What are the different types of abortion classifications?

Types of Abortion Classifications

Abortions are primarily classified by method (medical or surgical) and by gestational age (first or second trimester). These classifications guide clinical decision-making regarding appropriate techniques and safety considerations 1, 2.

Classification by Method

Medical Abortion

• Uses medications to terminate pregnancy without surgical intervention 1
• Primary medication regimens include:
  • Combined regimen of mifepristone followed by prostaglandin (most effective approach) 1
  • Prostaglandins alone (less effective than combined regimen) 1
  • Methotrexate followed by prostaglandin (alternative when mifepristone unavailable) 1

Surgical Abortion

• Involves physical removal of pregnancy tissue through instrumentation 3
• Main techniques include:
  • Vacuum aspiration (preferred over curettage for safety) 4
  • Dilation and evacuation (D&E) - most common method for second-trimester abortions 3, 2
  • Dilation and curettage (less preferred than vacuum aspiration) 4

Classification by Gestational Age

First Trimester Abortion (≤12 weeks)

• Most common timing for abortion procedures 1
• Methods:
  • Medical abortion with mifepristone 200mg followed by misoprostol is highly effective 4
  • Before 7 weeks: Oral, buccal, sublingual, or vaginal misoprostol can be used 4
  • After 7 weeks: Vaginal, sublingual, or buccal routes are more effective than oral administration 4
  • Surgical abortion via vacuum aspiration is the standard surgical approach 1

Second Trimester Abortion (>12 weeks)

• Represents approximately 10% of all abortions in the United States 3
• Methods:
  • D&E is the preferred surgical method, requiring adequate cervical preparation 2
  • Medical abortion with mifepristone-misoprostol regimen is also effective 2
  • When mifepristone is unavailable, misoprostol alone can be used 2

Classification by Timing Related to Pregnancy Status

Postabortion Categories

• First trimester abortion 5:

  • Procedural (surgical): Category 1 for most contraceptive methods
  • Medication abortion: Category 1 for most methods, Category 1/2 for DMPA
  • Spontaneous abortion with no intervention: Category 1 for all methods

• Second trimester abortion 5:

  • Procedural (surgical): Category 2 for IUDs, Category 1 for other methods
  • Medication abortion: Category 2 for IUDs, Category 1 for other methods
  • Spontaneous abortion with no intervention: Category 2 for IUDs, Category 1 for other methods

• Immediate postseptic abortion 5:

  • Category 4 (contraindicated) for IUDs
  • Category 1 for hormonal methods

Classification by Indication

Elective Abortion

• Performed at the request of the woman for non-medical reasons 4
• Timing is critical for method selection and safety considerations 4

Therapeutic Abortion

• Performed for maternal health reasons or fetal anomalies 3
• May be performed at later gestational ages depending on indication 3

Spontaneous Abortion (Miscarriage)

• Natural pregnancy loss without intervention 6, 7
• Risk factors include:
  • Advanced maternal age (≥35 years) increases risk significantly (OR 1.85; 95% CI, 1.35-2.52) 6
  • Low serum Anti-Müllerian Hormone levels (OR 1.91; 95% CI, 1.40-2.60) 6
  • Fetal chromosomal defects (account for up to 60% of all miscarriages) 7
  • Maternal congenital uterine abnormalities (affect up to 38% of women with recurrent miscarriage) 7

Clinical Considerations

• Medical abortion efficacy depends on route of administration:

  • Vaginal misoprostol is more effective than oral administration 1
  • Sublingual and buccal routes are similarly effective to vaginal but have higher rates of side effects 1

• Safety considerations:

  • D&E has greatest safety advantage in the 13-16 week interval 3
  • For later abortions, D&E and instillation methods have similar complication rates 3
  • Cervical preparation is recommended for all surgical abortions 4

• Post-abortion contraception:

  • Combined hormonal contraceptives can be started on the day of surgical abortion 4
  • For medical abortion, contraception can begin the same day as misoprostol or the day after 4
  • IUDs can be inserted on the day of surgical abortion or 10 days after mifepristone for medical abortion 4