Cesarean Scar Niche (Isthmocele) Imaging

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

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Full pathway

1. [Decision] Niche assessment (RMT and symptoms)
   Scar niche — residual myometrial thickness (RMT) and symptoms? (A niche (isthmocele) = poorly healed cesarean scar causing an indentation + thinned myometrium; postmenstrual spotting/dysmenorrhea/chronic pelvic pain/secondary infertility (retained blood, affecting cervical mucus and sperm). TVUS (examine when the endometrium is thinnest postmenstrually) + SIS show it better; measure niche depth, RMT, adjacent myometrium; risk factors multiple cesareans/smoking/diabetes/retroverted uterus. It is the CSP implantation site.)
   • Symptomatic (abnormal bleeding/secondary infertility) and thin RMT → Symptomatic + thin RMT · assess repair
   • Asymptomatic or incidental, reasonable RMT → Asymptomatic · follow-up
2. [End] Asymptomatic · follow-up
   Asymptomatic or incidental small niche, reasonable RMT: follow-up, usually no intervention; counsel those planning pregnancy about cesarean scar pregnancy (CSP) risk and the need to locate the sac in early pregnancy.
3. [End] Symptomatic + thin RMT · assess repair
   Symptomatic (postmenstrual bleeding/dysmenorrhea/secondary infertility) and thin RMT (e.g. <3 mm or <50% of adjacent myometrium): gynecology assessment for surgical repair (hysteroscopic niche resection, laparoscopic/transvaginal repair); TVUS/SIS quantify niche depth and RMT to guide decisions; alert for CSP if planning pregnancy.

Source guidelines & references

• Cesarean scar niche ultrasound assessment criteria (modified Delphi)

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

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