Placentae

Chris GriffinConsultant Maternal Fetal Medicine

King Edward Memorial HospitalPerth

Western Australia

Development of placenta

• Process of cellular changes– Cellular Division– Cellular hypertrophy– Cellular apoptosis

• Implantation– Upper part of post wall of

uterine body near midsagital plan

Early Ultrasound Findings

• 5 to 12 weeks Online essay

Vitelline duct at 6weeks+

Yolk sac at 5 weeks

Retro amniotic 11 weeks

Placental Lakes

Lakes

Hydatidiform mole

Placenta Praevia

• Risk factors– Previous CS

• 5% only fundal cf 15% no CS

• Lower implantaion site• Multiple pregnancy• IVF• Smoking

• Placenta Praevia– Second trimester TA

• 20% incidence of low lying• 1 to 2% major incidence• 50% resolve

– First Trimester TVS• 6% incidence• 1% incidence at 15 – 20

weeks• If placenta overlying

internal os by 1 cm then 100% sensitivity for PP with 85% specificity

TVS for placenta praevia

Morbidly Adherent Placenta

• Loss of echolucent area between bladder and uterus

• Bladder line: thinning or interruption of hyperechoic interface between uterine serosa and bladder wall

• Placental Lacuna with turbulent high velocity flow

Loss of echolucent area

Succenturiate Lobe

Two placental masses

Use colour flow

Succenturiate lobe Vasa Praevia

Velamentous cord insertion

Mangrove Sign

Placenta membranacea(placenta diffusa):

all the membranes are covered by functioning villi & placental tissue forms on all pheripheral chorion. Sonographically the placenta appears to cover most or the entire uterine wall. Often associated with placental anomalies such as; accreta, increta, percreta & vasa previa.

Vasa Praevia:• Complication in which fetal blood vessels cross over or come in

close proximity to the internal os. Associated with velementous cord insertion or placental morphological anomalies ie. Succinuate or bilobate

??Failure of rotation of the embryonic pole to the endometrium

Placenta teddy bear• London-based designer Alex Green (2008)

The placenta must first be cured with salt to kill bacteria and remove water. Green then softens the dried organ with a mixture of eggs and tannins.

Once he cuts and sews the bears, Green fills them with brown rice. Most end up to be 5 inches tall.

Other placental concerns

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Chorionicity

Placenta Grannum

Grade 0

Uniform moderate echogenicity

Smooth chorionic plate without indentations

1

• Grade 1• Mid 2nd trimester –early

3rd trimester (~18-29 wks)

• Subtle indentations of chorionic plate

• Small, diffuse calcifications (hyperechoic) randomly dispersed in placenta

2

• Grade 2• Late 3rd trimester (~30

wks to delivery) • Larger indentations

along chorionic plate • Larger calcifications in a

“dot-dash” configuration along the basilar plate

3• Grade 3• 39 wks – post dates • Complete indentations of

chorionic plate through to the basilar plate creating “cotyledons” (portions of placenta separated by the indentations)

• More irregular calcifications with significant shadowing

• May signify placental dysmaturity which can cause IUGR

• Associated with smoking, chronic hypertension, SLE, diabetes

Unusual stuff

• CVS using uterine manipulation with TVS probe