Ch. 22 Obstetric Sonography Overview Flashcards
Normal pregnancy is how long?
9 months, 40 weeks, 280 days; may last up to 42 weeks
The first trimester
time of conception to 12 weeks
The second trimester
13-26 weeks
The third trimester
27-40 weeks
Fetal age is determined by
LMP (may be referred to as menstrual or gestational age)
From the time of conception to 10 weeks the concepts is referred to as an
embryo
After 10 weeks the embryo will be referred to as
a fetus
37-42 gestational weeks is considered
term
Beyond 42 weeks of gestation is considered
post-term
Between 24-37 weeks of gestation is considered
preterm
The date of the LMP is the last date at which the patient started menstruation. It can be used to determine the _________(EDC), or more commonly referred to as the “due date.” The EDC will be calculated by the ultrasound machine once the LMP is entered into the machine’s obstetric calculation package.
estimated date of confinement
what is the term for pregnant
gravid
something that can cause birth defects or abnormalities within an embryo or fetus; examples include medications, tobacco products, chemicals, alcohol, and certain infections
Teratogen
the manual manipulation by a physician of a fetus that is in breech or transverse position to a cephalic position in order to facilitate vaginal delivery
external cephalic version
First-trimester sonograms may require the use of a ___- to ___-MHz or higher TV transducer to better visualize intrauterine structures and the adnexa. Typically, a ___- to ___-MHz TA transducer will allow sufficient penetration in most pregnant patients, while providing sufficient resolution. These frequency ranges will vary among ultrasound equipment.
5-to-10MHz; 3-to-5
*Obese pts may require lower frequency txds; in some thin pts a linear txd may be used
All transducers and transducer cords should undergo disinfection after performing an obstetric sonogram to prevent the spread of disease. TV transducers should undergo ________disinfection, and the manufacturer’s specified instructions should be followed.
high-level
diabetes that is preexisting to pregnancy
pregestational diabetes
diabetes acquired as a result of pregnancy
gestational diabetes
There are several common maternal clinical issues and stressors that occur during pregnancy, including skin changes, postural changes, back pain, constipation, contractions, dehydration, edema, gastrointestinal reflux disease, hemorrhoids, round ligament pain, urinary frequency, varicose vein, and even an increase for ________issues exists in some situations
cardiovascular
Patients in their late second or third trimester may suffer from _________, which is a reduction in blood return to the maternal heart caused by the gravid uterus compressing the maternal inferior vena cava.
supine hypotensive syndrome
The sonographer should position the pt in what position to alleviate the symptoms of supine hypotensive syndrome?
The sonographer can assist the patient into a right lateral or left lateral position to alleviate symptoms
Patients with supine hypotensive syndrome can complain of tachycardia, sweating, nausea, and _____
pallor
______ denotes the number of times a woman has been pregnant, whereas ______ denotes the number of pregnancies that led to the birth of a fetus at or beyond 20 weeks’ gestational age or of an infant who weighed at least 500 g
Gravidity; parity
Gathering a clinical history includes a basic inquiry into the patients past obstetric history by documenting gravidity (G) and parity (P). A more specific method can be further added using the TPAL description. These inquiries should include questions about previous pregnancies or fetal complications, diabetes, hypertension, infertility, and the general health of other children at the time of birth and currently. What does “TPAL” stand for?
(Term, Premature, Abortions, Live birth)
from an unknown origin
idiopathic
when the placenta covers or nearly covers the internal os of the cervix
placenta previa
the premature separation of the placenta from the uterine wall before the birth of the fetus
placental abruption
a condition of having an abnormal number of chromosomes
aneuploidy
has been pregnant more than once
Multigravida
has given birth more than once
Multiparous
not given birth
Nulliparous
first pregnancy
Primigravida
has given birth once
Primiparous
In the second trimester painless vaginal bleeding is most often associated with
placenta previa
In the second trimester painful vaginal bleeding is most often associated with
placental abruption
The ______ is a maternal blood test performed between 15 and 20 gestational weeks. It includes human chorionic gonadotropin (hCG), maternal serum alpha-fetoprotein (MSAFP), and estriol
triple screen
a maternal blood test that includes an analysis of human chorionic gonadotropin, alpha-fetoprotein, estriol, and inhibin A
quadruple screen
a peptide hormone secreted by the placenta during pregnancy
inhibin A
a hormone produced by the trophoblastic cells of the early placenta; may also be used as a tumor marker in nongravid patients and males
human chorionic gonadotropin
a protein produced by the fetal yolk sac, fetal gastrointestinal tract, and the fetal liver; may also be produced by some malignant tumors
alpha-fetoprotein (MSAFP)
an estrogenic hormone produced by the placenta
estriol
a protein that is produced by the placenta
pregnancy-associated plasma protein A (PAPP-A)
the anechoic space along the posterior aspect of the fetal neck
nuchal translucency (NT)
Early 1st trimester screening (11-14 weeks) is used to asses possibility of disease and is an analysis of
hCG, preganancy associated plasma protein A (PAPP-A), nuchal translucency
Biochemical marker produced by the fetus (maternal serum detection), reveal gender and highly accurate in detecting chromosomal anomalies including trisomies 21,18, and 13 and sex chromosome abnormalities, as early as 9 to 10 weeks’ gestation.
cell free DNA (cfDNA)
There are limitations to cfDNA, including that up to 2% of cfDNA tests are ______, it is limited to screening for only a _____ common aneuploidies. In addition, specific _______anomalies are not detected with cfDNA, and it loses its accuracy for ______ patients.
inconclusive;few;structural; obese
______ anomalies are not detected with cfDNA, and it loses its accuracy for _______.
Structural; obese patients.
A purpose of biophysical profile scoring is to investigate for signs of fetal _______. Each examination of the fetus lasts _________.
hypoxia; 30 minutes
Measured in an axial plane and taken around the abdomen at the level of the umbilical vein and fetal stomach. Other structures that may be seen, including the transverse thoracic spine, ribs, liver, right adrenal gland, and fetal gallbladder.
Abdominal circumference
Measured with an ellipse at the outer perimeter of the skull at the level of the third ventricle, thalamus, cavum septum pellucidum, and falx cerebri.
Head circumference
Measured at the long axis of the femoral diaphysis when the ultrasound beam is perpendicular to the shaft. The measurement is taken from the center of the femoral head and extends to the distal condyle.
Femur length
Measured from the outer edge of the proximal skull to the inner edge of the distal skull at the level of the third ventricle, thalamus, cavum septum pellucidum, and falx cerebri.
Biparietal diameter
The highest possible sonographic score is _____ points, or 2 points for each criterion accomplished. The nonstress test, also referred to as fetal cardiotocography, is worth 2 additional points. Therefore, if combined with a nonstress test, the highest possible score is ____ for a biophysical profile
8; 10
a noninvasive test performed on the fetus to evaluate fetal movement, heart rate, and reactivity of the heart rate to fetal movement; diagnostic use is to detect signs of fetal distress
Nonstress test
the herniation of the cranial or spinal meninges caused by an open cranial or spinal defect
meningocele
mass that results from spina bifida that contains the spinal cord and the meninges
myelomeningocele
At least one episode of stimulated fetal breathing lasting at least 30 seconds (observed by watching the fetal diaphragm)
2 points (BPP)- thoracic movements
A least three or more gross fetal body movements (simultaneous trunk and limb movements)
2 points (BPP)- fetal movements
At least one flexion to extension of a limb or one hand opening and closing
2 points (BPP)- fetal tone
At least one pocket of fluid that measures 1 cm in vertical diameter in two perpendicular planes
2 points (BPP)- amniotic fluid
At least two fetal heart accelerations (>15 beats/min and > 15 s) together with fetal movement
2 points (BPP)- nonstress test (BPP combined with nonstress test highest score = 10)
Presentation of the fetus is determined by identifying
fetal anatomy closest to the internal os of the cervix
Fetal lie can be described as
longitudinal, transverse, or, possibly, oblique
an _______ lie is when the fetus is obliquely lying or slanted in comparison to the maternal longitudinal axis
oblique
Most common fetal presentation
cephalic (head first/head down)
Fetus position in which fetal legs are flexed at the hips and there is flexion of the knees
complete breech
Fetus position in which the fetal buttocks is closest to the cervix
frank breech
Fetus position in which there is extension of at least one of the legs toward the cervix
Incomplete (footling) breech
Most common pelvic mass associated with pregnancy
corpus luteum cyst of the ovary (may mimic ectopic pregnancy because they can have a complex appearance, or a thick wall)
What artifact appears as a solid streak or a chain of parallel bands radiating away from a structure?
ring down
Which of the following is also referred to as trisomy 13?
patau syndrome
Pregnant patients who complain of right lower quadrant pain could be suffering from coexisting _______
acute appendicitis
Pregnant patients complaining of right upper quadrant pain could have ________
gallstones
Maternal __________ is common during late pregnancy. Dilation of the renal collecting system is most often secondary to the large size of the uterus with subsequent transient asymptomatic obstruction of the ureters.
hydronephrosis
the dilation of the renal collecting system resulting from the obstruction of the flow of urine from the kidney(s) to the bladder; also referred to as pelvocaliectasis or pelvicaliectasis
hydronephrosis
