Presentation byShrooti Shah

M.Sc. Nursing Batch 2011

1. Discuss abnormalities of placenta.2. Explain abnormalities related to

length of cord.3. Describe abnormalities of cord

impending blood flow.4. Discuss abnormalities related to

membranes.

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

In cases of absence of communicating blood vessels, it is called placenta spuria.

Incidence: 3%

If the succenturiate lobe is retained, following birth of the placenta, it may lead to:

1. Postpartum haemorrhage2. Subinvolution3. Uterine sepsis4. Polyp formation

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

Two types are described:1. Circumvallate placenta

2. Placenta marginata

The fetal surface is divided into a central depressed zone surrounded by a thickened white ring which is usually complete.

Vessels radiate from the cord insertion as far as the ring and then disappear from view.

The peripheral zone outside the ring is thicker and the edge is elevated and rounded.

There is increased chance of: Abortion Hydrorrhoea gravidarum Antepartum haemorrhage IUGR baby Preterm delivery Retained placenta or membranes

A thin fibrous ring is present at the margin of the chorionic plate where the fetal vessels appear to terminate.

Enroachment of some part over the lower segment.

Imperfect separation in the third stage.

Chance of retained placenta is more and manual removal becomes difficult.

These abnormalities are serious variations in which trophoblastic tissues invade the myometrium to varying depths.

They are much more likely with placenta previa or with implantation over a prior uterine incision or perforation.

The condition is usually associated when the placenta is implanted in lower

segment (Placenta praevia) or over the previously injured sites as in

caesarean section dilatation and curettage operation manual removal myomectomy

The diagnosis is only made during attempted manual removal

when the plane of cleavage between the placenta and uterine wall cannot be made out.

Ultrasound imaging, colour Doppler and MRI have all been valuable in the diagnosis.

Absence of decidua basalis Absence of Nitabuch’s fibrinoid layer Varying degree of penetration of the

villi into the muscle bundle (increta) or upto the serosal layer(percreta).

The risk includes hemorrhage, shock, infection and rarely

inversion of the uterus.

Abnormal length of cordShort cord Less than 20cm or commonly relative

due to entanglement of the cord round any fetal part.

In exceptional circumstances, the cord may be absent and the placenta may be attached to the liver as in exomphalus.

1. Prevent descent of the presenting part specially during labour

2. Separation of normally situated placenta3. Favour malpresentation4. Acute inversion5. Fetal growth restriction6. Intrapartum distress7. Failure of external version8. Two fold risk of death

Clinical Significance cord prolapse cord entanglement round the neck or

the body True knot False knots

Incidence of a single artery to be 0.63 percent in liveborns, 1.92 percent in perinatal deaths, and 3 percent in twins.

It is more common in twins and in babies born of diabetic mothers or in polyhydraminos.

It is frequently associated with congenital malformation of the fetus (10-20%). Renal and genital anomalies, Trisomy 18 are common.

There is increased chance of abortion, prematurity, IUGR and increased perinatal mortality

In many cases, a single umbilical artery is detected by routine sonographic screening.

Normal umbilical cord Single Umbilical Cord

Battledore placenta The cord is attached to the margin of the

placenta.

If associated with low implantation of the placenta, there is chance of cord compression in vaginal delivery leading to fetal anoxia or even death; otherwise, it has got little clinical significance.

The umbilical vessels spread within the membranes at a distance from the placental margin, which they reach surrounded only by a fold of amnion.

Although their incidence is approximately 1 percent, velamentous insertion develops in more commonly with placenta previa and multifetal gestations.

If the leash of blood vessels happen to traverse through the membranes overlying the internal os, infront of the presenting part, the condition is called vasa praevia.

In the presence of fetal bleeding, urgent delivery is essential either vaginally or by caesarean section.

The infant’s haemoglobin is estimated and if necessary, blood transfusion be carried out.

If the baby is dead, vaginal delivery is awaited.

Two complete and separate parts are present, each with cord leaving it. The bipartite cord joins short distance from the two parts of the placenta.

A tripartite placenta is similar but with three distinct parts.

KnotsFalse Knots

False knots appear as knobs protruding from the cord surface and are focal redundancies of a vessel or Wharton jelly, with no clinical significance.

Active fetal movements create cord knotting.

Incidence : approximately 1 percent, and these are more common in monoamnionic twins.

The risk of stillbirth is increased five- to tenfold.

The cord frequently becomes coiled around portions of the fetus.

Those looped around the neck are termed a nuchal cord

several large studies have reported one loop of nuchal cord in 20 to 34 percent of deliveries; two loops in 2.5 to 5 percent; and three loops in 0.2 to 0.5 percent

As labor progresses, contractions may compress the cord vessels and create fetal heart rate decelerations that persist until the contraction ceases.

Cord prolapse or fetal heart rate abnormalities is an associated labor finding.

Funic presentation may be identified antenatally with sonography and with color flow Doppler.

If present during labor, cesarean delivery is typically indicated.

This is a focal narrowing of the cord diameter that typically develops in the area of fetal umbilical insertion .

Absence of Wharton jelly and stenosis or obliteration of cord vessels at the narrow segment are characteristic pathological features.

Most fetuses are stillborn.

Associated with short cords, trauma, and entanglement.

They may result from a varix rupture, usually of the umbilical vein, with effusion of blood into the cord.

May be caused by umbilical vessel venipuncture

True cysts are epithelium-lined remnants of the allantois and may co-exist with a persistently patent urachus.

In contrast, the more common pseudocysts form from local degeneration of Wharton jelly.

Single umbilical cord cysts found in the first trimester tend to resolve completely, whereas multiple cysts may portend miscarriage or aneuploidy.

Moreover, pseudocysts persisting beyond this can be associated with structural and chromosomal anomalies defects, especially trisomy 18 and 13.

Intrauterine thrombosis of umbilical cord vessels is a rare event.

Approximately 70 percent are venous, 20 percent are venous and arterial, and 10 percent are arterial thromboses.

The presence of meconium in amnionic fluid is relatively common, and incidences range from 12 to 20 percent.

Staining of the amnion can be obvious within 1 to 3 hours after meconium passage.

More-prolonged exposure results in staining of the chorion, umbilical cord, and decidua.

First, in most fetuses, meconium passage is prevented by tonic anal sphincter contraction and by lack of intestinal peristalsis.

Secondly, vagal stimulation produced by cord or head compression may be associated with meconium passage in the absence of fetal distress.

Lastly, meconium passage is also associated with fetal acidosis, nonreassuring fetal heart rate patterns, and low Apgar scores

Routes of infection include1. Ascending infection from the lower

genital tract2. Hematogenous spread3. Direct spread from the endometrium or

fallopian tube4. And iatrogenic contamination during

invasive procedures.

Amnion nodosum is a placental lesion consisting of numerous small, light-tan nodules on the amnion that overlies the placenta.

It is considered a hallmark of prolonged and severe oligohydramnios.

 

Amnionic bands are caused when disruption of the amnion leads to formation of bands or strings that entrap the fetus and impair growth and development of the involved structure.

1. Dutta D.C. Textbook of obstetrics. Sixth edition. Calcutta, India; New Central Book agency (P) Ltd: 2004.

2. Cunningham, Leveno, Bloom etal. William’s obstetrics. 23rd edition. United states of America; McGraw Hill companies: 2010.

3. Fraser DM, Cooper MA. Myles Textbook of Midwives. Fourteenth edition. Edinburgh; Churchill Livingstone: 2003.

4. Jacob A. A comprehensive textbook of midwifery. Second edition. India; Jaypee Brothers Medical publishers (P) ltd.