The impact of age and number of oocytes retrieved on the cumulative live birth rate in women with poor ovarian response: A 15-year study.

Background: Approximately 15 % of women undergoing assisted reproductive treatment (ART) fall in the category of poor ovarian reserve defined as the retrieval of three or fewer oocytes following conventional ovarian stimulation with a daily gonadotrophin dose of 150-450 international units, according to the Bologna criteria. Low number of oocytes collected is, therefore, likely to translate to low chance of successful ART treatment.

Objectives: The objective of the study was to assess if age and number of oocytes retrieved influence the cumulative live birth rate (LBR) in women with poor ovarian response (POR) to controlled ovarian hyperstimulation.

Study Design: We have used anonymised, prospectively collected data spanning July 2004 until June 2019 on consecutive in vitro fertilisation (IVF) and intra-cytoplasmic sperm injection (ICSI) cycles performed at a tertiary fertility treatment unit. Women who underwent conventional ovarian stimulation with a starting daily gonadotrophin dose of 150-450 IU in their first or second IVF cycle where 1-3 oocytes were retrieved were included in the study, with women where four oocytes were retrieved formed a comparative control group. Only one cycle per patient was included.

Results: A total of 2,516 fresh IVF or ICSI cycles were analyzed. The overall clinical pregnancy and LBR in the cohort of included women were 16.4 % and 12.6 % respectively. The cumulative LBR per patient included was 13.1 %. When adjusting for age, treatment type, FSH at baseline, and daily gonadotrophin dose, a significant increase in cumulative LBR was observed for two (OR 2.63, 95 % CI 1.43-4.81), three (OR 3.74, 95 % CI 2.09-6.68) and four (OR 5.3, 95 %CI- 3.01-9.35) oocytes collected, compared to one oocyte only. A significantly lower chance of successful outcome was noted in women 43-45 years old versus younger age groups, irrespective of number of oocytes collected.

Conclusions: In this large cohort of women with POR, both age and number of oocytes retrieved are independent factors influencing the cumulative LBR after IVF treatment. Irrespective of age, retrieval of one additional oocyte is associated with an increase in the cumulative LBR per oocyte retrieval.