Home-based monitoring of ovulation to time frozen embryo transfers in the Netherlands (Antarctica-2): an open-label, nationwide, randomised, non-inferiority trial

High-impact journal publishing: the devil is in the detail!

Research in medicine is an indispensable tool to advance knowledge and improve patient care. This may be particularly true in the field of human reproduction as it is a relatively new field and treatment options are rapidly evolving. This is of particular importance in an emerging field like 'human reproduction', where treatment options evolve fast.The cornerstone of evidence-based knowledge, leading to evidence-based treatment decisions, is randomized controlled trials as they explore the benefits of new treatment approaches. The study design and performance are crucial and, if they are carried out correctly, solid conclusions can be drawn and be implemented in daily clinical routines. The dissemination of new findings throughout the scientific community occurs in the form of publications in scientific journals, and the importance of the journal is reflected in part by the impact factor. The peer review process before publication is fundamental in preventing flaws in the study design. Thus, readers of journals with a high impact factor usually rely on a thorough peer review process and therefore might not question the published data. However, even papers published in high-impact journals might not be free of flaws, so the aim of this paper is to encourage readers to be aware of this fact and critically read scientific papers as 'the devil lies in the details'.

Modified natural cycle allows a window of 7 days for frozen embryo transfer planning

RESEARCH QUESTION

Should ovulation be triggered in a modified natural cycle (mNC) with recombinant human chorionic gonadotrophin (rHCG) as soon as a mean follicle diameter of 17 mm is visible, or is more flexible planning possible?

DESIGN

This multicentre, retrospective, observational study of 3087 single frozen blastocyst transfers in mNC was carried out between January 2020 and September 2022. The inclusion criteria included endometrial thickness ≥7 mm and serum progesterone <1.5 ng/ml. The main outcome was ongoing pregnancy rate. Secondary end-points were pregnancy rate, implantation rate, clinical pregnancy rate and miscarriage rate. The mean follicle size at triggering was stratified into three groups (13.0-15.9, 16.0-18.9 and 19.0-22 mm).

RESULTS

The baseline characteristics between the groups did not vary significantly for age, body mass index and the donor's age for egg donation. No differences were found in pregnancy rate (64.5%, 60.2% and 57.4%; P = 0.19), clinical pregnancy rate (60.5%, 52.8% and 50.6%; P = 0.10), implantation rate (62.10%, 52.9% and 51.0%; P = 0.05) or miscarriage rate (15.0%, 22.2%; and 25.0%; P = 0.11). Although ongoing pregnancy rate (54.9%, 46.8% and 43.1%; P = 0.02) varied significantly in the univariable analysis, it was no longer significant after adjustment for the use of preimplantation genetic testing for aneuploidies and egg donation.

CONCLUSIONS

The findings showed rHCG could be flexibly administered with a mean follicle size between 13 and 22 mm as long as adequate endometrial characteristics are met, and serum progesterone is <1.5 ng/ml. Considering the follicular growth rate of 1-1.5 mm/day, this approach could allow a flexibility for FET scheduling of 6-7 days, simplifying mNC FET planning in clinical practice.