What can a patient with a history of miscarriage learn from the findings of a dilation and curettage (D&C) procedure regarding the cause of their miscarriage?

What Findings from D&C Can Reveal About Miscarriage Causes

The primary finding from D&C tissue analysis after miscarriage is chromosomal abnormalities, which are identified in approximately 71.6% of cases and represent the most common identifiable cause of pregnancy loss. 1

Key Diagnostic Information from D&C Tissue Analysis

Chromosomal Abnormalities (Most Common Finding)

• Karyotyping of tissue obtained during D&C identifies chromosomal abnormalities in approximately 71.6% of miscarriages, with this rate being higher than classic estimates but consistent with recent studies in infertile populations 1

• Trisomy is the most frequent chromosomal abnormality detected, with rates increasing in older patients (though not always reaching statistical significance) 1

• Monosomy X is more commonly identified in younger patients (under age 38), representing a distinct pattern of chromosomal loss 1

• The likelihood of finding chromosomal abnormalities increases significantly with maternal age, with patients having abnormal cytogenetics being older on average (38.6 years versus 36.3 years) 1

What D&C Findings Cannot Determine

• D&C tissue analysis has significant limitations - many practitioners do not uniformly recommend D&C for all patients at the time of miscarriage diagnosis, which means not all patients receive this potentially informative testing 1

• The absence of chorionic villi on pathology after D&C may indicate ectopic pregnancy rather than intrauterine pregnancy loss, requiring different diagnostic and management approaches 2

Clinical Algorithm for Obtaining Diagnostic Information

When to Pursue Tissue Analysis

• Consider chromosomal analysis particularly in patients with:
  • Advanced maternal age (≥35 years), as chromosomal abnormalities are more likely 1
  • Recurrent pregnancy losses (two or more), as this may guide future management 3
  • Desire for definitive cause determination to inform future pregnancy planning 1

Important Counseling Points

• Inform patients that finding a chromosomal abnormality provides reassurance that the miscarriage was likely due to a random genetic event rather than a preventable maternal factor 1

• Explain that approximately 28-29% of miscarriages will not reveal a chromosomal cause, meaning other factors (anatomic, hormonal, immunologic, or unexplained) may be responsible 1

• Discuss that the information obtained may be particularly valuable for older patients, as the classic association between advancing age and chromosomal abnormalities is consistently affirmed 1

Critical Limitations and Caveats

• The decision to perform D&C versus expectant or medical management should not be based solely on desire for tissue analysis, as D&C carries risks including increased rates of spontaneous preterm birth in future pregnancies (adjusted OR 1.64 for miscarriage managed by D&C) 3

• D&C may predispose to postpartum hemorrhage in subsequent pregnancies, with significantly higher incidence than previously reported averages 4

• Tissue analysis requires adequate sample collection - if chorionic villi are not obtained, the procedure may not yield diagnostic information and could indicate ectopic pregnancy 2