Introduction an absolute requirement for folate that is met entirely About 14% of individuals in Europe seek medical advice from endogenous sources. " Furthermore, the effective for infertility, of whom about half undergo in-vitro use of B vitamins is dependent on sequence variations fertilisation(IVF).1. Despite advances in the technology in the enzymes involved in their metabolism. Thus, used in IVF only a fifth of treatment cycles result in availability of B vitamins during the period immediately livebirths. Overall success of treatment seems largely preceding oocyte recovery and the B-vitamin related independent of the diagnosis of infertility or whether genotype of the mother or embryo might affect embryo IVF or intracytoplasmic sperm injection(ICSI)is used viability after IVF. The great majority of twins born after for fertilisation, 4s which suggests that factors other IVF are dizy gotic, resulting from the survival of more than those specific to the diagnosis-eg, poor sperm than one transferred embryo. Exposure to B vitamins quality-affect the success of treatment. To overcome might, therefore, also affect the incidence of twin births these unknown barriers and improve pregnancy rates, Our aim was to investigate the link between B-vitamin most IVF units transfer more than one embryo per intake and levels in the body and six variants in genes cycle. This practice increases the likelihood of multiple involved in B-vitamin metabolism, and the outcome of births and hence the risk of maternal and infant IVF mortality and morbidity. .8 The general factors that affect the success of ivf and the risk of twin births need Methods further research Participants Poor B-vitamin status and raised concentrations of Between October, 2000, and September, 2004, we did a homocysteine are associated with early loss of prospective cohort study to which we consecutively pregnancy, .1o whereas high concentrations of folic acid enrolled women undergoing fertility treatment at the have been associated with an increase in natural Aberdeen Reproduction Unit. We also obtained Dna twinning, though the latter connection remains from a separate cohort of women who were attending a controversial. Fertility probably also has a genetic pregnancy ultrasound scan at Aberdeen Maternity component, 1 4 and sequence variations in the genes Hospital. These women had conceived naturally and involved in the metabolism of B vitamins have been were carrying singleton pregnancies with no known linked to early pregnancy loss. 15. Little work has been abnormalities done on treatments for infertility per se, although there All women provided written informed consent, and are good biological reasons to suspect that B-vitamin Grampian Research Ethics Committee approved the exposure affects their outcome. The early embryo has study
2.材料和方法 (1)参与和选择的对象(病人或实验动物, 包括对照组)。指明年龄、性别、和其他对象 的重要特征等 (2)技术信息包括仪器设备应说明所用仪器 的型号,制造的国别和厂家等详细的参数等。 材料的来源、制备、选择标准,药品和试剂包 括普通名、系统名、剂量、服用规则等,尽量 避免用商标名。 (3)研究方法表述要精确、采用方法的理由, 数据査找、选择、提取、综合的方法
2．材料和方法 ◼ （1）参与和选择的对象 （病人或实验动物， 包括对照组）。指明年龄、性别、和其他对象 的重要特征等 ◼ （2）技术信息 包括仪器设备 应说明所用仪器 的型号，制造的国别和厂家等详细的参数等。 材料的来源、制备、选择标准，药品和试剂包 括普通名、系统名、剂量、服用规则等，尽量 避免用商标名。 ◼ （3）研究方法 表述要精确、采用方法的理由， 数据查找、选择、提取、综合的方法
(4)实验程序、操作要点包括获得结果 的过程 (5)统计学方法 详细说明统计学的术语、缩写、符号 统计学软件 并能使其他硏究人员能依据原始数据 再现报告的结果
（4）实验程序、操作要点 包括获得结果 的过程 （5）统计学方法 详细说明统计学的术语、缩写、符号、 统计学软件。 并能使其他研究人员能依据原始数据 再现报告的结果
临床疗效观察或临床病例分析论文 ■可用“对象和方法” ■涉及新的内容时,应详细而便于同行重复 借鉴 常规方法或重复前人的方法则可略或注明 文献出处即可 ■注:要显示为了解决问题,你的方法是可 靠的,你做了那些努力(而不是仅仅介绍 怎样做)
临床疗效观察或临床病例分析论文 ◼ 可用“对象和方法” ◼ 涉及新的内容时，应详细而便于同行重复、 借鉴。 ◼ 常规方法或重复前人的方法则可略或注明 文献出处即可 ◼ 注：要显示为了解决问题，你的方法是可 靠的，你做了那些努力（而不是仅仅介绍 怎样做）
3.结果 (1)针对研究的问题,合理的选择文本、表格 图示, 表格(具体数值及对比表达) 图(发展趋势的动态表达) (2)按照逻辑顺序,逐一列出结果
3．结果 （1）针对研究的问题，合理的选择文本、表格、 图示， 表格（具体数值及对比表达） 图（发展趋势的动态表达） （2）按照逻辑顺序，逐一列出结果