Background: Endometrial cavity fluid (ECF) is occasionally observed during assisted reproductive technology (ART) cycles. However, few reports have described its prevalence or significance.
Methods and results: We examined the relationships between ECF, clinical pregnancy rate (CPR), tubal factor infertility and ultrasound-visible (USV) hydrosalpinges. In 843 ART cycles involving 721 patients, ECF was observed during stimulation in 57 cycles and after human chorionic gonadotrophin (HCG) administration in 12 cycles, with an overall incidence of 8.2% (69/843). When ECF was observed during stimulation, the cancellation rate due to poor ovarian response was significantly higher (29.8 versus 16.9%, P <0.05) and the CPR per started cycle was significantly lower (26.3 versus 42.4%, P <0.05) than cycles without ECF. When ECF developed after HCG administration, the CPR was similar compared with that of the group for which ECF was not observed. In the 327 cycles involving tubal factor infertility patients, USV hydrosalpinges were noted in 71 cycles (71/327; 21.7%), and ECF developed in five of those cycles (5/71; 7.0%). A total of 27 cycles during which ECF developed (27/57, 47.4%) involved non-tubal factor patients.
Conclusions: ECF during stimulation was associated with increased cancellation rates and lower CPRs per started cycle, and was not associated with USV hydrosalpinges. Furthermore, ECF observed after HCG administration did not impact CPR and may represent a different clinical entity.