Gonadotropin stimulation demonstrates a ceiling effect on in vitro fertilization outcomes

Area of Science:

• Reproductive Endocrinology
• In Vitro Fertilization
• Clinical Embryology

Background:

• In vitro fertilization (IVF) outcomes are influenced by various factors, including oocyte yield and embryo development.
• Optimizing IVF protocols is crucial for improving pregnancy rates and patient success.

Purpose of the Study:

• To investigate the impact of oocyte retrieval numbers and the quantity of two-pronuclei (2PN) embryos on clinical pregnancy rates in IVF.
• To identify optimal thresholds for oocyte yield and 2PN embryo development for different age groups.

Main Methods:

• Retrospective analysis of data from 467 reproductive-aged women undergoing their first fresh nondonor IVF cycle.
• Evaluation of clinical pregnancy rates as the primary outcome measure.

Main Results:

• Clinical pregnancy rates peak around age 30 and decline linearly thereafter.
• For women under 37, peak rates were associated with retrieving 20 oocytes, developing five 2PN embryos, and transferring no more than two embryos.
• For women aged 37 and older, peak rates were linked to retrieving ten oocytes, developing ten 2PN embryos, and transferring no more than two embryos.

Conclusions:

• The number of oocytes retrieved and 2PN embryos developed significantly impacts IVF success.
• Age is a critical factor, necessitating different optimal thresholds for oocyte yield and 2PN embryo development.
• Transferring no more than two embryos is consistently associated with higher clinical pregnancy rates across age groups.