Prequel Terms Flashcards
Advanced Maternal Age
Maternal age older than 35 years
Amniocentesis
a procedure in which amniotic fluid is removed from the uterus for testing or treatment.
Anatomy Scan
a pregnancy ultrasound performed between 18–22 weeks of gestational age. The purpose of the ultrasound is to evaluate the development of the baby, detect any growth abnormalities early, and to assess for the presence of any congenital malformations.
Aneuploidy
the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46.
Alpha-fetoprotein (AFP)
a protein produced in the liver of a developing fetus. During a baby’s development, some ___ passes through the placenta and into the mother’s blood. An ___ test measures the level of ___ in pregnant women during the second trimester of pregnancy. Too much or too little ___ in a mother’s blood may be sign of a birth defect or other condition, such as an open neural tube defect.
During prenatal cell-free DNA
DNA from the mother and fetus is extracted from a maternal blood sample and screened for the increased chance for specific chromosome problems, such as Down syndrome, trisomy 13 and trisomy 18.
Chromosome
an organized package of DNA found in the nucleus of the cell. Different organisms have different numbers of ____. Humans have 23 pairs of chromosomes – 22 pairs of numbered ____, called autosomes, and one pair of sex ____, X and Y.
Chorionic Villus Sampling (CVS)
a method of prenatal diagnosis, which is a way to directly test for genetic conditions in the fetus. During the ___ test, a small sample of cells is taken from the placenta where it attaches to the wall of the uterus.
Euploid
The normal number of chromosomes for a species. In humans, the ___ number of chromosomes is 46
Expanded Eneuploidy Analysis (EAA)
The expansion of NIPS analysis from only the common ____ (chromosomes 13, 18, 21, X, Y) to all 46 chromosomes
Fetal Fraction
describes the proportion of the total cfDNA that is fetal in origin. The ‘fetal’ component is actually derived from placental trophoblast
First Trimester Screening
a 2-step prenatal screen that assesses the risk of a baby having trisomy 13, 18, or 21 (down syndrome). Typically, ___ is done between weeks 11 and 14 of the pregnancy
Integrated/Sequential Screen
two-stage screening that assesses the risk of a baby being born with Down syndrome, Trisomy 18, or Open Neural Tube Defects (ONTDs)
Intrauterine Growth Restriction (IUGR)
refers to a condition in which an unborn baby is smaller than it should be because it is not growing at a normal rate inside the womb. Delayed growth puts the baby at risk of certain health problems during pregnancy, delivery, and after birth
Karyotype
refers to a test to identify and evaluate the size, shape, and number of chromosomes in a sample of body cells.
Maternal-Fetal Medicine Specialist (MFM)
or perinatologist, is an ob-gyn with specialized training to manage high-risk pregnancies.
Microdeletion Syndrome
is a syndrome caused by a chromosomal deletion smaller than 5 million base pairs (5 Mb) spanning several genes that is too small to be detected by conventional cytogenetic methods or high resolution karyotyping (2–5 Mb).
Monosomy
is the state of having a single copy of a chromosome pair instead of the usual two copies found in diploid cells. ___, or partial ____, is the cause of some human diseases such as Turner syndrome and Cri du Chat syndrome
Noninvasive Prenatal Screening (NIPS)
is a method of determining the risk that the fetus will be born with certain genetic abnormalities [most often chromosomal aneuploidies – 13, 18, 21, X,Y]. ____ is considered noninvasive because it utilizes a blood sample from the pregnant woman to analyze small fragments of cell-free DNA, and does not pose any risk to the fetus. ____ is a screening test, which means that it will not give a definitive answer about whether or not a fetus has a genetic condition.
Nuchal Translucency Screening
is a test done during pregnancy. It uses ultrasound to measure the thickness of the fluid buildup at the back of the developing baby’s neck. If this area is thicker than normal, it can be an early sign of Down syndrome, trisomy 18, or heart problems.
Placenta
is an organ that develops in your uterus during pregnancy. This structure provides oxygen and nutrients to your growing baby and removes waste products from your baby’s blood. The ____ attaches to the wall of your uterus, and your baby’s umbilical cord arises from it.
Placental Insufficiency (uteroplacental vascular insufficiency)
is a complication of pregnancy when the placenta is unable to deliver an adequate supply of nutrients and oxygen to the fetus, and, thus, cannot fully support the developing baby.
Positive Predictive Value
is the probability that subjects with a positive screening test truly have the disease.
Products of Conception (POC)
is a medical term that refers to any tissues that developed during pregnancy - fetal tissue, placenta tissue, or other material that comes from fertilization. In the case of pregnancy loss, ____ describe material expelled from the vagina or surgically removed from the uterus.
Quad Screen Test
is a maternal blood screening test that looks for four specific substances: AFP, hCG, Estriol, and Inhibin-A.
Diagnostic Ultrasound (also called sonography or diagnostic medical sonography)
is an imaging method that uses high-frequency sound waves to produce images of structures within your body
Single Nucleotide Polymorphism (SNP)
The NIPS technology employed by Natera. This assay involves sequencing all cell-free DNA, and only maternal DNA from the buffy coat of a spun sample. A proprietary algorithm compares ____ patterns to determine the likelihood of an affected pregnancy
Spontaneous miscarriage/spontaneous abortion (SAB) miscarriage
is the spontaneous loss of a pregnancy before the 20th week. About 10 to 20 percent of known pregnancies end in miscarriage. But the actual number is likely higher because many miscarriages occur so early in pregnancy that a woman doesn’t realize she’s pregnant.
Pregnancy Termination/Abortion
is the removal of pregnancy tissue, products of conception or the fetus and placenta (after birth) from the uterus. In many cases, abortion is used to end a pregnancy when tests reveal that the fetus is abnormal. Therapeutic ____ refers to an abortion recommended when the mother’s health is at risk. The majority of _____ are performed during the first 12 weeks of pregnancy.
Triploidy
is a rare chromosomal abnormality in which fetuses are born with an extra set of chromosomes in their cells. Sadly, ____ is always fatal and there is no cure or treatment for the condition. Almost all (more than 99%) of babies with ____ are miscarried or stillborn. Of those born alive, most die in the hours or days following birth.
Trisomy
A type of aneuploidy characterized by the gain of an extra copy of a chromosome
Whole Genome Sequencing (WGS)
The NIPS technology employed by Myriad and most other NIPS laboratories. This assay involves sequencing small stretches of DNA (tags) across the genome, determining the chromosome of origin for each tag, and counting tags to infer the presence or absence of DNA segments/chromosomes.
