Circumvallate placenta

Circumvallate Placenta
The thickened ring of membranes on the fetal surface of a circumvallate placenta, making it appear as though the central part of the placenta has been exposed.
Specialty	Obstetrics

Circumvallate placenta is a rare condition affecting about 1-2% of pregnancies, in which the amnion and chorion fetal membranes essentially "double back" on the fetal side around the edges of the placenta.^[1] After delivery, a circumvallate placenta has a thick ring of membranes on its fetal surface.^[2] Circumvallate placenta is a placental morphological abnormality associated with increased fetal morbidity and mortality due to the restricted availability of nutrients and oxygen to the developing fetus.

In a circumvallate placenta, the chorionic plate, which forms the fetal surface of the placenta, tends to be smaller than the basal plate, which forms the maternal surface of the placenta. This results in the elevation of the placental margin and the appearance of an annular shape.^[3] The fetal surface is divided into a central depressed zone surrounded by a thickened white ring which is incomplete. The ring is situated at varying distances from the margin, or edges, of the placenta. This thick ring of membranes is composed of a double fold of amnion and chorion with degenerated decidua vera and fibrin in between. Blood vessels, supplying nutrients and carrying waste products to and from the developing fetus, radiate from the umbilical cord insertion to as far as the ring of membranes, and then disappears from view.^[4]

Signs & Symptoms

A circumvallate placenta does not always induce associated

• vaginal bleeding tends to occur at this site where the placenta is exposed and uncovered.^[3]
  In mothers presenting with vaginal bleeding, circumvallate placenta should be suspected as a possible cause of the vaginal bleeding.
• growth expectations during the course of the pregnancy.^[1]
• second trimester of pregnancy, it is suspected that a mother likely has a circumvallate placenta.^[1]

• Low birth weight: Lack of proper nutrition and blood flow to the fetus during pregnancy often results in decreased weight of the baby at birth.^{[medical citation needed]}
• low blood pressure.^{[medical citation needed}
  ]
• oxygenation
  from its mother.
• full-term delivery at about 40 weeks.^{[medical citation needed}
  ]
• Miscarriage: Loss of a fetus prior to birth via miscarriage can transpire if any of the above complications occur without prompt intervention and treatment.

Cause

Unfortunately, there is no known cause of circumvallate placenta and no major

Women with these risk factors are recommended additional surveillance during pregnancy to monitor fetal development and to be able to detect fetal, placental, or umbilical cord abnormalities as early as possible.

Pathophysiology/Mechanism

The

In a normal placenta, there is a smooth transition from the parenchymal villous chorion to the membranous chorion at the border of the placental plate. Fetal blood vessels subdivide from the umbilical cord and spread diagonally throughout the parenchyma towards the edge of the placental plate.^[4]

In a circumvallate placenta, the

If oligohydramnios occurs as a result of a circumvallate placenta, a treatment called amnioinfusion may be considered to replenish the amount of lost amniotic fluid within the amniotic sac. Amnioinfusion may help in preventing underdevelopment of the lungs.

If diagnosed with a circumvallate placenta, consistent

Circumvallate placenta is a very rare condition affecting pregnant women. This condition is a placental morphological abnormality, with the placenta being formed during the early periods of pregnancy. Women are able to become pregnant with the onset of ovulation and menstruation in early adolescence, with most women becoming pregnant during adulthood. Circumvallate placenta is currently known to affect about 1-2% of pregnancies. It is not virally transmissible to other individuals, nor can it be transferred through contact or respiration.^[1]

There are no specific

Due to the rare occurrences of circumvallate placenta, more extensive research trials are unavailable, resulting in data limitations. Therefore, the clinical importance of circumvallate placenta remains uncertain.^[3]

References