Recurrent pregnancy loss (RPL) is a reproductive disorder defined as two or more successive and spontaneous pregnancy losses (before 20 weeks of gestation), which affects approximately 1-2% of couples. At present, the causes of RPL remain unknown in a considerable number of cases, leading to complications in treatment and high levels of stress in couples. Idiopathic recurrent pregnancy loss (iRPL) has become one of the more complicated reproductive problems worldwide due to the lack of information about its etiology, which limits the counseling and treatment of patients. For that reason, iRPL requires further study of novel factors to provide scientific information for determining clinical prevention and targeted strategies. The aim of this study is to describe the most recent and promising progress in the identification of potential genetic and epigenetic risk factors for iRPL, expanding the genetic etiology of the disease.

Ovarian reserve (OR) is defined as the pool of follicles available to provide eggs cells throughout the fertile age in each woman and define the potential of fertility to predict the reproductive lifespan of women. Several studies have focused on the clinical use in order to identify women with a decreased ovarian function and to improve the clinical approach to these patients. In this chapter we will describe different OR markers such as antimullerian hormone (AMH) and follicle stimulating hormone (FSH), count by ultrasound of antral follicles (AFC) and ovarian volume. The measure of OR markers has been reported as an effective test to predict a possible failure of reproductive capacity and important tool in the primary prevention of infertility and other related problems. Therefore, we will show the clinical use of these markers in both healthy and infertile women studies. Additionally, we describe the most recent and promising progress in the OR evaluation by construction of algorithms.