Oocyte count at retrieval as predictor of pregnancy rate in different age groups in the Indian population

Abstract

Background: An important consideration while planning in vitro fertilization (IVF) is whether an age-specific oocyte number can predict treatment success. Identifying such thresholds may aid counselling regarding embryo pooling and the need for donor oocytes.

Methods: This retrospective, multicentric, cross-sectional study was conducted at Nova Fertility and IVF Clinics across India. Women aged 21-50 years undergoing IVF between August 2019 and July 2024 who met the inclusion and exclusion criteria were included. A total of 1994 patients were enrolled: 149 aged 21-25 years, 580 aged 26-30 years, 813 aged 31-35 years, 381 aged 36-40 years, and 71 aged >40 years. Clinical pregnancy rates were evaluated across age groups and varying mature oocyte (MII) yields using appropriate statistical methods.

Results: Total oocyte retrieved declined with advancing age, whereas the median number of mature oocytes remained relatively stable. The minimum MII oocyte number associated with successful outcomes decreased with increasing age: 9.5 at 21-25 years age, 7.5 at 31-35 years, and 4.5 at 36-40 years, increasing to 5.5 in women >40 years. There was a non -linear relation between age, oocyte yield and clinical pregnancy outcomes, with most favourable outcomes in women aged 26-35 years and low success rates at the extremes of reproductive age (<25 years and >36 years).

Conclusions: Although the mature oocyte number associated with successful IVF outcomes varies with age, oocyte number alone does not determine success. Thus, individualized counselling remains essential.