McDonald Sarah, Murphy Kellie, Beyene Joseph, Ohlsson Arne
Department of Obstetrics and Gynecology, Ottawa Hospital, University of Ottawa, Ontario, Canada.
Am J Obstet Gynecol. 2005 Jul;193(1):141-52. doi: 10.1016/j.ajog.2004.11.064.
Uncontrolled studies suggest that in vitro fertilization twins have increased rates of preterm birth and low birth weight and would warrant increased antenatal monitoring. The objective of this meta-analysis was to determine whether the incidence of poor obstetric outcomes is higher for in vitro fertilization twins than for spontaneously conceived twins who were matched for maternal age.
Medline and EMBASE were searched with comprehensive search strategies. Case-control and cohort studies of twins who were conceived by in vitro fertilization or in vitro fertilization/intracytoplasmic sperm injection, with the transfer of fresh embryos or cryopreserved (frozen) in women with infertility, and/or whose partners were subfertile or infertile, compared with naturally (spontaneously) conceived twins who were matched for maternal age (case-control studies) or which were controlled for it (cohort studies). Two reviewers independently assessed titles, abstracts, and study quality and extracted the data. Statistical analysis was performed with commercial statistical software. Dichotomous data were meta-analyzed with odds ratios as measures of effect size, and continuous data was meta-analyzed with mean differences. Interstudy variation was incorporated with the assumption of a random effects model for the treatment effect.
Compared with spontaneously conceived twins who were matched for maternal age, in vitro fertilization twins have an increased risk of preterm birth between 32 and 36 weeks of gestation (odds ratio, 1.48; 95% CI, 1.05-2.10), and an elevated risk of preterm birth at <37 weeks of gestation when parity is also matched for an odds ratio of 1.57 (95% CI, 1.01-2.44). There was an increased rate of cesarean delivery among in vitro fertilization twins (odds ratio, 1.33; 95% CI, 1.06-1.67). There were no significant differences in incidences of perinatal death, low birth weight infants, or congenital malformations.
In vitro fertilization twins have increased rates of preterm birth compared with spontaneously conceived twins who were matched for maternal age, despite the fact that their outcomes would be expected to be better because of the decreased proportion of monochorionic twins.
非对照研究表明，体外受精双胞胎早产和低出生体重的发生率增加，因此需要加强产前监测。本荟萃分析的目的是确定与年龄匹配的自然受孕双胞胎相比，体外受精双胞胎不良产科结局的发生率是否更高。
采用全面的检索策略对Medline和EMBASE进行检索。对通过体外受精或体外受精/卵胞浆内单精子注射受孕、在不孕妇女中移植新鲜胚胎或冷冻保存（冷冻）胚胎、和/或其伴侣为亚生育力或不育的双胞胎进行病例对照和队列研究，并与年龄匹配的自然（自发）受孕双胞胎（病例对照研究）或对此进行了对照的双胞胎（队列研究）进行比较。两名审阅者独立评估标题、摘要和研究质量并提取数据。使用商业统计软件进行统计分析。二分数据采用比值比作为效应量指标进行荟萃分析，连续数据采用平均差进行荟萃分析。研究间变异采用治疗效应的随机效应模型假设进行合并。
与年龄匹配的自然受孕双胞胎相比，体外受精双胞胎在妊娠32至36周之间早产风险增加（比值比，1.48；95%可信区间，1.05 - 2.10），当产次也匹配时，妊娠<37周早产风险升高，比值比为1.57（95%可信区间，1.01 - 2.44）。体外受精双胞胎剖宫产率增加（比值比，1.33；95%可信区间，1.06 - 1.67）。围产期死亡、低出生体重儿或先天性畸形的发生率无显著差异。
与年龄匹配的自然受孕双胞胎相比，体外受精双胞胎早产率增加，尽管由于单绒毛膜双胞胎比例降低，预期其结局会更好。
