For more than a decade, we have been screening embryos for chromosomal number abnormalities (aneuploidy) at InVia Fertility Specialists. The technical term used for this process is preimplantation genetic screening (PGS) or pre-implantation genetic diagnosis (PGD). By screening out “abnormal” embryos we are now routinely able to achieve excellent pregnancy rates with transfer of single embryos and thus significantly reducing the incidence of multiple pregnancies. PGD or PGS, thus, is the smart thing to do so much that we have coined the term SMART IVF to describe them.
A common question we get asked about the process is, “How many normal (euploid) embryos will I produce?” Demko et al addressed this very issue in a recent publication. They analyzed the relationship between maternal age and the rate of embryos that tested as euploid, the average number and proportion of normal embryos per IVF cycle and the possibility of retrieving at least one normal embryo.
Results of Study on Age and Number of Eggs Obtained After Preimplantation Genetic Screening
The study analyzed more than 46,000 embryos between 2009 and 2014.
In women aged 27 to 35 years, the median proportion of euploid embryos in each cycle remained constant at approximately 35% in day-3 biopsies and approximately 55% in day-5 biopsies, but it decreased rapidly after age 35.
On average, women in their late 20s had four euploid embryos (day 3 or day 5) per cycle, but this number decreased linearly (R2 R 0.983) after 35 years of age.
The effect of maternal age on the possibility of retrieving at least one normal embryo was similar, with a rapid exponential decline (R2 1⁄4 0.986).
At age 35, at least one euploid embryo can be expected in 85% of all cycles; this percentage drops to approximately 75% at age 40, and to approximately 45% by age 44.
Across all maternal ages, the euploid proportion and number of embryos per cycle were counterbalanced, so the number of euploid embryos per cycle was the same for day-3 and day-5 biopsies. This suggests that the loss of embryos from day 3 to day 5 was primarily due to aneuploidy.
They concluded that (1) 33% to 50% of all embryos screened in women aged 18 to 48 years are aneuploid and (2) the number and percentage of euploid embryos decreases with advancing maternal age.
At InVia Fertility Specialists, we have been offering SMART IVF (PGD or PGS) for many years. Currently, using this technology, we are having pregnancy rates approximating 70% with the transfer of a single embryo.
Dr. Karande is Board Certified in the specialty of Obstetrics and Gynecology as well as the subspecialty of Reproductive Endocrinology and Infertility. He is a Fellow of the American College of Obstetricians and Gynecologists and Member of the American Society for Reproductive Medicine.