26. Abnormalities of the placenta ,membranes and umbilical cord.

Question 1

what are the causes for hydroaminos ?

Answer 1

anencephaly - brainstem and cerebella spared
open spina bifida
esophageal atresia - cannot swallow

less common -

Hydramnios is more common in monozygotic twins, usually affecting the second sac.
In TTTS the recipient twin develops polydramnios

Rh disease- hydrops fetalis and fetal ascites

maternal diabetes

Chorioangioma of the placenta-

Question 2

what is the pathoetiology of hydro aminos in anencephaly ?

Answer 2

anencephaly / spinabifida
= transudation of fluid

excessive urination caused by stimulation cerebrospinal centres

impaired ADH release

absence of fetal swallowing

Question 3

definition of polyhydroaminos / hydroaminos ?

Answer 3

Anatomically -liquor amnii exceeds 2,000 mL

Clinical definition-
excessive liquor amnii causing discomfort to the patient and/or when imaging help is needed for clinical diagnosis of the lie and presentation of the foetus

Question 4

what are the signs and symptoms of hydro aminos ?

Answer 4

over distenstion of uterus - dyspnea

palpitation

edema of legs and varicosities , haemorrhoids

Fetal heart sound is not heard distinctly

Question 5

definition of oligohydroaminos ?

Answer 5

less than 200 mL at term. Sonographically, it is defined when the maximum vertical pocket of liquor is less than <2 cm or when amniotic fluid index (AFI) is less than 5 cm

Question 6

what is the diagnosis of hydro aminos ?

Answer 6

US -amniotic fluid index (AFI) is more than 24 cm and a deepest vertical pocket (DVP) is more than 8 cm

Amniotic fluid: Estimation of alpha fetoprotein - markedly elevated in open neural tube defect.

Question 7

what is the management of hydro aminos ?

Answer 7

minor degrees and moderate - rarely require treatmnet

DVP: ≥16 cm or if dyspnea and abdominal pain or difficult to walk and move around -
bed rest , diuretics , water and salt restriction are INEFFECTIVE.

COX-2 inhibitor / INDOMETHACIN = reduces fetal urine output

amniocentesis
less than 37 wks = slow decompression, chance of accidental hemorrhage is less

amniotomy

Question 8

complications of hydroaminos ?

Answer 8

Preeclampsia (25%)

Malpresentation

Premature rupture of the membranes

during labour :Cord prolapse
Uterine inertia
postpartum hemorrhage

Puerperium: Subinvolution

Question 9

etiology of oligohydroaminos occur?

Answer 9

fetal
chromosomal and congenital anomalies

pregnancy that continues beyond term
there is a 25 percent decrease in amniotic fluid volume beyond 41 weeks

obstruction of fetal urinary tract

renal agenesis

drugs :
prostaglandin synthase inhibitors
ACE use

maternal
uteroplascental insufficiency
hypertension

Question 10

what is the fetal prognosis on oligohydroaminos ?

Answer 10

fetal outcome poor in early onset oligohydroaminos

pulmonary hypoplasia is common

Question 11

what is the management of oligohydroaminos

Answer 11

c section or

Oral administration of water

amnioinfusion

Question 12

complication of oligohydroaminos ?

Answer 12

Abortion

Deformity - due to intra-amniotic adhesions or due to compression. The deformities include alteration in shape of the skull

Fetal pulmonary hypoplasia (may be the cause or effect)

Cord compression

Less fetal movements
Malpresentation

(breech) is common

Question 13

what complications of short umbilical cord ?

Answer 13

fetal growth restriction 
intrapartum distress 
placental abruption
prevent of fetal descend 
cannot do external version

Question 14

what is associated with long cords ?

Answer 14

cord prolapse

Question 15

what is the normal morphology of the umbilical cord ?

Answer 15

2 umbilical arteries
and 1 umbilical vein - both have a spiral course they twist around each other

umbilical vein carries oxygenated blood from the placenta towards the heart of
the fetus

umbilical arteries carry deoxygenated blood from the baby body away towards
the placenta

Question 16

what are the abnormalities of cord insertion ?

Answer 16

furcate insertion -umbilical vessel separate from the cord before their insertion into the placenta
these vessels are prone to twisting and thrombosis

battledore placental / marginal insertion - insertion of the umbilical cord in the margin of the placenta

velamentous insertion - Normally the umbilical cord inserts into the middle of

In velamentous cord insertion, the umbilical cord inserts
between the fetal membranes (choriamniotic membranes), then travels within the
membranes to the placenta (between the amnion
and the chorion). The exposed
vessels are not protected by Wharton’s jelly hence are
vulnerable to rupture
and inserts marginally

Question 17

what are the cord abnormalities capable of impending blow flow ?

Answer 17

False knots:
result a lot of wharton jelly leading to kinking of the vessels

true knots:
result from active fetal movements
even with true knot vessels are protected by wharton jelly

Loops: The cord frequently becomes coiled around portions of the fetus, usually the
neck. This is more likely with longer cords. Fortunately, coiling of the cord around the
neck is uncommon cause of antepartum fetal death or neurological damage

Torsion of the cord is rare. It results from fetal movements during which the cord normally becomes twisted

Cord stricture is more serious, and most infants with this finding are stillborn.The stricture is associated with an extreme focal deficiency in Wharton jelly

monoamnionic twinning, a significant fraction of the high perinatal mortality rate is attributed to entwining of the umbilical cords

Question 18

what other abnormalities are found within the cord ?

Answer 18

Cord cysts occasionally are found along the course of the cord and are designated true and false

True cysts are quite small and may be derived from remnants of the umbilical vesicle or the allantois

False cysts, which may attain considerable size, result from liquefaction of Wharton jelly

Question 19

measurements of all cord types ?

Answer 19

long cord more than 70cm

normal( 55-60)

less than 35 cm

Question 20

single umbilical artery are most commonly found in ?

Answer 20

twins
diabetic mother
epilepsy
preeclampsia

Question 21

single umbilical artery is frequently associated with ?

Answer 21

congenital malformation of the fetus

renal and genital anomalies

trisomy 18

oligohydroamnis

Question 22

what are the abnormalities of the placenta ?

Answer 22

bilobed placenta
placental previa
placenta accreta
placenta succenturiate

placenta extrachorialis : circumvallate placenta
and placenta marginal

Question 23

what is the morphology of placenta succenturiata ?

Answer 23

One (usual) or more small lobes of placenta, size of a cotyledon, placed at varying distances from the main placental margin.

Vessels connecting the main to the accessory lobe traverse through the membrane

absence of communicating blood vessels, it is called placenta spuria

Question 24

how do you diagnose placenta succenturiata ?

Answer 24

inspection of the placenta after its expulsion

With missing lobe:
(a) there is a gap in the chorion and (b) torn ends of blood vessels are found on the margin of the gap

Question 25

what is the clinical significance of placenta succenturiata

Answer 25

succenturiate lobe is retained it may lead to

Postpartum hemorrhage which may be primary or secondary
Subinvolution
Uterine sepsis

Question 26

what is the treatment of placenta succenturiata?

Answer 26

Whenever the diagnosis of missing lobe is made, exploration of the uterus and removal of the lobe under general anesthesia is to be done

Question 27

what causes placenta extrachorialis?

Answer 27

smaller chorionic plate (amnion and chorion) than the basal plate (decidua) and recurrent marginal hemorrhage diagnosed on US is thought to the the cause

Question 28

what is the morphology of placenta extrachorialis ?

Answer 28

the chorionic plate smaller than the basal plate of the Decidua
parts of chorionic villi not covered by the chorionic plate

so the fetal membrane - amnion and chorion rolls back in on itself to form a ring on the fetal surface

Question 29

what is the morphologial difference between circumvallate placenta and placenta marginata ?

Answer 29

circumvallate -thickened white ring which is usually complete
ring is situated at varying distance from the margin of the placenta
vessels radiate from the cord insertion as far as the ring and then disappear

marginata - thin fibrous ring where the fetal vessels terminate

Question 30

clinical significance of

placenta extrachorialis?

Answer 30

Hydrorrhea gravidarum (excessive watery vaginal discharge)

Antepartum hemorrhage

iugr

as placental abruption,

oligohydramnios, abnormal

cardiotocography,

preterm birth,

miscarriage

Question 31

what is clinically assessed of the fetal membranes ?

Answer 31

thickness
colour
bleeding

Question 32

what is the normal fetal membrane anatomy ?

Answer 32

consist of two different layers- the layer facing amniotic cavity called amnion and facing the placenta called the chorion - when pulled apart - the membranes should be translucent without any discolouration

Question 33

what does thickening of the fetal membranes suggest ?

Answer 33

chorioamnionitis

Question 34

what type of bleeding is present in the fetal membrane ?

Answer 34

subchorionic hemorrhage - bleeding o blood clots between uterus and fetal membrane /chorion membrane

Question 35

what is significant about the staining of the fetal membrane ?

Answer 35

should not be yellow or green - meconium

Question 36

what does the normal maternal side of the placenta look like ?

Answer 36

red colour , 2-4 cm thick , and the surfaces divided into lobules called cotyledons

Question 37

what do we ensure in the placenta of the maternal side

Answer 37

no gaps for any missing cotyledons

membrane should be inspected at the peripheral of the placental edge

calcification of placenta- third trimester is normal - however second trimester abnormal - leading to fetal growth restriction and distress

Question 38

if any missing cotyledons what can it cause ?

Answer 38

postpartum hemorrage and infectio