1st trimester anatomy & pathology (12%) Flashcards
the most common place for normal egg fertilization to occur is within which of the following fallopian tube segments
a. isthmus
b. interstitial
c. infundibulum
d. ampulla
a.
the ampulla segment is the widest and longest portion of the fallopian tube and fertilization most commonly occurs there. for this reason it is the most common site of ectopic implantation
when evaluating a first trimester fetus the reported crown rump length should be
a. the largest of at least 3 measurements
b. the smallest of at least 3 measurements
c. the largest of at least 5 measurements
d. the average of at least 3 measurements
d.
when evaluating a first trimester fetus the reported crown rump length should be the average of at least 3 measurements
the number of yolk sacs
a. can be used to determine the amnionicity of the multifetal pregnancy
b. can be used to determine the chorionicity of the multifetal pregnancy
c. can only be assessed with transvaginal ultrasound
is irrelevant in first trimester ultrasound evaluation
a
the number of yolk sacs can be used to determine the amnioncity of the multifetal pregnancy. 2 embryos + 2 yolk sacs = diamoniotic pregnancy; 2 embryos + 1 yolk sac = monoamniotic pregnancy
which of the following statements regarding twins is true
a. dizygous twins are always the same gender
b. conjoined twins are caused by cleavage of the morula within the first 4 days of pregnancy
c. most monozygous pregnancies are diamniotic
d. identical twins are always dizygotic
c
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
which of the following correctly describes how to perform a crown rump length on a 13 week fetus
a. measurements should demonstrate a straight line perpendicular to the long axis of the fetus
b. calipers placed on the inner edge of the skin of the fetal head and rump
c. fetal neck in neutral position with fluid between the fetal chin and anterior neck
d. parasagittal plane with the profile spine and rump visible
c
crown rump length:
fetus fills 2/3 of the field of view
midsagittal plane with the profile spine and rump visible
fetal neck in neutral position with fluid between the fetal chin and anterior neck
calipers placed on the outer edge of the skin of the fetal head and rump
measurement should demonstrate a straight line parallel to the long axis of the fetus
3 measurements are taken and the average reported
how are the long bones of the extremities evaluated in a 13 week fetus with suspected cardiac defects
a. measure the femur length and compare to the humeral length
b. document 3 long bones are present in each extremity
c. the thicknesses of the femoral diaphyses are documented
d. document that there are at least two long bones in each extremity
b
when evaluating a late 1st trimester fetus (12-13 wees 6 days) 3 long bones pre extremity should be documented. long bone length measurements are reserved for cases of suspected skeletal dysplasia. the femur cannot be reliability measured until after 14 weeks gestation
an ectopic pregnancy will almost always be seen on the _______
a. same side as the corpus luteal cyst
b. right side
c. opposite side from the corpus luteal cyst
d. left side
a
an ectopic pregnancy will almost always be seen on the same side as the corpus luteal cyst. the egg is released from the dominant follicle and a corpus luteum cyst forms. when the right ovary releases an egg it travels into the right fallopian tube. when the left ovary releases an egg it travels into the left fallopian tube. an ectopic implantation is most likely to occur in the ipsilateral fallopian tube
mid tricuspid regurgitation in a first trimester fetus is suggestive of
a. IUGR
b. aneuploidy
c. normal fetus
d. maternal diabetes
b
tricuspid regurgitation of any level is suggestive of aneuploidy. trisomy 13, 18, 21 have been associated with tricuspid regurgitation in the 1st trimester
which of the following is a possible maternal complication of diamniotic twins
a. twin to twin embolization
b. anemia
c. twin to twin transfusion
d. cord enlargement
b maternal complications with multifetal pregnancy: anemia pre-clampsia/eclampsia systemic HNT placental abruption pre-term labor post-partum hemorrhage
fetal complications with multifetal pregnancy:
increased risk of anomalies
umbilical cord knots/entanglement (monoamniotic twins)
cord compression
IUGR because placenta cannot meet fetal needs
difficult delivery compared to singleton pregnancy
which if 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 the spontaneous abortion is increased significantly. the yolk sac is not abnormal until the diameter exceeds 6mm
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
on transvaginal ultrasound the minimum mean sac diameter that should always demonstrate a yolk sac in a normal IUP is
a. 5mm
b. 20cm
c. 8mm
d. 10mm
c
on transvaginal ultrasound a mean sac diameter >8mm should demonstrate a yolk sac in a normal IUP and on transabdominal ultrasound a mean sac diameter >20mm should demonstrate a fetal pole in a normal IUP
average normal heart rate in an early first trimester pregnancy is \_\_\_\_\_\_ a. <100bpm b. 120-160bpm c. 100-115bpm d<137bpm
c
average normal heart rate in an early first trimester pregnancy is 100-115bpm
a fetal heart rate ______ indicates a significant risk for demise in the first trimester
a. less than 160bpm
b. less than 80bpm
c. less than 140 bpm
d. greater than 100bpm
b
a fetal heart rate less than 80bpm indicates a significant risk for demise in the first trimester. the normal heart rate in the early first trimest is 100-115bpm
at what gestational age does the CRL become less accurate for fetal dating
a. at 10th week
b. at the 12th week
c. at the 14th week
d. at the 16th week
b fetal curling can reduce the accuracy of the CRL measurement after the 11th week. fetal biometric measurements are used to determine fetal age after 12 weeks. biparietal diameter head circumference abdominal circumference and femur length
visualization of which of the following can help differentiate a normal intrauterine pregnancy (IUP) from pseudo-gestational sac associated with an ectopic pregnancy
a. corpus luteal cyst
b. yolk sac
c. decreased resistance to flow in the uterine arteries
d. increased blood flow velocity in the uterine arteries
b
a gestational sac in the uterus with a yolk sac indicates an IUP is present. a pseudo-sac seen in the uterus with a 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
a patient is admitted to the hospital with a pelvic pain, no bleeding and vomiting. an LMP of 6 weeks ago and the pregnancy test that was performed was positive. serial hCG levels are assessed 36 hours apart. the first reading was 1500/ml and the second reading was 4500/ml. ultrasound is ordered to assess the pregnancy. what should you expect to find on the exam
a. normal IUP
b. molar pregnancy or normal IUP
c. multiple pregnancy or fetus with trisomy
d. molar pregnancy or multiple pregnancy
d
an ectopic pregnancy demonstrates a slowly rising hCG level. normal pregnancy will cause hCG levels to double every two days. after 36hrs, the hCG levels of a normal IUP should be about 2500-2700ml. at 4500ml, the hCG has already tripled in 36hrs. molar pregnancy will cause a rapid increased similar to the increase seen with multiple pregnancies
the most common location of an ectopic pregnancy is
a. ampulla
b. interstitial
c. isthmus
d. cervical
a
the most common location for ectopic pregnancy is in the ampullary portion of the fallopian tube
which of the following describes the sonographic appearance of a normal nasal bone in a 1st trimester fetus
a. single linear reflection that is parallel to the maxilla
b. two parallel line, resembles and equal sign (=)
c. an echogenic foci at the tip of the nose
d. three parallel lines that are perpendicular to the frontal bone
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 and = sign
the mean sac diameter in a normal IUP will demonstrate ______ increase in size per day up until the 10th week of gestation
a. 1mm
b. 2mm
c. 3mm
d. 4mm
a
the mean sac diameter in a normal IUP will demonstrate 1mm increase in size per day until the 10th week gestation
which of the following demonstrates the lowest risk of embryonic demise
a. implantation in the lower uterine segment
b. TV ultrasound identifies a gestational sac with MSD 12mm and 5mm yolk sac but no embryo
c. thin, mildly echogenic trophoblastic reaction
d. multiple lobulations of the gestational sac
b
indications for embryonic demise include distorted sac shape, thin and weakly echogenic trophoblastic reaction, low implantation site. on transvaginal 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
the chorionic villi and membrane are formed from the
a. blastocyst
b. yolk sac
c. amnion
d. trophoblastic cells
d
trophoblastic cells - produce progesterone and hCG. involved with implantation, develop into chorionic villi then into placenta
which of the following is most suggestive of an inevitable abortion
a. spotting for 2 days
b. cervical dilation over 3cm
c. cervical length over 3cm
d. presence of vernix in the amniotic fluid
b inevitable abortion: bleeding more than one week cramping PROM cervical shortening <3cm dilatation >2cm
conception occurs approximately
a. 2 hours after ovulation
b. 7 days after ovulation
c. 4 weeks after the last menstruation
d. 2 weeks after the menstruation
d
conception occurs approximately 2 weeks after the last menstuation. an embryo that is described as 8 weeks from conception is the same as 10 weeks in gestational age reported on the ultrasound for that pregnancy. conceptual age: the exact date of conception +2 weeks = gestation age
diabetes mellitus is associated with
a. increased risk of embryonic demise and miscarriage in the first trimester
b. early lung maturation
c. fetal weight exceeding 4000 grams
d. NT defects without other associated defects
a
diabetes mellitus is associated with higher incidence of congenital anomalies than gestational diabetes, increased risk of embryonic demise and miscarriage in the first trimester, caudal regression, neural tube defects, anencephaly, microcephaly, duodenal and anal atresia, hydronephrosis, renal agenesis, VSD, ASD, coarctation, transposition, polydactyly, and club feet, single umbilical artery, IUGR and thinned placenta
the chorionicity and amnionicity of a twin pregnancy is determined by
a. timing of the cell division in the embryo
b. number of choromosomes
c. paternal genes
d. timing of the cell division in the zygote
d
the timing of the cell division determines the “type” of twins. monochorionic vs. dichorionic and monoamniotic vs diamniotic (or conjoined twins)
an asymptomatic patient presents for a viability scan. using the transvaginal approach a 15mm fetal pole is identified without cardiac activity. the yolk sac is present within the gestation sac. which of the following best describes these findings.
a. embryonic demise
b. normal pregnancy too early to see cardiac activity at this size
c. missed abortion
d. blighted ovum
a
a 15mm fetal pole indicates a 8 week 1 day old fetus. a blighted ovum would not have a fetal pole. a missed abortion refers to fetal death without evacuation for several months. the patients is asymptomatic with no bleeding. embryonic demise refers to death of the embryo
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 diamninotic twin gestation will produce two separate amniotic sacs. a membrane will be identified that separates the fetus. 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 o the following types of twin gestation will have the thickest membrane between the fetuses
a. monochorionic/ diamniotic
b. monochorionic/ monoamniotic
c. conjoined twins
d. dichorionic/ diamniotic
d
a dichrionic 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 2nn in thickness
which of the following carries the lowest risk of spontaneous abortion
a. significant leakage of amniotic fluid
b. vaginal spotting for the last 10 days
c. gestational sac implanted in the endometrial cavity near the uterine cornua
d. cervical os dilated to 4cm
c
if the gestational sac implants in the lower uterine segment the risk of spontaneous abortion in increased significantly. other causes for increased risk of spontaneous abortion include cervical dilation >3cm. PROM extended period of bleeding (1wk+)
the embryo of a normal pregnancy will increase in size approximately
a. 1mm every 2 days
b. 1mm every week
c. 1mm every day
d. 10mm every week
c
the embryo of a normal pregnancy will increase in size approximately 1mm per day
which of the following is/are a sign of spina bifida in a 13 week fetus
a. obliterated cisterna magna and intracranial translucency
b. lemon sign
c. narrow brainstem and dilated cisterna magna
d. banana sign
a
in early pregnancy the signs of spina bifida include compression of the choroid intracranial translucency and cisterna magna with an enlarged brainstem. these changes occur due to the posterior shift of the cranial contents. the typical banana and lemon sign are not well demonstrated in the first trimester because the cerebellum is not fully formed and the cranium is not fully ossified but vertebral evaluation is limited at this age
the gestational sac with ______are the first signs of an intrauterine pregnancy see with ultrasound
a. a corpus luteal cyst
b. decidual reaction of the endometrium
c. fluid in the endometrial canal
d. fluid in the posterior cul-de-sac
b
the first sign of an IUP seen on the ultrasound is the gestational sac with decidual reaction in 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
which biometric measurement is not used to estimated fetal age in a detailed evaluation of a 3 week fetus
a. biparietal diameter
b. femur length
c. abdomen circumference
d. head circumference
b
the femur length is not used in the late 1st trimester evaluation for fetal dating, but may be helpful for detection of abnormalities until after 14 weeks gestation
an asymptomatic patient presents for a viability scan in the first trimester. the ultrasound exam demonstrates a fetal pole that measures at 7 weeks 2 days. a 7mm yolk sac is identified. the fetal HR is evaluated by m-mode and is estimated at 76bpm. there is no evidence of subchorionic hemorrhage. which of the following statements is true.
a. blighted ovum is present
b. the yolk sac is abnormally enlarged but the fetal heart rate is normal
c. the fetal heart rate indicates potential demise but the yolk sac is normal
d. the yolk sac is abnormally enlarged and the fetal heart rate is lower than normal
d
there is not a fetal pole present in a blighted ovum. the normal yolk sac measures less than 5.6mm in the internal diameter. a fetus 6-9wks should have a heart rate over 100bpm. after 9wks the heart rate should stay above 140bpm. the average heart rate in the second trimester is 120-160bpm
a patient presents for a pelvic ultrasound due to pain and bloating. her LMP was 5 weeks ago 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. endometriosis
c. ruptured appendix
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
all of the following are layers of the endometrium that form with pregnancy except
a. decidua accreta
b. decidua basalis
c. decidua parietalis
d. decidua capsularis
a
decidua capsularis - tissue that envelops he blastocyst after implantation
decidua basalis - becomes maternal placenta blastocyst attaches to this layer
decidua parietalis - other tissue not involved in the implantation process
the ______ forms the outer layer of the placenta that is in contact with the endometrium
a. yolk sac
b. amnion
c. blastocyst
d. chorion
d
the chorion forms the outer layer of the placenta that is in contact with the endometrium
implantation of the fertilized egg occurs day ______ of the pregnancy
a. 20-23
b. 15-18
c. 18-20
d. 30-33
a
implantation of the fertilized egg occurs day 20-23 of the pregnancy
what abnormality occurs when two sperm fertilize the same egg?
a. trisomy 21
b. autosomal dominant x-linked disorder
c. trisomy 18
d. tripoidy
d
an egg that is fertilized two sperm will have an extra full set of chromosomes = tripoidy
what cardiac view is used to document proper fetal heart position on a first trimester exam
a. 4 chamber view
b. aortic arch view
c. left ventricle outflow tract view
d. 3 vessel trachea view
a
color doppler can be used to demonstrate the fetal heart structure when screening for suspected defects. the 4 heart chamber view and 3 vessel trachea view can be documented later in the first trimester. the 4 chamber view is used to document chamber size heart position cardiac axis, the cardiac axis can more easily displayed using the 4 chamber view and color doppler
