Your Embryos First 5 Days.

How do you know that Dominion Fertility’s IVF lab is A+?

One of the most important keys to success in any IVF cycle is the work that happens in the lab following the egg collection and fertilization. We are fortunate to have an outstanding IVF lab that contributes to our high success rates including a stunning 41 positive pregnancy tests in 49 frozen-thawed embryo transfers (FET) in January, 2019.




Day 0 is the day of the egg collection. The actual egg retrieval procedure is done under light sedation in our Arlington office. During IVF, we use fertility injections to stimulate extra follicles, usually ending up with 10-18 eggs.  Some women produce very few follicles [decreased ovarian reserve], and others produce many follicles [PCOS patients].

The eggs are fertilized on day 0.  In most of our IVF cycles, we utilize Intracytoplasmic Sperm Injection or ICSI which is a fertilization technique involving injecting a single sperm into each egg using a thin glass needle.

On day 1, our excellent team of embryologists examines every egg retrieved the previous day to check for fertilization. Eggs that fertilize normally will possess 2 distinct circles located within the interior of the egg…one of these is the genetic material (pronucleus or PN) from the egg and the other pronucleus is from the sperm. We call this normally fertilized egg a 2 PN egg.

The fertilized egg then starts dividing.  By day 2 it is 4 cells and by day 3 it is 6-10 cells (see 8 cell embryo below).

By day 5 the embryo should now consist of hundreds of cells organized into a hollow ball or blastocyst. The outer rim of cells are called the trophectoderm and these will ultimately become the placenta while the inner cell mass cells will become the fetus.

Not all day 3 embryos will grow to a blastocyst.  In general, about 50% do reach the blastocyst stage.

Fresh or Frozen Embryo Transfer – Which is Best?

Here are some points to consider.

1.     All PGT-A cycles are freeze all cycles. Patients electing to have PGT-A to check their embryos for aneuploidy need to defer a fresh transfer since the PGT-A results are not available until about a week after the embryo biopsy that is performed on Day 5 or Day 6 of IVF.

2.     All IVF cycles at Dominion are freeze all cycles. IVF results in an endometrium (uterine lining) that may be less than ideal because of the high estrogen levels and the significant drop in estrogen levels that occurs following an egg collection. This drop in estrogen can be especially profound in IVF using a Lupron trigger.

At Dominion Fertility we are focused on helping our patients attain a successful outcome and we remain innovative and flexible providing the widest range of treatment options.