The difference between quantity and quality
By Gorka Barrenetxea
The contribution of our team to the last ESHRE meeting held in Vienna has included a poster with oral defense entitled “Lack of predictive value of ovarian reserve tests for pregnancy likelihood. The huge difference between quantity and quality”.
Ovarian stimulation is a crucial part of an IVF procedure. The aim of this step of the cycle is to obtain an adequate number of oocytes to have the highest chance to achieve a pregnancy. In cases of low ovarian reserve “adequate” means as many as possible since the possibility of developing an euploid embryos increases. Among normoresponder patients, adequate means also as many as possible (once we are able to avoid ovarian hyperstimulation syndrome thanks to the implementation of agonist trigger).
A lot of different markers have been proposed to predict the number of eggs we can obtain after a given stimulation. Among them, the antral follicle count has been shown (by far) to be the most efficient according to the results of our study.
However, quantity does not mean quality. Thus, the factors capable to predict number of oocytes are not the best ones to predict the likelihood of an ongoing pregnancy. According to our data, age is the factor related to success in terms of pregnancy.
So, predictors of ovarian quantitative response to stimulation (the so called ovarian reserve tests) should not be offered as “fertility tests” since they are not independently related to pregnancy chance, neither after sexual intercourse nor after IVF treatments.