Description

• Vaginal bleeding during pregnancy has many causes and ranges in severity from benign with normal pregnancy outcome to life-threatening for both infant and mother.
• Etiology can be from the vagina, cervix, uterus, fetus, or placenta. The differential diagnosis is guided by the gestational age of the fetus.

Epidemiology

Prevalence

• In early pregnancy: 7–25% of patients
• In late pregnancy: 0.3–2% of patients

Etiology and Pathophysiology

• Many times, the cause is unknown.
• Anytime in pregnancy:
  • Cervicitis (infectious or noninfectious)
  • Vaginitis (infectious or noninfectious)
  • Vaginal or cervical trauma (including postcoital)
  • Cervical lesion (including polyps or warts) or neoplasia
  • Hyperemia of cervix (increased blood flow from pregnancy)
• Early pregnancy:
  • For up to 50% of early pregnancy bleeding, no cause is ever found.
  • Ectopic pregnancy: leading cause of 1st-trimester maternal death in the United States—must be excluded in every pregnant patient with bleeding. Risk factors: previous ectopic, trauma to fallopian tubes (tubal surgery, infection, tumor), congenital anomaly of tubes, in utero diethylstilbestrol (DES) exposure, current use of IUD, history of infertility, tobacco use
  • Spontaneous abortion: risk factors: advanced maternal age (AMA), alcohol use, tobacco use, anesthetic gas, heavy caffeine use, cocaine use, chronic maternal diseases (poorly controlled diabetes mellitus [DM], celiac disease, autoimmune diseases such as antiphospholipid syndrome), short interconception time (3 to 6 months), current use of IUD, maternal infection (e.g., herpes simplex virus [HSV], gonorrhea, chlamydia, toxoplasmosis, listeriosis, HIV, syphilis, malaria), medications (e.g., retinoids, methotrexate, NSAIDs), multiple previous therapeutic abortions, previous spontaneous abortion, toxins (arsenic, lead, polyurethane), uterine abnormalities (congenital, adhesions, fibroids); bleeding may be a cause and/or a consequence of early pregnancy loss.
  • Loss of one fetus from a multiple gestation (“vanishing twin”)
  • Implantation bleeding: benign, about 6 days after fertilization
  • Uterine fibroids
  • Subchorionic bleeding (or hematoma): in late 1st trimester
  • Low-lying placenta
  • Gestational trophoblastic disease: hydatidiform mole (most common), choriocarcinoma, or placental-site trophoblastic tumors
• Late pregnancy:
  • Bloody show of labor (loss of mucus plug)
  • Placenta previa: painless bleeding; occurs in 0.4% deliveries in the United States. Risk factors: previous history of placenta previa, previous uterine surgery (cesarean section, D&C), chronic hypertension, multiparity, multiple gestation, tobacco use, AMA
  • Placental abruption: (typically) painful bleeding; occurs in 1–2% deliveries in the United States. Risk factors: previous placental abruption, 1st-trimester bleeding, hypertension, preeclampsia, multiple gestation, tobacco, cocaine or methamphetamine use, unexplained elevated maternal α-fetoprotein, poly- or oligohydramnios, AMA, trauma to abdomen, premature rupture of membranes, thrombophilia, short umbilical cord, male fetus, chorioamnionitis, nutritional deficiency
  • Vasa previa: minimal bleeding with fetal distress; rare (1:2,500 deliveries). Risk factors: in vitro fertilization, multiple gestations, placental abnormalities (low-lying position, bilobate, succenturiate lobe, velamentous insertion of umbilical cord)
  • Placenta accreta, increta, percreta: risk factors: uterine scar (e.g., from cesarean section, endometrial ablation, or D&C), current placenta previa, AMA, tobacco use, multiparity, uterine anomalies, uterine fibroids, hypertension
  • Uterine rupture: typically presents with vaginal bleeding, abnormal fetal heart rate, and disordered or hypertonic uterine contractions with or without pain. Risk factors: previous cesarean section (most common), trauma, use of oxytocin or prostaglandins, multiparity, external cephalic version, placental abruption, shoulder dystocia, placenta percreta, müllerian duct anomalies, history of pelvic radiation

Risk Factors

See specific etiologies in earlier discussion.

General Prevention

• Address modifiable risk factors such as domestic violence and tobacco and drug use.
• If placenta or vasa previa, nothing per vagina