Window of Implantation in IVF

For a pregnancy to occur both an embryo and the uterus must be at exactly the right stage for implantation. There is a limited period of time where both the embryo and uterine lining will be at this stage, and this is called the “window of implantation”.

There is a range for both embryonic and uterine lining growth and they need to be in sync. We talked about this window of implantation and recent developments in how IVF medications may impact it on the Creating a Family show aired this week.




Research Reported This Week

For most women the window of implantation last about two to four days, but for some women the fertile window is shifted earlier or later in the cycle or is unusually brief. These women often have failed IVF cycles.

In a new test reported on this week in Spain, a biopsy of the endometrium is taken and the gene activity is analyzed. As the cells from the uterus enter the receptive phase a series of genes switch on and off in a reliable sequence that scientists may be able to read.

In a pilot study, the test was given to 85 women who had each experienced on average five rounds of IVF that had failed at the implantation stage. In these women, the fertile window was more likely to be shifted early or late, in some cases completely missing the day when the embryo is transferred in standard IVF protocols, the study found.

When the gene analysis was used as a guide, 33% of those treated had a successful implantation – considerably higher than would typically be seen for such a group.

New research, such as this, makes me feel so hopeful!