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12-09-2010 | Gynaecology | Article

Fertilization rate predicts implantation rate during assisted reproduction


Journal abstract

MedWire News: US researchers have shown that the rate of fertilization is an independent predictor of embryo implantation after IVF, with high implantation rates significantly improving the chances of an embryo implanting in the uterus compared with low rates.

The results "may be useful in modeling to guide decision making for the number of embryos to transfer," say Mitchell Rosen and colleagues from the University of California in San Francisco.

The implantation rate after 2,444 intracytoplasmic sperm injection (ICSI) cycles was 25.2 percent among couples who had a high fertilization rate (more than 50 percent of embryos), compared with only 17.8 percent among couples with a low fertilization rate.

The trend was similar among 1,159 conventional insemination cycles, where 75 percent or more embryos denotes high fertilization, with implantation rates of 32.1 versus 25.7 percent for high versus low fertilization, respectively.

Furthermore, after adjusting for potentially confounding factors such as patient age, multivariate analysis confirmed that a high fertilization rate independently predicts implantation, at odds ratios of 1.54 and 1.53 for ICSI and conventional insemination, respectively.

Rosen et al believe their results suggest that "fertilization rate may serve as a bioassay of oocyte health."

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Sarah Guy