Pregnancy Terms Glossary
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Tay-Sachs disease (TSD, Hexosaminidase A deficiency)


Small enlarged blood vessels near the surface of the skin 1 to 3 mm in width and several mm to centimeters in length.


Anything that can cause a birth defect such as a maternal condition (diabetes, PKU) , a drug (alcohol), a medication (valproic acid, isotretinoin) , an infectious agent (toxoplasmosis, cytomegalovirus) or a physical agent (ionizing radiation).

Term pregnancy

The four definitions of the types of ‘term’ deliveries are:

Early Term: Between 37 weeks 0 days and 38 weeks 6 days
Full Term: Between 39 weeks 0 days and 40 weeks 6 days
Late Term: Between 41 weeks 0 days and 41 weeks 6 days
Postterm: Between 42 weeks 0 days and beyond

Testicle (Testis)

Either of the two male reproductive organ found in the pouch (scrotum) below the penis. The testicles produce sperm and sex hormones.


A steroid hormone produced by the Leydig cells of the testicles (and to a lesser extent the ovaries and adrenal glands) that promotes the development of secondary male sexual  characteristics.

Normal Values
Male: 10 - 35 nmol/L (3 - 10 ng/mL)
Female: Less than 3.5 nmol/L ( < 1 ng/mL)
Prepubertal boys and girls: 0.17 - 0.7 nmol/L (0.05 -0.2 ng/mL)

Tetralogy of Fallot

A group of inherited blood disorders characterized by moderate to severe anemia. Thalassemias are caused by defects in the genes that control production of globins, the building blocks of hemoglobin (the oxygen carrying molecule in red blood cells).

The two main types of thalassemia are alpha-thalassemia and beta-thalassemia .

 α-Thalassemia-2 trait also known as Silent Carrier (α-Thalassemia-2 Trait)(One affected gene) has no consistent hematologic manifestations. The red blood cells are not microcytic, and Hb A2 and Hb F are normal. 



A lower than normal number (count) of platelets in the blood. Platelets are cell fragments in the blood that help to form blood clots.

150,000 to 450,000 platelets per microliter (x 10–6/Liter)

Persons with low platelet numbers may experience nosebleeds, gum bleeding , bruises and small red pinpoints on the skin (petechiae). Rarely persons will experience bleeding into the urine, gastrointestinal tract, or into the head with very low platelet numbers.

Common causes of thrombocytopenia during pregnancy include:

  • Gestational thrombocytopenia
  • Pre-eclampsia
  • HELLP syndrome
  • Immune thrombocytopenic purpura
  • Drugs
      Heparin, quinine, quinidine, zidovudine, sulfonamides, trimethoprim-sulfamethoxazole, gold compounds, sulfonamides, rifampin, valproic acid, phenytoin , digitalis ranitidine, cimetidine, procainamide, ampicillin, penicillin, alpha-methyl dopa, ethanol, aspirin, acetaminophen, indocin

    Less common:

  • Systemic lupus Erythematosus, antiphospholipid syndrome, human immunodeficiency virus (HIV) infection , B12 or folate deficiency, hyperthyroidism, massive transfusion, prosthetic heart valves, thrombotic Thrombocytopenic Purpura (TTP), sepsis , disseminated intravascular coagulation (DIC) , hypersplenism, hemolytic uremic syndrome, hereditary thrombocytopenias, alcoholism, leukemia, aplastic anemia

    Thrush (Candidiasis)

    A yeast (Candida) infection of the tongue , mouth , and throat characterized by white patches and ulcers. Thrush is usually seen in infants , but occurs with increased frequency in adults with diabetes or HIV.


    The concentration of an antibody in the blood. The titer is measured by diluting a sample until the antibody is no longer detectable. The result is given as the reciprocal (inverse) of the last dilution giving a measurable effect.


    • A blood sample (tube 1) has been diluted by 1/2  to produce tube 2,  tube 2 was

    • diluted by 1/2  to produce tube 3 and so forth.
    • A substance was added to each tube to detect antibody.
    • The 4th tube is the last dilution at which the antibody is detected, and it is 1/8 th the
    • strength of the original sample.
    • The titer of the antibody is therefore 8.















    A substance that decreases uterine contractions.

    Total iron-binding capacity (TIBC)

    A measurement of the amount of iron that can potentially be bound by transferrin.

    • If the iron stores in the body are low, fewer sites on the transferrin molecules will be filled by iron, and the TIBC will be higher. If the amount of transferrin is increased the TIBC will also be increased.
    • If the iron stores in the body are very high the or transferrin is decreased  then the TIBC will be low because most of the binding sites are filled. A low TIBC may be seen in hemochromatosis, sideroblastic anemia, and liver disease.

    Toxemia (Preeclampsia)


    An illness caused by the parasite, Toxoplasma gondii. Toxoplasma gondii is found in raw and undercooked meat; unwashed fruits and vegetables; dirty cat-litter boxes; and outdoor places where cat feces can be found.Fetal infection can occur via transplacental transmission.


    The protein found in blood that carries iron. The liver produces transferrin, and increases its production of transferrin in response to iron deficiency and pregnancy.

    Transferrin saturation (%)

    SEE Percent transferrin saturation (TSAT)

    Transposition of the great arteries (TGA, Transposition of the Great Vessels, TGV )

    A birth defect of the heart in which the the aorta and the pulmonary artery are switched (transposed). The aorta arises from the right ventricle instead of from the left ventricle, and the pulmonary artery arises from the left ventricle instead of arising from the right ventricle. In transposition of the great arteries the blood from the body enters the right side of the heart and flows into the aorta back to the body without receiving oxygen from the lungs.

    While in the uterus the fetus is able to maintain adequate delivery of oxygen  to the body because the formen ovale allows mixing of blood between the right and left atrium and the ductus arteriosus allows mixing of the blood between the pulmonary artery and the aorta. After delivery the baby will become blue due to lack of oxygen if these structures are not kept open.

     Then ductus may be kept open using drugs and t he foramen ovale can be enlarged with a catheter procedure which is performed in the first few days of life.  An  "Arterial Switch Operation"  carried out in the first week or two of life corrects the primary abnormality. T he small coronary arteries, which feed the heart muscle  are transferred as well.


    On ultrasound examination the junction of two amniotic sacs forms a 90 degree angle with the placenta, a T-shaped junction. There is no placental tissue extending between the amniotic membranes. The T-sign strongly indicates that there is a single placenta (monochorionic).

    Twin peak sign, Lambda sign

    On ultrasound examination the presence of a triangular projection of placental tissue extending between two amniotic sacs. The twin peak sign strongly indicates that there are two separate placentas (dichorionic).



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