Incidence of Uterine Scarring Following Dilation and Curettage
The incidence of uterine scarring following dilation and curettage (D&C) ranges from approximately 0.2% to 2.3%, with the risk being significantly higher in patients with pre-existing uterine abnormalities or when performed by inexperienced operators. 1
Risk Factors for Uterine Scarring After D&C
Operator Experience
- Inexperience is a major risk factor for complications during D&C procedures
- In a 7-year study of 11,914 D&C procedures, 23 uterine perforations occurred (0.19%), with 22 of these cases performed by trainees 1
Patient-Related Factors
- Previous cesarean section or uterine surgery
- Thin myometrium at the implantation site (<2 mm) increases risk of complications 2
- Larger gestational sac or mass (≥4.5 cm) in cases of cesarean scar pregnancy 2
Types of Uterine Scarring
Uterine Perforation
- Immediate complication occurring in approximately 0.2% of D&C procedures 1
- May lead to bleeding, infection, and subsequent scarring
Intrauterine Adhesions (Asherman's Syndrome)
- Formation of scar tissue within the uterine cavity
- Can cause amenorrhea, infertility, recurrent pregnancy loss, and abnormal placentation in subsequent pregnancies
Cesarean Scar Defects
- Particularly relevant in patients with previous cesarean deliveries
- Prevalence of cesarean section scar defects ranges between 24% and 88% when evaluated by ultrasonography 3
- Niche (cesarean section scar defect) prevalence varies between 56-84% using contrast-enhanced sonohysterography and 24-70% using transvaginal sonography 3
Prevention Strategies
Procedural Modifications
- Digital dilation of the cervix during procedures may reduce abnormal scarring
- In a study of cesarean sections, digital dilation of the internal cervical ostium significantly reduced abnormal scar formation (14.3% vs 40.6%) 4
Operator Training
- Ensuring adequate training and supervision for those performing D&C procedures
- Experienced operators have significantly lower complication rates 1
Monitoring and Follow-up
Post-Procedure Evaluation
- Ultrasound evaluation 40-42 days after procedure can assess healing of the uterine tissue 4
- Monitoring β-hCG levels after D&C for pregnancy tissue - a decrease rate of ≤66.42% on the first day after D&C is associated with persistent tissue and potential scarring 2
Special Considerations for Cesarean Scar Pregnancy
- Ultrasound-guided D&C is recommended only when:
- Cesarean scar is >3 mm thick
- Blood flow around the gestational sac is not abundant
- Maximum diameter of gestational sac is <30 mm 5
- For high-risk cases (thin scar, large gestational sac), alternative approaches should be considered to prevent complications 5
Impact on Future Fertility
- D&C alone versus uterine artery embolization (UAE) combined with D&C for cesarean scar pregnancy shows:
- Longer menstrual recovery time with UAE+D&C (2.0 months vs 1.0 month)
- Decreased menstrual blood volume in 79% of UAE+D&C patients vs 18% in D&C alone
- However, no significant difference in subsequent pregnancy rates (75% vs 78%) or birth rates (63% vs 56%) 6
While the incidence of uterine scarring following D&C is relatively low, the consequences can be significant for future fertility and pregnancy outcomes. Proper patient selection, experienced operators, and appropriate techniques are essential to minimize these risks.