Navigating IVF: A Young Couple’s Journey to Conception – ARC Summit

In this example, we consider a 25-year-old undergoing in vitro fertilization (IVF). Due to her age and likely high ovarian responsiveness, she might produce between 15 to 20 oocytes. However, not all oocytes will be mature; typically, we might expect 13 to 18 of these to reach the mature metaphase 2 (M2) stage. These are then fertilized either through conventional methods or by intracytoplasmic sperm injection (ICSI).

The fertilization rate for such procedures generally ranges from 60 to 70%, resulting in about 9 to 14 zygotes or day-one embryos. Tracking the development of these embryos, by day two, we usually see four-cell embryos; by day three, these progress to six to eight cells. By days five to seven, ideally, we achieve a blastocyst consisting of 60 to 80 cells. However, it’s important to note that not all zygotes will develop into blastocysts—only about 50% reach this stage, partly due to potential anomalies in the sperm or egg involved.

Many couples inquire about the possibility of testing eggs and sperm for chromosomal normality before fertilization to determine the best candidates for fertilization and injection. Unfortunately, such testing is not feasible because the process would destroy these single cells.

The viability and chromosomal integrity of embryos are typically assessed through preimplantation genetic diagnosis (PGD). This involves biopsying five to seven cells from the trophectoderm, the outer layer of a blastocyst that develops into the future placenta. This biopsy helps determine whether an embryo is chromosomally normal, guiding decisions on embryo selection for implantation.