Valerie Hill - Bleeding

What are the major causes of late pregnancy bleeding?

• Major causes include placenta previa and placental abruption and variations in the insertion of the cord and the placenta.

Placenta Previa

• The placenta is implanted so low in the uterus that it partially or completely covers the cervix. This causes tearing and subsequent bleeding as the cervix effaces and dilates

• If the edge of the placenta touches the edge of the cervical os, it is described as 0mm. An overlap of more than 15mm is associated with an increased likelihood of placenta previa at term. 

• Sometimes, placenta previa can resolve on its own as uterine growth continues throughout the pregnancy causing the placenta to migrate away from the os and toward the fundus.

Complete Placenta Previa

• The placenta covers the cervical os completely

Marginal Placenta Previa

If the edge of the placenta is seen in TVUS to be 2.5cm or closer to the internal cervical os

Low Lying Placenta

The exact relationship of the placenta to the internal cervical os has not been determined, or if placenta previa is diagnosed in the second trimester (as this may fix itself as mentioned above)

Symptoms of Placenta Previa

• Painless bright red bleeding in the second or third trimester.

• Diagnosed with ultrasound.

• Presenting part of the fetus high because placenta low, causing greater fundal height.

• All patients with painless vaginal bleeding after 20 weeks assumed to have previa unless otherwise proved.

Management of Placenta Previa

• US every 2 weeks.

• If less than 34 weeks betamethasone given to increase lung maturity and the patient is placed on pelvic rest.

• At 37 weeks C section can be scheduled.

• If a vaginal exam is needed (very rare and not preferred), the patient is in the room for a c section cuz the exam could trigger massive bleeding (double setup procedure).

• At or beyond 36 weeks, patients are immediately scheduled for a C section. Vaginal birth may ONLY be attempted in patients with marginal placenta previa who have minimal bleeding.

Placental Abruption

• Premature separation of the placenta. Can be partial or complete. Can result in hemorrhage.

Symptoms of Placental Abruption

Intense localized uterine pain, with or without bleeding.

Diagnosis of Placental Abruption

Strongly suspected in people with sudden onset of intense localized uterine pain (with or without bleeding). Initial assessment similar to placenta previa. Fundal height measured over time to detect concealed bleeding.

Couvelaire Uterus

Purplish copper colored uterus that occurs when blood accumulates between the separated placenta and the uterine wall.

Mild Separation

10-20%. Minimal dark red bleeding <500ml. No shock, coagulopathy, tonicity or tenderness/pain. Location of the placenta, fetal presentation, FHR, and hypertension are all normal.

Moderate Separation

20-50%. Absent (if concealed) or moderate dark red bleeding of 1-1.5L. Mild shock, occasional DIC, increased tonicity, moderate to severe pain. Normal placenta and fetal position. Atypical FHR and hypertension commonly present.

Severe Seperation

 Absent (if concealed) or severe dark red bleeding of >1.5L. Sudden profound shock, frquent DIC, tetanic boardlike uterus, agonizing pain. Normal placenta and fetal position. Abnormal FHR that can cause death and HTN.

Management of Placental Abruption

• Mild abruption before 36 weeks results in expectant care unless condition worsens in which case betamethasone for lungs → birth.

• Vaginal birth may be attempted if mother and baby are hemodynamically and otherwise stable (or if the baby is dead).

Placenta Accreta, Incretra, and Percreta

• Placenta Accreta: When the placenta extends beyond the normal endometrial barrier and deeper into uterine tissue

• Placenta Increta: When the placenta extends into the myometrium

• Placent Percreta: When the placenta extends beyond the uterine tissue

• Massive hemorrhage can occur with these conditions and C section through a fundal incision followed by hysterectomy may be necessary. If the patient is not actively bleeding, a C section is scheduled for 34-36 weeks.

Vasa previa

In vasa previa the vessels of the umbilical cord are implanted into the thin fetal membranes outside the placenta rather than in the placenta itself. This drastically reduces protection of these vessels (protected only by the membranes rather than the wharton's jelly). We now can diagnose this with ultrasound rather than waiting for vaginal bleeding to find out. Vasa previa can cause a fetus to bleed to death if the vessels are damaged.

Velementous Insertion of the Cord

• Umbilical vessels begin to branch at the membranes before going deeper into the placenta

Succenturiate Placenta

• The placenta has divided into two or more masses leaving vessels hanging between each mass. 

Battledore Insertion of the cord

The cord attaches to the margins of the placenta.