Approach to Assessing Vaginal Bleeding

Initial Assessment

The American College of Radiology recommends assessing hemodynamic stability and determining pregnancy status immediately, followed by ultrasound imaging before any digital pelvic examination in pregnant patients to avoid catastrophic hemorrhage from placental abnormalities 1, 2
Determine pregnancy status immediately through urine or serum beta-hCG testing, as this fundamentally changes the diagnostic approach 2
Obtain quantitative beta-hCG level regardless of ultrasound findings in pregnant patients 2
Digital pelvic examination must be avoided until ultrasound excludes placenta previa, low-lying placenta, and vasa previa in second and third trimester bleeding, as examination before imaging can precipitate catastrophic hemorrhage 1, 2

In pregnant patients with second and third trimester bleeding, approximately 50% of cases have no identifiable reason, while placenta previa is the most common diagnosis made 1
Placental abruption affects approximately 1% of pregnancies and is associated with worse perinatal outcome than marginal placental separation 1
Ectopic pregnancy occurs in 7-20% of pregnancy of unknown location cases 2
Miscarriage is a possible diagnosis in pregnant patients with vaginal bleeding 1

In pregnant patients with second/third trimester bleeding, evaluate for miscarriage or preterm labor symptoms through history and physical examination 1

Perform ultrasound first before any digital examination in second and third trimester bleeding 1, 2
Speculum examination to assess for cervical lesions, polyps, or inflammation after placental abnormalities are excluded 2
Evaluate uterine contractions or increased tone in pregnancy-related bleeding 2

Transvaginal ultrasound is the primary diagnostic tool in pregnant patients, providing better resolution than transabdominal ultrasound 2
Quantitative beta-hCG level is essential in pregnant patients 2
If intrauterine pregnancy is confirmed, ectopic pregnancy is essentially ruled out, except in rare cases of heterotopic pregnancy 2
Ultrasound is the mainstay for making accurate diagnoses in second and third trimester bleeding 1

For subchorionic hemorrhage with viable pregnancy, schedule follow-up ultrasound in 1-2 weeks 2
For pregnancy of unknown location, continue serial beta-hCG measurements until diagnosis is established 2
Second and third trimester pathologic bleeding may require hospitalization and/or delivery 1

Confirmed or suspected ectopic pregnancy requires immediate specialist consultation 2
Second/third trimester bleeding with placenta previa, vasa previa, placental abruption, or uterine rupture requires immediate specialist consultation 1
Pregnancy of unknown location requiring serial monitoring requires gynecology referral 2

Never perform digital pelvic examination before ultrasound in pregnant patients with second/third trimester bleeding, as this can cause catastrophic hemorrhage with placenta previa or vasa previa 1, 2
Ultrasound misses up to 50% of placental abruptions, so clinical correlation is essential 2
In pregnancy of unknown location, approximately 7-20% will be ectopic pregnancies, so close follow-up with serial beta-hCG is mandatory 2