Estudio de la fisiopatología de la luteinización precoz mediante la comparación de diversos marcadores en un modelo de donación de ovocitos

Introduction

Approximately 50% of infertile couples that wish to have children will need assisted reproductive techniques involving ovarian stimulation. This technique affects oocyte and embryo quality through the development of follicles of different sizes and functional stages, thus creating hormonal patterns that differ from the natural follicular cycle. Many researchers employ the term premature luteinisation to describe the case of patients who, in cycles of ovarian stimulation, present with higher levels of progesterone (P) when ovulation is triggered. However, the pathophysiological effect of this elevation is uncertain. This study examines the pathophysiology of premature luteinisation, analysing its influence on oocyte quality.

Material and methods

A comparison is made of the outcomes for donated oocytes, according to whether they were obtained from ovarian stimulation cycles with or without premature luteinisation, as defined by the following markers: index of prolonged P luteinisation; P/number of follicles; P/oestradiol; and P/oocytes. In addition, a stepwise linear regression model was constructed, in which the dependent variable was levels of P when ovulation was triggered, and the candidate variables, the follicular markers shown to be significant in univariate regression analysis.

Results

No differences in pregnancy rates were recorded when the embryos were obtained from cycles with or without premature luteinisation, regardless of the marker considered. After fitting a stepwise multiple linear regression model for the dependent variable P when ovulation was triggered, the variables included in the model were P/number of follicles and the number of follicles.

Conclusions

It is concluded that the premature luteinisation observed in cycles of ovarian stimulation seems to be the consequence of the growth of multiple follicles, on the one hand, and of the development of ovarian follicles that have a metabolic pattern which differs from that of natural cycle follicles, on the other. It is also concluded that high levels of P are not prejudicial to oocyte quality and that their negative effect on the results of assisted reproduction could arise in the endometrium.