Cesarean-Scar Defect (Isthmocele) and Its Impact on Fertility, Implantation, and IVF Outcomes: A Systematic Review

To systematically evaluate evidence published between 2020 and 2025 on the relationship between cesarean-scar defect (isthmocele) and infertility, with emphasis on implantation failure, recurrent implantation failure (RIF), abnormal uterine environment, and outcomes of IVF and embryo transfer.

A structured search of PubMed, Embase, Scopus, and Cochrane Library was performed for studies published from January 2020 to January 2025 using predefined keywords (“isthmocele,” “cesarean-scar defect,” “infertility,” “implantation failure,” “IVF outcomes”). Inclusion criteria were human studies assessing fertility or IVF outcomes in women with radiologically confirmed isthmocele. Case reports without outcome data, studies lacking imaging confirmation, and non-human research were excluded. Twelve eligible studies were synthesized qualitatively due to heterogeneity in diagnostic criteria, defect measurements, and clinical reporting.

Across contemporary studies, isthmocele was associated with significantly impaired reproductive outcomes. Fluid accumulation within the niche, chronic endometrial inflammation, and altered uterine contractility contributed to reduced implantation rates (12–28%), increased early miscarriage, and higher rates of recurrent implantation failure compared with women without a scar defect. Several studies demonstrated 2–3× higher implantation failure when intrauterine fluid was present at the time of embryo transfer. Isthmocele also correlated with abnormal endometrial maturation, progesterone resistance patterns, and disrupted embryo endometrium synchrony.
Interventional studies reported that surgical correction (hysteroscopic or laparoscopic repair) improved reproductive outcomes, with implantation rates rising to 32–48% and clinical pregnancy rates improving by nearly 20–30% in selected populations.

Evidence from 2020–2025 indicates that cesarean-scar defect is an underrecognized yet clinically significant cause of infertility, implantation failure, and suboptimal IVF outcomes. The defect disrupts endometrial receptivity through fluid retention, inflammation, and mechanical distortion of the uterine cavity. Standardized recognition and early management of isthmocele may prevent years of unexplained infertility and significantly optimize IVF outcomes in a large, underdiagnosed patient population.