1. Third-Trimester Bleeding Hasan Ismail July 2015
2. Third-trimester bleeding, ranging from spotting to massive
hemorrhage, occurs in 2% to 6% of all pregnancies. The differential
diagnosis includes: Bloody show from labor Abruptio placentae (AP)
Placenta previa (PP) Vasa previa (VP) Cervicitis, postcoital
bleeding, trauma, uterine rupture, and carcinoma. AP, PP, and VP
can lead to significant maternal and fetal morbidity and
mortality.
3. ABRUPTIO PLACENTAE AP is the premature separation of the
normally implanted placenta from the uterine wall due to
maternal/uterine bleeding into the decidua basalis.
4. Epidemiology One third of all antepartum bleeding is due to
AP, with an incidence of 1 in 75 to 1 in 225 births. AP recurs in
5% to 17% of pregnancies after one prior episode and up to 25%
after two prior episodes. There is a 7% incidence of stillbirth in
future pregnancies after AP leading to fetal death.
5. Etiology Bleeding does not correlate with abruption size.
Blood in the basalis layer stimulates forceful, classically
tetanic, uterine contractions leading to ischemic abdominal pain.
AP is associated with maternal hypertension, advanced maternal age,
multiparity, cocaine use, tobacco use, chorioamnionitis, and
trauma. Many cases are idiopathic. Chronic hypertension,
superimposed preeclampsia, or severe pre- ec-lampsia have fivefold
increased risk of severe abruption compared to normotensive
women.
6. Antihypertensive medications ??
7. Cigarette smoking increases the risk of stillbirth from AP
by 2.5-fold. Rapid changes in intrauterine volume can lead to
abruption, such as in rupture of membranes or therapeutic
amnioreduction with polyhydramnios or during delivery of multiple
gestations. Abruption occurs more frequently when the placenta
implants on abnormal uterine surfaces as with submucous myomas or
uterine anomalies. Hyperhomocysteinemia, Factor V Leiden, and
prothrombin 20210 mutations (thrombophilias) are associated with an
increased risk of abruption.
8. Complications Hemorrhagic shock (if massive loss) Maternal
(DIC) can occur and is found in 10% to 20% of AP with stillbirth.
Extravasation of blood directly into the uterine muscle
(Couvelaire's uterus) can lead to uterine atony and massive
postpartum hemorrhage. Fetal hypoxia may occur, leading to acute
fetal distress, hypoxic-ischemic encephalopathy,premature delivery,
and fetal death. Milder chronic abruption may lead to growth
restriction, major malformations, or anemia.
9. Diagnosis History and Physical Examination Classically
presents late in pregnancy with vaginal bleeding and acute severe
constantabdominal pain. Immediately : Maternal vital signs, fetal
heart rate assessment, and uterine tone Mark or record the fundal
height to follow expansion of concealed hemorrhage. Defer digital
cervical exam until PP and VP have been R/O Ultrasound is
insensitive in diagnosing AP, but large abruptions may be seen as
hypoechoic areas underlying the placenta. Perform a speculum exam
to evaluate vaginal or cervical lacerations and the amount of
bleeding. If discharge or signs of cervicitis are noted, obtain a
wet prep, potassium hydroxide slide (KOH), and cervical swabs for
gonorrhea and chlamydia testing.
