P-655 Live birth rate in the fresh cycle associated with number of oocytes in ovarian stimulation with individualised follitropin delta: an individual patient data meta-analysis
Authors: Pinborg A , Engberg Jepsen I , Falahati A , Moley K , Santos-Ribeiro S , Macklon N  S , Lobo R 
Published: July 2024

Abstract

Study question
What is the optimum number of oocytes retrieved to achieve a live birth for women undergoing ovarian stimulation with individualised follitropin delta?

Summary answer
The live birth rate (LBR) in the fresh cycle was highest in the range of 8-14 oocytes retrieved, peaking at 11 oocytes.

What is known already
The number of oocytes retrieved following ovarian stimulation for assisted reproductive technologies is regarded a prognostic marker of pregnancy outcome, where high numbers increase chances of live birth but also the risk of complications, especially ovarian hyperstimulation syndrome (OHSS). Thus, an optimum range of oocytes retrieved is essential. Still, there is no consensus regarding this range in fresh cycles. Optimum numbers between 6 and 15 oocytes have been suggested, taking the risk of OHSS into consideration. The individualised dosing algorithm for the recombinant follicle-stimulating hormone follitropin delta has a target range of 8–14 oocytes.

Study design, size, duration
Individual patient data meta-analysis of 1772 patients from 5 randomised controlled trials using individualised dosing of follitropin delta for ovarian stimulation, with fixed daily dosing based on serum anti-Müllerian hormone (AMH) and body weight. The analysis included patients with ≥1 oocyte retrieved. Outcomes of LBR and OHSS in the fresh stimulation cycle were evaluated in relation to number of oocytes retrieved. Subgroup analyses were performed based on age, AMH and number of oocytes retrieved.

Participants/materials, setting, methods
Participants were women, 18–42 years, undergoing first or second in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) cycle in a GnRH antagonist/long agonist protocol with human chorionic gonadotrophin or GnRH agonist triggering and IVF/ICSI. Single or double embryo/blastocyst transfer was performed on Day 3/5. All pregnancies were followed until birth. Predicted live birth was obtained using a logistic regression analysis with fractional polynomials to assess the association between number of oocytes retrieved and live birth.

Main results and the role of chance
The studied population (n = 1772) had a mean age of 32.6 years and median AMH of 17.7 pmol/l. Mean number of oocytes retrieved was 10.4, the LBR was 32.1% and the OHSS rate (any grade and onset) was 6.6%. The LBR steadily increased with the number of oocytes retrieved up to a plateau starting at 8 oocytes, with a LBR above 34% in the range of 8-14 oocytes retrieved, peaking at 34.9% for 11 oocytes. Beyond 14 oocytes, LBR gradually declined. By number of oocytes (grouped), the LBR was 27.8%, 33.6% and 30.9% at 1-7, 8-14 and ≥15 oocytes. In patients with embryo transfer, corresponding rates were 32.8%, 37.2% and 38.7%. In the subgroup analyses, LBR decreased with increasing age (32.7%, 30.7% and 23.4% at &lt; 35, 35-37 and 38-42 years) while it was similar for AMH &lt;15 and ≥15 pmol/l (30.4% and 31.3%, respectively). LBR was highest at 8-14 oocytes in patients &lt;35 years (28.0%, 36.2% and 32.4% at 1-7, 8-14 and ≥15 oocytes), while it was consistently low (&lt;26%) in patients 38-42 years, irrespective of number of oocytes retrieved. The OHSS rate (any grade) increased from 2.1% with 1-7 oocytes, to 5.2% with 8-14 oocytes and 17.0% with ≥15 oocytes.

Limitations, reasons for caution
A limitation of this study is the small number of patients with &gt;20 oocytes retrieved in the studied population.

Wider implications of the findings
The current individual patient data meta-analysis suggests an optimum range of 8-14 oocytes retrieved to achieve a live birth in fresh cycles with follitropin delta. Furthermore, the analysis demonstrates a marked increase in OHSS rate from 15 oocytes retrieved. The results support the appropriateness of individualised follitropin delta dosing regimen.

Trial registration number
NCT01956110, NCT03228680, NCT03296527, NCT03564509, NCT03809429