First trimester abortion

Background

• Estimates are up to 15% of pregnancies end in a 1st trimester abortion usually due to fetal chromosomal abnormalities

Abortion Types

Classification	Characteristics	OS	Fetal Tissue Passage	Misc
Threatened	Abdominal pain or bleeding; < 20 weeks gestation	Closed	No	If < 11 weeks (with fetal cardiac activity) 90% progress to term. If between 11 and 20 weeks 50% progress to term
Inevitable	Abdominal pain or bleeding; < 20 weeks gestation	Open	No
Incomplete	Abdominal pain or bleeding; < 20 weeks gestation	Open	Yes, some
Complete	Abdominal pain or bleeding; < 20 weeks gestation	Closed	Yes, complete expulsion of products	Distinguish from ectopic based on decreasing hCG and/or decreased bleeding
Missed	Fetal death at <20 weeks without passage of any fetal tissue for 4 weeks after fetal death	Closed	No
Septic	Infection of the uterus during a miscarriage. Most commonly caused by retained products of conception	Open	No, or may be incomplete	Uterine tenderness and purulent discharge from the OS may be present

Clinical Features

• Visualize any clots or bleeding from external os
• Assess internal os as open or closed based on ability to pass finger through os
• Pregnancy ≤ 13 weeks

Differential Diagnosis

Vaginal Bleeding in Pregnancy (<20wks)

• Ectopic pregnancy
• Subchorionic hematoma
• First Trimester Abortion
  • Complete Abortion
  • Incomplete Abortion
  • Inevitable Abortion
  • Missed Abortion
  • Septic abortion
  • Threatened Abortion
• Gestational trophoblastic disease
  • Consider when pregnancy-induced hypertension is seen before 24 wks of gestation
• Heterotopic pregnancy
• Implantation bleeding
• Molar pregnancy
• Non-pregnancy related bleeding
  • Cervicitis
  • Fibroids
  • Implantation bleeding

Diagnosis

Workup

• Pelvic or Trans-abdominal ultrasound to assess fetal dating and heart rate
• Type and Screen/ABO
• Hemoglobin

Evaluation

• See Vaginal Bleed Pregnant (less than 20wks)

Management

• RhoGam if Rh Negative
• IVF and/or PRBCs if severe bleeding
• Misoprostol only for < 12 wks gestation, high success rate for the following
  • Incomplete AB: 600 mcg PO single dose
  • Missed AB: 800 mcg vaginally single dose
  • Supportive care with anti-emetic and NSAIDs for misoprostol side effects
• D&C and OB/gyn c/s may be necessary if medical management fails or continuous products/vaginal bleeding > 7-14 days

Disposition

• Discharge with close OB followup for repeat ultrasound
• Urgent OBGYN consult if active hemorrhage and need for Dilation and Curretage

See Also

• Vaginal Bleeding (Main)
• Vaginal Bleed Pregnant (less than 20wks)

References

• Hasan R, Baird DD, Herring AH, Olshan AF, Jonsson Funk ML, Hartmann KE. Association between first-trimester vaginal bleeding and miscarriage. Obstet Gynecol. Oct 2009;114(4):860-7