1st Trimester Anatomy & Pathology 12% Flashcards
What is the minimum international reference preparation value for bHCG that indicates a gestational sac should definitely be visualized by transabdominal ultrasound?
a. 1000 units/ml
b. 1500 units/ml
c. 2000 units/ml
d. 4000 units/ml
D
IRP levels for transabdominal ultrasound = 4000 units/ml is the minimum bHCG level for identifying an intrauterine pregnancy.
Which of the following is most suggestive of an inevitable abortion?
a. cervical dilatation over 3cm
b. spotting for 2 days
c. cervical length over 3cm
d. presence of vernix in the amniotic fluid
A
Inevitable abortion = bleeding more than 1 week, cramping, PROM, cervical shortening <3cm, dilatation > 2cm.
When evaluating the ductus venosus with spectral Doppler:
a. color Doppler is used to demonstrate the umbilical vein, ductus venosus and heart in the same image
b. high filter settings and slow sweep speed are preferred
c. a left parasagittal view of the fetal trunk is obtained
d. a 2-3mm sample is used
A
To evaluate the DV, obtain a right parasagittal view of the fetal trunk and apply color Doppler to demonstrate the umbilical vein, ductus venosus and heart. A 1mm or less sample volume is used to avoid sampling adjacent vessels. A cursor angle of less than 30 degrees should be used for the sample. Low filter settings and fast sweep speed will best display the A-wave. A normal ductus venosus waveform is biphasic with a positive A-wave. An abnormal ductus venosus waveform demonstrates a negative or reversed A-wave.
Fetal cardiac activity can first be visualized with transvaginal sonography at approximately what gestational age?
a. 5 weeks
b. 6 weeks
c. 6.5 weeks
d. 7 weeks
B Transvaginal approach: gestational sac @ 4 wks yolk sac @ 5.5 wks heart @ 6 wks
What abnormality occurs when two sperm fertilize the same egg?
a. trisomy 18
b. trisomy 21
c. triploidy
d. autosomal dominant x-linked disorder
C
An egg that is fertilized by two sperm will have an extra full set of chromosomes = triploidy
Which of the following is a sonographic sign of an abnormal 8 week intrauterine pregnancy?
a. yolk sac diameter 5mm
b. double bleb sign
c. gestational sac located in the lower uterine segment
d. fetal heart rate of 120bpm
C
If the gestational sac implants in the lower uterine segment, the risk of spontaneous abortion is increased significantly. The yolk sac is not abnormal until the diameter exceeds 6mm.
The AIUM defines a late 1st trimester ultrasound evaluation as an exam performed on a fetus that is between:
a. 9 and 11 weeks
b. 10 and 12 weeks 6 days
c. 12 and 13 weeks 6 days
d. 11 and 13 weeks
C
The AIUM defines a late 1st trimester ultrasound evaluation as an exam performed on a fetus that is between 12 weeks and 13 weeks 6 days.
Which of the following is a sign of impending fetal demise?
a. Robert sign
b. Deuel sign
c. irregular gestational sac shape
d. Spalding sign
C
Expected poor outcomes include: irregular sac shape, low sac position, thin trophoblastic reaction, weakly echogenic trophoblastic reaction, heart rate <100bpm, abnormal yolk sac size and shape, and calcified yolk sac. The other three choices are sonographic signs of demise that are seen several days after demise occurs.
Which of the following is NOT commonly associated with anencephaly?
a. oligohydramnios
b. exophthalmos
c. macroglossia
d. increased MSAFP
A
Anencephaly is seen with other spinal defects, exophthalmos (bulging eyes), macroglossia and polyhydramnios. Increased MSAFP is a clinical sign of anencephaly.
A patient presets for a fetal viability scan with an LMP 10 weeks ago. She has been experiencing light vaginal spotting for the last week. The transvaginal exam demonstrates a 2 cm cresent shaped hypoechoic area between the chorion and right uterine wall. These findings are most suggestive of:
a. partial molar pregnancy
b. subchorionic hemorrhage
c. placental abruption
d. normal first trimester pregnancy
B
A subchorionic hemorrhage causes vaginal spotting in the first trimester. Bleeding occurs between the uterine wall and the chorion. The fluid accumulations are typically cresent shaped. Most resolve spontaneously, but can lead to spontaneous abortion.
During fetal development, which of the following describes the maternal component of the placenta?
a. chorion frondosum
b. amniotic membrane
c. decidua basalis
d. decidua capsularis
C
The chorion frondosum refers to the fetal portion of the placenta located within the gestational sac. The decidua basalis refers to the placental tissue attached to the uterine wall.
Crown rump length (CRL) measures 7mm. What is the estimated gestational age of the pregnancy?
a. 7 weeks
b. 10 weeks
c. 5 weeks
d. 8 weeks
A Gestational age (days) = CRL + 42 GA = 7mm + 42 = 49 days 49 days = 7 weeks
Visualization of which of the following can help differentiate a normal intrauterine pregnancy (IUP) from a pseudo-gestational sac associated with an ectopic pregnancy?
a. corpus luteal cyst
b. increased blood flow velocity in the uterine arteries
c. decreased resistance to flow in the uterine arteries
d. yolk sac
D
A gestational sac in the uterus with a yolk sac indicates an IUP is present. A pseudo-sac seen in the uterus with an ectopic pregnancy would not contain a yolk sac. Both an ectopic and normal IUP can demonstrate a corpus luteal cyst and decreased resistance in the uterine arteries because these changes occur due to hormone stimulation that occurs with both types of pregnancy.
The gestational sac with __________ are the first signs of an intrauterine pregnancy seen with ultrasound.
a. fluid in the endometrial canal
b. decidual reaction of the endometrium
c. a corpus luteal cyst
d. fluid in the posterior cul-de-sac
B
The first sign of an IUP seen on ultrasound is the gestational sac with decidual reaction in implantation. Double decidual sac sign or intradecidual sign due to implantation seen at 5.5-6 weeks. If a patient with suspected pregnancy demonstrates a fluid filled structure in the endometrial canal, but no decidual reaction, the patient should be thoroughly evaluated for ectopic pregnancy.
During fetal development, which of the following describes the fetal component of the placenta?
a. chorion frondosum
b. decidua basalis
c. amniotic membrane
d. decidua capsularis
A
The chorion frondosum refers to the fetal portion of the placenta located within the gestational sac. The decidua basalis refers to the placental tissue attached to the uterine wall.
Megacystitis in a first trimester is diagnosed when the bladder length is greater than or equal to:
a. 5mm
b. 10mm
c. 7mm
d. 3mm
C
Megacystitis in a first trimester is dignosed when the bladder length is greater than or equal to 7mm. It can be associated with aneuploidy.
The yolk sac is considered normal in size when the inner diameter is less than ________.
a. 3mm
b. 5mm
c. 6mm
d. 8mm
C
A yolk sac > 6mm usually indicates a blighted ovum or fetal abnormalities if a fetal pole is detected.
When is PW Doppler appropriate to evaluate the first trimester fetus?
a. when IUGR is suspected
b. PW Doppler should never be used to evaluate a first trimester
c. when aneuploidy is suspected
d. when fetal anemia is suspected
C
PW Doppler should not be used on the standard first trimester exam. If aneuploidy, skeletal dysplasia or congenital heart disease is suspected, then it is appropriate to evaluate the ductus venosus and the tricuspid valve. Care must be taken to keep the Thermal Index at or below 0.7. IUGR and anemia are not typically diagnosed until the 2nd trimester or later.
The most common location of an ectopic pregnancy is:
a. cervical
b. ampulla
c. isthmus
d. interstitial
B
The most common location for ectopic pregnancy is in the ampullary portion of the fallopian tube.
Which of the following is responsible for the symptoms of early pregnancy, such as nausea and vomiting?
a. bHCG
b. AFP
c. progesterone
d. estrogen
C
Progesterone:
Responsible for premenstrual symptoms and symptoms of pregnancy (N/V)
Responsible for endometrial proliferation AFTER ovulation to prepare for implantation
Blocks the development of new follicles
Stimulates uterine blood supply for pregnancy
Causes breasts to prepare for lactation but inhibits lactation during pregnancy
Causes formation of cervical mucus plug in pregnancy
All of the following are signs of embryonic demise, except:
a. double bleb sign
b. 7mm yolk sac
c. distorted gestational sac
d. calcified yolk sac
A
The double bleb sign is a sign of an early intrauterine pregnancy. An enlarged or calcified yolk sac is a sign of embryonic demise. A distorted or irregular gestational sac is also indicative of demise.
A 26 year old patient presents with a positive pregnancy test and an approximate age of 7 weeks 3 days from her LMP. Beta hCG levels are significantly higher than a 7 week gestation. The exam shows a large heterogeneous solid mass measuring 6 x 4 x 3 cm within the endometrial cavity. The uterus measures 10 x 6 x 5cm. What is the most likely explanation for the sonographic findings described?
a. heterotopic pregnancy
b. leiomyosarcoma
c. hydatidiform mole
d. Chorioadenoma destruens
C
A hydatidiform molar pregnancy is an abnormality of the placenta and rarely involves the formation of a fetus. It is marked by high levels of Human Chorionic Gonadotropin (hCG). Molar pregnancies grow much more rapidly, compared to normal fetal growth. It has the appearance of a large and random collection of grape-like cell clusters. In some cases it can be malignant and requires chemotherapy or radiation treatment after surgical removal.
Which of the following carries the lowest risk of spontaneous abortion?
a. cervical os dilated to 4cm
b. gestational sac implanted in the endometrial cavity near the uterine cornua
c. vaginal spotting for the last ten days
d. significant leakage of amniotic fluid
B
If the gestational sac implants in the lower uterine segment, the risk of spontaneous abortion is increased significantly. Other causes for increased risk of spontaneous abortion include cervical dilation > 3cm, PROM, extended period of bleeding (1 wk +).
Which of the following is the recommended method to document fetal number in an early pregnancy?
a. count the number of amniotic sacs, with or without an embryo
b. count the number of visible embryos
c. count the number of areas with early placental formation
d. count the number of yolk sacs present in the gestational sac(s)
B
When documenting fetal number, only count embryos. Incomplete fusion of the amnion and chorion or elevation of the chorionic membrane by intrauterine hemorrhage can mimic the appearance of a second sac.
Which of the following early embryologic structures procedure progesterone?
a. morula
b. blastocyst
c. trophoblastic cells
d. zygote
C
Trophoblastic cells produce progesterone and bhCG in very early pregnancy. These cells develop into the chorionic villi of the placenta.
Which of the following types of twin gestation will have the highest risk for conjoined twins?
a. monochorionic/monoamniotic
b. monochorionic/diamniotic
c. dichorionic/diamniotic
d. dizygotic
A
A diamniotic twin gestation will produce two separate amniotic sacs. A membrane will be identified that separates the fetuses. A monoamniotic twin gestation will have no membrane to separate the fetuses. The absence of this membrane leads to increased risk for cord entanglement, nuchal cord and conjoined twins.
Which of the following types of twin gestation will have the thickest membrane between the fetuses?
a. conjoined twins
b. monochorionic/monoamniotic
c. dichorionic/diamniotic
d. monochorionic/diamniotic
C
A dichorionic diamniotic twin gestation will produce two separate placentas and two amniotic sacs. A membrane will be identified that separates the fetuses. The membrane will be greater than 2mm in thickness.
When evaluating a first trimester fetus, the reported crown rump length should be:
a. the largest of at least 3 measurements
b. the average of at least 3 measurements
c. the largest of at least 5 measurements
d. the smallest of at least 3 measurements
B
When evaluating a first trimester fetus, the reported crown rump length should be the average of at least 3 measurements.
Which of the following statements regarding twins is true?
a. conjoined twins are caused by cleavage of the morula within the first 4 days of pregnancy
b. identical twins are always dizygotic
c. dizygous twins are always the same gender
d. most monozygous pregnancies are diamniotic
D
Identical twins are always monozygotic. Monozygous twins are always the same gender. Conjoined twins are caused by cleavage of the morula after the 13th day of pregnancy. Most monozygous pregnancies are diamniotic.
What is the most common cause of demise in the first trimester?
a. chromosomal abnormalities
b. prior history of abortion
c. maternal smoking
d. uterine trauma
A
The most common cause of demise in the first trimester is due to chromosomal abnormalities.
Which of the following describes the sonographic appearance of a normal nasal bone in a 1st trimester fetus?
a. three parallel lines that are perpendicular to the frontal brone
b. two parallel lines, resembles an equals sign (=)
c. single linear reflection that is parallel to the maxilla
d. an echogenic foci at the tip of the nose
B
The normal nasal bone in a fetus is identified as a hyperechoic line that is posterior to the echogenic skin line. The nasal bone should be greater echogenicity to the skin reflection. The two echogenic lines are parallel and said to resemble an = sign.
Which of the following demonstrates the lowest risk of embryonic demise?
a. thin, mildly echogenic trophoblastic reaction
b. multiple lobulations of the gestational sac
c. TV ultrasound identifies a gestational sac with MSD 12mm and 5mm yolk sac but no embryo
d. implantation in the lower uterine segment
C
Indications for embryonic demise include distorted sac shape, thin and weakly echogenic trophoblastic reaction, low implantation site. On TV ultrasound, an embryo should be identified with a 16mm or greater MSD. A yolk sac less than 5.6mm in diameter is normal. The yolk sac should be identified with a 8mm or greater MSD.
A normal ductus venosus waveform in the first trimester fetus demonstrates:
a. a biphasic pattern with antegrade A-wave
b. a continuous antegrade flow pattern with limited pulsatility
c. a biphasic pattern with retrograde A-wave
d. a triphasic flow pattern with 2 phases moving in the retrograde direction
A
In the 1st trimester, a normal ductus venosus waveform is biphasic with a positive A-wave. An abnormal ductus venosus waveform demonstrates a negative or reversed A-wave, which suggests aneuploidy may be present.
The _______ forms the outer layer of the placenta that is in contact with the endometrium.
a. yolk sac
b. blastocyst
c. chorion
d. amnion
C
The chorion forms the outer layer of the placenta that is in contact with the endometrium.
The chorionic villi and membrane are formed from the:
a. yolk sac
b. trophoblastic cells
c. blastocyst
d. amnion
B
Trophoblastic Cells: produce progesterone and hCG, involved with implantation, develop into chorionic villi then into placenta.
The discriminatory bhCG level refers to:
a. bhCG levels associated with ectopic pregnancy
b. bhCG levels associated with molar pregnancy
c. bhCG levels in blood that correspond with the first possible sonographic visualization of the gestational sac
d. bhCG levels in blood that MUST correspond with the sonographic visualization of the gestational sac
D
The discriminatory bhCG levels refers to bhCG levels in blood that MUST correspond with the sonographic visualization of the gestational sac, (5w2d). The threshold levels refers to bhCG levels in blood that correspond with the first possible sonographic visualization of the gestational sac, (4w3d).
All of the following are layers of the endometrium that form with pregnancy, except:
a. decidua capsularis
b. decidua parietalis
c. decidua basalis
d. decidua accreta
D
Decidua Capsularis: tissue that envelops the blastocyst after implantation
Decidua Basalis: becomes maternal placenta, blastocyst attaches to this layer
Decidua Parietalis: other tissue not involved in the implantation process
The number of yolk sac:
a. can be used to determine the amnionicity of the mutlifetal pregnancy
b. is irrelevant in first trimester ultrasound evaluation
c. can be used to determine the chorionicity of the multifetal pregnancy
d. can only be assessed with transvaginal ultrasound
A
The number of the yolk sacs can be used to determine the amnionicity of the multifetal pregnancy. 2 embryos + 2 yolk sacs = diamniotic pregnancy; 2 embryos + 1 yolk sac = monoamniotic pregnancy
A patient presents for a pelvic ultrasound due to pain and bloating. Her LMP was 5 weeks ago and and bhCG levels are at 10unit/ml. A mild amount of anechoic fluid is noted in the posterior cul de sac. All of the following are a potential cause for the fluid accumulation, except:
a. ovulation
b. ruptured appendix
c. endometriosis
d. ectopic
D
The bhCG levels indicate there is no pregnancy present. An ectopic pregnancy would cause bhCG levels of 1000units/ml plus in a 5 week gestation.
Using transvaginal sonography, the yolk sac can be identified as early as week ____ of the pregnancy.
a. 3
b. 4
c. 5
d. 6
C
Using transvaginal sonography, the yolk sac can be identified as early as week 5 of the pregnancy. Using transabdominal sonography, the yolk sac can be identified as early as week 7 of the pregnancy.
Which of the following signs indicates an abnormal early pregnancy?
a. Chadwick sign
b. Murphy sign
c. Cullen sign
d. Hegar sign
C
The Cullen sign indicates the presence of bluish discoloration around the maternal umbilicus. The discoloration is associated with an intraperitoneal hemorrhage. A ruptured ectopic could cause the bleed. Pain, bleeding and a positive pregnancy test accompanied by the Cullen sign is highly suspicious for a ruptured ectopic.
Hegar sign refers to the softening of the lower uterine segment with pregnancy. The OB physician will palpate the uterus during the pelvic exam.
Chadwick sign refers to the bluish discoloration of the vaginal walls due to engorgement of the veins. This is a normal finding in early pregnancy. The OB physician will visualize this sign of the pelvic exam.
