Antepartum bleeding or hemorrhage is defined as any vaginal bleeding that takes place after 20 weeks gestation until the start of labour. It occurs in approximately 2-5% of all pregnancies (Women's Hospital, 2011).
In the third trimester of pregnancy, the blood supply to the uterus increases dramatically to approximately 20% of cardiac output. Therefore, uterine bleeding, which can have various causes, can lead to profound blood loss and hemodynamic instability. It is one of the most significant causes of maternal death during the second and third trimester of pregnancy.
Meridith is a 44 year-old woman who is 32 weeks gestation. After an uneventful ride on a motorcycle she stood up to find she was sitting in a large pool of blood. There was no associated pain. Her husband immediately drove her to the hospital.
Obstetrical causes of bleeding include:
Other causes include cervical, vaginal, or uterine causes such as:
Also consider, in the differential diagosis:
Labour itself often results in bleeding, and must be considered.
Questions regarding the bleeding include:
Ask for symptoms of shock
Past obstetrical history
Vitals (assess for shock)
Mental status exam (confusion, lethargy, loss of consciousness)
Avoid vaginal exam until placenta previa has been ruled out.
A sterile, gentle speculum exam may be done to assess for:
Fetal monitoring should also be performed.
If abdominal or back pain occurs with vaginal bleeding, abruption of the placenta should be ruled out.
A bedside clot test may be done by placing blood at room temperature for six minutes to assess for DIC.
Ultrasound, including transvaginal doppler, can be done to assess for:
Electronic fetal monitoring, if available, can be used to assess the fetal status.
Management depends on the suspected cause of hemorrhage, stability of mother and fetus, and viability of the fetus. A stable woman and fetus should be monitored for 12-24 hours, as the risk of recurrent bleeding is high. Transfer to an adequate facility with surgical treatment options and intensive premature neonatal care might be indicated.
If unstable, the patient needs vigorous intravenous fluid resuscitation. Vital signs and urine output can be used to monitor the hemodynamic status of the patient. Oxygen supplementation and pain management is also a part of acute management. Use of blood and blood products may be indicated. Continuous fetal monitoring should be provided.
Monitor for disseminated intravascular coagulopathy. If DIC is present, immediate correction is necessary.
Fetomaternal hemorrhage can be identified with a Kleihauer-Betke test. According to the test results, Rhogam should be given to all mothers who are of Rh negative bloodtype.
If the fetus is not viable (20- 24 wks of gestation), the goal is to stabilize the mother and monitor the progress. If fetus is between 24 weeks and 36 weeks of gestation, corticosteroids may be considered for fetal lung maturity, and the fetus should be monitored continuously.
If the gestational age is 36 weeks or more, treatment should depend on the cause:
The vasculature of the uterus is largely derived from the uterine and ovarian arteries. The uterine artery branches from the iliac artery, while the ovarian artery arises directly from the aorta. As mentioned in the introduction, the cardiac output to the uterus increases from 1% to 20% during pregnancy, meaning blood loss can quickly become catastrophic.
Uterine vessels terminate within the endometrial decidua to form spiral arteries. During the development of the placenta, spiral arteries are extensively modified by the placental trophoblasts. As their architecture is established, blood flows into the placenta and leaves spiral arteries to flow around the intervillous space, bathing the chorionic villi. Please visit placenta for greater detail.
Bleeding from placental abruption begins in the endometrial decidua, sometimes following rupture of spiral arteries.
Current diagnosis and treament: Obstetrics and Gynecology, Decherney et al.
authors: Kim Colangelo, David LaPierre