Department of Obstetrics & Gynecology, Maulana Azad Medical College, New Delhi, India.
Ultrasound Obstet Gynecol. 2012 Aug;40(2):128-34. doi: 10.1002/uog.10152. Epub 2012 Jul 13.
To review the available evidence regarding pregnancy loss following first-trimester chorionic villus sampling (CVS) and mid-trimester genetic amniocentesis in twins.
We searched the MEDLINE database from January 1990 to May 2011 for randomized and cohort studies reporting on the risk of pregnancy loss after first-trimester CVS performed between 9 and 14 weeks and after genetic amniocentesis performed between 14 and 22 weeks. Where appropriate, we calculated pooled proportions and relative risks with 95% CI.
No randomized studies were found. For CVS, nine studies fulfilled the inclusion criteria. The overall pregnancy-loss rate was 3.84% (95% CI, 2.48-5.47; n = 4). The rate of pregnancy loss before 20 weeks was 2.75% (95% CI, 1.28-4.75; n = 3) and before 28 weeks was 3.44% (95% CI, 1.67-5.81; n = 3). For amniocentesis, the overall pregnancy-loss rate was 3.07% (95% CI, 1.83-4.61; n = 4). The rate of pregnancy loss before 20 weeks was 2.25% (95% CI, 1.23-3.57; n = 2), before 24 weeks was 2.54% (95% CI, 1.43-3.96; n = 9) and before 28 weeks was 1.70% (95% CI, 0.37-3.97; n = 5). Pooled data from four case-control studies showed a higher risk (2.59% vs. 1.53%) of pregnancy loss before 24 weeks following amniocentesis (relative risk = 1.81; 95% CI, 1.02-3.19). There were no statistically significant differences in reported pregnancy loss between transabdominal and transcervical approaches, use of a single-needle system vs. a double-needle system and single uterine entry vs. double uterine entry in the CVS group. Similarly, in the amniocentesis group, there was no statistically significant difference in fetal loss between the single uterine entry vs. the double uterine entry.
In the absence of randomized studies, it is not possible to estimate accurately the excess risk following invasive procedures in twins. Currently available data show similar overall pregnancy-loss rates for both amniocentesis and CVS with the excess risk of around 1% above the background risk.
回顾第一孕期绒毛膜采样（CVS）和中期遗传羊膜穿刺术在双胞胎中导致妊娠丢失的现有证据。
我们从 1990 年 1 月至 2011 年 5 月，检索 MEDLINE 数据库，查找在 9 至 14 周进行第一孕期 CVS 和在 14 至 22 周进行遗传羊膜穿刺术的随机和队列研究，报告妊娠丢失风险。在适当的情况下，我们计算了汇总比例和 95%置信区间的相对风险。
未发现随机研究。对于 CVS，有 9 项研究符合纳入标准。总的妊娠丢失率为 3.84%（95%CI，2.48-5.47；n=4）。20 周前的妊娠丢失率为 2.75%（95%CI，1.28-4.75；n=3），28 周前的妊娠丢失率为 3.44%（95%CI，1.67-5.81；n=3）。对于羊膜穿刺术，总的妊娠丢失率为 3.07%（95%CI，1.83-4.61；n=4）。20 周前的妊娠丢失率为 2.25%（95%CI，1.23-3.57；n=2），24 周前的妊娠丢失率为 2.54%（95%CI，1.43-3.96；n=9），28 周前的妊娠丢失率为 1.70%（95%CI，0.37-3.97；n=5）。四项病例对照研究的汇总数据显示，羊膜穿刺术导致 24 周前妊娠丢失的风险更高（2.59% vs. 1.53%）（相对风险=1.81；95%CI，1.02-3.19）。在 CVS 组中，经腹和经宫颈途径、使用单针系统与双针系统、单次子宫进入与双次子宫进入之间，报告的妊娠丢失无统计学显著差异。同样，在羊膜穿刺组中，单次子宫进入与双次子宫进入之间的胎儿丢失也无统计学显著差异。
由于缺乏随机研究，目前尚无法准确估计双胞胎中侵入性操作后的额外风险。目前的可用数据显示，羊膜穿刺术和 CVS 的总体妊娠丢失率相似，额外风险约为背景风险的 1%。
