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placenta previa

Image: “Placenta previa” by OpenStax College. License: CC BY 3.0

Placenta Previa

Definition of Placenta Previa

Placenta previa refers to the dystopic position of the placenta in the isthmus region. About 10 out of 200 pregnancies are affected by this condition.

Etiology of Placenta Previa

Scarring of the endometrium can cause placenta previa; such scars could result from curettage or after a cesarean section or multiple birth.

Clinical Presentation of Placenta Previa

The lower uterine segment is stretched after uterine contraction. This shears the placenta away from the adhesive surface causing bleeding to occur.

Typically, the first bleeding is observed in the 3rd trimester. Initially, this bleeding stems from the intravillous region, indicating that maternal blood is involved. Later, fetal blood may also be involved. Thus, blood tests for hemoglobin F are indicated.

Diagnosis of Placenta Previa

placenta previa x-ray

Image: Anterior placenta previa. The placenta (arrow) has completely covered the internal os (arrowhead). By: Openi. License: CC BY 2.0

The diagnosis of placenta previa is based on ultrasound examination. If placenta previa is noted, the pregnant woman should be hospitalized and strict bed rest is indicated.

Note: In the presence of these symptoms, vaginal examination is strictly contraindicated.

Treatment of Placenta Previa

In a few cases, vaginal birth can be attempted. In most cases, however, a cesarean section should be considered. For non-copious bleeding before the 34th week of pregnancy, tocolysis should be performed. Thereafter, a cesarean section should be planned.

Placental Abruption

Definition of Placental Abruption

placenta detachment

Image: Placental abruption. By: BruceBlaus. License: CC BY 3.0

Placental abruption is the complete or partial detachment of the placenta before the birth of the child. It is a notable emergency for mother and child.

Pathogenesis of Placental Abruption

Often, hypertensive diseases in pregnancy or uterine abnormalities lead to the premature detachment of the placenta. Bleeding out of the uterine vessels can occur as a result. Thus, a retroplacental hematoma develops, which leads to the detachment of the placenta.

Clinical Picture of Placental Abruption

Usually, sudden severe abdominal pain is noted. Additionally, vaginal bleeding and a continuously contracted uterus are present. This acute situation threatens the child due to an insufficient supply of oxygen, and usually, acute hypoxia results. The severe blood loss also endangers the mother. Further, amniotic fluid embolism can occur with an acute coagulation disorder.

Diagnosis of Placental Abruption

On clinical examination, the uterus is very rigid and pressure-sensitive. The movements of the child decrease due to hypoxia, and cardiotocography findings become pathological.

Treatment of Placental Abruption

Only an emergency cesarean section can save the child’s life.

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