Risk of Placenta Accreta After Myomectomy with Endometrial Cavity Entry
A. Increase - The risk of placenta accreta is increased in future pregnancies after myomectomy with entry into the endometrial cavity.
Understanding the Mechanism
The pathophysiology directly explains why myomectomy increases accreta risk. The American College of Obstetricians and Gynecologists explains that placenta accreta spectrum develops when defects in the endometrial-myometrial interface lead to failure of normal decidualization in areas of uterine scarring, allowing abnormally deep placental anchoring and trophoblast infiltration 1. When the endometrial cavity is entered during myomectomy, this creates precisely the type of disruption within the uterine cavity that damages the endometrial-myometrial interface, affecting scar tissue development and increasing the likelihood of placenta accreta 1.
Evidence Supporting Increased Risk
Prior uterine surgeries are explicitly listed as established risk factors for placenta accreta spectrum by the American College of Obstetricians and Gynecologists, alongside cesarean delivery, curettage, and Asherman syndrome 1.
Case reports and observational studies specifically document placenta accreta occurring at myomectomy sites, particularly when the placenta overlies the area of prior uterine surgery 2, 3.
Women undergoing cesarean delivery after prior myomectomy face significantly elevated surgical complications, including a 243% increased risk of cesarean hysterectomy (aOR 3.43) and 180% increased risk of intraoperative transfusion (aOR 2.8), suggesting underlying abnormal placentation 4.
Clinical Implications for This Patient
This 30-year-old nulligravid woman now carries a documented risk factor that requires specific management in future pregnancies:
She should undergo careful ultrasound evaluation in any subsequent pregnancy to assess for placenta accreta spectrum, particularly if the placenta overlies the myomectomy site 2, 3.
If placenta previa develops overlying the myomectomy scar, her risk escalates dramatically - similar to the well-established cesarean scar-previa combination that creates 11-67% accreta risk depending on number of prior surgeries 1.
Gray-scale ultrasound should be the first-line imaging modality, looking for loss of the normal hypoechoic retroplacental zone, placental lacunae, thinning of the uterine serosa-bladder interface, and abnormal placental vascularity 5.
Important Caveats
The absolute magnitude of increased risk after myomectomy is not as precisely quantified as it is for cesarean delivery, where systematic reviews show 0.3% risk after one cesarean increasing to 6.74% after five cesareans 1. However, the biological mechanism is identical - uterine scarring disrupting the endometrial-myometrial interface 1.
Entry into the endometrial cavity is particularly significant because it creates a full-thickness defect similar to cesarean delivery, rather than a subserosal defect that would not involve the decidual layer 1.