Fetopathological investigations after induced abortions performed in mid-term gemini pregnancies

Multiple pregnancies present a special obstetric condition whose importance has increased due to the spread of assisted reproductive techniques.We have processed the fetopathological data of 43 abortions induced in mid-term gemini pregnancies, owing to malformations affecting one or both fetuses.67.4% of the gemini pregnancies were conceived naturally and 32.6% by assisted reproduction techniques. The most commonly occurring malformations affected the fetuses’ cardiovascular and central nervous systems. Positive histories could be detected in 23% of the cases. The male-to-female ratio was found to be 1.14. In the majority of the cases with central nervous system malformation, fetus “A” was affected (85.7%). In 29.4% of the cases, monochorionic placentation was established. Ultrasonography and fetopatological findings yielded perfectly matching results in 78.9% of the cases.The incidence of fetal malformations is probably not higher among fetuses conceived by assisted reproduction techniques compared to the ones conceived naturally. Fetal central nervous system malformations usually affect fetus “A”. Based on the results of the fetopathological examinations, ultrasonography is a reliable method in the diagnostics of malformations affecting twin fetuses. Fetal echocardiography is indicated simply because of the pregnancy being a multiple one.     

Incidence of spontaneous abortion among pregnancies produced by assisted reproductive technology

BACKGROUND: There has been increasing number of pregnancies following assisted reproductive technology treatment and their survival is understandably a matter of interest. The relative risk of spontaneous abortion in these pregnancies remains unclear. The objectives of this study were to quantify the relative risk in assisted reproductive technology pregnancies in relation to two cohorts of naturally conceived pregnancies and to assess the possible risk factors for spontaneous abortion among assisted reproductive technology pregnancies. METHODS: Three cohorts of pregnancies, 1945 pregnancies conceived following assisted reproductive technology treatment in a tertiary infertility clinic, 549 natural pregnancies in a prospective study of lifestyle and pregnancy (the Ford cohort), and 4265 pregnancies from another cohort (the Treloar cohort), were used in the study. RESULTS: After adjusting for age, the relative risk of spontaneous abortion was 1.20 (95% CI 1.03-1.46) in the assisted reproductive technology cohort in comparison with the Ford cohort. Within the assisted reproductive technology cohort, a history of spontaneous abortion predicted increased risk, while a low level of ovarian stimulation seemed to be related to a reduced risk. CONCLUSIONS: The study showed that the risk of spontaneous abortion was slightly increased in the assisted reproductive technology pregnancies after adjusting for maternal age and previous spontaneous abortion. Within the assisted reproductive technology cohort, several variables, including the level of stimulation, appeared to be linked with the risk of spontaneous abortion.     

Increased risk of placenta previa in pregnancies following IVF/ICSI; a comparison of ART and non-ART pregnancies in the same mother

BACKGROUND: The risk of placenta previa may be increased in pregnancies conceived by assisted reproduction technology (ART). Whether the increased risk is due to factors related to the reproductive technology, or associated with maternal factors, is not known. METHODS: In a nationwide population-based study, we included 845,384 pregnancies reported to the Medical Birth Registry of Norway between 1988 and 2002 and compared the risk of placenta previa in 7568 pregnancies conceived after assisted fertilization, with the risk in naturally conceived pregnancies. To study the influence of ART more directly, we compared the risk of placenta previa between consecutive pregnancies among 1349 women who had conceived both naturally and after assisted fertilization. Odds ratios (OR), adjusted for maternal age, parity, previous Caesarean section and time interval between pregnancies were estimated using logistic regression. RESULTS: There was a six-fold higher risk of placenta previa in singleton pregnancies conceived by assisted fertilization compared with naturally conceived pregnancies [adjusted OR 5.6, 95% confidence interval (CI) 4.4-7.0]. Among mothers who had conceived both naturally and after assisted fertilization, the risk of placenta previa was nearly three-fold higher in the pregnancy following assisted fertilization (adjusted OR 2.9, 95% CI 1.4-6.1), compared with that in the naturally conceived pregnancy. CONCLUSIONS: The use of ART is associated with an increased risk of placenta previa. Our findings suggest that the increased risk may be caused by factors related to the reproductive technology.     

辅助生殖技术与自然受孕双胎妊娠结局临床分析

目的探讨辅助生殖技术受孕双胎妊娠与自然受孕双胎妊娠围生期的结局。方法回顾分析288例双胎妊娠孕妇,其中121例辅助生殖技术受孕双胎妊娠孕妇为研究组,同期自然受孕双胎孕妇167例为对照组,记录、比较两组并发症、分娩方式及围产儿结局等情况。结果研究组孕妇平均年龄高于对照组[（30．31±3．329）岁vs（28．93±4．641）岁],分娩孕周早于对照组[（35．2±4．37）周vs（36．2±3．02）周],顺产率明显低于对照组（2．48％vs11．38％）,差异均有统计学意义（P〈0．05）。研究组的胎膜早破、妊娠期高血压疾病、妊娠期贫血发生率、新生儿窒息率明显低于对照组,差异均有统计学意义（P〈0．05）。研究组晚期流产、妊娠期糖尿病、羊水过多等发生率高于对照组,但差异无统计学意义（P〉0．05）。研究组新生儿平均体重、双胎之一胎死宫内及胎儿畸形率与对照组比较,差异无统计学意义（P〉0．05）。结论辅助生殖技术受孕双胎与自然受孕双胎相比,胎膜早破、妊娠期高血压疾病及贫血发生率低,而晚期流产、妊娠期糖尿病及羊水过多发生率相对偏高,且分娩孕周早。故应加强其孕中期宫颈长度检测及早产预测,必要时行宫颈环扎术,降低晚期流产及早产率,并加强妊娠期血糖监测及膳食管理,降低妊娠期糖尿病发生率。     

Nuchal translucency measurement and pregnancy outcome after assisted conception versus spontaneously conceived twins

BACKGROUND: Nuchal translucency (NT) measurement for Down's syndrome screening or detecting various fetal anomalies is a reliable sonographic marker. This study evaluates the contribution of NT screening in spontaneously conceived and assisted conception twin pregnancies. METHODS AND RESULTS: Maternal age at measurement, chorionicity, ultrasound features, karyotype results and pregnancy outcome were recorded prospectively and compared in 83 assisted reproduction treatment and 91 spontaneously conceived twins. Pregnancy outcome was evaluated according to maternal age, method of conception, NT data and chorionicity. NT measurements (> or =95 centiles of the normal range) were considered screen-positive and mid-pregnancy fetal karyotyping was advised. Complicated pregnancy outcome, which could be signalled by increased NT, was defined as either chromosomal abnormalities, severe structural defects or fetal demise. Based on NT measurements, 16 fetuses (4.6%) were found to be screen-positive. Five of them had chromosomal aneuploidy and selective termination was performed. The parents also opted for this procedure in another five fetuses because of major structural abnormality diagnosed during NT assessment. No other chromosomal or major fetal abnormality were found post-natally. Although no difference was found in NT, crown-rump length and maternal age between spontaneous and assisted reproduction technology twin pregnancies, the former group had a significantly higher rate of screen-positive results (7 versus 2%, P = 0.047), amniocentesis uptake (33 versus 22%, P = 0.014), monochorionic twining (32 versus 4%, P = 0.001) and complicated pregnancy outcome (11 versus 5%, P = 0.02). CONCLUSION: The present study confirms that first trimester target scanning can improve outcome by early detection and management of cases with an anomalous co-twin. It also identifies some differences between spontaneously and artificially conceived twin pregnancies in relation to this area of testing.     

Risk of spontaneous abortion in singleton and twin pregnancies after IVF/ICSI

BACKGROUND: The risk of spontaneous first trimester abortion is estimated to be between 10 and 20%. Although it is common knowledge that the incidence of abortion decreases as pregnancy progresses, exact data in relation to the duration of pregnancy are scarce. METHODS: We reviewed 1597 clinical IVF/ICSI pregnancies with known outcome and tabulated the number of miscarriages or fetal demise per intervals of 2 weeks. We furthermore compared the outcome in terms of fetal survival of 1200 singleton pregnancies with that of 397 twin pregnancies. RESULTS: The overall incidence of non-ongoing singleton pregnancies was 21.7%. Fetal death, after positive heart activity had been recorded, occurred in 12.2% of singleton pregnancies. The overall incidence of spontaneous abortion in twin pregnancies was 17.1% (12.1% vanishing twins and 5.0% complete miscarriages). The incidence of miscarriage in the twin pregnancies, expressed per gestational sac, was 11.1%. Once fetal heart activity was present, the risk of abortion (per gestational sac) was 7.3%, which is significantly lower than that in singleton pregnancies. CONCLUSIONS: Our data give an estimate of the probability of miscarriage or fetal demise at any given period of the first trimester both for singleton and twin pregnancies. Twin pregnancies after IVF have a better potential for survival than singleton pregnancies.     

Maternal plasma DNA testing for aneuploidy in pregnancies achieved by assisted reproductive technologies

PurposeWe sought to compare measurements of circulating cell-free DNA as well as Down syndrome test results in women with naturally conceived pregnancies with those conceived using assisted reproductive technologies.MethodsData regarding assisted reproductive technologies were readily available from seven enrollment sites participating in an external clinical validation trial of nested case/control design. Measurements of circulating cell-free fetal and total DNA, fetal fraction (ratio of fetal to total DNA), chromosome-specific z-scores, and karyotype results were available for analysis.ResultsAnalyses were restricted to 632 euploid (5.2% assisted reproductive technologies) and 73 Down syndrome (13.7% assisted reproductive technologies), including 16 twin pregnancies. No differences were found for fetal or total circulating cell-free DNA, or for the fetal fraction in euploid (P = 0.70) or Down syndrome (P = 0.58) pregnancies by method of conception. There appeared to be systematic z-score reductions for chromosomes 21, 18, and 13 in assisted reproductive technologies versus natural euploid pregnancies (P = 0.048, 0.0032, and 0.36, respectively).ConclusionAssisted reproductive technologies and naturally conceived pregnancies contribute similar levels of circulating cell-free DNA into maternal circulation. Small differences in the z-scores of pregnancies achieved by assisted reproductive technologies were observed and do not appear to be test-related artifacts. However, the findings need confirmation before any consideration of changes to testing and reporting protocols.     

ROC曲线对妊娠结局预测模式的评价

目的通过监测正常早孕、自然流产与异位妊娠妇女血清绒毛膜促性腺激素(β-HCG)及孕酮(P)水平,建立正常早孕、自然流产与异位妊娠的妊娠结局预测模式,并利用ROC曲线评价其预测妊娠结局的能力。方法选择正常早期单胎妊娠对照组191例,自然流产患者150例、异位妊娠患者204例。用电发光免疫法测血清β-HCG及P水平,建立单独β-HCG、P以及β-HCG和P联合积分预测模式。结果正常早孕组孕龄血清β-HCG平均值为(7812.52±3599.29)IU/L,P平均值为(35.27±12.91)nmol/L;自然流产组血清β-HCG平均值为(1298.07±1808.83)IU/L,P平均值为(6.66±4.42)nmol/L;异位妊娠组β-HCG平均值为(2118.23±2905.75)IU/L,P平均值为(6.37±5.58)nmol/L;自然流产组血清β-HCG及P水平明显低于正常早孕对照组,独立样本t检验t=21.75,P=0.000(95%CI:5925.31-7103.79)及t=28.49,P=0.000(95%CI:26.52-30.46),差异有显著性意义;异位妊娠组血清β-HCG及P水平明显低于正常早孕对照组,独立样本t检验t=17.25,P=0.000(95%CI:5045.02-6﹤343.57)及t=28.32,P=0.000(95%CI:26.79-30.79),差异有显著性意义;自然流产组与异位妊娠组血清β-HCG差异有显著性意义,t=-3.27,P=0.001(P<0.05),两组P水平差异无统计学意义,t=0.57,P=0.57(P>0.05);通过ROC曲线分析血清β-HCG、P水平及联合积分预测妊娠结局的能力,曲线下面积分别为0.879、0.973、0.984,(P值均<0.05),95%CI分别为(0.845-0.913)、(0.959-0.986)、(0.973-0.994)。结论单独P较β-HCG水平具有更好的预测非正常妊娠的能力;联合积分预测妊娠结局的能力最强;单独P和联合积分与单独β-HCG预测妊娠结局的能力的差异有统计学意义,但二者的差异无统计学意义;随妊娠时间的延长,正常早孕β-HCG水平有迅速增加的趋势,异位妊娠有缓慢增加的趋势,而自然流产则有降低趋势;P水平不能有效区分自然流产与异位妊娠。     

Perinatal complications of assisted reproduction

The main perinatal complications of assisted reproduction include congenital malformation, chromosomal aberrations, multiple pregnancy, and prematurity. Earlier studies and in vitro fertilization (IVF) registries showed that there was no increased incidence of congenital malformations in children conceived by IVF/intracytoplasmic sperm injection (ICSI). However, a large Australian study has found that by one year of age, the incidence of congenital malformations in IVF/ICSI children is increased in comparison with those naturally conceived. Several investigators found a slight but increased risk of chromosomal aberrations in ICSI children. Multiple pregnancy is a major cause of increased perinatal mortality due to increased incidence of both prematurity and congenital malformations. Even in singleton pregnancies conceived by assisted reproductive technologies, the risk of prematurity and newborns small for gestational age is increased. In this article, recently published work on perinatal complications associated with assisted reproductive technologies is reviewed.     

Reduction of multifetal pregnancies to twins does not increase obstetric or perinatal risks.

Selective reduction in cases of multiple fetuses is used more often nowadays due to the increased number of multiple pregnancies resulting from assisted reproduction. In this retrospective study, we investigated whether twin pregnancies derived from fetal reduction carry a higher obstetric and perinatal risk compared to standard twin pregnancies. We found that the rate of miscarriage was 10.6% in the reduction group (n = 158) compared to 9.5% in the controls (n = 135). Mean gestational age at delivery was 35.7 weeks in the reduction group versus 35.1 weeks in the control group. Mean neonatal weight at birth was 2.260 g (800-3.750 g) in the reduction group compared to 2.240 g (540-3.360 g) in controls. Perinatal mortality rate was 49.3 per thousand after reduction and 42.0 per thousand in the control group. There was no statistically significant difference in any of the above parameters. Therefore, multifetal pregnancy reduction to twins does not appear to increase obstetric or perinatal risks.     

辅助生育技术与自然受孕双胎妊娠结局的临床分析

目的探讨辅助生育技术与自然受孕两种不同方式双胎妊娠的临床结局。方法回顾性分析我院2005年-2008年7月分娩的143例辅助生育技术受孕双胎孕妇（ART组）和108例自然受孕双胎孕妇（对照组）的孕期合并症、分娩方式及围产儿儿结局。结果（1）ART组孕妇平均年龄（33．1±4．0）岁,对照组为（28．2±4．0）岁,两组比较差异有极显著性（P〈0．001）。（2）不良孕产史发生率ART组高于对照组（13．7％vs3．7％）,差异有极显著性（P〈0．01）;初次产检孕周,ART组为（13．1±5．4）周,对照组为（17．4±6．9）周,ART组的孕期产检次数为（8．2±2．8）次,对照组为（6．7±3．1）,均有极显著性差异（P≤0．001）。（3）ART组分娩孕周为（35．1±2．1）周,对照组为（34．4±2．4）周,ART组34周及以上分娩率高于对照组（P〈0．05）;妊娠期高血压疾病的发生率ART组低于对照组。（4）ART组新生儿平均出生体重（2394．3±38．04）g,对照组为（2184．9±53．20）g,差异有极显著性（P=0．001）。ART组极低出生体重儿发生率低于对照组。新生儿窒息、围产儿死亡率、一胎胎死宫内、先天性畸形的发生率,两组均无显著差异。结论ART助孕双胎孕妇更加重视孕期保健,分娩孕周延长,妊娠期高血压疾病的发生率较低,ART助孕组单卵双胎的比例较低．围产儿结局与自然爱孕双胎相似．     

Wisconsin stillbirth services program: a multifocal approach to stillbirth analysis

Stillbirth accounts for about 26,000 deaths annually in the US. In most previous studies, discrete causes are identified in less than half of all stillbirths. In order to identify causes and non-causal but potentially contributing abnormalities, we analyzed 416 of the most recent (2004-2010) Wisconsin Stillbirth Service Program (WiSSP) cases from a multifocal approach. In 70% of cases a cause sufficient to independently explain the demise was identified including 40% placental, 21.5% fetal, and 12.7% maternal. Results for stillbirths and second trimester miscarriages did not differ significantly. In 95% of cases at least one cause or non-causal abnormality was recognizable, and in two-thirds of cases, more than one cause or non-causal abnormality was identified. In cases with maternal cause, the placenta was virtually always abnormal. Both placentas (59%) and fetuses (38%) were frequently smaller than expected for gestational age. Previous miscarriage and/or stillbirth were risk factors for second and third trimester losses, with 35% of previous pregnancies ending in fetal demise. Recommendations include complete evaluation of all second and third trimester losses with special attention to placental pathology and thorough investigation for multiple causes or abnormalities whether or not a primary cause is initially recognized. Improved understanding of the causes of late miscarriage and stillbirth may contribute to recognition and management of pregnancies at risk and eventually to prevention of stillbirth.     

VEGF与复发性流产的研究进展

VEGF（血管内皮生长因子）在正常妊娠中发挥重要的作用，其表达水平异常将导致病理性妊娠的发生。本文通过介绍VEGF与复发性流产发病的关系，为研究复发性流产的发病机制及其临床防治措施提供依据。     

散点图对妊娠结局预测模式的评价

目的利用散点图直观分析正常早孕、自然流产与异位妊娠妇女血清绒毛膜促性腺激素（β-HCG）及孕酮（P）水平配对分布趋势,结合孕龄的差异,建立一种新的妊娠结局预测模式。方法选择正常早期单胎妊娠对照组191例,自然流产患者150例、异位妊娠患者204例。用电发光免疫法测血清β-HCG及P水平。结果正常早孕组孕龄血清β-HCG平均值为（7812.52±3599.29）IU/L,P平均值为（35.27±12.91）nmol/L;自然流产组血清β-HCG平均值为（1298.07±1808.83）IU/L,P平均值为（6.66±4.42）nmol/L;异位妊娠组β-HCG平均值为（2118.23±2905.75）IU/L,P平均值为（6.37±5.58）nmol/L;自然流产组血清β-HCG及P水平明显低于正常早孕对照组,独立样本T检验t=21.75,P=0.000（95%CI：5925.31-7103.79）及t=28.49,P=0.000（95%CI：26.52-30.46）,差异有显著性意义;异位妊娠组血清β-HCG及P水平明显低于正常早孕对照组,独立样本t检验,t=17.25,P=0.000（95%CI：5045.02-6〈343.57）及t=28.32,P=0.000（95%CI：26.79-30.79）,差异有显著性意义;自然流产组与异位妊娠组血清β-HCG差异有显著性意义,t=﹣3.27,P=0.001（P〈0.05）,两组P水平差异无统计学意义,t=0.57,P=0.57（P〉0.05）;通过绘制血清β-HCG及P水平分布散点图直观显示正常早孕组聚集在以P为纵坐标25-60nmol/L,以血清β-HCG为横坐标的5000-10000IU/L范围内（发生率59.69%）,而自然流产组与异位妊娠组聚集在P〈10nmol/L,HCG〈2000IU/L范围（发生率64.78%）。在孕龄≤49天,P〉20nmol/L均为正常早孕,孕龄〉70天,P〈10nmol/L,均为非正常早孕。结论 P较β-HCG水平具有更好的预测非正常妊娠的能力;结合孕龄利用散点图P与β-HCG联合预测更为准确、直观;随妊娠时间的延长,正常早孕β-HCG水平有迅速增加的趋势,异位妊娠有缓慢增加的趋势,而自然流产则有降低趋势;P水平不能有效区分然流产与异位妊娠。孕龄≤49天,P〉20nmol/L可作为正常早孕的诊断标准,孕龄〉70天,P〈10nmol/L可作为非正常早孕的诊断标准。     

The risk of fetal loss following a prenatal diagnosis of trisomy 13 or trisomy 18

The objective of this study is to determine the risk of fetal loss (spontaneous abortion or stillbirth) following a prenatal diagnosis of trisomy 13 (T13; Patau syndrome) or trisomy 18 (T18; Edwards syndrome). Five regional congenital anomaly registers in England and Wales provided details on the outcomes of 198 pregnancies prenatally diagnosed with T13 and 538 prenatally diagnosed with T18. For each pregnancy the time from prenatal diagnosis until birth, miscarriage or termination occurred was calculated and these times were analyzed using Kaplan-Meier survival functions. Our results showed that between 12 weeks gestation and term an estimated 49% (95% CI: 29-73%) of pregnancies diagnosed with T13 and 72% (61-81%) of pregnancies diagnosed with T18 ended in a miscarriage or stillbirth. Between 18 weeks and term the proportions were 42% (18-72%) for T13 and 65% (57-79%) for T18 and between 24 weeks and term the proportions were 35% (5-70%) for T13 and 59% (49-77%) for T18. Male fetuses with T18 appeared to be more likely to be lost than female fetuses. These are the most precise estimates currently available for the risk of loss in a general population. These estimates should be useful in counseling women who are carrying an affected fetus and knowing the risk of fetal loss is essential to compare the performance of prenatal screening programs occurring in the first and second trimester.     

The feasibility of nuchal translucency measurement in higher order multiple gestations achieved by assisted reproduction.

Nuchal translucency (NT) measurement for screening chromosomal abnormalities and detecting fetal anomalies is an effective ultrasonographic marker, originally developed for singleton pregnancies. This study sought to evaluate the feasibility of NT measurements in higher order multiple gestations. Pregnant patients who conceived following assisted reproduction and were carrying three or more fetuses were enrolled in the study. Each fetus was ultrasonographically assessed, a NT measurement was obtained, and the findings were used for counselling prior to any invasive procedure. In all, 24 pregnant patients, initially carrying 79 fetuses aged 10-14 weeks of gestation, were compared with 79 consecutively matched, singleton controls, naturally conceived, having similar crown-rump lengths (+/- 3 mm). NT measurements were feasible for both study and control fetuses, which exhibited similar NT measurements for 5th, 50th and 95th centiles. Also, mean NT thicknesses [measurements in mm or multiple of the medians (MOM)] were similar for both groups (1.41 +/- 0.41 and 1.35 +/- 0.39 mm respectively and 0.87 +/- 0.23 and 0.83 +/- 0.25 MOM respectively). Prenatally no chromosomal abnormalities were detected in either group, and, of those infants who had no karyotyping, no traits were observed that warranted chromosomal analysis. NT measurements are feasible in higher order multiple gestations. Since there is no other effective screening modality for these pregnancies, it seems reasonable to recommend NT measurement for antenatal screening services for higher order multiple gestations.     

妊娠4～9周孕妇血清雌二醇变化与妊娠结局的关系

目的探讨妊娠4～9周孕妇血清雌二醇（E2）变化与妊娠结局的关系。方法选择在本院就诊的妊娠4～9周的孕妇,根据孕妇妊娠结局分为正常妊娠组和胚胎停育组,正常妊娠组又根据有无复发性流产病史者分为两组,各组按孕周又分为6个亚组。采用化学发光分析法检测各组孕妇血清E2水平,并进行比较分析。结果正常妊娠组妊娠4～9周孕妇每周血清E2水平随妊娠周数增加而增加,有复发性流产病史的患者和无复发性流产的患者各孕周E2水平的变化差异无统计学意义（P〉0.05）;而胚胎停育组随孕周增加呈下降趋势。与正常妊娠组的相应孕周两两比较胚胎停育组各个孕周孕妇血清E2水平相应均数显著偏低（P〈0.05）。结论胚胎停育孕妇各孕周血清E2水平均显著下降,提示E2可能是维持早期妊娠的重要因素之一。     

Occurrence of other reproductive failures among women with recurrent spontaneous abortion

We have previously reported an association between recurrent spontaneous abortion and ectopic pregnancy. We now report that not only ectopic pregnancy, but also other reproductive failures including hydatidiform moles, preterm births, and stillbirths are also associated with recurrent spontaneous abortion. The obstetrical histories of 455 women who had experienced two or more consecutive spontaneous abortions were studied for the occurrence of term births, preterm births, stillbirths, spontaneous abortions, ectopic pregnancies, and hydatidiform moles. The observed frequencies of these reproductive outcomes were compared with the expected frequencies of 920 term births, 80 preterm births, five stillbirths, 150 spontaneous abortions, 14.5 ectopic pregnancies and 0.5 molar pregnancies per 1,000 livebirths. The 455 women had experienced 1,968 pregnancies of which 184 were term births, 30 were preterm births, 16 were stillbirths, 1,669 were spontaneous abortions, 63 were ectopic pregnancies, and six were molar pregnancies. The ratio of observed to expected values was term births 0.1, preterm births 1.6, stillbirths 14.0, spontaneous abortion 6.6, ectopic pregnancy 2.6, and molar pregnancy 7.1. The gravid specific proportions of reproductive outcomes were constant suggesting comorbidity or common cause(s). The commonality that links these types of reproductive failure will provide insight into the mechanisms of reproductive wastage.     

ART后自然减胎的相关因素及妊娠结局分析

目的探讨辅助生殖技术（ART）助孕妊娠后发生自然减胎（SPR）发生的相关因素和对妊娠结局的影响。方法回顾性分析2003年1月-2008年12月我院ART术后妊娠的3506例患者,分析与SPR有关的因素和妊娠结局。结果ART后SPR的发生与移植的胚胎质量有关;发生SPR后出生低体重儿和早产的可能性增大;SPR发生越晚,其产科异常结局风险越大。结论选择优质胚胎的单胚胎移植（SET）,可能是有效避免多胎妊娠,减少SPR发生的根本之举。此外,在对多胎妊娠实行选择性减胎时应充分考虑SPR的发生时间及发生率。     

Fetal reduction in multifetal pregnancy--ethical dilemmas

As a result of the increased use of drugs that enhance fertility, and the advent of in vitro fertilization and embryo transfer over the last 2 decades, the incidence of multifetal pregnancies has increased exponentially. In parallel with this increase methods of care for women carrying multiple fetuses have become more complex and well developed. Importantly, it has become obvious that in the case of such pregnancies the rates of mortality and morbidity of both fetuses and mothers, particularly in cases where four or more fetuses are involved, are extremely high. Improvements in the techniques of assisted fertilization should result in fewer iatrogenic multifetal pregnancies and a commensurate decrease in related risks. Fetal reduction seems to be an acceptable method of improving maternal and fetal outcome in high order multiple pregnancies despite the many unresolved medical and ethical dilemmas.