MIAMI BEACH — Clinical acumen is crucial to diagnosis and management of antepartum hemorrhage of both known and unknown origin, according to a presentation at an ob.gyn. conference sponsored by the University of Miami.
Placenta previa and abruption are more common presentations, whereas vasa previa occurs less frequently.
However, vasa previa—where blood vessels cross the cervical opening—can cause massive hemorrhaging.
Prenatal diagnosis via ultrasound improves survival, compared with diagnosis at delivery.
There are fewer data regarding hemorrhage of unknown origin, but pooled findings from several studies suggest a threefold increased risk of premature birth and twofold increased risk of stillbirth, Dr. Amanda Cotter said.
There is an increased risk of mortality with hemorrhage, Dr. Cotter said. In one study of 108 obstetric maternal deaths in North Carolina, cardiomyopathy was the leading cause of mortality, responsible for 21% (Obstet. Gynecol. 2005;106:1228–34). Hemorrhage was the second leading cause, a culprit in 14% of deaths.
Placenta previa causes approximately 20% of all cases of antepartum hemorrhage, Dr. Cotter said. It has an incidence of 1 in 200 live births. Sentinel bleed at about 30 weeks' gestation is another indicator of placenta previa, Dr. Cotter said. About 10% of women with this condition present without bleeding or pain, making it an ultrasound diagnosis. Another 20% of patients experience contractions with bleeding. The remaining 70% of women with placenta previa present with painless bleeding.
“Some women report standing up and blood runs down their leg and puddles on the floor,” said Dr. Cotter, a faculty member in the division of maternal fetal medicine, University of Miami.
“We must use ultrasound to do this diagnosis—but is it transabdominal or transvaginal?” Dr. Cotter asked. Only an experienced operator should perform transvaginal ultrasound in a bleeding patient, she said. “You have to prevent the probe from entering the cervix and causing any fetal insult.” Therefore, transabdominal is the preferred approach to ultrasound in these patients.
“Rule out placental separation, even with previa, to improve our diagnostic accuracy,” Dr. Cotter said.
Risk for placenta accreta—an abnormally firm attachment of the placenta to the uterine wall—varies depending on a patient's history. For example, a woman with no history of previa or cesarean section has a 5% risk, Dr. Cotter said. If she had a previous previa and one cesarean, the risk is approximately 24%.
The risk increases to 67% for a woman with a previous previa and a history of multiple cesarean deliveries. “This also applies to patients with multiple, previous D&Cs,” she added.
Ultrasound will show placenta previa or low-lying placenta. Dr. Cotter cited the case of a 35-year-old woman who presented for a routine pregnancy exam. She had blood vessels formed across the myometrium from her uterus to her bladder.
“I knew this was a placenta accreta—I left the placenta in without touching it at all—and did a breach delivery via C-section,” Dr. Cotter said. “She did very well, had no bleeding in postpartum period, and had normal resumption of her menses. I performed a tubal ligation with her permission at the same time so she should not be back in the same situation.”
Placental abruption is often associated with substance abuse during pregnancy, particularly cocaine. Ultrasound might show a retroplacental or preplacental hematoma, and increased placental thickness and echogenicity, Dr. Cotter said. “You can also sometimes see a subchorionic collection.”
Vasa previa occurs with an incidence of 1 in 2,500 pregnancies. “We don't see this as often,” Dr. Cotter said. It occurs when blood vessels transverse the internal cervical os.
“Once these membranes rupture, you will have massive bleeding,” she noted.
Early detection is important. In a study of 155 pregnancies complicated by vasa previa, 39% were diagnosed prenatally and the fetal survival rate was 97% (Obstet. Gynecol. 2004;103:937–42). In contrast, in the 61% diagnosed at delivery, survival dropped to 44%.
“Use color flow Doppler to confirm the diagnosis,” Dr. Cotter recommended.
The etiology of antepartum hemorrhage is unknown in 2%–3% of cases, Dr. Cotter said. Bleeding in these cases is associated with adverse outcomes.
“The most likely reason these people are bleeding is they have very tiny abruptions. So we have to monitor for preterm delivery and closely monitor the fetus up to delivery,” she added.
A meeting attendee asked if a physical examination of the cervix should be the first step when a patient presents with bleeding and does not have a diagnosis. “No, I would do an ultrasound first before I do an exam,” Dr. Cotter replied.
There is a paucity of data in the literature regarding this presentation, Dr. Cotter said. Pooled data from four studies suggest a threefold increase in risk of premature birth and twofold increase in risk of stillbirth with bleeding of unknown origin, she said. “It is important to counsel our patients with bleeding of unknown origin that they are at increased risk. I hope you will leave here and have a heightened awareness about increased risk of preterm delivery.”