Class 10: U/S in 1st Trimester Flashcards by Jenelle Nuqui

what is ovulation?

when an ovary releases an ovum

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what happens if fertilization of an ovum occurs?

corpus luteum cyst stays & the endometrium grows

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what happens if fertilization of an ovum doesn’t occur?

estrogen & progesterone levels decrease, corpus luteum regresses, and menstruation starts

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how long does sperm remain viable in the female reproductive tract?

24-72 hours

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how much sperm is considered clinical infertility?

less than 20 million sperm/ml

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term for the functional maturation of sperm?

capacitation

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what is the process of capacitation?

the process where the sperm’s glycoprotein coat is removed by substances secreted by FT & UT

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what happens when the sperm’s glycoprotein coat is removed?

sperm becomes hyperactive & acrosomal reaction occurs when in contact with ovum

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what does the acrosomal reaction do?

acrosome from sperm breaks down outer membrane of ovum to penetrate ovum

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where does fertilization most commonly occur?

ampulla of FT

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when does fertilization occur?

about 24-36 hours after ovulation

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when does implantation occur?

about 6 days after ovulation

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how many chromosomes are in a zygote?

46 chromosomes

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what is a zygote?

sperm fertilizes an ovum, merge genetic content to make zygote

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how many cells are in a morula cell?

16 cells

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the ____ implants in the uterine cavity

blastocyst

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what is the trophoblast of the blastocyst?

the outermost layer of cells

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what is the outer layer of the trophoblast?

synctiotrophoblast

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what is the inner layer of the trophoblast?

cytotrophoblast

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what hormone does the trophoblast produce?

HCG

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what does the trophoblastic tissue form to invade the endometrium?

chorionic villi

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what is the fetal side of the placenta called?

chorionic site

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what does the inner cell mass of the blastocele form into?

embryo, amnion, and yolk sac

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what does the blastocyst become?

embryo

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what is the gravid endometrium become?

the decidua

3 layers of the decidua?

1. decidual basilis 2. decidual capsularis 3. decidual parietalis/vera

where is the decidua basilis?

the thickened endometrium at the site of implantation

the decidua basilis is the fetal side of the placenta. T/F?

false; it is the maternal side

what is the decidua capsularis?

endometrium that forms & thickens around the chorion away from the placenta

which decidual layer lines the gestational sac?

decidua capsularis

which decidual layer projects into the uterine lumen?

decidua capsularis

which decidual layer lines the uterine cavity?

decidua parietalis/vera

what is the double decidual sac sign?

the interface bw the decidua capsularis & parietalis

the ____ sign is a sign of viable gestation

decidua sac sign

what are the 3 fetal membranes?

amnion, chorion, yolk sac

2 functions of the yolk sac?

1. provides nutrients for embryo 2. hematopoiesis

how does the endometrium look like in the first trimester on US?

lush echogenic endometrium that represents the double decidual sac sign

1st US appearance of an IUP?

gestational sac

1st structure seen in the GS?

secondary yolk sac

2nd structure seen in GS?

embryo

shape of the GS on US?

round, oval, tear drop

location of the GS within the UT?

at the UT fundus or eccentrically placed position in mid-UT

what is the decidual wall thickness?

> 3 mm

what is the first lab value to be tested for pregnancy?

HCG levels

what are the 2 preps for HCG levels?

1. 1st IRP: 1st international reference preparation 2. 2IS: 2nd international standard

which prep has HCG quantities double the other?

1st IRP (2)(2IS)=IRP

the GS should be seen at 4.5 weeks (TV) from LMP when HCG reaches 2IS levels of ___ mIU/ml

500 mIU/ml

The GS should be seen at 6 weeks (TA) from LMP when HCG reaches 2IS levels of ___ mIU/ml

1800 mIU/ml

an unseen yolk sac TV when the MSD is ___ is abnormal

> 8mm

an unseen yolk sac TA when the MSD is ___ is abnormal

> 20 mm

which plane do you measure the MSD on?

both SAG & TRV

MSD formula?

MSD=LWH/3

the MSD is used up to ___ of gestation +/- ___

8 weeks +/- 2 weeks

which measurement is the most accurate measurement in pregnancy?

CRL

the CRL can be used. up to ___ of gestation

12 weeks

what does the MSD measure?

gestational sac

what does the CRL measure?

embryo

what measurement detects cardiac activity of the fetus?

fetal heart motion -- m-mode

what is the vitelline duct?

a duct that connects the midgut & yolk sac

what 2 structures merge to form the umbilical cord?

vitelline duct & allantois

when does the heart start pumping?

21 days after conception

what size is the embryo when we are able to detect cardiac activity?

embryo is 5+ mm

when does herniation of the gut occur?

7-8 weeks

when does the herniated gut return to the body?

9-10 weeks

when is herniation of the gut abnormal?

after 12 weeks

the embryo should be seen TA when MSD measures ____

25+ mm

the embryo should be seen TV when MSD measures ___

16+mm

what weeks is the conceptus considered an embryo?

1st day of LMP to week 10

what weeks is the conceptus considered the fetus?

week 10 to birth

3 ways to date the conceptus in the 1st trimester?

1. patient's LMP 2. MSD 3. CRL

what is the normal order of structures seen within the early GS for the amnion, embryo, and yolk sac?

1. yolk sac 2. embryo 3. amnion

it may be normal to see an embryo without amnion. T/F?

true

it may be normal to see amnion without an embryo. T/F?

false -- may indicate a nonviable/anembryonic pregnancy

what is another name for a failed IUP?

miscarriage

what is considered a failed IUP?

a gestational sac without a yolk sac

a GS without a yolk sac when MSD measures ____ TV is considered a miscarriage

> 8 mm

a GS without a yolk sac when MSD measure ____ TA is considered a miscarriage

> 20 mm

how is a blighted ovum diagnosed?

a GS without fetal pole or yolk sac

another name for a blighted ovum?

anembryonic pregnancy

3 clinical findings for a blighted ovum?

1. vaginal bleeding 2. low HCG levels 3. decreasing S&S of pregnancy

a GS without an embryo with an MSD of ___ TV is considered an anembryonic pregnancy

16 mm

a GS without an embryo with an MSD of ___ TA is considered an anembryonic pregnancy

25 mm

US can detect a heartbeat when an embryo is ___ mm

> 5mm

what is considered an abortion/spontaneous abortion/miscarriage

termination of pregnancy < 20 weeks gestation

what is a complete abortion?

all products of conception are expelled

US appearance of complete abortion?

normal thin endo, empty UT, no corpus luteum cyst

clinical findings of complete AB?

quickly declining HCG bleeding & cramps

what is an incomplete abortion?

there are still retained POC in the UT

U/S appearance of an incomplete abortion?

thick, irregular endo fluid in endo embryonic parts with or without shadowing

what is a missed abortion?

an embryo without cardiac activity (no flow w CD) and not expelled

US appearance of GS & cervix with missed AB?

GS is intact & closed cx

what is a threatened abortion?

patient presenting vaginal bleeding with closed cx prior 20 weeks

a threatened abortion is clinical findings only. T/F?

true

US appearance of threatened AB

normal appearance with intact GS & live embryo. cervix is closed

what is the length of a normal cervix?

3-4 cm

what length is considered an incompetent cervix?

<2.5 cm

other names for inevitable abortion?

imminent abortion/abortion in progress

what is inevitable abortion?

when IUP is moving towards the cervix; dilated cervix; patient has profuse bleeding

what is a septic abortion?

abortion due to infection

what is therapeutic abortion?

termination of pregnancy by D&C or surgical means

difference between therapeutic vs elective abortion?

therapeutic is due to mom or fetus' life in danger; elective is the mom's choice

what is habitual abortion?

repeated SAB

lab values for all types of abortion?

decreasing HCG levels

what is the most common cause off bleeding in the 1st trimester?

subchorionic hemorrhage

what is another name for subchorionic hemorrhage?

perinatal hemorrhage

when can a subchorionic hemorrhage occur?

at the time of implantationg

where does a subchorionic hemorrhage occur?

between the uterine wall & GS/chorion

S&S of subchorionic hemorrhage?

spotting or bleeding with or without contractions

2 outcomes for subchorionic hemorrhage

1. spontaneously regress 2. spontaneous abortion if large hemorrhage