Abnormal Placenta

Abnormal Placenta Leave the first rating Terms in this set (56) Science MedicineObstetrics Save After the ______ attaches to the endometrial surface, it begins the process of implantation In the early stage of implantation, the trophoblast differentiates into what cell layers?After the blastocyst attaches to the endometrial surface, it begins the process of implantation.In the early stage of implantation, the trophoblast

begins to differentiate into two cell layers: the

outer syncytiotrophoblast and the inner cytotrophoblast -syncytiotrophoblast = part that invades -cytotrophoblast = still around the blastocyst Placenta

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Placenta

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What happens as the trophoblast invades the decua?As the trophoblast invades the decidua, it breaks down decidual blood filled spaces known as lacune Network evolves into the intervillous spaces of the placenta.How does the normal placenta appear on US?Relatively homogeneous Retroplacental clear space is hypoechoic Venous laking Normal placenta attaches to the decidua ______ Normal placenta attaches to the decidua basalis.At the delivery, the placenta separates at the decidual plane with an abrupt cessation of intra- placental flow as the myometrium contracts.

Describe placenta migration How does it change from the 1st semester to the 3rd?What is this due to?In the 1st and 2nd trimester sonograms will show a low lying placenta or placenta previa that will convert to a normal higher position when re- evaluated in the 3rd trimester. This is referred to as "placental migration or retraction". This is believed to be due to differential growth rates between the uterus and placenta.

Image:

-Would measure cervix along the hyperechoic strip (inner to outer) -Measure from placenta to inner os Normal placental dimensions

Length:

20wks 23wks Thickness 20wks 23wks

Length:

<14cm>3cm abnormal at 20 weeks >4cm abnormal at 23 weeks

Placental Disk:

Where should the cord meet at the placenta?The cord should insert into the middle of the placenta.Abnormal insertion of the cord can have an adverse effect on the efficiency of the placenta What are succenturiate lobes?What is a concern if they are not reported?-Succenturiate lobe(s) can be single or multiple lobes connected to the main body of placenta by velamentous connection of the umbilical vessel (vessels traversing the membrane).-There is arterial and venous connections to the main portion of the placenta (colour Doppler) -If the accessory lobe is not reported on the antenatal sonogram, one concern is the placental accessory lobe is retained after delivery -The location of the vascular connection between the main placenta and the succenturiate lobe is important, because if the vessels are in proximity of the cervix this could be Vesa Previa -Accessory lobe can lie over the cervix (placental previa)