Want to download this guide to read later? Guide to IVF Lab Results

The laboratory component of your IVF journey should not be mysterious, and we always welcome your questions. The science behind growing embryos in vitro is constantly evolving as we strive to make the culture environment as natural as possible to optimize your chance of success.

Recent studies have shown us that growing embryos for 5 or 6 days before transfer and freezing (when they will have reached the “blastocyst” stage) has some crucial advantages:

  • Growing embryos for 5 days instead of 3 is an excellent selection tool: only a proportion of embryos will become blastocysts, the others will stop growing.
  • If the embryo becomes a blastocyst it has a much higher chance of implanting. This means fewer embryos can be transferred in order to achieve a healthy pregnancy, and the risk of multiples is subsequently reduced. It also allows us to eliminate poorer quality embryos which would not have made a pregnancy.
  • For successful implantation, the stage of the embryo and the lining of the uterus must be “in sync”, and this is more easily achieved when the embryo is at the blastocyst stage, matching more closely with what happens in a natural cycle.

At PCRM we have a reliable, reproducible culture system, and because of this we are happy to grow everyone’s embryos to day 5 before transfer. There is no way to know for sure whether all embryos that fail in culture would also have failed in utero, but we believe that there is no harm caused to your embryos by five days of growing in the lab. What follows is a brief outline of what will be happening to your embryos for the six days that they will be in the Lab: Guide to IVF Lab Results