生育力下降现状的生殖医学对策——生育力保存

Reproductive Strategies for Declining Fertility:Fertility Preservation

全球育龄人群呈现生育力下降趋势,人类生育问题面临巨大的挑战,生育力保存技术应运而生。生育力保存,即针对因恶性肿瘤放化疗及其他一些影响生育的疾病,为患者保存生育能力。本文从生育力保存现状、生育力保存方法和应用、儿童的生育力保存、生育力保存的实施这4个方面,对生育力保存作一综述。人类生育力保存主要应用于早期及预后良好的年轻及儿童肿瘤患者,影响性腺功能的慢性疾病和环境暴露因素。生育力保存的方法包括女性的卵母细胞冷冻、胚胎冷冻和卵巢组织冷冻,和男性的精子冷冻和睾丸组织冷冻。青春期前的儿童只能采取卵巢组织冷冻或睾丸组织冷冻。当患者有生育需求时,复苏冷冻的精子进行辅助生育,复苏冷冻的胚胎或复苏冷冻的卵母细胞体外受精后的胚胎进行胚胎移植,或者复苏冷冻的性腺组织进行自体移植,实现其生育后代的目的。生育力保存为人类生育提供新的方法,应遵循伦理原则,充分保障患者及其子代的权益。

There is a global trend of declining fertility among people of childbearing age and mankind is confronted with great challenges of fertility problems.As a result,fertility preservation technology has emerged.Fertility preservation involves interventions and procedures aimed at preserving the patients’chances of having children when their fertility may have been impaired by their medical conditions or the treatments thereof,for example,chemotherapy and/or radiotherapy for cancer.The changes in patients’fertility can be temporary or permanent damage.Fertility preservation can help people diagnosed with cancer or other non-malignant diseases.More and more fertility preservation methods are being used to preserve the fertility of cancer patients and protect their reproductive organs from gonadotoxicity.Fertility preservation may be appropriate for young patients with early-stage cancers and good prognosis before they undergo treatments(chemotherapy and/or radiotherapy)that can negatively affect their fertility.It is also appropriate for patients with chronic conditions or those who have encountered environmental exposures that affect their gonadal function.Fertility preservation methods include oocyte cryopreservation,embryo cryopreservation,and ovarian tissue cryopreservation(OTC)for women and sperm freezing and testicular tissue freezing for men.The survival rates of children and adolescents diagnosed with malignant tumors have been steadily increasing as a result of advances in cancer treatments.Cryopreservation of oocytes and sperm is recognized as a well-established and successful strategy for fertility preservation in pubertal patients.OTC is the sole option for prepubertal girls.On the other hand,cryopreservation of immature testicular tissue remains the only alternative for prepubertal boys,but the technology is still in the experimental stage.A review showed that the utilization rate of cryopreserved semen ranged from 2.6%to 21.5%.In the case of cryopreserved female reproductive materials,the utilization rate ranged from 3.1%to 8.7%for oocytes,approximately from 9%to 22.4%for embryos,and from 6.9%to 30.3%for ovarian tissue.When patients have needs for fertility treatment,cryopreserved vitrified oocytes are resuscitated and in vitro fertilization-embryo transfer(IVF-ET)was performed to help patients accomplish their reproductive objectives,with the live birth rate(LBR)being 32%.On the other hand,when cryopreserved embryos are resuscitated and transferred,the LBR was 41%.OTC has the advantage of restoring natural fertility and presents a LBR of 33%,compared with the LBR of 19%among 266 IVF patients.In addition,OTC has the benefit of restoring the endocrine function.It has been observed that the shortest recovery time of the first menstruation after transplantation was 3.9 months,and the recovery rate of ovarian function reached 100%.To date,a growing number of cancer survivors and patients with other diseases are benefiting from fertility preservation measures.In the face of declining human fertility,fertility preservation provides a new approach to human reproduction.Fertility preservation should be applied in line with the ethical principles so as to fully protect the rights and interests of patients and their offsprings.