Question

Explain the placental and Umbilical cord insertion variations with diagram?

1. Abruptio placentae\& its classification

2. Placenta praevia & its classification

3. Placenta accrete

4. Placenta increta

5. Placenta percreta

6. Succenturiate placenta

7. Circumvallate placenta

8. Battledore placenta

9. velamentous insertion of umbilical cord

10. Placenta Bipartite, Tripartite

Answer 1

Abruptio placentae is defined as the premature separation of the placenta from the uterus. Patients with abruptio placentae, also called placental abruption, typically present with bleeding, uterine contractions, and fetal distress. A significant cause of third-trimester bleeding associated with fetal and maternal morbidity and mortality, placental abruption must be considered whenever bleeding is encountered in the second half of pregnancy.

Classification of placental abruption
Classification of placental abruption is based on extent of separation (ie, partial vs complete) and location of separation (ie, marginal vs central). Clinical classification is as follows:

Class 0 - Asymptomatic

Class 1 - Mild (represents approximately 48% of all cases)

Class 2 - Moderate (represents approximately 27% of all cases)

Class 3 - Severe (represents approximately 24% of all cases)

A diagnosis of class 0 is made retrospectively by finding an organized blood clot or a depressed area on a delivered placenta.

Class 1 characteristics include the following:

• No vaginal bleeding to mild vaginal bleeding
• Slightly tender uterus
• Normal maternal BP and heart rate
• No coagulopathy
• No fetal distress

Class 2 characteristics include the following:

• No vaginal bleeding to moderate vaginal bleeding
• Moderate to severe uterine tenderness with possible tetanic contractions
• Maternal tachycardia with orthostatic changes in BP and heart rate
• Fetal distress
• Hypofibrinogenemia (ie, 50-250 mg/dL)

Class 3 characteristics include the following:

• No vaginal bleeding to heavy vaginal bleeding
• Very painful tetanic uterus
• Maternal shock
• Hypofibrinogenemia (ie, < 150 mg/dL)
• Coagulopathy
• Fetal death

Placenta praevia is when the placenta attaches inside the uterus but near or over the cervical opening. Symptoms include vaginal bleeding in the second half of pregnancy. The bleeding is bright red and tends not to be associated with pain. Complications may include placenta accreta, dangerously low blood pressure, or bleeding after delivery. Complications for the baby may include fetal growth restriction. Risk factors include pregnancy at an older age and smoking as well as prior cesarean section, labor induction, or termination of pregnancy. Diagnosis is by ultrasound. It is classified as a complication of pregnancy. For those who are less than 36 weeks pregnant with only a small amount of bleeding recommendations may include bed rest and avoiding sexual intercourse. For those after 36 weeks of pregnancy or with a significant amount of bleeding, cesarean section is generally recommended. In those less than 36 weeks pregnant, corticosteroids may be given to speed development of the baby's lungs. Cases that occur in early pregnancy may resolve on their own. It affects approximately 0.5% of pregnancies. After four cesarean sections, however, it affects 10% of pregnancies. Rates of disease have increased over the late 20th century and early 21st century.

Classification

Major: Placenta is in lower uterine segment, and the lower edge covers the internal os
Minor: Placenta is in lower uterine segment, but the lower edge does not cover the internal os

Other than that placenta previa can be also classified as :

Complete : When the placenta completely covers the cervix.

Partial : When the placenta partially covers the cervix.

Marginal : When the placenta ends near the edge of the cervix, about 2 cm from the internal cervical os.

Placenta accreta occurs when all or part of the placenta attaches abnormally to the myometrium (the muscular layer of the uterine wall). Three grades of abnormal placental attachment are defined according to the depth of attachment and invasion into the muscular layers of the uterus:

Accreta – chorionic villi attach to the myometrium, rather than being restricted within the decidua basalis.
Increta – chorionic villi invade into the myometrium.
Percreta – chorionic villi invade through the perimetrium (uterine serosa).
Because of abnormal attachment to the myometrium, placenta accreta is associated with an increased risk of heavy bleeding at the time of attempted vaginal delivery. The need for transfusion of blood products is frequent, and surgical removal of the uterus (hysterectomy) is sometimes required to control life-threatening bleeding.

Placenta Increta occurs when the placenta attaches even deeper into the uterine wall and does penetrate into the uterine muscle. Placenta increta accounts for approximately 15% of all cases.

Placenta Percreta occurs when the placenta penetrates through the entire uterine wall and attaches to another organ such as the bladder. Placenta percreta is the least common of the three conditions accounting for approximately 5% of all cases.

Succenturiate placenta is a morphological abnormality, in which there is one or multiple accessory lobes connected to the main part of the placenta by blood vessels1. A bilobate placenta is a similar anomaly and it is not clear from the literature what the exact difference if any exist. As on gross morphologic examination, it is possible to see two separate portions of the placenta: the main portion to which the umbilical cord is connected, and the succenturiate lobe. It is important not to confuse this with the placenta that covers two major aspects of the uterine cavity. In the later case, there is a fold of connecting placenta tissue. Sometimes, it is possible that a myometrial contraction can simulate a succenturiate lobe, but in this condition there is no boundary between the lobe and the myometrium and it usually disappears within 30 minutes or less.

Circumvallate placenta is a placental morphological abnormalitiy, a subtype of placenta extrachorialis in which the fetal membranes (chorion and amnion) "double back" on the fetal side around the edge of the placenta. After delivery, a circumvallate placenta has a thick ring of membranes on its fetal surface. 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 distance from the margin of the placenta. The ring is composed of a double fold of amnion and chorion with degenerated decidua vera and fibrin in between. Vessels radiate from the cord insertion as far as the ring and then disappear from the view. Complete circumvallate placenta occurs in approximately 1% of pregnancies. It is diagnosed prenatally by medical ultrasonography. The condition is associated with perinatal complications such as placental abruption, oligohydramnios, abnormal cardiotocography, preterm birth, and miscarriage.

Battledore placenta is a placenta in which the umbilical cord is attached at the placental margin; so called because of the fancied resemblance to the racquet used in badminton. The shortest distance between the cord insertion and placental edge is within 2cm. The incidence of battledore placenta is 7-9% in singleton pregnancies, and 24-33% in twin pregnancies.Complications associated with battledore placenta are fetal distress intrauterine growth restriction ,preterm labor, and slightly decreased birth weight. It has been estimated that 30% of births have some type of umbilical cord abnormality.This statistic implies a potential for fetal harm that may not be appreciated by public health authorities Because of limited research in this issue it is not known how many fetuses are harmed by their umbilical cords. The issue of umbilical cord related fetal harm and fetal stillbirth is unaddressed in modern reproductive care. Although observations of umbilical cord related deaths have not necessarily proven causation, it is difficult not to ask. What is the relationship?. It is time to answer this question and to see the full relationship of abnormal umbilical cord and perinatal complications.

Velamentous insertion of umbilical cord is an abnormal condition during pregnancy. Normally, the umbilical cord inserts into the middle of the placenta as it develops. In velamentous cord insertion, the umbilical cord inserts into 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 and hence are vulnerable to rupture. Rupture is especially likely if the vessels are near the cervix, in which case they may rupture in early labor, likely resulting in a stillbirth. This is a serious condition called vasa previa. Not every pregnancy with a velamentous cord insertion results in vasa previa, only those in which the blood vessels are near the cervix. When a velamentous cord insertion is discovered, the obstetrician will monitor the pregnancy closely for the presence of vasa previa. If the blood vessels are near the cervix, the baby will be delivered via cesarean section as early as 35 weeks to prevent the mother from going into labor, which is associated with a high infant mortality. Early detection can reduce the need for emergency cesarean sections.

Placenta Bipartite, Tripartite to be classified as Bilobed and Trilobed Placentas the two or three lobes of a placenta should be separated by a membrane and be of equal or near equal size. There is no certain information on how multilobed placentas are formed. A bipartite placenta in one pregnancy may be followed by greater-than-expected frequency of bipartite placenta in the next pregnancy. This raises the possibility that some multilobed placentas have genetic origin. The umbilical cord most often inserts into the membranes between the two lobes of bipartite placentas but in about one-third of cases it inserts into the larger of the two lobes. The two clinical manifestations of multilobed placetas most often cited are bleeding in the first trimester of pregnancy, and a failure of one of the lobes to separate at delivery with consequent postpartum hemorrhage. There are also published reports that bilobed placentas increase in frequency with advanced maternal age and with a maternal history of infertility. Antecedent risk factors include maternal cigarette smoking during pregnancy, mother being >34 yrs of age, excessive vomiting during the first trimester of pregnancy, diabetes mellitus, and one of the parents or a sibling having a chronic seizure disorder. Taking all these risk factors into consideration, multilobed placentas do not have any unfavorable short-term or long-term pregnancy outcomes. Vasa previa results from a bilobed placenta when fetal vessels joining the two lobes of the placenta are located between the baby's presenting part and the cervix or if the cord insertion is located between the two lobes (velamentous insertion of a bilobed placenta).