Medical research and reproductive medicine in an ethical context: a critical commentary on the paper dealing with uterine lavage published by Munné et al.

A recent study published in Human Reproduction claimed that uterine lavage offers a non-surgical, minimally invasive strategy for the recovery of human embryos from fertile women who do not want or need IVF for medical reasons but who desire preimplantation genetic testing (PGT) for embryos. To prove this hypothesis, the researchers recruited dozens of young Mexican women. The prospective oocyte donors underwent ovarian stimulation to induce the production of multiple mature oocytes. Subsequently, these women were inseminated by donor semen. A few days later, the developing embryos were collected by uterine lavage (uterine flushing) and subjected to genetic testing for aneuploidies (PGT-A). Oocyte donors with persistently elevated hCG levels, indicating the implantation of one or more embryos after uterine lavage, had to undergo uterine curettage and/or treatment with methotrexate. A critical opinion paper discussing the aforementioned study was published by De Santis and colleagues and has raised critical issues that are largely technical in nature. However, this opinion paper neglects-from our point of view-critical issues of the Mexican study regarding ethical principles and moral standards in human research. These aspects are summarized below.

Determinants of cumulative ART live-birth rates in a single-center study: age, fertilization modality, and first-cycle outcome.

PURPOSE: To analyze cumulative and single-cycle success rates of IVF and intracytoplasmic sperm injection (ICSI) separately in relation to female age, fertilization modality, and first-cycle outcome. METHODS: The study involved 2997 patients and couples, respectively, who underwent 5339 fresh and 3006 cryo cycles using pronuclear-stage oocytes. Fertilization was achieved by the conventional IVF or ICSI. Because of legal restrictions in Germany, no embryo selection was performed. All cycles were documented prospectively. Kaplan-Meier survival rates were calculated for all treatment cycles and transferred embryos. RESULTS: Essentially, the success of assisted reproductive technology (ART) depends on a woman's age and on skilful counselling. Cumulative pregnancy and live-birth rates are the best indicators of successful ART. Probably for the first time, we determined these cumulative rates separately for IVF and ICSI, and found them to be almost identical. Live-birth rates reached 70-95 %, except for women aged over 40 years, whose chances of life birth are limited to about 25 %. Live-birth rate per retrieval was 25.61 % for IVF and 26.3 % for ICSI. Time to pregnancy was shorter for women who underwent a successful treatment in their first cycle. CONCLUSIONS: The primary intention for the choice of fertilization modality between IVF and ICSI is the prevention of a relative or total fertilization failure. Such treatment failure is best prevented through ICSI, which results in slightly higher clinical pregnancy rates per started cycle. After embryo transfer, there are no differences in the success rates of IVF and ICSI. The supposed cumulative live-birth rates are useful as a basis for counselling subfertile couples to help reduce the high discontinuation rate, which is still the main reason for inefficacy in ART. Following an unsuccessful first treatment cycle, the prognosis remains positive, but until success is achieved, more treatment cycles are necessary.