Term
| Percutaneous umbilical blood sampling (PUBS) |
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Definition
| Provides direct access to fetal circulation in 1st & 2nd trimesters. Used for fetal blood sampling and transfusion. Umbilical cord is punctured near its insertion into the placenta, a small amount of blood is removed and tested immediately by the Kleihauer-Betke procedure (Apt test) to ensure that it is fetal in origin. Indicated for prenatal diagnosis of inherited blood disorders, karyotyping of malformed fetuses, detection of fetal infection, isoimmunization, and thrombocytopenia. It is becoming replaced by placental biopsy because it is safer, easier, and faster. |
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Term
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Definition
| production by an individual of antibodies against constituents of the tissues of another individual of the same species |
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Term
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Definition
| deficiency of platelets in the blood. This causes bleeding into the tissues, bruising, and slow blood clotting after injury. |
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Term
| What is aplpha-fetoprotein |
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Definition
| Alpha-fetoprotein (MSAFP) levels are used as a SCREENING tool for Neural Tube Defects (NTDs). Using this, about 80% to 85% of all NTDs and abdominal wall defects can be detected early. Used reliably between 15 and 20 weeks. If indicated by MSAFP, patients are subject to more definitive procedures such as amniocentesis and ultrasound. |
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Term
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Definition
Double screening: for human chorionic gonadotropin (hCG) and pregnancy-associated placental protein (PAPP-A) is used in the first trimester (11-14 weeks) and it looks for Trisomy 21 (down syndrome).
Triple screening: for alpha-fetoprotien (MSAFP), unconjugated estriol, and hCG is used in the second trimester (16-18 weeks) and it looks for trisomy 21 and 18 (Edwards syndrome-intrauterine growth retardation).
Quad screening: for inhibin A, MSAFP, unconjugated estriol, and hCG is used in the second trimester (16-18 weeks) and it further increases the chance of identifying down syndrome at an early stage. |
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Term
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Definition
| A screening tool for rH incompatibility. If the maternal titer for Rh antibodies is greater than 1:8, amniocentesis for determination of bilirubin in amniotic fluid is indicated to establish the severity of fetal hemolytic anemia. However, as previously discussed, middle cerebral artery Doppler studies to determine the degree of fetal hemolysis have almost entirely replaced serial amniocentesis. |
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Term
| What is cell free DNA screen? |
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Definition
| A sample of maternal blood is obtained by venipuncture and sent to a commercial laboratory. Results are usually available in about 10 business days. The screen has been shown to be 98% effective at detecting trisomy 21 and 99% effective at detecting trisomies 13 or 18. Can be performed any time after 10 weeks of gestation. |
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Term
| What is the nonstress test? |
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Definition
| The basis for the NST is that the normal fetus produces characteristic heart rate patterns in response to fetal movement, uterine contractions, or stimulation. The FHR is recorded with a Doppler transducer, and a tocodynamometer is applied to detect uterine contractions or fetal movements. The tracing is observed for signs of fetal activity and a concurrent acceleration of FHR. Takes 20-30 minutes. Results are either reactive or nonreactive. Test is repeated twice a week until term. |
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Term
| Vibroacoustic stimulation |
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Definition
also called the fetal acoustic stimulation
test (FAST), The fetus is monitored for 5 minutes before stimulation to obtain a baseline FHR. If the fetal baseline pattern is nonreactive, the sound source is then activated for 3 seconds on the maternal abdomen over the fetal head. The desired result is a reactive NST, which usually occurs within 3 minutes of stimulation. The test may be repeated at 1 minute intervals up to 3 times when no response is noted. |
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Term
| What is the daily fetal movement count? |
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Definition
| Also called a kick count, is a reassuring sign of fetal health. In the third trimester the fetus makes about 30 body movements each hour. Mother recognizes 70% to 80% of these movements. Count once a day for 60 minutes, count 2 or 3 times daily for 2 hours or until 10 movements are counted, or all fetal movements in a 12-hour period each day until a minimum of 10 movements are counted. A count of fewer than three fetal movements within 1 hour warrants further evaluation by a NST or CST and a complete or mBPP. Fetal movement is usually not present during the fetal sleep cycle. Also, they do not decrease as the woman nears term. |
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Term
| Types of ultrasound scans |
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Definition
2D: Standard medical scan. Sound waves are sent straight down from the ultrasound transducer. Image produced includes only two dimensions. Viewed in black, white, or shades of gray.
3D: Used for diagnostic purposes and enjoyment of pregnant women. Sound waves are sent out at different angles, producing a three-dimensional image. Displayed in sepia tones rather than in black and white.
4D: This scan adds time to the 3D scan. Images are recorded and played back in succession. As
the image is continuously updated, the fetus is viewed in real time. |
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Term
| Abdominal ultrasonography |
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Definition
| More useful after the first trimester when the pregnant uterus becomes an abdominal organ. Woman usually should have a full bladder to displace the uterus upward to provide a better image of the fetus. She is positioned with small pillows under her head and knees. |
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Term
| Transvaginal ultrasonography |
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Definition
| A probe is inserted into the vagina, allows pelvic anatomic features to be evaluated in greater detail and intrauterine pregnancy to be diagnosed earlier. A transvaginal ultrasound is well tolerated by most pregnant women because it removes the need for a full bladder. It is useful in obese women whose thick abdominal layers cannot be penetrated with an abdominal approach. The procedure is not physically painful. Optimally used in the first trimester to detect ectopic pregnancies, monitor the developing embryo, help identify abnormalities, and help establish gestational age. |
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Term
| Levels of ultrasonography |
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Definition
Standard exam: is most frequent, can be performed by ultrasonographers or nurses, who have had special training. In the second and third trimesters a standard ultrasound exam is used to evaluate fetal presentation, amniotic fluid volume, cardiac activity, placental position, fetal growth parameters, and number of fetuses.
Limited exam: is performed ID fetal presentation during labor or to estimate AFV.
Specialized or targeted exam: is performed if a woman is suspected of carrying an anatomically or physiologically abnormal fetus. |
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Term
| Indications for use of ultrasonography |
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Definition
During the first trimester ultrasound exam is performed to obtain number, size, and location of gestational sacs; presence or absence of fetal cardiac and body movements; presence or absence of uterine abnormalities or adnexal masses; and pregnancy dating.
During the second and third trimesters the following information is sought: fetal viability, number, position, gestational age, growth pattern, and anomalies; amniotic fluid volume; placental location and condition; presence of uterine fibroids or anomalies; presence of adnexal masses; and cervical length. |
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Term
| Indications for use of ultrasonography: Fetal heart activity |
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Definition
| Fetal heart activity can be demonstrated by about 6 weeks of gestation using transvaginal ultrasound. Good views of the fetal cardiac anatomy are possible in most patients at 13 weeks of gestation. Fetal death can be confirmed by lack of heart motion along with the presence of fetal scalp edema and maceration and overlap of the cranial bones. |
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Term
| Indications for use of ultrasonography: Gestational age |
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Definition
| Gestational dating by ultrasonography is indicated for conditions such as uncertain dates for the last normal menstrual period, recent discontinuation of oral contraceptives, a bleeding episode during the first trimester, uterine size that does not agree with dates, and other high risk conditions. Exams performed for pregnancy dating between 14 and 22 weeks of gestation is comparable to one performed during the first trimester in terms of accuracy. However, after that time ultrasound dating is less reliable because of variability in fetal size. |
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Term
| Indications for use of ultrasonography: Fetal growth |
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Definition
| Conditions that require ultrasound of fetal growth include poor maternal weight gain or pattern of weight gain, previous pregnancy with IUGR, chronic infections, ingestion of drugs (tobacco, alcohol, over-the-counter and street drugs), maternal diabetes, hypertension, multifetal pregnancy, and other medical or surgical complications. |
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Term
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Definition
| Symmetric IUGR reflects a chronic or long standing insult and may be caused by low genetic growth potential, intrauterine infection, chromosomal anomaly, maternal undernutrition, or heavy smoking. Asymmetric growth suggests an acute or late-occurring deprivation such as placental insufficiency resulting from hypertension, renal disease, or cardiovascular disease. |
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Term
| Define nuchal translucency |
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Definition
A prenatal screening technique which uses
ultrasound measurement of fluid in the nape of the fetal neck between 10 and 14 weeks of gestation to identify possible fetal abnormalities. A fluid collection that is greater than 3mm is considered abnormal.
[image] |
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Term
| Define trisomy 13, 18, and 21 |
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Definition
13: also called Patau syndrome, is a genetic disorder in which a person has 3 copies of genetic material from chromosome 13, instead of the usual 2 copies. Rarely, the extra material may be attached to another chromosome, known as translocation.
18: also called Edwards syndrome, is a chromosomal condition associated with abnormalities in many parts of the body. Individuals with trisomy 18 often have slow growth before birth (intrauterine growth retardation) and a low birth weight.
21: the most common form of Down syndrome, caused by an extra copy of chromosome number 21 |
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Term
| What is doppler blood flow analysis? |
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Definition
| RBC velocity waveforms from the umbilical and uterine arteries, reported as systolic/diastolic (S/D) ratios, can be first detected at 15 weeks of pregnancy. Because of the progressive decline in resistance in both the umbilical and uterine arteries, this ratio normally decreases as pregnancy advances. Findings of absent or reversed end-diastolic blood flow and S/D ratios above 3 indicate placental vascular disease. |
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Term
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Definition
| Increased amniotic fluid. Subjective criteria for polyhydramnios include multiple large pockets of fluid, the impression of a floating fetus, and free movement of fetal limbs. Hydramnios is usually defined as pockets of amniotic fluid measuring more than 8cm. Polyhydramnios is associated with neural tube defects (NTDs), obstruction of the fetal gastrointestinal tract, multiple fetuses, and fetal hydrops. |
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Term
| Define amniotic fluid index |
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Definition
| The total AFV can be evaluated by a method in which the vertical depths (in centimeters) of the largest pocket of amniotic fluid in all four quadrants surrounding the maternal umbilicus are totaled, providing an amniotic fluid index. A normal AFI is 10cm or greater, with the upper range of normal around 25cm. AFI values between 5 and 10cm are considered to be low normal, whereas an AFI of less than 5cm indicates oligohydramnios. |
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Term
| What is the biophysical profile (BPP)? |
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Definition
| a noninvasive dynamic assessment of a fetus that is based on acute and chronic markers of fetal disease. The BPP includes AFV, FBMs, fetal movements, and fetal tone determined by ultrasound and fetal heart rate (FHR) reactivity determined by means of the nonstress test. A BPP of 8 or 10 with a normal AFV is considered normal. |
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Term
| What is the modified BPP? |
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Definition
| The mBPP combines the nonstress test, which assesses the current fetal condition, with measurement of the quantity of amniotic fluid, an indicator of placental function over a longer period of time. The AFI (rather than the AFV) is often used to measure the amount of amniotic fluid present. Desired test results are a reactive nonstress test and a normal AFI. |
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Term
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Definition
| MRI provides excellent pictures of soft tissue. Unlike CT, ionizing radiation is not used. Therefore vascular structures within the body can be visualized and evaluated without injecting an iodinated contrast medium, thus eliminating any known biologic risk. |
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Term
| At what week in gestation is amniocentesis possible? |
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Definition
| After 14 weeks of pregnancy. |
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Term
| What is phosphatidylglycerol (PG)? |
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Definition
Late in pregnancy accurate assessment of fetal
lung maturity is possible by examining amniotic fluid for the presence of phosphatidylglycerol (PG). |
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Term
| What is doppler velocimetry? |
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Definition
| Doppler velocimetry of the fetal middle cerebral artery is now the method of choice to monitor accurately and noninvasively for fetal anemia in isoimmunized pregnancies. |
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Term
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Definition
| production by an individual of antibodies against constituents of the tissues of another individual of the same species (as when transfused with blood from one belonging to a different blood group) — called also alloimmunization. |
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Term
| What is chorionic villus sampling? |
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Definition
CVS can be performed in the first or second trimester, ideally between 10 and 13 weeks of gestation, and involves the removal of a small tissue specimen from the fetal portion of the placenta. Because chorionic villi originate in the zygote, this tissue reflects the genetic makeup of the fetus. CVS procedures can be accomplished transcervically or transabdominally.
[image]
[image] |
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Term
| Explain the contraction stress test (CST) |
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Definition
| The CST or oxytocin challenge test (OCT) purpose was to identify the jeopardized fetus that was stable at rest but showed compromise after stress (looking for late decelerations). Two types of CST are nipple-stimulated contraction test and OCT. Contraindications for CST are preterm labor, placenta previa, vasa previa, reduced cervical competence, multiple gestations, and previous classic incision for cesarean birth. CST results are negative, positive, equivocal, suspicious, or unsatisfactory. If no late decelerations are observed with the contractions, the findings are considered negative (negative is the desired outcome) |
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Term
| Nipple-stimulated contraction test |
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Definition
| The woman applies warm, moist washcloths to both breasts for several minutes. She is then asked to massage one nipple for 10 minutes. Massaging the nipple causes a release of oxytocin from the posterior pituitary. An alternative approach is for her to massage one nipple through her clothes for 2 minutes, rest for 5 minutes, and repeat the as necessary. When adequate contraction (defined as uterine contractions lasting more than 90 seconds or five or more contractions in 10 minutes) occurs, stimulation should be stopped. |
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Term
| Oxytocin-stimulated contraction test |
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Definition
| An IV infusion of oxytocin 30 units in 500mL fluid is infused into the tubing of the main IV line through a piggyback and delivered by infusion pump. Infusion is to begin at 0.5 milliunits/min and double the dose every 20 minutes until three uterine contractions of moderate intensity, each lasting 40 to 60 seconds, are observed within a 10-minute period. |
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