Preface

Infertility affects approximately 15% of couples of reproductive ages, and this percentage keeps increasing. Current infertility treatment through in vitro fertilization (IVF) can achieve approximately 80% of accumulated live birth rates, with even greater rates in young patients and patients who use donor egg IVF. High live birth rates rely on many advanced technologies in infertility treatment, including more accurate clinical diagnosis and patient management as well as state-of-theart IVF technologies. Even though new treatment options are available, there are still many unknown factors affecting laboratory and clinical outcomes and thus improvements are still needed. This book focuses on such topics as recurrent failed embryo implantation, non-invasive preimplantation genetic diagnosis (PGT), oocyte cryopreservation, cryopreservation of small numbers of sperm, and embryo culture technologies.

This book contains thirteen chapters on five topics. The first section includes Chapters 1–5 and discusses recurrent failed implantation. The chapters review the general reasons and mechanisms of recurrent failed implantation, the effects of anatomy abnormalities in the uterus (e.g., fibroids) on infertility, endometrial receptivity in patients with polycystic ovary syndrome (PCOS), and current PGT technologies, emphasizing non-invasive PGT and its benefits to IVF patients.

The second topic includes two chapters related to oocyte cryopreservation. During the past decade, oocyte cryopreservation has been added to humanassisted reproduction technologies and has benefited many women. Chapter 6 reviews and discusses the ethical issues of oocyte cryopreservation, while Chapter 7 reports clinical outcomes of oocyte cryopreservation in different categories of patients.

The third topic includes four chapters. Chapter 8 discusses male infertility and Chapter 9 examines the molecular mechanisms of heavy metals on male infertility, with a focus on sperm capacitation and fertilization. Chapter 10 reviews literature on rare sperm cryopreservation and Chapter 11 presents a very efficient method of cryopreservation of small numbers of spermatozoa.

The fourth topic includes Chapter 12, which discusses the potential role of kisspeptins in human reproduction.

The final topic includes Chapter 13, which reports the authors' research results on different incubators for embryo development and their effectiveness to maintain temperature and pH during embryo culture.

Although this book does not cover all interesting topics in infertility and assisted reproduction, the collected chapters certainly deliver new information and data valuable to clinicians, embryologists, and others in infertility treatment.

I would like to thank the contributors who shared their intellectual and practical laboratory expertise and experiences with infertility treatment and with those who will enter the field in the future. I also want to thank Ms. Jasna Bozic at IntechOpen for her assistance, without which publication of this book would not have been possible.

> **Wei-Hua Wang** Prelude Fertility, Houston, USA
