Blastocyst Transfer and Assisted Hatching at WCFC
In a standard IVF cycle, an embryo is cultured for three days prior to being transferred. With a blastocyst culture, the culture is extended for an additional two days to track further progress of the developing embryo. The longer the embryo is cultured in the laboratory, the longer one of our highly experienced embryologists will have to monitor its growth and potential for an embryo transfer. There is a great deal of research that supports the fact that embryos that can't survive to blastocyst stage have a high occurrence of chromosomal abnormities which would result in miscarriage or no pregnancy at all. Blastocyst culture is demanding and requires special skills in sequential media handling. Because the needs of a blastocyst are unique, a highly qualified scientist and meticulous laboratory conditions are essential. Our team of embryologists have 20 years experience performing this advanced procedure. Since only the hardiest embryos will survive 5 days of lab culture, a patient must produce at least 6 embryos on the third day of development so that about one-half will survive until blastocyst formation.Typically, 2 blastocyst stage embryos are transferred and if surplus ones remain, they can be frozen. Patients with very few available embryos are best served by transferring on day 2 or 3. In cases of unexplained infertility or multiple failed IVF attempts, blastocyst culture may be the only way to counsel our patients about future attempts.
Introduced in the 1990s, assisted hatching is a procedure that may help to improve your chances of a successful IVF outcome. It is specifically recommended for couples who are most at risk of poor IVF outcomes.
It is performed to help an embryo hatch out of its protective outer layering (zona pellicuda) and implant into the uterus. The zona pellicuda protects the embryo until it reaches the blastocyst stage of development. Successful implantation into the uterine lining requires the embryo to hatch out of the zona pellicuda and attach to the walls of the uterus. Sometimes the zona pellicuda is too thick and the embryo does not have enough energy to hatch out of this layer. Assisted Hatching helps these embryos hatch out from the zona pellicuda by creating a small opening in this outer layering.
Assisted hatching is a delicate procedure performed using micromanipulation techniques, under a microscope on second or third day of embryo development. The embryo is placed in a Petri dish containing buffered culture media under oil. A holding pipette is then used to keep the embryo in place. The embryologist maneuvers the embryos until a large gap of space (periventilline space) is seen between the zona and embryo's cells. The PZD needle is threaded into one side of the zona and out the other side without damaging the embryo. A slit in the zona where the needle was threaded, is the end result. The embryo is then rinsed in culture media and placed back into the incubator until the embryo transfer takes place.
Only an embryologist can determine which embryos qualify for hatching, by observing the embryos shape and zona characteristics during embryo culture. The following conditions may indicate when assisted hatching is recommended:
- Patients over the age of 37
- Women with elevated FSH on day 3 of their menstrual cycle
- Couples with failed IVF cycles
- Couples embryos with exceptionally thick zona pellicudas.