Why Do We Prefer to Transfer Embryos at the Blastocyst Stage?

Blastocyst Stage

Why Do We Prefer to Transfer Embryos at the Blastocyst Stage?

By Dr. Edouard Servy|May 25th, 2015|

For the first 10 years following the birth of the first IVF baby in 1978, all embryos were transferred two or three days following fertilization. Why? At the time, embryo culture was limited by the simplicity of the available culture media which would not allow growth in the incubator after the third day.

In nature, fertilization takes place inside a woman, or “in vivo,” at the end of the Fallopian tube where the embryo spends the first three or four days of its life. Then it travels for one day, covering a distance of two to three inches, before being expelled into the uterine cavity in the form of a blastocyst that will soon hatch and implant itself in its biological nest.

This meant that the first IVF pioneers had only one option, to place the two or three day embryo in the uterus and hope that Mother Nature would be kind enough to let it grow undisturbed until nesting time arrived. Allowing the embryos to reach the fifth day or blastocyst stage made sense. But, how could we achieve that goal?



We still consider that there are indications for day 3 transfers. On occasion, there are reasons to feel that certain early embryos are not thriving in culture and we must transfer them early under the presumption that they might have a better chance to survive in the maternal incubator. Interestingly, I recently read that more than 50% of IVF centers in this country are still transferring embryos only on day 2 or 3. The reasons given are:

  1. “Less working hours in the lab, saving time and overhead.”
  2. “Lack of trust in the culture media or incubators.”
  3. “Preference for the maternal incubator, which means the uterus.”

At SMFI, whenever possible, we transfer at the blastocyst stage, meaning about 90% of the time. Our embryologists work hard and long hours. They do not hesitate to sacrifice time for better results.

See original blog post here: Transferring Embryos at Blastocyst Stage

About the Author: Dr. Edouard Servy

Dr. Edouard Servy

Edouard Servy, MD, is the founder of Servy Fertility Institute and an expert in infertility treatment, including in vitro fertilization (IVF), hysteroscopic and laparoscopic surgery. He is also trained in Internal Medicine with a focus on Endocrinology and metabolic disease. As a recipient of the highly prized Irene Bernard grant, Dr. Servy came to Augusta, Georgia, in 1969 for a research fellowship under endocrinology pioneers Dr. Robert B. Greenblatt and Dr. Virendra Mahesh. After completing his training, Dr. Servy established his private practice in Augusta. Dr. Servy’s lab was responsible for the first intrauterine insemination and the first IVF-embryo transfer at blastocyst stage in the United States, as well as the first live birth after cryopreservation at the blastocyst stage following ICSI in the world.

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