Where babies happen

3146 Deming Way
Middleton, WI 53562

Phone: 608-824-0075 | Fax: 608-829-0748

Embryo Interpretation

The information below will outline what we expect to see each day with your embryos.

Day 0: Egg retrieval day. You will learn how many eggs are retrieved, then later in the day sperm will be added to them.

Day 1: This is the day we see how many eggs are fertilized, they are called embryos now.

Day 2: This is the first day that we can really see embryo quality. They are graded on a 1 to 4 scale, with 1 being best quality and 4 being worst. Most pregnancies come from grade 1 and 2 embryos. Don’t be surprised if a couple of extra embryos appear on this day, some are just “late bloomers”. This may occasionally be embryo transfer day as well.

Day 3: If any embryo has between 5 and 8 cells on this day, it is of good quality. It is also graded on a 1 to 4 scale, with 1 being best quality and 4 being worst. This might be the day of embryo transfer if the embryos are not of great quality or if there aren’t more than 8 embryos.

Day 4: Now the embryo is called a morula, and consists of dozens of cells forming a ball. If that ball of cells is becoming compacted, then it is better quality and more likely to make it to day 5 (blastocyst).

Day 5: Today the embryo consists of over a hundred cells and is called a blastocyst. There are 4 blastocyst stages: 1) early, 2) full, 3) expanded, and 4) hatched. On day 5 most embryos are early or full, but if they are expanded or hatched, then they are of excellent quality. This is the usual transfer day.

Day 6: This is the final day of egg growth in the plastic petri dish. If embryos are going to be frozen, this is usually the day. Only those embryos that are of excellent quality (expanded and hatched) are frozen, as these are the most likely to survive a thaw and create a pregnancy.

You will receive a call each day beginning day 1, usually between 1 and 3 pm, with updates on your embryos.

In general, only 30% of the embryos created on day 1 make it to day 5 or 6 in the plastic petri dish.

 We will make the final decision about which day to transfer your embryos based upon the quality and number of embryos. Initially your plan may be for a day 5 embryo transfer, but will be switched to day 2 or 3 if the embryo quality doesn’t look great. You may also have embryos that look so great that an earlier transfer (days 2 or 3) may be postponed to day 5. Please be prepared for changes during your cycle!