Test 1 (1st tri. & ectopic) Flashcards
what are the weeks in the first trimester?
the first 13 weeks following LMP
how big does the embryo grow in the first trimester?
80 mm
what are the phases of the 1st trimester?
- conceptus phase
- embryonic phase
- fetal phase
conceptus phase
3-5 weeks
-occurs about 2 weeks after a women’s last menstraul period
embryonic phase
6-10 weeks
fetal phase
10-12 weeks
Stomodeum
precursor to the mouth
Vitelline artery
circulates blood from the primitve aorta of the early developing embryo to the yolk sac
allantois
collect liquid waste from the embryo, as wel as to exchange gases used by the embryo. Involved in the development of the urinary bladder
cloaca
structure for the intestinal, urinary, and genital tracts
what is seen in 4.3-5 weeks?
- possible small GS
- possible double decidual sac sign (DDSS)
- possible intradecidual sac sign (IDSS)
what is seen in 5.1-5.5 weeks?
gestational sac
what is seen in 5.5-6 weeks?
- YS
- GS should be around 6 mm in diamter
- double bleb sign
what should be seen over 6 weeks?
- fetal pole on endovag
- fetal heart rate 100-115 bpm
- GS should be around 10mm in diameter
what should we see at 6.5 weeks?
-CRL about 5 mm
what should we see at 7-8 weeks?
- CRL between 11-16 mm
- cephalad and caudal poles identified
what should we see at 8-9 weeks?
- CRL between 17-23 mm
- limb buds appear
- head is seen seperate from body
what should we see 9-10 weeks?
- CRL between 23-32 mm
- FHR 170-180 bpm
- fetal movement
- rhombencephalon
- nuchal transluceny
what should the b-hCG be at when we see GS transabdominally?
> 1800mIU/mL
what should the b-hCG be at when we see GS transvaginally?
> 1000mIU/mL
how fast does b-hCG grow?
double every 2-3 days
what should MSD measure when a yolk sac should be visable?
20mm
what should MSD measure when an embryo should be visable?
25mm
what should CRL measure when a cardaic activity should be visable?
7mm
An embryo should be seen ______days after a scan with a gestational sac without a yolk sac
= 14 days
An embryo should be seen _______ days after a scan with a gestational sac and a yolk sac
=11
pseudocyesis
false pregnancy
belief that you are carrying a baby when you are not really carrying a child becasue you have all or many of the symotoms
couvade
men experience sympathetic pregnancy
what symptoms happen with couvade?
- weight gain
- nausea
- backache
what is useful to confirm an early intrauterine pregnancy?
DDSS
what does the DDSS consist of?
-decidua parietalis
-decidua capsularis
(where they adhere is the decidua basalis)
pseudogestational sac
- intrauterine anechoic sac-like structure that may be mistaken for an early viable pregnancy.
- represents endometrial breakdown of a decidual cast cyst
how do you differentiate a pseudogestational sac from an true GS sac?
- central location
- oval shape
- lack of a thick chorionic ring
double bleb sign
- visualization of a GS containing a yolk sacand an amniotic sac giving an appearance of two small bubbles.
- embryonic disc is located between the two bubbles.
why os double bleb sign an important feature?
important featre of intrauterine pregnancy becuase it distinguishes a pregnancy from a psedogestational sac or a decidual cast cyst
-should not be confused with the DDSS
anembryonic pregnancy (blighted ovum)
gestational sac which develops without an embryo
-no fetal pole on endovag when MSD >25mm
what is the first sign of early pregnancy on US?
gestational sac
- seen on endovag at about 5 weeks
- MSD=2-3mm
how do you distinguisg a true GS from a pserdogestational sac?
- normal eccenteric location
- presence of yolk sac
- presence of DDSS
- postive beta-hCG shows its a good sign its a pregnancy
how fast does the normal gestatonal sac grow per day?
1mm
what plays a critical role in embryogenesis?
yolk sacq
what are the functions of the yolk sac?
- provision of nutrients to the embryo before placenta
- embryonic hematopoiesis
- origin of the epithelium lining of the gastro-intestinal and respiratory tracts
- production of albumin, AFP, and other proteins during embryonic period
- becomes incorporated into gut on embryo
what is the maximmun diameter of the yolk sac?
6mm and 10 weeks menstral age
what does an abnormally large yolk sac indicate?
a poor OB outcome
when does the yolk sac decline?
after 9 weeks
what is abnormal yolk sac size or shape caused by?
poor embryonic development or demise
what is indicative of a long standing embryonic demise?
calcified YS without blood flow
what do slow growing tumors develop from?
trophoblastic cells
what are the 4 types of gestationa tropho blastic disease?
- hydatidiform mole
- invasive mole
- choricarcinoma
- placetal-site trophoblastic tumor (PSTT)
what is another name for molar pregnancy?
hydatidiform mole
what is the most common type of trophoblastic tumor?
hydatidiform mole (molar pregnancy)
which gestational trophoblastic diseases are bengin and which are malignant?
BENIGN -hydatidiform mole -invasive mole MALIGNANT -choriocarcinoma -invasive mole
what is the normal blood flow of intrauterine arteries in a normal pregnancy?
1st trimester-high resistance, low diastolic veloicites except implantation site
2nd / 3rd trimester-resistance reduces
what is the blood flow in a molar pregnancy and why?
-high velocity
-low impedance waveforms
because arterial invasion by abnormally proliferating trophoblast
what do Arterio-venous shunts associated with neovascularization within the invasive myometrial mass result in?
appearance of chaotic vasculature with colour aliasing
what does colour and spectral doppler look like for a gestational trophoblastic disease?
reveals a mosaic pattern within the cystic spaces representing turbulent flow. Spectral analysis reveals high velocity and low impedance pulsatile flow
what is the swiss cheese appearance associated with?
complete hydatidiform mole representing the hydropic villi
what is complete hydatidiform mole associated with?
theca lutein cysts
what causes the swiss cheese appearance?
cystic degeneration of chorionic villi
Chorioadenoma Destruens
- malignant
- invasive mole
Choriocarcinoma
- malignant
- wil metastisize
what is the etiology theories of trophoblastic disease?
- Pathologic pregnancy with the primary defect the BLIGHTED OVUM
- Non active chromosomes in the ovum therefore no fetus - Neoplastic proliferation of trophoblast resulting in early fetal demise
what increases the incidence of trophoblastic disease?
- south asia
- recurrent
- increases with age. poverty, malnutrituon
what are clinical and sonographic features of trophoblastic disease?
- increased beta HCG levels
- hyperemesis gravidarum
- theca lutein cysts
- hypertendsion with PreEclampsia
- excessive uterine size
- toxemia (pregnancy induced hypertension)
- hyperthyroidism
- VAGINAL BLEEDING
- large for dates
- absence of fetus
is having a twin pregnancy, 1 molar and one not possible?
no
complete hydatiform mole
sperm fertilizes an egg that does not contain maternal DNA (DNA only from father)
what is the chromosomal pattern for complete hydatiform mole?
46 xx with all the chromosomes of paternal origin (diploid karyotype)
how is complete hydatiform mole characterized?
- proliferation of the trophoblast
- absence of fetus , cord, and amniotic membrane
what is the sonographic appearance of a complete hydatiform mole?
-enlarged uterus
-central heterogenous echogenic mass expands endo canal
-mass conatins multiple cysts of varrying size=hydropic villi
(BUNCH OF GRAPES)