OB: Section I. Obstetric Sonography 3/6
Estimated date of delivery (EDD)
due date, calculated by adding 280 days to the first day of the last menstrual period; also called estimated date of confinement (EDC).
Conceptual age
duration of pregnancy, counted from fertilization, expressed in hours or days, also called embryonic age or post ovulatory age.
Gestational age (GA)
duration of pregnancy, counted from the first day of the LMP, expressed in weeks and days or fractions of weeks. A pregnancy usually lasts 280 days, or 40 weeks.
Missed abortion
early failed pregnancy that remains in the uterus
Blastocyst
early gestation consisting of a thin outer layer of cells (trophoblast), a fluid-filled cavity, and an inner cell mass (embryoblast).
fetal stage begins following the
embryonic period after about 11 weeks
Blighted ovum
empty gestational sac seen in an embryonic pregnancy
Hyperemesis
excessive vomiting during pregnancy sometimes called hyperemesis gravidarum
Inevitable abortion
failed early pregnancy that is in process of being expelled from the uterus
what assists the ova to move into and through the fallopian tube?
fimbriae, contractile walls, and celia. NOT: infundibulum
Gestational sac
first sonographic evidence of an intrauterine pregnancy, the fluid-filled blastocyst.
Hydatidiform mole
form of gestational trophoblastic disease resulting from abnormal fertilization in which there is proliferation of swollen chorionic villi. Also called a molar pregnancy.
Estrogen
group of hormones, primarily produced in the ovaries, which affect secondary sex characteristics and menstrual cycle.
ultrasound in the fisrt trimester is mostly used to demonstrate
hCG level and CRL
Gamete
haploid cell that, when merged with a gamete from the opposite sex, creates a diploid zygote.
gametes are..
haploid cells with 23 chromosomes
Progesterone
hormone produced by the corpus luteum and the placenta
Human chorionic gonadotropin (hCG)
hormone produced by trophoblast cells of the blastocyst, which extends the life of the corpus luteum in the ovary; most pregnancy tests are based on this
Molar pregnancy
hydatidiform mole
Gestational trophoblastic neoplasia
invasive or metastatic form of gestational trophoblastic disease.
Amniocentesis
invasive procedure in which a quantity of the amniotic fluid is removed from the amniotic sac for analysis of the fetal cells or for presence of certain chemicals in the fluid itself; may also be performed as a palliative measure in patients with severe polyhydramnios.
Chorionic villus sampling
invasive procedure in which the chorionic villi of an early pregnancy are removed for analysis
Theca-lutein cysts
large, often bilateral ovarian cysts, the formation which is usually stimulated by excessive levels of circulating human chorionic gonadotropin (hCG).
which hormone triggers ovulation
luteinizing
the placenta will mature from early pregnancy to release all but the following
luteinizing hormone
Crown-rump lenght (CRL)
measurement of the longest axis of an embryo to determine gestational age
Chorion
membrane around the chorionic cavity, made up of trophoblast cells and extraembryonic mesoderm.
Amnion
membrane enclosing the amniotic cavity and embryo or fetus
the whip-like tail of the sperm contains,
mitochondria
a cluster or ball of forming cells is a?
morula
the head of sperm cells contain...
nucleus, which house enzymes allowing for penetration of the outer layer of the ovum.
Anembryonic pregnancy
pregnancy that has fail prior to the development of an identifiable embryo or in which embryonic tissue has been resorbed after early embryo demise
Follicle-stimulating hormone (FSH)
produced by the anterior pituitary, which stimulates the maturation of ovarian follicles.
Luteinizing hormone (LH)
produced by the anterior pituitary, which triggers ovulation in females.
Conceptus
product of fertilization, including all stages from zygote to fetus.
a ruptured follicle, or corpus lutem releases
progesterone
Corpus luteum
progesterone-secreting structure formed by a follicle after releasing its oocyte.
the 5 brain vesicles, which will become the lateral ventricles, the 3rd ventricle, and the upper and lower parts of the 4th ventricle, and the connections between them develop from the
prosencephalon and rhombencephalon
Pregnancy-associated plasma protein A (PAPP-A)
protein produced by the trophoblasts; abnormal levels of PAPP-A may be associated with increased risk of chromosomal abnormalities
zygote
singe cell resulting from the fusion of two gametes.
once the ovum is fertilized, the structure is called a ..
single diploid cell, conceptus, or the zygote
Morula
solid cluster of undifferentiated cells formed by repeated cleavage of the single cell that resulted from the fusion of two gametes.
Gestational trophoblastic disease
spectrum of disorders that begin at fertilization and involve abnormal proliferation of the trophoblasts that in a normal pregnancy form the placenta; may become invasive, malignant, and metastasize.
Miscarriage
spontaneous failure and expulsion of an early pregnancy.
Umbilical vesicle / Yolk sac
structure within the cavity of the blastocyst, which provides nourishment to the embryo and produces its first blood cells; the secondary umbilical vesicle (yolk sac) is the first structure to be sonographically identified within the gestational sac.
Nucal translucency (NT)
subcutaneous fluid in the posterior region of the neck of embryos and fetuses up to 14 weeks' gestational age; abnormally large NTs have been associated with a higher risk of chromosomal and structural abnormalities.
the double sac sign is developed by two layers of deciduas:
the decidua capsularis and the decidua parietalis
the amniotic cavity is formed within the
tick epiblast, adjacent to the trophoblast.
the first blood cells in the embryo are produced by the
umbilical vesicle and are transferred to and from through the vitelline veins and arteries.
what prevents more than one sperm entering an ovum?
zona pellucida
implantation of the blastocyst cannot happen until the
zona pellucida disintegrates.
nourishment from the endometrial glands crosses the
zona pellucida, enter the morula, and forms a fluid-filled cavity called the blastocyst.
the endometrial layers are
a thin basal layer adjacent to the myometrium and functional layer of connective tissue.
Complete hydatidiform mole
abnormal fertilization of an oocyte that contains no maternal chromosomes, resulting in the proliferation of swollen chorionic villi and the absence of identifiable embryonic structures.
Partial hydatidiform mole
abnormal fertilization resulting in one maternal and 2 paternal sets of chromosomes (triploidy), leading to the development of an abnormal fetus and placenta.
Tachycardia
abnormally rapid heart rate.
Bradycardia
abnormally slow heart rate.
At what age have the rudimentary forms of all embryonic organs and structures developed?
almost 11 weeks menstrual/gestational age.
Acrosome
area located in the head of the sperm containing enzymes to aid in penetration of the oocyte.
Mean sac Diameter (MSD)
average diameter of the gestational sac, used to determine gestational age.
a blastocyst consists of all of the following:
blastocele, trophoblast, and embryoblast. Except: blastocite
Chorion Villi
budlike outward growths, counted from the trophoblast cells and extraembryonic mesoderm
Decidualization
changes in the endometrium to allow implantation of a blastocyst.
the first structure seen sonographically within the uterus in early pregnancy is the
chorionic sac
24 to 30 hours after fertilization, rapid cell division occurs. It is known as
clevage
Subchorionic hemorrhage
crescent-shaped sonolucent collection of blood between the gestational sac and the uterine wall.
prepatory changes in the endometrium allowing for implantation include
decidualization
the portion of the endometrium related to blastocyst attachment is the?
deciduas basalis
fetal placenta occupies the
deciduas basalis portion of the endometrium, leaving the basal layer intact.
the yolk sac becomes part of the embryonic gut and contributes to:
digestive, respiratory, and urogenital development
sonography may detect a blastocyst embedded in the decidua as early as
11 days after conception
what is the normal resting heart rate of a 3rd trimeter fetus?
110 to 160 beats per minute.
Second trimester
14 weeks to the end of the 27 week
spontaneous pregnancy loss usually happens in the
1st trimester
a 5 week yolk sac measures about
2.3 millimeters in diameter and enlarges to 5.6 mm at 11 weeks, then disappears by 12 weeks gestational age.
Third trimester
28 weeks to delivery
a normal gestation lasts approximately
280 days
the first visualized structure within the gestational sac is the
2nd yolk sac
the embryonic disc contains
3 germ cell layers from which all future organs and tissue is derived.
the developing cluster of cells travels through the fallopian tube and reaches the uterus about
4 days after fertilization.
the most accurate measurement for dating in early pregnancy is the
CRL
At which gestational age does the yolk sac image between the chorion and amnion?
Carnegie stage 20
Which brain structure can be identified in this sonogram?
Choroid plexus
Where does implantation of the embryo occur?
Endometrium
What hormone does the mature ovarian follicle secrete?
Estradiol
the pituitary produces ..
FSH, which at puberty causes follicles to mature and fill with fluid
Which of the following is the solid ball of developing cells that occurs after fertilization?
Morula
when the nuchal translucency (NT) measurement is combined with
PAPP-A and free B-hCG, the detection rate for trisomy 21 increases to 86%
CHAPTER 14 ------------------------------------------------
SONOGRAPHIC EVALUATION OF 1ST TRIMESTER COMPLICATIONS
First timester
0 days (LMP) to the end of the 13th week
ultrasound measurement errors due to beam width and machine calibration of
1 or 2 mm per 10 cm are acceptable
3 criteria for interstitial pregnancy are:
1, An empty uterine cavity. 2, A gestational sac greater than 1 cm from the most lateral point of the endometrial cavity. 3, A gestational sac surrounded by a thin myometrial layer.
at what level of b-hcg concentration should a normal intrauterine pregnancy be seen?
1,500 to 2,500 mIU/mL
spontaneous pregnancy loss before 20 weeks occurs in approximately what percentage of population?
10 to 20%
the placenta can be well documented as a discoid structure transabdominally at
12 weeks
what percent of pregnancies in the US are ectopic?
2%
a gestational sac without an embryo or yolk sac with a mean sac diameter greater than
2.0 cm generally predicts pregnancy failure
Using the Jeanty table, what is the BPD measurement range for a 15 week fetus? (For this item, use table in the textbook.)
2.2 to 2.5 cm
tubal rupture occurs in
21% of ectopic pregnancies
to estimate an accurate fetal age, the BPD measurements should be obtained before:
33 weeks
Nuchal cord
360 degree wrapping of the umbilical cord around the fetal neck.
Using the Hadlock table, what is the gestational age for a fetus with a head circumference of 342.7 millimeters? (For this item, use table in the textbook.)
39.1 weeks
How many days long does the ovulation period last?
4 days
the normal duration of pregnancy is
40 weeks from LMP
measurement errors occur as many as
45% of fetuses in the circumstance of external uterine pressure with the BPD measurement.
B-hCG levels should double approximately every:
48 hours
In a normal pregnancy, how long does it take the B-hCG to double?
48 hours
a typical placenta weights
480 to 600 gams
transvaginal sonography should demonstrate a fetal pole with cardiac motion at
5.5 to 8 weeks of gestation
generic abnormalities cause
50 to 70% of pregnancy failures
what percent of patients with ectopic pregnancy have no symptoms?
50%
indications of possible embryonic demise:
6 mm embryo without cardiac activity. No double bleb sign with a < 5 mm embryo. Enlarged amniotic sac with < 5 mm embryo.
when are ectopic pregnancies usually diagnosed?
6 to 10 weeks
the implantation window begins
6 to 8 days after ovulation and lasts for approximately 4 days.
what b-hcg levels are necessary to visualize an IUP using transabdominal approach?
6,500 mIU/mL
CHAPTER 18 ----------------------------------------------
ABNORMALITIES OF THE PLACENTA & UMBILICAL CORD
CHAPTER 16 ------------------------------------------
ASSESSMENT OF FETAL AGE & SIZE OF THE 2ND & 3RD TRIMESTER
Which of the following defines a heterotopic pregnancy?
An intrauterine pregnancy (IUP) coexisting with an ectopic pregnancy
Which type of resolution is half of the spatial pulse length?
Axial
the most exact orbit measurement is the
BOD
the most common and routine measurement to assess the fetal growth and well being are
BPD, HC, AC and FL
common fetal body ratios are
BPD/FL, HC/AC, and AC/FL
select the correct CI formula
BPD/FOD X 100
Which of the following terms describes an oocyte without maternal chromosomes resulting in proliferation of swollen chorionic villi and the absence of identifiable embryonic structures?
Complete hydatidiform mole
What anatomy is indicated by the arrows?
Double sac sign
the fetal expected birth date is known as the
EDC or the EDD
Which phase of pregnancy provides the most accurate dating?
Early embryo measurements
Which of the following best defines the sonographic appearance for an inevitable abortion?
Empty low-lying gestational sac, open cervix.
Which of the following is the most commonly used measurement to estimate fetal age?
FL
Marcrosomia
Fetus over 4,000 grams (8 lb, 13 oz)
Which of the following is the differential for an intraplacental lesion?
Fibrin deposition
What is the most likely cause for the sonographic visualization of hypoechoic areas in the intervillous spaces beneath the chorion that lack flow?
Fibrin deposits
Which maternal factor results in delayed placental maturation of a five centimeter placenta?
Gestational diabetes
signs of tubal rupture may include all of the following:
Hypotension. Rebound tenderness. Tachycardia. Except: urinary tract infection
Which of the following placental greases demonstrates basal and interlobular septal calcifications?
III
Which type of ectopic pregnancy implants on previous cesarean scars?
Intramural
Which form of placenta previa lies within two centimeters of the internal cervical os?
Low-lying placenta
Which hormone triggers ovulation?
Luteinizing
which is the only procedure that does not require ultrasound guideance
MCA doppler
gold standard modality for diagnosing and locating abdominal ectopic pregnancies
MRI
select the measurement not usually included in a first trimester screening for assessing risk in a chromosomally abnormal fetus.
MSD
marginal cord insertion in sonograpic image
Marginal
Which of the following is the spontaneous failure and expulsion of an early pregnancy?
Miscarriage
Which of the following is the structure indicated by the arrow?
Omphalocele
What is the most likely cause for the sonographic finding on a 26- year-old, G2P1, patient presenting with complaints of pain and bleeding with a high risk history due to uncontrolled hypertension and a previous sonographic examination?
Placenta abruption
Which of the following is the implantation of the placenta low in the uterus resulting in total or partial covering of the cervix?
Placenta previa
Predictive value
Precision rate or the probability of disease.
Which acquired maternal problem results in a placenta thickness of less than two centimeters?
Preeclampsia
What is the area between the myometrium and placenta?
Retroplacental
CHAPTER 15 ---------------------------------------
SONOGRAPHIC ASSESSMENT OF THE ECTOPIC PREGNANCY
CHAPTER 17 ------------------------------------------
THE FETAL ENVIRONMENT
CHAPTER 13 --------------------------------------
THE USE OF ULTRASOUND IN THE 1ST TRIMESTER
Which term describes an abnormally fast heart rate?
Thachycardia
What anatomic landmarks help determine the correct level to measure the HC?
Thalamus, falx, cavum septum pellucidum
Which of the following is a chromosomal cause for a thick placenta?
Triploidy
Which of the following describes the sonographic characteristic of excessive Wharton's jelly?
Variably echogenic, soft tissue mass with three vessels visible.
Which of the following term describes the mucous tissue surrounding the umbilical cord?
Wharton's jelly
A pseudosac is
a fluid collection caused by bleeding form the decidualized endometrium
if ultrasound is equivocal in the diagnosis of ectopic pregnancy:
a laparoscopy may be used for diagnosis
routine obstetric ultrasound done between approximately 6 and 12 weeks divulging a normal singleton fetus demonstrates
a miscarriage rate of 1.6%
color doppler presents as
a ring of fire around a viable ectopic pregnancy
a pregnancy less than 20 weeks with vaginal bleeding is termed
a threatened abortion
which ectopic pregnancy location can support a pregnancy the longest before detection?
abdominal
symptoms of general malaise, nausea, vomiting, vaginal bleeding, and painful fetal movements are associated with
abdominal ectopic prenancy
Placenta accreta, increta, and percreta
abnormal attachment of the placenta to the uterus with different terms used to describe the depth of placental invasion
hydatidiform moles are caused by;
abnormal fertilization
Placenta hydrops
abnormal fluid accumulation coexisting with fetal hydrops
Aneuploidy
abnormal number of chromosomes
an endometrial stripe thickness less than 8 mm suggests an
abnormal or ectopic pregnancy
Circumvallate placenta
abnormally attached placenta with a peripheral raised ring
the sliding sac sign suggests an
abortion in progress
What is the mIU/mL discriminatory cutoff for B-hCG.?
above 1,500 to 2,500
sonography can detect central nervous system abnormalities, such as
acrania/anencephaly, spina bifida, encephalocele, holoprosencephaly, and Dandy-Walker malformation.
the most accurate fetal measurements are taken
along the beam axis using the axial resolution
fertilization generally occurs in the ..
ampullary portion of the fallopian tube.
most ectopic pregnancies occur in the
ampullary portion of the oviduct.
if the fetal head is very low in the pelvis,
an endovaginal transducer may allow BPD measuements
b-hcg levels increase and then plateau at
approximately 9 to 11 weeks
Retroplacental
area between the myometrium and placenta
extrachorial placenta
attachment of the placental membranes to the fetal surface of the placenta rather than to the underlying villous placental margin
an aborting gestational sac will appear
avascular with color doppler
accurate measurements are partially determined by
axial and lateral image resolution
Annular placenta
bandlike placenta encircling the internal uterus
False knot
bending, twisting, and bulging of the umbilical cord vessels mimicking a knot in the umbilical cord.
B-hCG
beta human chorionic gonadotropin; a glycoprotein hormone produced in pregnancy that is made by the embryo soon after conception and later by the placenta
macrosomia is defined as a
birth weight 4,000 grams or higher
select a fetal characteristic that is not a 3rd trimester individuation
bradycardia
the femur measurement
can be reliably used after 14 weeks gestation
Braxton-Hicks
cause bulging into the amniotic cavity
MTX, known as methotrexate, interferes with
cell division and is used to manage ectopic pregnancy in a conservative manner
Omphalocele
central anterior abdominal wall defect of the umbilicus where abdominal organs are contained by a covering membrane consisting of peritoneum, Wharton's jelly, and amnion
a normal cord insertion is called
central insertion
What is the most likely diagnosis for the sonographic appearance of a circumscribed complex mass protruding from the fetal surface of the placenta?
chorioangioma
theca lutein cysts are usually stimulated by excessive levels of hCG and are related to:
complete molar pregnancy
a ruptured tubal pregnancy presents as a
complex mass-like area representing hemorrhage and free fluid.
heterotopic pregnancy
concomitant intrauterine pregnancy and ectopic pregnancy.
limb-body wall complex
condition characterized by multiple complex fetal anomalies and a short umbilical cord
ectopic pregnancies diagnosed in early gestation allow for
conservative methods of treatment
Velamentous insertion
cord attachment to the edge of the placenta
Vasa previa
crossing of the cervix by the umbilical cord coexisting with a velamentous cord insertion or placental succenturiate.
retroperitoneal complex is
decidua basalis and portions of myometrium
the "empty amnion sign" means
definitive evidence of pregnancy failure
Cord prolapse
delivery of the cord before the fetus
an embryo measuring 5mm or greater should
demonstrate cardiac activity
repeated or serial levels of b-hcg are necessary to
detect and increase, decrease or leveling of the hormone.
a fetus with a long and narrow head is called
dolichocephalic
which phase of pregnancy provides the most accurate dating?
early embryo measurements
if the crown-rump length is more than 2 standard deviations below the mean for the expected gestational age,
early-onset intra uterine growth restriction may be suspected .
the perfect technique for measuring the fetal abdomen and head circumference is the
ellipse
sonographic appearance for an inevitable abortion
empty low-lying gestational sac and open cervix
the purpose of 2nd and 3rd trimester measurements of a fetus are
estimating fetal age and determining the size and development
Hyperthyroidism
excessive activity of thyroid
Bilobed placenta (succenturiate lobe)
extra placental lobe smaller than the placenta
what is a possible outcome of amnion rupture before the fetal age of 16 weeks?
extra-amniotic pregnancy/extra-amniotic coelom
Trophoblast
extraembryonic tissue that develops into the placenta
what is the pathway from the uterine cavity to the peritoneal cavity?
fallopian tubes
body stalk anomaly
fatal condition associated with multiple congenital anomalies and absence of the umbilical cord
cerebellar size is generally unaffected by
fetal growth disturbances and is independent of the shape of the cranium
Placenta membranacea
fetal membranes covered by chorionic villi due to failure of chorion differentiation into the chorion laeve and chorion frondosum
Aneurysm
focal dilatation of an artery
intrauterine contraceptive device (IUD)
form of birth control; small, plastic, or copper, usually T-shaped device, with a string attached to the end that is inserted into the uterus.
beam width artifact tends to make measurement points
fuzzy, therefore, cursors should be placed at the edge of the most definite echo observed, but should not include beam width artifact
interstitial pregnancy
gestation located in the intramyometrial segment of the fallopian tube.
cornual pregnancy
gestation located within a rudimentary uterine horn or one horn of a bicornuate or septated uterus.
Abdominal pregnancy
gestation located within the intra-peritoneal cavity, apart from tubal, ovarian, or intraligamentous sites.
abdominal pregnancy
gestation located within the intraperitoneal cavity apart from tubal, ovarian, or intralegamentous sites.
Intramural pregnancy
gestation located within the myometrium of the uterus
intramural
gestation located within the myometrium of the uterus
ovarian pregnancy
gestation located within the ovary
an intrauterine mass over 3.45 cm in largest diameter, a thin endometrium, and low resistance arterial Doppler flow is likely a form of
gestational trophoblastic disease.
Beta human chorionic gonadotropin (B-hCG)
glycoprotein hormone produced in pregnancy that is made by the developing embryo soon after conception and later by the placenta.
what laboratory value is useful when a smaller than expected gestational sac is seen with ultrasound?
hCG
enlarged ovaries are frequently seen during complete molar pregnancy as a result of elevated
hCG levels
Triploid, triploidy
having three copies of each chromosome.
Morison's pouch
hepatorenal recess; deep recess of the peritoneal cavity on the right side extending upward between the liver and the kidney; gravity-dependent portion f the peritoneal cavity when in the supine position,
cervical pregnancy frequently presents on ultrasound as a
hourglass-shaped uterus
when using a valid published fetal growth chart, it is important to know
how the measurements were generated, so that the examiner uses the same methodology that the chart was compiled on.
tubal ring sign
hyperechoic ring of trophoblastic tissue that surrounds an extrauterine gestational sac
Tubal ring sign
hyperechoic ring of trophoblastic tissue that surrounds an extrauterine gestational sac.
toxemia of pregnancy presents as pregnancy-induced
hypertension, proteinuria, edema, and headache and may progress to seizures (eclampsia).
ectopic pregnancy
implantation of a fertilized ovum in any area outside of the endometrial cavity
increased hCG lab levels and clinical signs and symptoms associated with complete molar pregnancies are more severe than
in partial moles
Respiratory insufficiency
inadequate absorption of oxygen and/or inadequate expulsion of carbon dioxide
the increase in C-section scar pregnancies is probably due to the
increase in number of the c-section deliveries
thinning of the myometrium behind the placenta may indicate the following
increta, accreta, and percreta. Except: adherence
pelvic inflammatory disease (PID)
infection of the female reproductive tract that results from microorganisms transmitted especially during sexual intercourse or by other means such as surgery, abortion, or parturition
Valsalva
inhalation and suspension of breath coupled with abdominal muscle contraction to increase abdominal pressure.
procedures that cause an injury to the myometrium, including curettage, hysteroscopy, myomectomy, metroplasty, and cesarean section can be the cause for
intramural pregnancy
Thrombosis
intraplacental area of hemorrhage and clot
heterotopic pregnancy means pregnancy
intrauterine and extrauterine, simultaneous
What is the most likely cord pathology demonstrated on the image?
large umbilical cord cyst pg 415
A complete hydatidiform mole usually results in:
large-for-dates uterus and vaginal bleeding
uterine vessels are most abundant along the
lateral uterine wall
early onset intrauterine growth restriction is defined as crown-rump length at
least 2 standard deviation below the mean for expected gestational age.
pregnancy failure is most likely to occur when the fetal heart rate is?
less than 110 beats per minute at 6.3 to 7 weeks
discriminatory cutoff
level of B-hCG at which a normal intrauterine pregnancy can be seen with sonography.
Synechia (Asherman syndrome)
linear, extra amniotic tissue that projects into the amniotic cavity with no restriction of fetal movement
Cotyledons
lobule or subdivision of maternal placenta containing fetal vessels, chorionic villi, and the intervillous space
molar pregnancy has the ability to develop into
locally invasive or metastatic gestational trophoblastic neoplasia, GTN aka choriocarcinoma
tall parents tend to have
long babies
placental blood flow should demonstrate as
low resistance
Placenta previa
low uterine implantation of the placenta resulting in total or partial covering of the cervix
which fibroid is most likely to obstruct vaginal delivery, requiring a cesarean delivery.
lower uterine segment
fetal weight by ultrasound is usually requested to rule out all of the following
macrosomia, IUGR, and possible low birth weight. Except: BPP
differences in fetal growth parameters can be caused by
maternal smoking, altitude and genetics
Occipito-frontal diameter (OFD)
measurement from the frontal to the occipital obtained at the same level as BPD.
normal pregnancies occur in all but where?
medial to the interstitial portion of the fallopian tubes.
Axial resolution
minimum distance between two bright echoes along the path of the ultrasound beam, which is half the spatial pulse length.
Lateral resolution
minimum distance between two bright echoes at right angels (perpendicular) to the ultrasound beam path directly related to the beam width and focal zone.
Wharton's jelly
mucous tissue surrounding the umbilical cord
the preferred measurement method for fetal growth is
multiple measurements in a cluster
the most accurate fetal measurement can be obtained from
multiple parameters
the intramural segment of the tube is surrounded by
myometrium, which allows for increased expansion compared to other tubal sections.
Does NOT indicate possible embryonic demise:
no cardiac activity with a < 5 mm embryo and a double bleb sign
determining sonographic dates for a fetus using a single parameter is
not desirable, especially in late pregnancy
marginal insertion (aka, battledore placenta)
occurs when the umbilical cord inserts at the placental margin instead of centrally
ectopic pregnancy can be caused by
oviduct surgical history
cervical pregnancy is rare and linked to all of the following, except
ovulation induction techniques
cervical incompetence is
painless cervical dilatation
what structures are seen in an accurate BPD measurement?
parietal, sphenoid, and petrous ridges
lateral resolution is
path of the beam
Fertilization
penetration of an oocyte by a sperm to form a diploid zygote.
Gastroschisis
periumbilical abdominal wall defect, typically to the right of normal cord insertion, that allows for free-floating bowel in the amniotic fluid.
Which of the following describes growth of the chorionic villi superficially into the myometrium?
placenta accreta
an abnormally thin placenta detected over most of the uterine cavity is
placenta membranacea
an overly distended maternal urinary bladder may cause misleading appearance of
placenta previa
Bilobed placenta
placenta where the lobes are nearly equal in size and the cord inserts into the chorionic bridge of tissue that connects the two lobes
Battledore placenta
placenta with umbilical cord inserted into the border
Intervillous spaces (sinus)
placental spaces that communicate with maternal vessels
the role of sonography in early threatened pregnancy is not to alter the outcome, but to
predict which will continue to term.
pregnancy of unknown location (PUL)
pregnancy in which no signs of an intrauterine pregnancy or ectopic pregnancy are seen by sonography
Pregnancy of unknown location (PUL)
pregnancy in which no signs of an intrauterine pregnancy or ectopic pregnancy are seen by sonography.
Toxemia of pregnancy
pregnancy induced hypertension, proteinuria, edema and headache (preeclampsia), which may progress to the development of seizures (eclampsia)
cervical pregnancy
pregnancy located within the endocervical canal
Abruptio placentae
premature separation of the placenta from the uterus
Which of the following identifies the sonographic finding in the uterus which is made up of bleeding from the decidualized endometrium?
pseudosac
Cephalic index (CI)
ratio of the PBD to the OFD
True knot
result of the fetus actually passing through a loop or loops of umbilical cord creating one or more knots in the cord
a yolk sac with healthiest characteristics is
round in shape
a positive pregnancy test without visualization of uterine contents, adnexal mass, and free fluid indicate
ruptured ectopic pregnancy
hypovolemic shock
shock due to a decrease in blood volume.
platycephaly is
shortening of the vertical dimension of the skull and widening of both diameters of the transverse plane.
in vitro fertilization (IVF)
sperm is placed with an unfertilized egg in a petri dish to achieve fertilization; the embryo is then transferred into the uterus to begin a pregnancy or cryopreserved for future use.
Incomplete abortion
spontaneous abortion in which some products of conception remain in the uterus.
Cerclage
stitch placed into the incompetent cervix to prevent opening
if the umbilical/portal junction is not visualized while attempting an AC measurement, use the level of the fetal
stomach
the risk of spontaneous mis carriage, preeclampsia, placental abnormalities, or preterm delivery is increased by crescent-shaped sonolucent fluid between the gestational sac and the uterine wall is called:
subchorionic hematoma
Hemodynamically unstable patients with a known ectopic pregnancy require
surgical management, the most successful being laparoscopy.
Placentomegaly
term that refers to a thickened placenta
Mickey Mouse sign
term used to describe the cross-section of the three-vessel umbilical cord or the portal triad (portal vein, hepatic artery, common bile duct)
the area most likely to collect fluid in the right abdomen, between liver and kidney is called
the Morrison's pouch
MFP (multiple fetal parameter) is
the average gestational age determined by 4 common measurements of the fetus
short and frequent pulses yield
the greatest axial resolution
a hemorrhage due to ectopic rupture of the oviduct is most severe in
the interstitial portion
the more measurements obtained and averaged during a fetal ultrasound
the more accurate the fetal age estimate.
a sonogram is ordered to date a pregnancy if
the patient is unsure of LMP and if clinical exam of the uterus does not agree with the patient's reported LMP
ultrasund demonstrates and incomplete abortion as a
thickened endometrium or hyperechoic tissue within the uterus
Which fetal leg bone is medial and larger?
tibia
Placental infarction
tissue death resulting form circulatory obstruction
the recommended technique to obtain an accurate AC is
to first locate the long axis of the fetal spine
if the b-hcg level is above the discriminatory cutoff and no IUP is visualized, through
transabdominal, transvaginal sonography should be performed
Which of the following is a cause for abruption placenta?
trauma
double decidual sac sign (DDS)
two concentric hyperechoic rings (representing the echogenic base of the endometrium and the decidua capsularis/chorion levae) surrounding the anechoic gestational sac in a normal intrauterine pregnancy
double decidual sac sign
two concentric hyperechoic rings, representing the echogenic base of the endometrium and the decidua capsularis/chorion leave, surrounding the anechoic gestational sac in a normal intrauterine pregnancy.
Which term describes a method of assessing the degree of umbilical cord coiling?
umbilical coiling index
A correct AC measurement demonstrates the
umbilical vein junction with the portal vein perpendicular to the spine
a blighted ovum is also called an
unembrionic pregnancy.
an HC measurement should be obtained
using outer edge of the calvarium at the level of BPD
Braxton-Hicks
uterine contractions that do not lead to labor
uterine size estimation by physical examination to determine pregnancy age may be INACCURATE due to all of the following:
uterine fibroids, maternal obesity, and surgical scars. Except: parity
Threatened abortion, threatened miscarriage
vaginal bleeding in early pregnancy of less than 20 weeks; may be accompanied by pain or cramping.
ectopic pregnancy symptoms usually present as
vaginal bleeding, pelvic pain, and palpable adnexal mass.
What occurs when the intramembranous vessels course across the internal cervical os?
vasa previa
Breus' mole
very rare condition where there is massive subchorionic thrombosis of the placenta secondary to extreme venous obstruction
Sliding sac sign
when gentle pressure from the transducer moves the gestational sac
sliding sac sign
when gentle pressure from the transducer moves the gestational sac
Vernix caseosum
white, cheesecake coating of fetal skin
Which of the following is the blastocyst layer that eventually develops into the embryonic portion of the placenta?
Trophoblast
Which of the following is the structure that produces the embryo's first blood cells?
Umbilical vesicle