Bleeding With IUP

Anne Kennedy, MD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Is there a gestational sac?
- Imperative to differentiate a normal early gestational sac from a pseudosac seen in ectopic pregnancy
- If no intrauterine pregnancy (IUP) look for adnexal mass, echogenic fluid in cul-de-sac
Where is the sac located?
- Compare to prior studies if available
Has there been appropriate interval development?
- Must know normal developmental milestones
Normal sac development
- Intradecidual sac sign (IDSS) earliest sign of IUP
- IDSS seen by 4-4.5 weeks after last menstrual period (LMP)
- Gestational sac “burrows” into endometrium
- Echogenic ring is eccentric to linear interface of endometrial surfaces
  - Must follow to confirm appropriate growth/milestones
- Double decidual sac sign (DDSS) seen by 5-5.5 weeks post LMP
  - Initially described as first reliable transabdominal sign of IUP
  - Decidua parietalis (endometrium) surrounds decidua capsularis (gestational sac) = two echogenic rings
Pseudosac associated with ectopic pregnancy
- No DDSS
- Flatter shape than normal gestational sac
- Central in cavity rather than eccentric
Even if normal IUP seen beware heterotopic pregnancy if patient symptomatic/has risk factors
Placenta previa/abruption are NOT first trimester diagnoses
- Placenta often covers internal os in first trimester
- Placenta large relative to uterine size
- Lower uterine segment (LUS) elongates after 28 weeks
- Placental trophotropism results in migration of placenta away from cervix/LUS as pregnancy progresses

Helpful Clues for Common Diagnoses

Failed Pregnancy
- Cardiac activity will be absent
- Sac being expelled from uterus, may contain yolk sac or embryo
- Sac often flattened/irregular shape
- Sac in endometrial/cervical canal not implanted into uterus
- Color Doppler shows lack of normal trophoblastic flow
Perigestational Hemorrhage
- May be asymptomatic or present with vaginal bleeding
- Echogenic fluid deep to chorion
  - Becomes hypoechoic over time
- Normal gestational sac contents
Early Normal Pregnancy
- Bleeding in pregnancy before visualization of gestational sac (presumed to be implantation bleeding)
  - Follow all apparent IDSS to ensure normal developmental milestones
  - Beware tiny cystic structures in endometrium, may be dilated endometrial glands
- Idiopathic bleeding: Normal sac/embryo seen but no obvious collection of blood
Anembryonic Pregnancy
- No visible embryo in gestational sac with diameter ≥ 18 mm by transvaginal exam
- Look for “empty amnion” sign

Helpful Clues for Less Common Diagnoses

Partial Mole
- Vaginal bleeding
- Abnormal embryo/fetus
- Placenta may look normal or appear cystic
- “Chorionic bump” correlates strongly with partial mole
Twin Demise
- One normal gestational sac
- One sac with variety of appearances
  - Perigestational hemorrhage
  - Embryonic demise
  - Anembryonic gestation

Helpful Clues for Rare Diagnoses

Interstitial Ectopic
- Look for interstitial line sign
- Eccentric placement of sac in relation to uterine cavity
- < 5 mm of surrounding myometrium very suggestive
Cervical Ectopic
- Sac implanted in cervical stroma
- Look for rim of tissue around sac rather than sac within endocervical canal
- Sac positioned low in uterus but still perfused (compared to abortion in progress with flattened sac, lack of perfusion)
C-section Scar Ectopic
- Gestational sac implants into scar from prior C-section, extends to serosa
Heterotopic Pregnancy
- Intrauterine & ectopic pregnancy
- Look for adnexal mass, echogenic fluid in addition to IUP
  - Differential: Normal IUP with hemorrhagic corpus luteum
- Risk factors for heterotopic pregnancy
  - Assisted reproduction
  - Intrauterine contraceptive device
  - History of pelvic inflammatory disease
  - History of endometriosis

Other Essential Information

Important to recognize unusual (other than tubal) ectopics
- Pregnancy is “in uterus” but not in correct place
- C-section scar ectopic treated with systemic methotrexate or percutaneous injection
- Risk of torrential bleeding/emergent hysterectomy if curettage attempted in cervical ectopic
- Interstitial ectopic also best treated conservatively if patient stable

Alternative Differential Approaches

Bleeding with intrauterine sac but no fetal pole
- Anembryonic pregnancy
- Pseudosac from ectopic pregnancy
- Perigestational hemorrhage
Bleeding with an embryo
- Perigestational hemorrhage
- Idiopathic (no obvious collection of blood)
Bleeding with no visible IUP
- Very early normal pregnancy
- Complete abortion
- Tubal ectopic pregnancy