Hydrosalpinx fluid does not adversely affect the normal development of human embryos and implantation in vitro.

Several retrospectively designed studies have shown an association between the presence of hydrosalpinx and impaired implantation and pregnancy rates among in-vitro fertilization (IVF) patients. In the present study we have evaluated the influence of hydrosalpinx fluid on normal human embryo development and implantation. Surplus, donated frozen embryos (n = 183) from IVF patients were used to study the effects on blastocyst development of hydrosalpinx fluid at concentrations of 50 and 100% compared with controls in S2 medium. The fluids were analysed for concentrations of electrolytes, osmolarity, protein content, endotoxin levels, bacterial or fungal contamination, pH and haemoglobin content. There was no difference in blastocyst development in cultures under mineral oil when control cultures (15/42 = 36%) were compared with cultures in 50% hydrosalpinx fluid (32/96 = 33%). The only biochemical parameter which correlated with capacity for blastocyst development was pH in hydrosalpinx fluid/medium (50/50%) after equilibration in 5% CO2 in air. When embryos were cultured in 100% hydrosalpinx fluid the blastocyst development was 14% (5/36) in comparison to control 33% (3/9). The original experiment was repeated in an open culture system without the protection of mineral oil but still in the presence of 50% hydrosalpinx fluid. The rate of blastocyst development was within the same range in the open system. In three separate experiments, the capability of expanded blastocyst to implant on multilayer artificial endometrium was tested. In these experiments, 1/3, 4/5 and 9/9 blastocysts implanted. The present study demonstrates that hydrosalpinx fluid does not generally exert any major negative effects on in-vitro development of human embryos or on the implantation process in vitro.