van Dunné F M, Doggen C J M, Heemskerk M, Rosendaal F R, Helmerhorst F M
Department of Obstetrics, Gynaecology and Reproductive Medicine, Leiden University Medical Center, P.O.Box 9600, 2300 RC Leiden, The Netherlands.
Hum Reprod. 2005 Mar;20(3):802-6. doi: 10.1093/humrep/deh640. Epub 2004 Dec 23.
Factor V Leiden mutation (Arg506Gln) increases the likelihood of venous thrombosis; it may also have a positive effect through facilitation of embryo implantation. This may manifest itself as a reduced time to pregnancy (increased fecundity) and fewer miscarriages in the first trimester.
From March 1999 onwards, consecutive patients with a first venous thrombosis (VT) were recruited. The first 115 female VT patients with factor V Leiden and 230 age-matched female VT patients without factor V Leiden were included. All patients, unaware of their genotype, received a structured questionnaire.
Of the 297 (86%) women who returned the questionnaire, 220 had been pregnant at least once. Time to first pregnancy was unaffected by carrier status: 58% factor V Leiden carriers reported a pregnancy within 3 months compared to 54% non-carriers. The miscarriage proportion was 14%, similar in both groups. First trimester miscarriage was less frequent among carriers (46%) than among non-carriers (95%) (relative risk 0.5, 95% confidence interval 0.3-0.9).
Factor V Leiden mutation may support embryo implantation, as factor V Leiden carriers had fewer miscarriages in the first trimester with a similar overall miscarriage rate. Miscarriage of embryos with poor viability may be postponed until the second trimester in factor V Leiden carriers. Fecundity was not influenced by factor V Leiden status.
凝血因子V莱顿突变（Arg506Gln）会增加静脉血栓形成的可能性；它也可能通过促进胚胎着床产生积极影响。这可能表现为缩短受孕时间（生育力增加）以及孕早期流产次数减少。
从1999年3月起，招募首次发生静脉血栓形成（VT）的连续患者。纳入了首批115名携带凝血因子V莱顿突变的女性VT患者以及230名年龄匹配的不携带凝血因子V莱顿突变的女性VT患者。所有患者均不知晓自己的基因型，接受了一份结构化问卷。
在297名（86%）回复问卷的女性中，220名至少怀孕过一次。首次怀孕的时间不受携带状态的影响：58%的凝血因子V莱顿突变携带者报告在3个月内怀孕，相比之下，非携带者为54%。流产比例为14%，两组相似。携带者中孕早期流产的发生率（46%）低于非携带者（95%）（相对风险0.5，95%置信区间0.3 - 0.9）。
凝血因子V莱顿突变可能支持胚胎着床，因为凝血因子V莱顿突变携带者孕早期流产次数较少，总体流产率相似。凝血因子V莱顿突变携带者中，生存能力差的胚胎流产可能会推迟到孕中期。生育力不受凝血因子V莱顿状态的影响。
