WHAT IS BLASTOCYST?
Typically, embryos from in vitro fertilization are transferred back into a woman’s uterus at the 4- to 8-cell stage two to three days after egg retrieval. On average, close to one-half of 4 to 8 cell embryos at day 2 or 3 are chromosomally abnormal. By culturing these embryos for an additional 2 to 3 days, more chromosomally normal embryos will be selected out naturally and developed to the blastocyst (5-day- old) stage in the laboratory. Usually, only the best embryos can grow to the blastocyst stage and the pregnancy rate per blastocyst transferred is better than 3-day- old embryos.
IS BLASTOCYST TRANSFER PREFERABLE TO A DAY 3 EMBRYO?
Blastocyst transfer allows the option of single embryo transfer. This is particularly helpful to reduce the chance of multiple pregnancies and reduce the rate of miscarriage. Any couple wishing to avoid the chance of multiple for any reason may choose single blastocyst transfer. However, blastocyst culture has a significant increased risk of no embryo transfer due to arrest of embryonic development before reaching blastocyst stage.
“EVEN MIRACLES TAKES A LITTLE TIME.”
IS BLASTOCYST AN OPTION FOR ALL IVF PATIENTS?
Blastocyst transfer is not an option for all IVF patients. It is not suitable when there are less than three viable good quality embryos available. The technique is most successful with patients who are younger and have many eggs available at retrieval.
WHAT ARE THE ADVANTAGES OF BLASTOCYTS TRANSFER?
In natural conception, fertilized eggs do not enter the uterus until five days after fertilization. Some reports suggest that blastocyst transfer may be helpful for some women with multiple failed cycles, since the uterus may be more receptive five days after retrieval and because the uterus is contracting less frequently, therefore being less likely to expel the blastocysts. Another advantage of developing all embryos to the blastocyst stage is that it makes embryo cryopreservation (freezing) more efficient, since embryos without the capacity for full development are not frozen.