Multiple pregnancy with two chorionic sacs
Multiple pregnancy with one chorionic sac
Formed at 23 days when the primary yolk sac is pinched off by the extraembryonic coelom
secondary yolk sac
Length of time calculated from the first day of the last normal menstrual period to the point at which the pregnancy is being assessed
multiple pregnancy with one amniotic sac
Conceptus resulting from union of male and female gametes
Age calculated from when conception occurs
Multiple pregnancy with two amniotic sacs
First site of formation of red blood cells that will nourish the embryo
primary yolk sac
High-frequency transducer that is inserted into the vaginal canal to obtain better definition of first-trimester pregnancy.
Uterine decidua on the surface of the implantation site
Surrounds the amniotic cavity and contains the yolk sac
Hormone secreted by the trophoblastic cells of the blastocyst; laboratory test indicates pregnancy when values are elevated
human chorionic gonadotropin
Time between 4 and 10 weeks' gestation
The umbilical duct connecting the yolk sac with the embryo
Most accurate measurement of the embryo in the first trimester
Production and development of blood cells
Mean sac diameter
Interface between the decidua capsularis and the echogenic, highly vascular endometrium
double decidual sac sign
Cavity in which the fetus exists; forms early in gestation; fills with amniotic fluid to protect the fetus
Uterine decidual surface on the maternal side of the placenta
Invasive diagnostic genetic testing that involves sampling zygotic cells from developing placental tissue
chorionic villi sampling
Clinicians and sonographers use ________ to date the pregnancy, with the first day of the last menstrual period as the beginning of gestation.
In the first 9 menstrual weeks, the conceptus is called an ________
For the first time after the first 9 weeks, the embryo is called a ________.
The gestational age (age known as postmenstrual age) is calculated by adding ____ weeks to conceptual age.
The fertilized ovum, which now should be referred to as a ________, undergoes rapid cellular division to form the 16-cell morula.
The blastocyst typically enters the uterus 4-5 days after fertilization, with implantation occurring _______ days after ovulation.
Although the organ function remains as minimal, the ________ system is the first organ to develop rapidly, with the first heartbeats noted between 5.5 and 6.5 weeks
Gestational sac size and hCG levels increase ________ until 8 menstrual weeks
After 8 weeks, hCG levels ________ and subsequently decline while the gestational sac continues to grow.
A normal gestational sac can be consistently demonstrated when the hCG level reanges between __________mIU/mL.
The sonographer must be aware that when the hCG level is elevated and the gestational sac is not seen within the uterus, an ________ pregnancy should be considered.
The interface between the decidua capsularis and the echogenic, highly vascularized endometrium forms the _____________________
double decidual sac
The gestational sac size grows at a predictable rate of ____ mm per day in early pregnancy
The first intragestational sac anatomy seen is the sonographic ________ sac, which is routinely visualized between 5 and 5.5 weeks' gestation.
The limb buds are embryologically recognized during the ______ week of gestation.
The spine is also developing during the embryonic period, particularly in the ________ weeks of gestation.
The embryonic face undergoes significant evolution starting in the 5th week of gestation, with palate fusion beginning around the_______ week of gestation
At approximately 10 weeks' gestation, the midgut loop continues to grow and rotate before it descends into the fetal abdomen at about the _____ week
The cystic rhomboid fossa can sonographically be imaged routinely from the _______ week of gestation.
It is important to note that the________ventricles completely fill the cerebral vault at this time in gestation
Sonographically, the gestational sac size or mean sac diameter (MSD) is determine by calcalation the average sum of the________,________, and _______ of the gestational sac.
length, width, height
4. developing follicle
Label the diagram of normal conception
2. connecting stalk
3. emrbyonic disc
4. yolk sac
6. chorionic cavity
7. amniotic sac
8. umbilical card
9. yolk sac
11. connecting stalk
12. yolk sac
13. chorionic cavity
14. smooth chorion
16. amniotic sac
17. umbilical cord
18. yolk sac remnant
label the development of amnion, yolk sac, and embryo
gestational sac(chorionic cavity)
Identify the sonographic findings in this 5-week intrauterine gestation
Identify the structure that the arrows are pointing to in this 6-week gestation
curved arrow: amniotic membrane
straight arrows: umbilical cord
In this 8-week gestation, name the structure that the curved arrow is pointing to. Name the structure that the straight arrows are pointing to.
What important fetal measurement does this image demonstrate?
Identify what the letter "C" represents
Identify the disklike structure adjacent to the yolk sac.
Name the type of multiple gestation you would predict from this image.
Name the type of multiple gestations demonstrated by this sonogram.
Failure to visualize the yolk sac, with a minimum of _____ mm MSD, using transvaginal sonography, should provoke suspicion of abnormal pregnancy.
Transabdominal studies have shown that the yolk sac should be seen within mean sac diameters of _______ mm and should always be visualized with a mean sac diameter of 20 mm.
The growth rate of the yolk sac has been reported to be approximately ______ mm per millimeter of growth of the MSD when the MSD is less that 15 mm.
The early embryo is not identified with transvaginal sonography until heart motion is detected and the crown-rump length measures approximately _____ mm.
The embryonic period is the time between _____ and 10 weeks' gestation.
The primitive neural tube closes by _____ weeks' gestation.
At _______ weeks, three primary vesicles are seen within the fetal brain: the prosencephalon, the mesencephalon, and the rhomencephalon.
During development, the midgut loop of the bowel continues to grow and rotate before it descends into the fetal abdomen at about the_____ week.
Using transvaginal sonography, multiple gestations can readily be diagnosed at very early stages, between ________ weeks
5.5 & 6.5
Sonographically, dichorionic and diamniotic twins appear as _____ separate gestational sacs with individual trophoblastic tissue, which allows the appearance of a thick dividing membrane.
Monochorionic-diamniotic twins appear to be contained within _______ chorionic sac; _____ amnion(s); ______ yolk sac(s), and two embryos are identified.
one, two, two, two
The monozygotic, monoamniotic-monodichorionic twin gestation shows _____ gestational sac with _____ amniotic membrane, which may contain one or two yolk sacs and two-embryos within the simgle amniotic membrane.
Measurement that includes both fetal orbits at the same time to predict gestational age
Used in the first trimester to estimate appropriate gestational age with menstrual dates
gestational sac diameter
Method whereby the fetus is categorized into small, average, or large growth percentile
growth-adjusted sonar age
Fetal transverse cranial diameter at the level of the thalamus and cavum septum pelluciidum
Most accurate measurement for determining gestational age; made in the first trimester
Used to determine the start date for human pregnancies
last menstrual period
Measurement at the level of the stomach, left portal vein, and left umbilical sign
Heart rate before the 9th week of gestation
eembryonic heart rate
Measurement from the humeral head to the distal end of the humerus
Size and proportionality of the fetal parameter expressed as age
age range analysis
Normal fetus that measures smaller than dates
small for gestational age
Average age of multiple fetal parameter's age
Measurement of the femoral diaphysis
Flattening of the vertex of the skull
Condition in which the orbits are spaced far apart
Refers to the shape of the cerebellum when a spinal defect is present
Failure of the vertebrae to close
Absence of one or both eyes
Fetal head is relatively narrow in the transverse plane and is elongated in the anteroposterior plane
Condition of having a relatively high cranial vault with a high or peaked appearance
Abnormally small eyes
Fetal head is relatively wide in the transverse diameter and shortened in the anteroposterior plane
Occurs with spina bifida; frontal loves collapse inward
Condition in which fetus is not growing as fast as normal; usually considered malnourished or abnormal
intrauterine growth restriction (IUGR)
Sonographically, the earliest sign of intrauterine pregnancy is the _______, which appears an echogenic, thickening filling of the fundal region of the endometrial cavity occurring at approximately 3-4 weeks' gestation.
At 5 weeks, the average of the three perpendicular internal diameters of the gestational sac, calculateed as the mean of the _______ diameter, the ________ diameter, and the _______ diameter, can provide an adequuate estimation of menstrual age.
anteroposterior, transverse, longitudinal
The sac grows rapidly in the first ____ weeks, with an average increase of 1 mm per day.
when the gestational sac exceeds _______ mm in mean internal diapeter, a yolk sac should be seen.
Normal yolk sac size should be less than _____ mm; greater than _____ mm has been associated with poor pregnancy outcome
When the mean gestational sac diameter exceeds ____ mm, an embryo with definite cardiac activity should be well visualized with transvaginal scanning.
The embryonic echoes can be identified as early as 38-39 days menstrual age, and the CRL is usually ______ mm at this age.
The most accurate sonographic technique for establishing gestational age in the first trimester is
In general, the CRL should increase at a rate of _____ mm per day
Absence of an embryo by 7-8 weeks' gestation is consistent with an embryonic demise or an _______ pregnancy
If a nomogram is not readily available to identify gestational age, a convenient formula is gestational age is weeks equals _______.
CRL in cm + 6
In the second trimester, the gestational age parameters extend to ______ diameter, ______circumference, _______ circumference, and ______ length.
biparietal, head, abdominal, femur
The reproducibility of the BPD is +/- ______ mm (+/- 2 standard deviations.
Growth of the fetal skull slows from ____ mm per week in the second trimester to _____ mm per week in the third trimester.
The fetal head should be imaged in a transverse ________ section, ideally with the fetus in a direct occiput transverse position.
The BPD should be measured perpendicular to the fetal skull at the level of the ________ and ________.
thalamus, cavum septi pellucidi
Intracranial landmarks should include the ________ anteriorly and posteriorly, the ________ anteriorly in the midline, and the ________ in the atrium of each lateral ventricle.
falx, cavum septi pellucidi, choroid plexus
The head shape should be ________, not round, because this can lead to overestimation of gestational age, just as a flattened or compressed head can lead to underestimation of gestational age
The calipers should be placed from the ________ edge of the parietal bone to the ________ edge of the opposite parietal bone, or "outer edge to inner edge."
The proper coronal view should be ________ to the standard transverse HC view passing through the thalamus.
One can ________ gestational age from a dolichocephalic head or ________ with brachycephaly.
The AC is very useful in monitoring normal fetal growth and detecting fetal growth disturbances, such as IUGR, and macrosomia; however, it is more useful as a ________ than in predicting gestational age.
The fetal abdomen should be measured in a transverse plane at the level of the ________ where the ________ vein branches into the left portal sinus.
The abdomen should be more ________ than oval because an oval shape indicates an oblique cut resulting in a false estimation of size.
The ________ length is an especially useful parameter that can be used to date a pregnancy when a fetal head cannot be measured because of position, or when there is a fetal head anomaly.
Often an echo from the near side of the cartilaginous distal femoral condyles will be seen, call the "________"; this should not be included in the measure of the diaphysis.
distal femoral point
The tibia and fibula can be measured by first identifying the ________, then following it down until the two parallel bones can be identified
Humerus length is sometimes more difficult to measure than the femur length because the humerus usually is found very close to the fetal ________ but can exhibit a wide range of motion.
The ulna can be distinguished from the radius because it penetrates much more deeply into the ________.
yolk sac, 4 weeks gestational age
Identify the small structure within the gestational sac and estimate the gestational age
what is being measured in this image?
sp=spine, st=stomach, abdominal circumference
Identify the labeled structures in this image
Which measurement is being made at this level?
distal femoral point, femur
Name the structure the arrow is pointing to.
name the structure being measured
A fertilized ovum is called a ________
The most accurate aging measurement is taken _______ in pregnancy.
Follicle that releases mature ovum hemorrhages and collapses to for the corpus luteum and secretes ________ and _________
The blostocyst contains trophoblastic cells and "inner mass". This later forms the ________
Blastocyst typically enters uterus _______ days after fertilization
During implantation, protoelytic enzymes produced by trophoblasts "eat into" decidual tissue. This creates spaces for _____________.
At approzimately 23 days menstrual age, primary yolk sac is pinched off, forming _____________, which is what is seen sonographically.
secondary yolk sac
The cardiovascular system undergoes rapid development, with initial heartbeat occurring between __________ weeks.
The last two weeks of the first trimester (weeks _______) constitute the beginning of the fetal period.
11 & 12
HCG ________ every 3.5 days in a normal pregnancy
HCG levels ______ prior to loss of pregnancy
The decidua basalis is closest to the ________, and the decidua capsularis is closest to the ________.
Typically, fundal location is noted within the endometrium but closest to the _______.
The gestational sac should appear round or oval. If elongated or angled, this is __________
Mean Sac Diameter- average size of gestational sac
The fetus appears _________ sonographically.
C- gestational sac
what are the structures labelled A, B, & C.
The MOST ACCURATE dating measurement is ______
Normal diameter of yolk sac should not exceed ____ mm
Typically, the yolk sac is reabsorbed and no longer seen sonographically by _____ weeks
CRL should measure ______ mm at 5.5 to 6 weeks
The fetus resides in the __________ cavity.
Amnion and chorion membranes will be seen at _____ weeks
Fusion of membranes, known as _________, occurs at approximately ___________ weeks.
chorioamniotic fusion, 14-15
Time between 4 & 10 weeks of gestation often considered __________ period.
Developing spine may be visualized sonographically as _______ ___________ lines at 6 weeks gestation
The first organ to function within the embryo is the _________
70% of multiple gestations are ________
The most dangerous multiple combination is _________
identify A & B in image above
Identify labelled structures in this illustration of a 40 day old embryonic brain
spine demonstrated by parallel echogenic lines with a sonolucent center
Identify which structure the arrow is pointing to in this sonogram of an 8-week embryo
By 8 weeks, three primary vessels are seen within the fetal brain: the prosencephalon, the mesencephalon, and the _________
The rhombencephalon is divided into two segments, the cephalic portion, or ________ and the caudal component, or _________
Sonographically, limb buds may be detected from the ______ week on. _______ limbs form first
Calcification of long bones begins at _______ weeks.
Frontal cranial bones begin to calcify at ________ weeks
Anterior abdominal wall developed by _____ weeks' gestation
Small bowel appears as ___________ within base of umbilical cord.
After _______ weeks of gestation, echogenic umbilical cord mass no longer visualized.