Some researchers and clinicians believe embryo morphology and development characteristics can be used to assess the viability of IVF embryos to increase chances of a successful pregnancy.
Healthy embryos, i.e. the most viable zygotes that will develop into blastocysts and further seem to follow a specific growth pattern between development day 3 and re-implantation on day 5:
Growth from 2 to 3 cells should be seen in 9 – 11 hours, from 3 to 4 cells in under 2 hours. Reaching day 5 is a critical as the embryo will be re-implanted into the uterus and will attach to the endometrium. The normal development process is shown in figure 1 (source: CMFT NHS):
Embryo morphology is graded on a scale of 1 to 5 as shown in fig 2 (source: CMFT NHS):
Embryo cell division can be monitored through the use of an “embryoscope”, an incubator with integrated camera. Time-lapse pictures are analysed by an embryologist to help select viable embryos. Systems that help the monitoring process are e.g. the “Early Embryo Viability Assessment” (Eeva) software by Auxogyn.
Cell tracking and embryo assessment with Eeva (YouTube)