Infertility is still a problem with a high prevalence rate in the world at the moment. Infertility affects about 8-12% of couples at reproductive age, and even affects up to 30% of the population in some areas. Statistics show that among married women, the incidence of primary infertility varies in women at different ages. For 15-34 years old women is about 7.3-9.1%, 35-39 years old about 25%, and 40-44 years old is about 30%.

There are many causes of infertility, among which male factors account for about 26%; female abnormal ovulation functions account for 21%, fallopian tube problems account for 14%, endometriosis accounts for 6%, dyspareunia account for 6%, cervix problems account for 3% and other unknown causes account for 28%.

Clinical statistics show that approximate 15-25% of women have experienced miscarriage. Most of the miscarriages occurred before 10 weeks of pregnancy, mainly due to chromosomal abnormality. However, "Recurrent Pregnancy Loss (RPL)” is a different disease. Recurrent Pregnancy Loss is defined as having more than two miscarriages. Among them, about 5% of women have experienced miscarriages two times, and only 1% have experienced more than three times.

There are many causes of Recurrent Pregnancy Loss, including genes, age, antiphospholipid syndrome (APS), thrombophilias, hormone or metabolic disease, infection, autoimmunity, sperm quality, lifestyle and other issues. Here we mainly include three articles with representative clinical treatment guidelines (2017 European Society of Human Reproduction and Embryology, ESHRE; 2013 American Society for Reproductive Medicine, ASRM; and 2011 Royal College of Obstetricians and Gynaecologists, RCOG) to integrate and discuss factors and treatment guidelines of Recurrent Pregnancy Loss.

Infertility patients with recurrent pregnancy loss have always been a huge challenge in the field of reproductive medicine. Experts have been finding the factors that may cause recurrent pregnancy loss, and actively want to increase the success rate of pregnancy. Among the factors, thrombosis and autoimmunity are two important factors of infertility. We now pursue evidence-based medicine and require evidence in every decision making, however each patient is an independent individual.

Under evidence-based and precision medicine, how should we strike a balance to find out the real causes of each infertility patient and seek the best treatment strategy?

Facing each client's condition cautiously, actively observing the treatment process, finding the best treatment policy and humbly consulting experts in various fields are the directions we strive for. Only in this way can we have the chance to break through the dilemma of reproductive medicine.