoms of anencephaly are:Absence of the skull Absence of parts of the brain Facial feature abnormalities Severe developmental delayHeart defects may be present in 1 out of 5 cases. Exams and Tests An ultrasound during pregnancy is done to confirm the diagnosis. The ultrasound may reveal too much fluid in the uterus. This condition is called polyhydramnios.UltrasoundA pregnancy ultrasound is an imaging test that uses sound waves to create a picture of how a baby is developing in the womb. It is also used to chec...ImageRead Article Now Book Mark Article PolyhydramniosPolyhydramnios occurs when too much amniotic fluid builds up during pregnancy. It is also called amniotic fluid disorder, or hydramnios.ImageRead Article Now Book Mark Article The mother may also have these tests during pregnancy:Amniocentesis (to look for increased levels of alpha-fetoprotein) AmniocentesisAmniocentesis is a test that can be done during pregnancy to look for certain problems in the developing baby. These problems include:Birth defectsG...ImageRead Article Now Book Mark Article Alpha-fetoproteinAlpha fetoprotein (AFP) is a protein produced by the liver and yolk sac of a developing baby during pregnancy. AFP levels go down soon after birth. ...ImageRead Article Now Book Mark Article Alpha-fetoprotein level (increased levels suggest a neural tube defect) Urine estriol level A pre-pregnancy serum folic acid test may also be done. Treatment There is no current treatment. Talk to your health care provider about care decisions. Outlook (Prognosis) This condition most often causes death within a few days after birth. When to Contact a Medical Professional A provider usually detects this condition during routine prenatal testing and ultrasound. Otherwise, it is recognized at birth.If anencephaly is detected before birth, further counseling will be needed. Prevention There is good evidence that folic acid can help reduce the risk for certain birth defects, including anencephaly. Women who are pregnant or planning to become pregnant should take a multivitamin with folic acid every day. Many foods are now fortified with folic acid to help prevent these kinds of birth defects.Getting enough folic acid can cut the chances of neural tube defects in half.Folic acidTaking folic acid before and during pregnancy can reduce the risk for certain birth defects. These include spina bifida, anencephaly, and some heart...ImageRead Article Now Book Mark Article Open ReferencesReferencesDean B, Doherty D. Congenital malformations of the central nervous system. In: Gleason CA, Sawyer T, eds. Avery's Diseases of the Newborn. 11th ed. Philadelphia, PA: Elsevier; 2024:chap 53.Kinsman SL, Johnston MV. Congenital anomalies of the central nervous system. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 609.Sarnat HB, Flores-Sarnat L. Developmental disorders of the nervous system. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff''s Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 89.AllVideoImagesTogUltrasound, normal fetus - ventricles of brain - illustration This is a normal fetal ultrasound performed at 17 weeks gestation. The development of the brain and nervous system begins early in fetal development. During an ultrasound, the technician usually looks for the presence of brain ventricles. Ventricles are spaces in the brain that are filled with fluid. In this early ultrasound, the ventricles can be seen as light lines extending through the skull, seen in the upper right side of the image. The cross hair is pointing to the front of the skull, and directly to the right, the lines of the ventricles are visible.Ultrasound, normal fetus - ventricles of brainillustrationUltrasound, normal fetus - ventricles of brain - illustration This is a normal fetal ultrasound performed at 17 weeks gestation. The development of the brain and nervous system begins early in fetal development. During an ultrasound, the technician usually looks for the presence of brain ventricles. Ventricles are spaces in the brain that are filled with fluid. In this early ultrasound, the ventricles can be seen as light lines extending through the skull, seen in the upper right side of the image. The cross hair is pointing to the front of the skull, and directly to the right, the lines of the ventricles are visible.Ultrasound, normal fetus - ventricles of brainillustrationRelated Information Toxins(Special Topic)Folic acid in diet(Nutrition)Vitamins and Phytonutrients - InDepth(In-Depth) Review Date: 4/28/2023 Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. 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AnencephalyAprosencephaly with open craniumAnencephaly is the absence of a large part of the brain and the skull. Causes Anencephaly is one of the most common neural tube defects. Neural tube defects are birth defects that affect the tissue that becomes the spinal cord and brain.Anencephaly occurs early in the development of an unborn baby. It results when the upper part of the neural tube fails to close. The exact cause is not known. Possible causes include:Environmental toxins ToxinsToxins are substances created by plants and animals that are poisonous (toxic) to humans. Toxins may also include some medicines that are helpful in...ImageRead Article Now Book Mark Article Low intake of folic acid by the mother during pregnancyFolic acidFolic acid and folate are both terms for a type of B vitamin (vitamin B9). Folate is a B vitamin that occurs naturally in foods such as green leafy v...ImageRead Article Now Book Mark Article The exact number of cases of anencephaly is unknown. Many of these pregnancies result in miscarriage. Having one infant with this condition increases the risk of having another child with neural tube defects. Symptoms Symptoms of anencephaly are:Absence of the skull Absence of parts of the brain Facial feature abnormalities Severe developmental delayHeart defects may be present in 1 out of 5 cases. Exams and Tests An ultrasound during pregnancy is done to confirm the diagnosis. The ultrasound may reveal too much fluid in the uterus. This condition is called polyhydramnios.UltrasoundA pregnancy ultrasound is an imaging test that uses sound waves to create a picture of how a baby is developing in the womb. It is also used to chec...ImageRead Article Now Book Mark Article PolyhydramniosPolyhydramnios occurs when too much amniotic fluid builds up during pregnancy. It is also called amniotic fluid disorder, or hydramnios.ImageRead Article Now Book Mark Article The mother may also have these tests during pregnancy:Amniocentesis (to look for increased levels of alpha-fetoprotein) AmniocentesisAmniocentesis is a test that can be done during pregnancy to look for certain problems in the developing baby. These problems include:Birth defectsG...ImageRead Article Now Book Mark Article Alpha-fetoproteinAlpha fetoprotein (AFP) is a protein produced by the liver and yolk sac of a developing baby during pregnancy. AFP levels go down soon after birth. ...ImageRead Article Now Book Mark Article Alpha-fetoprotein level (increased levels suggest a neural tube defect) Urine estriol level A pre-pregnancy serum folic acid test may also be done. Treatment There is no current treatment. Talk to your health care provider about care decisions. Outlook (Prognosis) This condition most often causes death within a few days after birth. When to Contact a Medical Professional A provider usually detects this condition during routine prenatal testing and ultrasound. Otherwise, it is recognized at birth.If anencephaly is detected before birth, further counseling will be needed. Prevention There is good evidence that folic acid can help reduce the risk for certain birth defects, including anencephaly. Women who are pregnant or planning to become pregnant should take a multivitamin with folic acid every day. Many foods are now fortified with folic acid to help prevent these kinds of birth defects.Getting enough folic acid can cut the chances of neural tube defects in half.Folic acidTaking folic acid before and during pregnancy can reduce the risk for certain birth defects. These include spina bifida, anencephaly, and some heart...ImageRead Article Now Book Mark Article Open ReferencesReferencesDean B, Doherty D. Congenital malformations of the central nervous system. In: Gleason CA, Sawyer T, eds. Avery's Diseases of the Newborn. 11th ed. Philadelphia, PA: Elsevier; 2024:chap 53.Kinsman SL, Johnston MV. Congenital anomalies of the central nervous system. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 609.Sarnat HB, Flores-Sarnat L. Developmental disorders of the nervous system. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff''s Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 89.