OB Test 1 Flashcards
What are the 4 segments of the Fallopian Tube?
ampulla, isthmus, infidibular and fimbrae
Which part of the fallopian tube is the most distal?
fimbrae
Which part of the fallopian tube is the most proximal/medial and which one is the longest?
Isthmus: Proximal/medial
Ampulla: Longest
The Role of hCG
The hormone, human chorionic gonadotropin (a.k.a. hCG), is produced by _____ tissue and forms the basis of current pregnancy tests.
It is made by cells that form the _____, which nourishes the egg after it has been fertilized and becomes attached to the uterine wall.
It is believed to support the corpus luteum (remaining follicle “cyst” which produced the egg that was fertilized) thereby assuring a continuous supply of _____;
In the 1st trimester, hCG can first be detected by a normal blood test about _____ days after conception and about ___-___ days by a urine test.
hCG levels are first detected _____ weeks after the LMP (_____ days after ovulation), Doubles every ___-___ days and PLATEAUS at ___-___ weeks, then declines gradually
trophoblastic placenta progesterone 11 12 14 3 14 2 3 8 9
2 Common types of hCG tests
_____ hCG tests:
”+ or “-“ (Ex. home pregnancy test)
- urine test
- Just looks to see if hCG is present in the blood
_____ hCG test:
Actually dates pregnancy from “hCG” levels
- Blood (serum) test
- measures the amount of hCG actually present in the blood.
- Serum quantitative hCG may be correlated with gestational age.
qualitative
quantitative
hCG levels are important to determine the following:
Abnormal hCG levels
Greater than expected for dates
Associated with:
- Incorrect _____
- Gestational _____ disease
- Multiple _____
Less than expected for dates
Associated with:
- _____ pregnancy
- _____ demise
dates trophoblastic gestations ectopic embryonic
hCG - Q & A
What can a low hCG level mean? (Should be retested in 48-72 hrs)
- _____ of pregnancy dating
- Possible _____ or blighted ovum
- _____ pregnancy
What can a high hCG level mean? (should be retested in 48-72 hrs)
- _____ of pregnancy dating
- _____ pregnancy
- _____ pregnancy
What to expect of hCG levels after a pregnancy loss?
-levels return to a non-pregnant range about ___-___ weeks after a pregnancy loss has occurred.
Can anything interfere with hCG levels?
-Nothing should interfere with a hCG level except medications that contain _____. These medications are often used in fertility treatments and you health care provider should advise you on how they may affect a test. All other medications such as antibiotics, pain relievers, contraception or other hormone medications should not have any affect on a test that measures hCG.
miscalculation miscarriage ectopic miscalculation molar multiple 4 6 hCG
Importance of hCG levels
- An important use of serum hCG levels in the 1st trimester concerns the discrimination between a normal intrauterine pregnancy and an abnormal pregnancy that be _____.
- If the serum hCG concentration exceeds the discriminatory level of 800-1,000 units/liter (2 IS) and 1,000-2,000 units/liter (first IRB), then an intrauterine gestational sac should be visible with _____ sonography.
- If the hCG values exceed these levels and an intrauterine gestational sac is not visible, then _____ pregnancy or recent spontaneous _____ is possible.
ectopic
transvaginal
ectopic
abortionn
Can see the GS transabdominally ___-___ weeks LMP - 18-7,340 mlU/ml, 1,080-56,500 mlU/ml
See fetal pole ____-____ weeks LMP - 7,650-229,000 mlU/ml
5
6
7
8
NL hCG:
- Doubles every ___-___ hrs
- Subdoubles (Decrease) w/ _____ pregnancy
- Increases w/ _____ gestations
- Increases w/ _____ pregnancy(gestational trophoblastic disaese)
24 48 ectopic multiple molar
Development of the Embryo
- The next stage (after GS, YS) =_____
- characterized by the formation of the most _____ organs and _____ body structures
- Organ formation begins about ____ weeks after fertilization, the brain and spinal cord (neural tube) begins to develop. The heart and major blood vessels begin to develop by about day ___ or ___.
- The heart begins to pump fluid through blood vessels by day _____, and the first red blood cells appear the next day. Blood vessels continue to develop in the embryo and placenta.
- Almost all organs are completely formed by about ___ weeks after fertilization (which equals ___ weeks of pregnancy). The exceptions are the brain and spinal cord, which continue to mature throughout pregnancy.
- Most malformations occur during the period when organs are forming. During this period, the embryo is most vulnerable to the effects of _____, _____, and _____ Therefore, a pregnant woman should not be given any live-virus vaccinations or take any drugs during this period unless they are considered essential to protect her health
- Should be identified sonographically at approx ___ weeks
embryo 3 16 17 20 8 10 drugs radiation viruses 7
Development of the Fetus
- At the end of the 8th week after fertilization (10 weeks of pregnancy), the embryo is considered a _____ and the structures that have already formed grow and develop.
- By 12 weeks of pregnancy, the fetus fills the entire _____.
- By about 14 weeks, the _____ can be identified
- About 16 to 20 weeks, fetal _____ felt
- By about 23 to 24 weeks, the fetus has a chance of survival outside the _____.
- The _____ continue to mature until near the time of delivery. The _____ accumulates new cells throughout pregnancy and the first year of life after birth.
fetus uterus sex movement uterus lungs brain
Placenta/Chorion Frondosum & Embryo at approx 8 weeks
At approx. 8 weeks of pregnancy:
-The chorion frondosum surface (from the decidual _____ layer of endometrium is the embryonic portion of the placenta, which will later be known as the _____
- CF consist of finger-like projections, or _____, of the chorion surface which extends to meet the maternal portion of the placenta near the endometrial wall of the uterus.
- The chorion frondosum extends to meet the maternal portion of the placenta, which is composed of the _____ pool of maternal blood from material arteries and veins; this allows for diffusion of oxygen and of waste gases (such as carbon dioxide) between the membranous layers through a supply of arterial and venous blood from the maternal vessels
- A _____ membrane separates the embryo’s blood in the villi from the mother’s blood that flows through the space surrounding the villi (This arrangement allows materials to be exchanged between blood of mother and that of the embryo.
- The embryo “floats” in fluid (_____fluid), which is contained in a sac (_____ sac). The amniotic fluid provides a space in which the embryo can grow freely. The fluid also helps protect the embryo from injury. The amniotic sac is strong and resilient.
basalis placenta villi intervillous thin amniotic amniotic
Ultrasound “Markers” useful in determining early pregnancy and viability of the pregnancy include the following:
- _____ _____ _____ _____ (DDSS or DSS)
- _____ sac
- Fetal _____ and Measurement
- Fetal _____ and Activity
- Number of Gestational _____ and _____ sacs
Double Decidual Sac Sign yolk pole heart sacs yolk
Double Decidual Sac Sign (DDSS/DSS) & Gestational Sac (GS)
- DDSS is sonographically known as the “_____ decidual reaction”
- The 1st INTRAUTERINE STRUCTURE SEEN WITH US, IN nl PREGNANCY, is the _____ _____ (GS) with an ECHOGENIC THICKENED RIM CALLED THE DDSS; almost always seen with _____ US between 4.0-4.5 menstrual weeks (2-2.5 weeks after fertilization).
- A nl _____ is round or oval and located within the fundus or mid portion of the uterus. SONO characteristic: Anechoic sac with Echogenic (bright) rim and eccentric position within the endometrial cavity all help differentiate a “true” gestational sac from a pseudo gestational sac (seen with ectopic pregnancy). A pseudo sac will not havw the DDSS sono characteristic.
trophoblastic
gestational sac
transvaginal
GS
Important characteristic of the GS is the “double sac sign.” The inner portion of the double layer of the GS (decidua reaction) is the decidua _____ and the outer portion layer is the decidua _____/_____. This sign confirms the presence of an intrauterine pregnancy (IUP).
The GS MEASUREMENT is referred to as the _____ _____ _____ (MSD) which is the mean/average of 3 dimensions: Length, Width, and AP measurements which must be obtained, inner wall to inner wall. These measurements will obtain a GA until a fetal pole can be identified and measured. The fetal pole or CRL measurement will become the most accurate measurement for dating the pregnancy in the 1st trimester. NL GS GROWTH IS APPROX _____mm/day (helpful in F/U cases)
-Abnormal GS appearance that may indicate pregnancy failure are: GS > than 8mm without a _____ sac, distorted GC shape, or abnormally low positioned sac within the endometrial cavity
capsularis parietalis/vera mean sac diameter 1 yolk
Measuring the GS
Gestational Sac Volume/Size requires 3 measurements:
MSD or GS Formula: MSD= L x H (AP) x W/3
- _____, _____, _____
- _____ view (1) - length measurement is taken
- _____ view or _____ view (2) - AP measurement
- _____ measurement (3) - can ONLY be taken in transverse view
measure from inner to inner to include only the anechoic area because the echogenic rim is decidual reaction of implantation
AP SAG Width sagittal transverse sagittal width
The Yolk Sac(within chorionic cavity)
- The _____ sac is a membrane sac outside the embryo that is connected by a tube (the yolk stalk) though the umbilical opening to the embryo’s midgut
- Serves an an early site for formation of _____ and over time is incorporated into the primitive gut of the embryo.
- Situated on the _____ aspect (front/AP) of the embryo, filled with fluid _____ fluid, therefore anechoic with hyperechoic rim sonographically
- _____ fluid may possible be utilized for the nourishment of embryo. Blood circulates through a wide-meshed capillary plexus, returned by the vitelline veins to the tubular heart of the embryo. This constitutes the vitelline circulation, and it’s nutritive material is absorbed by the embryo
- End of the 4th week the ____ presents with the appearance of a small round or pear-shaped vesicle (umbilical vesicle) opening into the digestive tube by a long narrow tube, the vitelline duct, situated between the amnion and the chorion and may lie on or at a varying distance from the placenta
- Undergoes complete obliteration during the 7th week, but in about 3% of cases it persists as a diverticulum from the small intestine, _____ diverticulum, which is situated about 3 or 4 ft above the ileocolic junction, and may be attached by a fibrous cord to the abdominal wall at the umbilicus.
- Meckel’s diverticulum = persistent _____ duct
yolk blood ventral vitelline vitelline YS Meckel's vitelline
SHORTLY AFTER THE 1ST APEARANCE OF THE GS IS THE 1ST STRUCTURE SEEN SONOGRAPHICALLY AS AN IUP IS THE _____ SAC:
- Is the 1st structure visible within the GS
- lies within the _____ cavity
- seen between ____-___ weeks gestation
- thin-walled spherical object near border of the hyperechoic rim with anechoic center
- attached to the embryo by the yolk _____ (vitelline duct)
- As embryonic cavity begins to enlarge, the YS (lies within the chorionic cavity,so it’s considered to be extra-amniotic) “moves away” from the embryo as the pregnancy progresses in 1st trimester, eventually detaches from the yolk _____; no longer seen after 12 weeks of gestation
-The yolk sac should always be seen when a GS measures greater than _____ mm.
A nl YS is round, measures less than _____ mm
-If the YS measures greater than 6 mm, is bizarre in shape or is calcified, f/u exam is indicate; most pregnancies with abnormal yolk sac will fail.
yolk chorionic 4.0 5.0 stalk stalk 10 6
“Double-Bleb Sign”
- an early nl “sono appearance” that can be seen within the GS
- Produced by _____ and AC
- _____ is not yet visible at this stage
YS
embryo
Fetal Pole (Embryo) Measurement
- After cardiac activity is seen in the thickened linear tissue (FP) adjacent to the YS, this linear structure will continue to grow and the FP -embryo becomes more visible as a _____ within the GS;
- SONO Appearance: elongated, curvature, echogenic “fetal pole”
- FP (embryo/fetus) 1st measured at about ___-___ weeks of pregnancy; measurement is from crown to rump (L). Embryonic cardiac activity should always be seen when an embryo measures greater than 5 mm.
- Between 8-10 weeks, the _____ a fluid filled cavity the hindbrain of the fetal head, is easily identified. This chamber eventually becomes the 4th ventricle and central canal of the brain and spinal cord, only seen in 1st trimester normally
- Normal physiologic bowel herniation is also routinely seen before _____ weeks.
fetus 5.5 7 rhombencephalon 14
Fetal pole measurement or “_____ _____ length” (CRL) is THE MOST ACCURATE ULTRASOUND PARAMETER FOR PREGNANCY DATING. It is usually obtained in preference to measurement of individual body parts until about ___-___ weeks
crown rump
12
13
Implantation
- Implantation occurs when the _____ burrows into the endometrium. A small blood clot helps secure the conceptus in the endometrium.
- At this stage, _____ cells from the blastocyst begin to penetrate the endometrium: 7 days after fertilization.
- Blastocyst/Trophoblast burrows deeper beneath the _____ and causes endometrium reaction and may cause a small amount of bleeding.
3 distinct layers of decidualized endometrium result from this deeper “burrowing”:
-Decidua _____/Decidua _____ (area of placenta development)
- Decidua _____/Decidua _____(the layer between the basalis and capsularis)
- Decidua _____ (surrounds the fetus, ‘inside’ of vera)
3 layers = thickening = _____ decidual layering (thick echogenic ring)
blastocyst trophoblastic endometrium basalis placentalis parietalis vera capsularis double
3 Decidual Layers and SONO Features
- Decidua _____ closes over and surrounds blastocyst/trophoblast = fetus
- Decidua _____/_____ - portion of the endometrium that underlies the implantation site; forms a compact layer, called the decidual (_____) plate and it contributes to the maternal portion of the placenta.
- Decidua _____/_____ is the decidua lining that is the remainder of the endometrial cavity other than the area called basalis/placentalis
capsularis
basalis/placentalis
basal
vera/parietalis
3 DECIDUAL LAYERS AND THEIR SONOGRAPHIC IMPORTANCE
The 3 layers are seen on an ultrasound image as a “_____ _____ _____ _____” (DDSS/DDS) which is a normal reaction to implantation
- Useful feature in early pregnancy on ultrasound because it distinguished between an early _____ pregnancy (IUP) = pregnancy that will produce a fetus) and a pseudogestational sac (will never produce a fetus)
- Consists of decidua _____/_____ (lining the endometrial cavity)
- decidua _____ (lining the GS surrounding the fetus); seen as 2 concentric rings surrounding an anechoic gestational sac; the area that the 2 layers adhere/imbed, is the decidua _____/_____ (site of future placental formation)
double decidual sac sign intrauterine parietalis/vera capsularis basalis/placentalis
Chorionic/Amniotic Membranes and Cavities of the GS
The _____ sac is the sac in which the fetus develops and comprised of 2 membranes/cavities
- The inner membrane, the _____, contains the amniotic fluid and the fetus.
- The outer membrane, the _____, is part of placenta
gestational
amnion
chorion
Chorio - Amniotic Separation
- The _____ and the _____ begin to fuse by the middle of the 1st trimester.
- Fusion is usually complete by ___-___ weeks of pregnancy.
- Sonographic identification of the separation of the two membranes is a normal finding and is not associated with poor outcome of the pregnancy
amnion
chorion
12
16
_____ is the membrane that contains amniotic fluid/cavity and the fetal pole is within this cavity
_____ is up against the endometrium wall and not seen sonographically as a structure only an area
_____ cavity is only seen in 1st trimester and contains only the yolk sac; this cavity will diminish as 1st trimester ends and 2nd trimester begins
amnion
chorion
chorionic
Hemodynamic changes
- _____ tissue provides the developing conceptus with some nutrients and oxygen. Since embryonic tissue is highly active metabolically, a continuous supply of oxygenated blood is necessary and area should be documented.
- Represented by Doppler spectral WFs with _____ velocity, _____ resistance flow
trophoblastic
high
low
LMP (Last Menstrual Period) A.K.A. LNMP (Last Normal Menstrual Period)
Last Menstrual Period (Last Normal Menstrual Period) = _____ day of LAST NORMAL Period
-_____Age/_____Age = the age of a pregnancy from the LNMP date
The _____ day of the woman’s last nl menstrual period (LMP) is most commonly used to mark the initiation of pregnancy for the calculation of gestational age/menstrual age.
-_____ Age/_____Age/_____ Age = the age of the embryonic/fetus at fertilization/conception
1st gestational menstrual first embryonic fetal fertilization
Fetal Cardiac Activity
- Usually first seen between ___-___ weeks
- FHT’s is documents by:
“___-Mode” Ultrasound- The M-mode cursor is placed through the cardiac pulsations, and activity along the cursor is displayed over time on the right side of the screen.
_____ Wave Doppler (heart sounds heard) PW cursor is placed thru the cardiac pulsations and it detects the fetal heartbeat or the velocity of movement of a structure
Normally, the fetal heart rate is relatively slow (around ___bpm) when first seen at 5 weeks gestation. The rate then increases to an average of ____bpm at 8 weeks, then gradually declines through the rest of the first trimester
5.0
6.0
M
Pulse
110
160
In 1st trimester, when can we see GS, YS and FHR on Ultrasound
Gestational sac - Transabdominal = _____ weeks, Transvaginal = _____ weeks
yolk sac - Transabdominal = ____-____ weeks, Transvaginal = _____ weeks
embryo with fetal cardiac activity = ____-____ weeks, Transvaginal = ___-___ weeks
5 4.5 5,6 5 6,7 5,6
Gestational Sac
- identification of a gestational sac (GS) within the endometrial cavity is the
- 1st songoraphic evidence that a normal, intrauterine pregnancy is present. A
- GS is ALWAYS seen in a NL _____ when the following discriminatory levels
are achieved:
- Serum sHcG >800 -1,000 mlU/ml (_____) (Usinf 2ls).
- Serum sHcG > 1800 mlU/ml (_____) (using 2ls).
Certain LMP greater than or equal to 5 weeks
Normal Sonographic Criteria:
- Double sac sign
- Round, oval, well defined
- Echogenic, intact borders
- Positioned in the fundus or mid-uterus
- Grows =1mm/day
- Yolk sac present when MSD greater than or equal to 13 mm
IUP
Endovaginal
Transabdominal
Mean Gestational Sac Diameter (MSD) Measurement
-Mean sac _____ can be used to date an early 1st trimester prior to the identification of a crown rump length
-A mean diameter is calculated from three planar sections.
MSD = (AP + long + trans) / 3
- _____ imaging and measurements are more accurate
- MSD - CRL > 5mm is associated with a high risk of SAB
size
endovaginal
CROWN RUMP LENGTH
MOST ACCURATE OF ALL MEASUREMENTS THROUGHOUT PREGNANCY.
- Accuracy is within ___-___ days if measured properly.
- Measured- top of _____ to bottom of _____ excluding legs.
- Embryonic pole should be visible if MSD measures ____mm or more (TransAbdominal)
RULE OF THUMB:
Size in cm + 6 = GA in weeks
RULE OF THUMB:
Size in mm + 42 = GA in days
3, 5
head
rump
25
Measure OF Viability
GS may be identified = Age (weeks) _____, GSS (mm) _____
GS always identified = Age (weeks) _____, GSS (mm) _____
Yolk sac identified = Age (weeks) _____, GSS (mm) _____
Cardiac activity identified = Age (weeks) _____, GSS (mm) _____
Embryonic pole identified = Age (weeks) ___-___, GSS (mm) _____
4.5 2 5 5 5 10 6,7 18 6,7 18
By _____ weeks of gestation the crown rump length of the embryo reaches 5 mm and the embryo can be seen as a separate structure from the yolk sac and cardiac pulsations should be visible. The mean gestational sac size 18-20 mm.
Limb buds are embryologically recognizable during the _____ week of gestations projecting at ninety degrees off the body.
6
seventh
By _____ weeks of gestation the amniotic and chorionic cavities can be delineated as separate structures. The amniotic cavity progressively enlarges and fuses with the chorion at 12-16 weeks of gestation.
8
