With a successful egg retrieval behind me, I am now realizing that the real pain in the IVF process isn’t the retrieval, or the nightly injections, or the side effects – it’s the waiting. After the eggs are retrieved, there are three major milestones that must be reached: Fertilization, Cleavage, and Blastocyst. This progression takes place over just five to seven days, but the waiting feels like an eternity as each passing day brings another progress report from the embryology lab regarding the fate of your embryos. Without further ado, here are the results of our first IVF waiting game.
Fertilization: After the eggs are retrieved, the first milestone is fertilization. Although the ICSI method* of fertilization has improved success rates overall, not all eggs will successfully fertilize. The average success rate for ICSI fertilization is ~70%.
*If you recall from this post, ICSI is a fancy way of saying “inject sperm into egg.” The procedure isolates a single healthy sperm in an andrology lab and then injects that sperm directly into the egg. Due to its extremely high success rates, our IVF clinic only uses the ICSI method of fertilization.
Our Results: Out of the 6 eggs retrieved, 5 eggs were mature and 4 eggs fertilized via ICSI. This gives us an 80% fertilization rate, which is above the average. Dr. M. is pleased with this and so are we. 🙂
Cleavage Stage – Day 3 Progress Report: Once fertilized, the eggs are now embryos and continue their development in incubation within an embryology lab. After growing for three days, the embryos are referred to as “cleavage stage” embryos, as the cells in the embryo are dividing (or cleaving) but the embryo itself is not growing in size. Day 3 embryos are observed under a high-power microscope to determine their viability of successfully progressing to a “blastocyst” stage embryo. Typically, a normally growing day 3 embryo will contain between 6 and 10 cells.
Our Day 3 Results: Out of our 4 fertilized embryos, 3 have progressed to 8 cells. Unfortunately, our fourth embryo is still only at 4 cells and will most likely be out of the running. Out of the 3 that are successfully progressing, we received the following percentages for blastocyst success: 59%, 63%, 70%. Dr. M. says that these are excellent results and a very good indicator of the embryos’ overall genetic complements. We are very happy! 🙂
Blastocyst Stage – Day 5 Progress Report: After day three, embryos continue their development in incubation until they reach “blastocyst” stage, which typically occurs on day five or day six. Blastocyst embryos are comprised of over 200 cells and have an inner and outer mass. Although each person is different, only about 50% of embryos will progress to the blastocyst stage in incubation. According to Advanced Fertility, this high attrition rate is due to the inherent “weakness” of human embryos and the artificial environment of the incubation.
So why push the embryos to day 5 of development if it may mean that over half won’t survive? AF states: “The goal of in vitro fertilization and embryo culture is to provide high quality embryos which are capable of continued development and result in live births. By culturing embryos to day 5 we will find that some of them have not become blastocysts – allowing us an opportunity to choose the most competent embryos for transfer.”**
In this way, developing an embryo to blastocyst stage allows a natural “weeding out” process of the most viable embryos for pregnancy. Although we are prepared to lose some, we know that what remains will be better suited for transfer.
**(please note that all IVF cycles are different. Your RE may recommend a “day 3” embryo freeze or transfer for various reasons.)
Once an embryo has reached blastocyst stage, it can be transferred to a woman’s body for implantation or it can be safely biopsied for genetic screening. We are doing the latter, since it’s precisely the reason we are undergoing IVF. The genetic screening occurs by carefully removing one cell from the embryo and placing that cell on a slide for testing. The embryo is then frozen via cyropreservation via the vitrification technique (basically what Darth Vader does to Hans Solo in Star Wars: the Empire Strikes Back).
Our Results: Unfortunately, “Day 5” for our little embryos occurred over the weekend, so we had to wait until Monday to find out how many made it — nothing like throwing in a nice weekend cliffhanger to this already tedious time! To distract ourselves, we travelled to Philadelphia for the weekend to visit with friends and celebrate our three little embryos still in the running, who we had started to refer to as “Huey, Dewey, and Louie.”
On Sunday we returned back to N.Y.C. and on Monday we received our final report: Out of the 3 embryos we were tracking, FOUR had made it to blastocyst stage. We were shocked, as we had initially been told that the fourth was out of the running, but apparently the little fighter had caught up to its siblings.
“Huey, Dewey, Louie…and Stewie?” We’ll take it! 🙂
Dr. M. told us that she was very happy with these results. Although I only produced 5 mature eggs, FOUR made it through all the hurdles to blastocyst stage. She said that often out of 20 eggs only 4 will be left at blastocyst stage – so I feel very good about the quality of our embryos and our lack of any major drop off.
Our next steps are to send the biopsied cells to Reproductive Genetic Innovations in Chicago. This is the genetic lab that our clinic uses for its PGD and PGS testing. We will be testing for the genetic disease we are trying to avoid first (via PGD), then based on those results we will test the remaining embryos for chromosomal abnormalities (via PGS). Unfortunately, this entire process involves several weeks of (you guessed it) waiting, as the lab has to finish making our special probe for the genetic testing.