Study finds trigger-day LH threshold tied to better IVF outcomes

Researchers at Guangzhou Medical University identified 1.6 IU/L as a key luteinising hormone threshold on the day ovulation is triggered in IVF and ICSI cycles. The study found higher live birth and pregnancy rates above that level, offering fertility clinics a data-backed way to refine hormone management.

Why it matters: - Fertility clinics often adjust hormone levels during IVF and ICSI to improve the chance of implantation and live birth. - The study offers a specific trigger-day luteinising hormone threshold that could help specialists individualize ovarian stimulation protocols. - Better LH targeting may improve outcomes for patients undergoing assisted reproduction.

What happened: - A Guangzhou Medical University research team led by Dr. Jianqiao Liu and Dr. Haiying Liu studied LH levels on the day ovulation was triggered. - The retrospective cohort study was published Jan. 8, 2025 in BJOG: An International Journal of Obstetrics & Gynaecology. - The analysis covered 6,107 IVF and intracytoplasmic sperm injection embryo transfer cycles from the Third Affiliated Hospital of Guangzhou Medical University. - The cycles ran between January 2018 and February 2023.

The details: - The researchers used statistical methods to let the data identify the most meaningful LH cutoff instead of relying on preset definitions. - The study identified 1.6 IU/L as the key threshold on trigger day. - Patients at or below 1.6 IU/L were placed in the low LH group. - Patients above 1.6 IU/L were placed in the high LH group. - The high LH group had a 42.9% live birth rate, compared with 36.9% in the low LH group. - Ongoing pregnancy rates and clinical pregnancy rates were also higher in the high LH group. - The high LH group produced fewer oocytes on average. - Dr. Liu said the result may reflect the importance of oocyte and embryo quality over quantity. - The team found that higher LH was linked to lower progesterone levels on trigger day. - Lower progesterone may support a more receptive uterine environment for implantation. - The paper’s title is "Optimising Luteinising Hormone Levels on Trigger Day for Improved Ovarian Response and Pregnancy Outcomes in Gonadotropin-Releasing Hormone Antagonist Protocols: A Retrospective Cohort Study." - The DOI is 10.1111/1471-0528.18064.

Between the lines: - The study addresses a long-running problem in reproductive medicine: past LH studies used inconsistent cutoffs, which made results hard to compare. - A data-driven threshold may give fertility doctors a more practical way to stratify patients before embryo transfer. - The findings also reinforce that hormone balance may matter as much as egg yield in assisted reproduction.

What's next: - The researchers said further work could help optimize fertility treatments and improve the odds of successful pregnancies and healthy births. - Fertility specialists may use the threshold as one more input when adjusting ovarian stimulation and LH management. - Additional studies will be needed before the approach becomes routine across ART programs.

The bottom line: - A trigger-day LH level above 1.6 IU/L was associated with better IVF and ICSI pregnancy outcomes in this study, pointing to a more precise way to manage fertility treatment.