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

• In early pregnancy: 7–25% of patients
• In late pregnancy: 0.3–2% of patients (1)

Risk Factors

See specific etiologies below

General Prevention

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

Etiology

• Many times the cause is unknown.
• Anytime in pregnancy:
  • Cervicitis (infectious or noninfectious)
  • Vaginal or cervical trauma (including postcoital)
  • Cervical lesion 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 US (2). Risk factors: Previous ectopic, trauma to fallopian tubes (tubal surgery, infection, tumor), congenital anomaly of tubes, in utero 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 DM, celiac disease, autoimmune diseases such as antiphospholipid syndrome), short interconceptional time (3–6 months), IUD in place, maternal infection (e.g., 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)
  • Implantation bleeding: Benign, about 6 days after fertilization (2)
  • Uterine fibroids
  • Subchorionic bleed: In late 1st trimester (2)
  • Low-lying placenta
  • Gestational trophoblastic disease: Hydatidiform mole (most common), choriocarcinoma, or placental-site trophoblastic tumors (2)
• Late pregnancy:
  • Bloody show of labor
  • Placenta previa: Painless bleeding; occurs in 0.4% deliveries in the US. Risk factors: Previous history of placenta previa, previous uterine surgery (cesarean section, D&C), chronic hypertension, multiparity, multiple gestation, tobacco use, AMA (3)
  • Placental abruption: Painful bleeding; occurs in 1–2% deliveries in the US. 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, sudden uterine decompression, premature rupture of membranes, thrombophilia, short umbilical cord, chorioamnionitis, nutritional deficiency, male fetus (1,3)
  • Vasa previa: Minimal bleeding with fetal distress; rare (1:2,500 deliveries). Risk factors: In vitro fertilization, multiple gestation, 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: 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 (4)