Chapter 5 (Obstetrics): Antepartum hemorrhage

Question 1

What are the obstetric and nonobstetric causes of antepartum hemorrhage?

Answer 1

Obstetric:

1. Placental–> Placenta previa, placental abruption and vasa previa
2. Maternal–> Uterine rupture
3. Fetal–> Fetal vessel rupture

Nonobstetric:

1. Cervical–>Severe cervicitis, polyps, cervical dysplasia/cancer
2. Vaginal/vulvar–> Lacerations, varices and cancer
3. Other–> Hemorrhoids, Congenital bleeding disorder, abdominal or pelvic trauma, and hematuria

Question 2

What is placenta previa? What types do we have?

Answer 2

1. Placenta previa is defined as abnormal implantation of the placenta over the internal cervical os.
2. Complete previa, partial previa and marginal previa

Question 3

What are the fetal complications of placental previa?

Answer 3

• Preterm delivery and its complications
• PPROM
• IUGR
• Malpresentation
• Congenital abnormalities

Question 4

What is placenta accreta, increta and percreta?

Answer 4

Placenta previa may also be complicated by an associated placenta accreta (placenta previa accreta). Placenta accreta is a condition in which the placenta invades into and is inseparable from the uterine wall. When the invasion extends into the myometrium, this is termed a placenta increta. When the invasion is through the myometrium and the serosa, this is termed a placenta percreta. In some cases of placenta percreta, the invasion may involve other organs such as the bladder anteriorly or the rectum posteriorly.

Question 5

What are the risk factors of placenta previa?

Answer 5

Prior uterine surgeries (ex. myomectomy or uterine septum resection), cesarean delivery, multiparity, advanced maternal age, smoking, previous placenta previa

Question 6

What are the symptoms of placenta previa, accreta and increta and percreta?

Answer 6

Placenta previa–> Sudden and profuse painless vaginal bleeding.

Placenta accreta (and increta)–> Usually asymptomatic

Placenta percreta–> Hematuria and rectal bleeding (if it invades bladder and rectum respectively)

Question 7

How do we diagnose placenta previa?

Answer 7

The diagnosis of placenta previa can be made via ultrasonography with a sensitivity of greater than 95%. If made before the third trimester in pregnancy, a follow-up ultrasound is often obtained in the third trimester to determine if the previa has resolved.

Question 8

What is the treatment in placenta previa?

Answer 8

1. Strict pelvic rest (no intercourse)
2. Ceserean delivery if indicated (unstoppable labor, fetal distress and life-threatening hemorrhage)
3. Placenta accreta/increta/percreta–> Total abdominal hysterectomy

Question 9

What is placental abruption and what may it lead to?

Answer 9

Placental abruption (abruptio placentae) is the premature separation of the normally implanted placenta from the uterine wall, resulting in hemorrhage between the uterine wall and the placenta. Large placental separations may result in premature delivery, uterine tetany, disseminated intravascular coagulation (DIC), hypovolemic shock, and even perinatal death

Question 10

What are the main predisposing factors to placental abruption?

Answer 10

Maternal hypertension, prior history of placental abruption, maternal cocaine use, tobacco use, external maternal trauma, and rapid decompression of the overdistended uterus.

Question 11

What is concealed hemorrhage and external hemorrhage?

Answer 11

In 20% of placental separations, bleeding is confined within the uterine cavity and is referred to as a concealed hemorrhage. In the remaining 80% of placental separations, the blood dissects downward toward the cervix, resulting in a revealed or external hemorrhage.

Question 12

What are symptoms of placental abruption? What are the findings on physical examination?

Answer 12

• The classic presentation of placental abruption is third-trimester vaginal bleeding associated with severe abdominal pain and/or frequent, strong contractions.
• On physical examination, a patient with placental abruption will often have vaginal bleeding and a firm, tender uterus. On tocometer, small frequent contractions are usually seen along with tetanic contractions. On fetal monitoring, nonreassuring fetal heart tracing is frequently seen secondary to hypoxia.

Question 13

How do we diagnose placental abruption?

Answer 13

The diagnosis of placental abruption is primarily clinical. Only 2% to 25% of abruptions are diagnosed by ultrasound (evidenced by a retroplacental clot). However, because abruption can present clinically in a similar fashion to placenta previa with vaginal bleeding, ultrasonography is routinely performed to rule out previa in cases of suspected abruption.

Question 14

How do we treat placental abruption?

Answer 14

• Deliver immediately if bleeding is life-threatening or fetal testing is nonreassuring
• Watchful waiting if patient is stable

Question 15

What is uterine rupture and when do they usually occur?

Answer 15

Uterine rupture represents a potential obstetric catastrophe and can lead to both maternal and fetal death. Most complete uterine ruptures occur during the course of labor.

Question 16

What are uterine ruptures associated with?

Answer 16

More than 90% of all uterine ruptures are associated with a prior uterine scar either from cesarean section or other uterine surgery. Uterine ruptures without a prior uterine scar may be related to an abdominal trauma (e.g., auto accidents, external or internal version procedures), associated with labor or delivery (e.g., improper oxytocin use or excessive fundal pressure), or spontaneously initiated (e.g., placenta percreta, multiple gestation, grand multiparity, invasive mole, or choriocarcinoma).

Question 17

What are the signs and symptoms of uterine rupture?

Answer 17

The presentation of uterine rupture is highly variable. Typically, it is characterized by the sudden onset of intense abdominal pain. Vaginal bleeding, if present, may vary from spotting to severe hemorrhage. Nonreassuring fetal testing, abnormal abdominal contour, cessation of uterine contractions, disappearance of fetal heart tones, and regression of the presenting fetal part are other signs of uterine rupture

Question 18

What are the management of uterine rupture?

Answer 18

Management of uterine rupture requires immediate laparotomy and delivery of the fetus. If feasible, the rupture site should be repaired and hemostasis obtained. In cases of large rupture extensions, repair may not be feasible and the patient may require a hysterectomy

Question 19

Why do fetal vessel rupture occur?

Answer 19

Most pregnancies complicated by rupture of a fetal vessel are due to velamentous cord insertion where the blood vessels insert between the amnion and chorion away from the placenta instead of inserting directly into the chorionic plate. Because the vessels course unprotected through the membranes before inserting on the placental margin, they are vulnerable to rupture, shearing, or laceration. In addition, these unprotected vessels may cross over the internal cervical os (vasa previa), making them vulnerable to compression by the presenting fetal part or to being torn when the membranes are ruptured.

Question 20

What is clinical presentation of fetal vessel rupture?

Answer 20

In fortunate cases the fetal vessels are palpated and recognized through the dilated cervix. More commonly, the presentation of a fetal vessel rupture is vaginal bleeding associated with a sinusoidal variation of the FHR indicative of fetal anemia.

Question 21

How do we diagnose fetal vessel rupture?

Answer 21

1. Antepartum period-> Ultrasound
2. Diagnosis at the time of vaginal bleeding can be accomplished by the Apt test or examination of the blood for nucleated (fetal) RBCs.

Question 22

How do we treat fetal vessel rupture?

Answer 22

Given the high risk of fetal exsanguination and death (the vascular volume of the term fetus is <250mL), the treatment of a ruptured fetal vessel is emergent cesarean delivery.