Circumvallate placenta is a structural variant of placenta which is characterized by chorionic plate being too small on the fetal side of placenta. The disparity of two sides of plate leads the membrane of fetal and placental side to fold back. Due to the misalignment the blood supply and nutritional supply can be compromised.
Circumvallate placenta can cause severe complications during the time of pregnancy as well as at the time of delivery. It can lead to persistent bleeding in 1st and 2nd trimester, miscarriage, preterm delivery, placental abruption, intra uterine growth retardation of fetus etc.The condition is rare but when present needs monitoring at the time of delivery for healthy outcome.
The exact cause of circumvallate placenta is not known. There are many instances of pregnant women delivering healthy baby with circumvallate placenta, however, careful monitoring is needed to prevent or manage complications once the condition is known during the time of pregnancy.
What Causes Circumvallate Placenta?
Placenta is a disc shaped structure situated inside the uterus. Its one surface is attached to the lining of uterus and the fetal side of placenta has an umbilical cord originating from it.Umbilical cord acts as a transitory pipe to carry out blood, oxygen and nutrients from placenta to the fetus. The placenta has two membranes called chorion and amnion. Chorion membrane is present between fetus and the placenta whereas amnion covers and protects the embryo.
Circumvallate placenta is not a disease but a structural variation of a placenta. The exact cause of this condition is not known. It occurs in 1 or 2 percent of pregnant woman. This condition can develop in any pregnant women and at any age the woman becomes pregnant.
Complications Of Circumvallate Placenta
As such there are no specific clinical features of circumvallate placenta. However, if the condition is present it can cause development of several complications during pregnancy and at the time of delivery. Some of these complications can result in bad prognosis at the maternal aspect as well as for the fetus. It can cause ascending infection.
Circumvallate placenta can impair smooth passage of nutrition, blood and oxygen to the fetus. As a result the growth of fetus can be hampered. Bleeding from vagina persistently during first trimester and second trimester often increases suspicion of circumvallate placenta.
This condition can cause complications such as plancetal abruption (placenta becomes separate prematurely during the third trimester leading to massive bleeding), miscarriage, Preterm birth, oligohydramnios (reduced amniotic fluid).
Diagnosis And Treatment For Circumvallate Placenta
Circumvallate placenta is diagnosed by:
- Detailed history of the patient.
- Sonography findings: The margin of placenta is round with its edge uplifted. This is a typical variant of placenta usually detected during sonography done on a pregnant woman when there is a suspicion of circumvallate placenta. Unfortunately in many cases the condition is difficult to detect even on sonography.
- Examination of placenta after delivery.
There is no specific treatment schedule or protocol for circumvallate placenta. Many women deliver a normal healthy baby even if they have circumvallate placenta. However, considering the risk and complications associated with circumvallate placenta, obstetrician takes maximum care and monitoring to manage and safely deliver the infant.
Many women are advised to take complete bed rest once the condition is detected. This may help them to carry on the pregnancy till full term. The prognosis depends how early the condition is detected and how efficiently the complications are managed.