A condition characterized by slight to moderate short stature, hypertelorism, small nose with anteverted nares, broad philtrum, orthodontic problems, brachydactyly, prominent umbilicus,  and shawl scrotum. A spectrum of behavioral disorders may be part of the AAS phenotype. May be at increased risk for mental deficiency.  The condition is transmitted by mutations in a gene called FGDY1 in band p11.21 on the X chromosome and follows an X-linked recessive inheritance (sex-linked) pattern.

See Also: Online Mendelian Inheritance in Man®

Abdomen (The Belly)

The body cavity below the chest that contains the stomach, liver, intestines and other organs.

An acceleration is an abrupt increase in the fetal heart rate above baseline with onset to peak of the acceleration less than 30 seconds and less than 2 minutes in duration.

Adequate accelerations are defined as:

Shortening of the hands or feet

Active Labor

The active phase (active labor) of labor begins when the cervix is opened (dilated) to 6 cm in the presence of uterine contractions. During the active phase uterine contractions become more frequent, the cervix dilates more quickly, and the baby descends into the pelvis.

Cervical dilation of at least 2 cm with membranes visible at 16 0/7 to 22 6/7 weeks' gestation as used by Owen J et al.
 

Owen J, et al. Multicenter randomized trial of cerclage for preterm birth prevention in high-risk women with shortened midtrimester cervical length. Am J Obstet Gynecol. 2009 Oct;201(4):375.e1-8.PMID:19788970
 

A birth defect in which there is partial or complete absence of the corpus callosum (the bundle of nerve fibers that connects the two hemispheres of the brain). 

ACC may occur as an isolated defect, but it is frequently associated with other malformations, chromosomal abnormalities (trisomy 18 an trisomy 8), and genetic syndromes. The outcome of the abnormality depends on the underlying cause and the presence of other structural defects. Isolated ACC (in particular partial ACC) is associated with no or mild neurologic impairment in a large proportion of cases. ACC occurring as part of a syndrome may be associated with severe mental retardation and seizures. ACC does not cause death in the majority of children.

Ultrasound findings include absence of the corpus callosum and cavum septum pellucidum, 'teardrop' configuration of the lateral ventricles, dilatation and upward  displacement of the third ventricle (interhemispheric "cyst") , and abnormal branching of the anterior cerebral artery. Magnetic resonance imaging is sometimes useful in confirming the diagnosis. 

Additional abnormalities commonly found in association with ACC include Chiari malformations, schizencephaly, encephaloceles, Dandy-Walker malformations, holoprosencephaly, heart defects, and GI or genitourinary malformations.

The risk of recurrence is ~ 1% for sporadic cases, 25% if ACC is associated with an  autosomal recessive cause, and 50% of males will be affected if inherited as an  X-linked recessive disorder.

Alloimmunization (Isoimmunization)

Production of an antibody against antigens produced by members of the same species.
 

A protein produced by the fetal liver and yolk sac that can be detected in the mother's blood. Alpha-fetoprotein levels rise gradually throughout most of pregnancy and level off near term. High levels of alpha-fetoprotein are associated with a more advanced pregnancy than expected, multiple pregnancy, fetal death (including a vanished twin), an opening in the spine (spina bifida), an opening in the head (anencephaly), or an opening in the abdominal wall (gastroschisis).  Low levels may be associated with Down syndrome, trisomy 18, and some cases of Turner syndrome.

Amniocentesis

A procedure in which a needle is inserted into the uterus and a sample of the fluid surrounding the fetus is drawn out. The procedure may be done to evaluate the fetal chromosomes, to determine fetal lung maturity, or to obtain fluid to culture for possible infections. The procedure may also be performed to remove an excessive amount of amniotic fluid.

Amnioinfusion

Infusion of fluid (usually normal saline or lactated Ringer's solution) into the amniotic cavity.

Amniotic fluid

Amniotic Fluid Index (AFI)

Amniotic sac

The membrane (amnion) that surrounds the fetus and the amniotic fluid.

Amniotic sheet

Amniotomy (artificial rupture of membranes , AROM)

A procedure performed (often using a plastic device that looks like a crochet needle ) to open the amniotic sac usually for the purpose of inducing or speeding up the progress of labor .

Anemia

Decreased amount of normal hemoglobin in blood. Hemoglobin is the substance in red blood cells that carries oxygen.

Anencephaly

A birth defect resulting in the absence of a major portion of the skull and brain. Anencephaly results when the upper portion of the neural tube fails to close. The condition is not compatible with life, and infants usually die within a few days after delivery. See picture

Anesthesia

Loss of sensation.

Angle of insonation

Angelman syndrome ("Happy Puppet Syndrome")

A disorder characterized by a large jaw and open-mouthed expression revealing the tongue, severe speech impairment, motor and intellectual retardation, ataxia, poor muscle tone, seizures, frequent laughing, smiling, and excitability. The disorder is usually caused by abnormalities of chromosome 15. 

A deletion of chromosome in the 15q11-q13 region accounts for up to 75% of cases and has a less than 1% recurrence risk. Mutations in the UBE3A gene on chromosome 15 accounts for 6 to 20% of cases and has a recurrence risk of less than 1% unless the patient's mother carries the UBE3A mutation on her own paternally inherited chromosome 15. In the latter case there is a 50% recurrence risk. Angelman syndrome is less commonly caused by inheritance of two copies of chromosome 15 from the father and no maternal copy of chromosome 15 (uniparental disomy) , or mutations in the imprinting center of the UBE3A gene.

Aniridia

Absent or partially absent iris accompanied by macular and optic nerve hypoplasia. Symptoms include poor vision  sensitivity to light (photophobia), and nystagmus. Frequently associated  abnormalities  include glaucoma and cataracts.  Mutation of the PAX 6 gene or deletion of a regulatory region controlling its expression, appears to be responsible for aniridia occurring  as an isolated ocular defect . The condition is autosomal dominant.

Aniridia may also occur as part of the Wilms tumor-aniridia-genital anomalies-retardation (WAGR) syndrome, with a deletion of 11p13 involving the PAX6 (aniridia) locus and the adjacent WT1 (Wilms tumor) locus.

Anomaly

Malformation or abnormality.

Antenatal

Before birth.

Antenatal steroids

Steroids (either betamethasone or dexamethasone) given to help the fetal lungs and other organs mature more rapidly. Antenatal steroids are given when preterm delivery is anticipated between 24 and 34 weeks' gestation with intact membranes, and at 24 to 32 weeks' with ruptured membranes.

Antepartum

Before delivery or birth.

Anterior

In front

Antibody (Immunoglobulin)

Proteins secreted by white blood cells (lymphocytes) that bind to foreign molecules. Antibodies attach to the antigens and destroy the invader directly , or label them for removal by your white blood cells.Antibodies (immunoglobulins) are grouped into five classes or isotypes: IgG, IgA, IgM, IgD, and IgE.

A molecules that stimulates antibody production is called an antigen (antibody generator). 

Anticardiolipin antibodies (ACA, aCL Antibody)

An antibody that attaches to cardiolipin , a fatty molecule,  found mostly in the mitochondrial inner membrane where it is synthesized from phosphatidylglycerol  . ACA may be found in several diseases including antiphospholipid syndrome and systemic lupus erythematosus (SLE). Three classes of cardiolipin antibodies may be present in the blood: IgG, IgM and/or IgA.

Anti-c antibody (little c antibody)

A protein made by the immune system that binds to a molecule called the c antigen found on the surface of red blood cells. The c antigen is part of the Rhesus blood group system which consists of several antigens (D , E , e , c, C, ). The antibody hastens removal of the c antigen (and the foreign blood cells) from the body.

A protein made by the immune system that binds to a molecule called the D antigen found on the surface of red blood cells. The D antigen is part of the Rhesus blood group system which consists of several antigens (D , E , e , c, C, ). The antibody hastens removal of the D antigen (and the foreign blood cells) from the body.

Arrest of descent

Second-stage arrest may be diagnosed if there has been
"No progress (descent or rotation) for
4 hours or more in nulliparous women with an epidural
3 hours or more in nulliparous women without an epidural
3 hours or more in multiparous women with epidural
2 hours or more in multiparous women without an epidural"

Spong CY, et. al. Preventing the first cesarean delivery: summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, and American College of Obstetricians and Gynecologists Workshop. Obstet Gynecol. 2012 Nov;120(5):1181-93. doi http://10.1097/AOG.0b013e3182704880. PMID: 23090537

Arrest of dilatation

For spontaneous labor:
6 cm or greater dilation with membrane rupture AND 4 hours or more of adequate contractions (e.g., > 200 Montevideo units) OR
6 hours or more if contractions inadequate with no cervical change

For induced labor:
6 cm or greater dilation with membrane rupture or 5 cm or greater without membrane rupture AND 4 hours or more of adequate contractions (e.g., > 200 Montevideo units) OR
6 hours or more if contractions inadequate with no cervical change [4].

Spong CY, et. al. Preventing the first cesarean delivery: summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, and American College of Obstetricians and Gynecologists Workshop. Obstet Gynecol. 2012 Nov;120(5):1181-93. doi http://10.1097/AOG.0b013e3182704880. PMID: 23090537

Artificial rupture of membranes (AROM)

See amniotomy.

Ascites

Aspirate

To inhale into liquid or food into the lungs, or to draw (fluid) by suction
 

Augmentation of  labor

Autologous transfusion

"Infusion of  blood or blood component to the same individual from whom it was taken"

Autosomal dominant

A trait determined by a gene on any chromosome other than a sex chromosome (X or Y) that requires only one gene for the trait to be expressed. The chance of passing the trait to an offspring is at least 50% for each pregnancy.
 See Diagram

Autosomal recessive

A trait determined by a gene on any chromosome other than a sex chromosome (X or Y) that requires two genes for the trait to be expressed. A person with only one copy of the gene is said to be a carrier for the trait.
 See Diagram