extrafetal assessment of 2nd + 3rd trimester

normal cervical length

equal or greater than 3cm

short cx length

less than 2.5 cm

risks for preterm births

short cx

multiple pregnancy

past preterm births

prior cx surgery

repeated abortions

uterine anomalies

incompetent cervix means

cervix incapable of retaining pregnancy to term

usual cause of cx insufficiency

cx trauma or des exposure

when do they recommend cervical cerclage

less than 1.6cm

how is cx measured

from internal os to external os

3 measurements (keep shortest)

what is the most reliable approach for cervical evaluation

transvaginal

should bladder be empty or full for cx eval

empty

where should cx be measured

from v shaped or flat internal os to triangular shaped external os

AP width should be even on ant and post cervix

why do we use transfundal pressure to assess cervix

contraction of muscle changes length of cervix

mimics contraction of uterus

use shortest length of

what is funneling

amniotic fluid making its way into cervical canal

how does funneling appear on US

anechoic beak like fluid collection near internal os

how to measure funneling

width of funneling

length of remaining cx

placenta has what two portions

maternal and fetal

the functional layer of a womans endometrium in a pregnant woman is called the

decidua

3 layers of decidua

decidua basalis

decidua capsularis

decidua parietalis

where is decidua basalis

where blastocyst implants

becomes maternal part of placenta

where is decidua parietalis

area surrounding uterine cavity (not where placenta is)

where is decidua capsularis

area over the blasocyst

what is considered low lying placenta

1-2cm from cx

why is it specially important to note placenta in multiple gestations

identification of distinct placentas can help determine chorionicity

when is it common to see low lying placenta

in 3rd trimester

when should you diagnose LLP

after 32 weeks

what is placenta previa

when placenta is covering some or all of the internal os

what are the placenta grading classifications

grade 0, 1, 2 or 3

grade 0 placenta

no calc

grade 1 placenta

some calc

grade 2 placenta

calcs along basal plate and lobular appearance

grade 3 placenta

coarse echotexture, lobulated w calcs + placental lakes

what does premature maturation of placenta suggest

placental insufficiency

why might placenta mature early

smoking

mt hypertension

iugr

multi gestations

why might placenta not mature

gest diabetes

normal placental weight

450-550g

normal placental thickness

less than 24 wk ga = less than 4cm

thin placenta

less than 1.5 cm

can be caused by maternal/fetal cause of eccentric cord placement

placenta previa risk factors

multiparous

prior c section

hx of theraputic abortion

abnormal fetal positon

AMA

symptoms of placenta previa

painless bleeding

what is placenta accreta

abnormal attachment to myometrium

placental accreta is

invasion of villi into decidua

placenta increta

invasion of villi into myometrium

placenta percreta

invasion of villi into serosa and possible adjacent structures

risk factors for placenta accreta

placenta previa

prior uterine surgery

AMA

placenta accreta risks to mother

placenta will not detach during birth resulting in hemorrhage

succenturiate placenta

presence of one or more accessory lobes of placenta with connecting vessel

succenturiate risks

more likely to have abnormal cord insertion

circumvallate placenta

abnormal attachment of membranes to placenta

raised/rolled edge

clinical risks of circumvallate

IUGR

premature rupture of membranes

placental abruption

premature labor

what is battledore cord insertion

marginal cord insertion

associated with IUGR

what is velamentous cord insertion

cord insertion into free membranes of placenta

no whartons jelly over cord

risks of velamentous cord insertion

vasa previa

IUGR

prematurity

fetal anomalies

what is chorangioma

most common benign tumor of placenta

how does chorangioma appear

round hypoechoic mass of placenta

below chorionic plate near cord insertion

mildly vascular

what is placental abruption

premature separation of placenta from uterine linng

why is placental abruption so dangerous

can cause perinatal mortality

how doe placental abruption appear clinically

abdominal pain

vaginal bleeding

maternal shock

fetal distress

preterm labor

risk factors for placental abruption

prior abruption

trauma

mat hypertension

circumvallate placenta

fibroids

mat smoking/drug use

what is retroplacental abruption

high pressure bleed caused by rupture of spiral arteries

most risky form

what is marginal abruption

edge of placenta separates from uterus

most common form of abruption

what is amniotic band syndrome

fibrous strands of ruptured amnion trapping fetal parts

when does amniotic band syndrome occur

1st tri

what occurs as a result of amniotic band syndrome

facial abnormalities, limb abnormalities, visceral abnormalities

(cleft lip associated with)

what is an amniotic sheet

associated with uterine synechiae

thick echogenic linear structure

how many umbilical veins and arteries in the cord

2 arteries 1 vein

what is whartons jelly

gelatinous tissue to protect cord

where is normal cord insertion

center of placenta

anterior abd wall superior to bladder

most common cord abnormality

2 vessel cord

how do you prove 2 cord vessel

show cross section of cord w 2 vessels

only one artery coursing around fetal bladder

two vessels shown coursing around the fetal bladder are most likely what

the umbilical arteries

what is considered short umbilical cord

less than 35 cm

what is considered long umbilical cord

over 80 cm

what cord abnormality is common with monoamniotic multiple gestation

cord knot

entanglement of cord around fetal neck is known as

nuchal cord

what is vasa previa

fetal vessels between presenting part and internal cervical os

most common tumor of cord

hemangioma

indications for umbilical cord doppler

IUGR

abnormal bpp

abnormal afi

multi gest

abnormal UC doppler would show

high resistive flow

what does amniotic fluid do

protects fetus

allows for movement

regulates temp

prevents amnion adherence

promotes lung growth and development

structures responsible for amniotic fluid production

amniotic membrane

umbilical cord

kidneys

skin

lungs

structures responsible for amniotic fluid removal

GI tract

lungs

membrane

cord

why is AFV important

correlates GA to EFW

abnormal AFV can indicate issues

polyhydramnios fluid volume

1500-2000 ml

polyhydramnios maternal causes

rh isoimmunization

diabetes