First trimester abortion

Background

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

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

Complete Abortion

• <12 weeks + no IUP
• Distinguish from ectopic based on decreasing hCG, decreased bleeding
• Only need to send hCG if unable to examine POC

Threatened Abortion

• Closed os + IUP + bloody vaginal dischrage or frank bleeding
• If <11wk >90% go to term
• If between 11 and 20wk 50% go to term

Inevitable Abortion

• Open os + contractions/cramps

Incomplete Abortion

• >12 wks + passage of only portion of POC

Missed Abortion

• Fetal death at <20wk w/o passage of any fetal tissue for 4wk after fetal death

Septic abortion

• Evidence of infection during any stage of abortion
• Most commonly caused by retained products of conception

Workup

• Pelvic or Transabdominal ultasound to assess fetal dating and heartrate
• Type and Screen
• RhoGam if Rh Negative
• Hemaglobin

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)

Sources

• 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