BACKGROUND<\/p>\n
Intact frozen-thawed embryos have a greater potential than damaged embryos to establish successful pregnancies. This study aimed to determine whether elevated concentrations of sucrose during freezing would increase the proportion of patients with ≥50% of embryos intact after thawing (primary outcome), and improve clinical outcome.<\/p>\n
METHODS<\/p>\n
In a two arm, parallel group, pragmatic trial, IVF\/ICSI couples were randomized prospectively to have their supernumerary embryos frozen in a medium containing 0.1 M sucrose (control; n<\/I> = 99) or 0.3 M sucrose (intervention; n<\/I> = 102).<\/p>\n
RESULTS<\/p>\n
More control (74\/99) than intervention (63\/102) couples had at least one embryo thawed (P<\/I> = 0.07). Significantly more (P<\/I> = 0.005) intervention (53\/63) than control (45\/74) couples had ≥50% of embryos intact. Freezing in a medium containing 0.3 M sucrose increased by 3.4-fold [95% confidence interval (CI) (1.45, 7.82)] the likelihood of a couple having ≥50% of their embryos intact. In the fresh cycle, live birth rate per transfer was similar in the control (35\/95) and intervention (36\/93) groups (P<\/I> = 0.91). More control (19\/63) than intervention (9\/59) couples had a live birth after frozen embryo transfer (P<\/I> = 0.08). When fresh and frozen cycles were combined, fewer intervention (n<\/I> = 102) than control (n<\/I> = 99) couples had at least one live birth (42 versus 53%). The difference in cumulative live birth rate was not significant [hazard ratio = 0.75, 95% CI (0.49, 1.13); P<\/I> = 0.17].<\/p>\n
CONCLUSIONS<\/p>\n
Increasing the concentration of sucrose in the freezing medium improves embryo survival, but this is not reflected by increased cumulative birth rates.<\/p>\n
Clinical Trials Registration number: ISRCTN93314892.<\/p>\n","protected":false},"excerpt":{"rendered":"
BACKGROUND Intact frozen-thawed embryos have a greater potential than damaged embryos to establish successful pregnancies. This study aimed to determine whether elevated concentrations of sucrose during freezing would increase the proportion of patients with ≥50% of embryos intact after thawing … Continue reading