Maternal serum alpha-fetoprotein screening programs and quality control for laboratories performing maternal serum and amniotic fluid alpha-fetoprotein assays: policy statement. American Society of Human Genetics.

Maternal serum alpha-fetoprotein (MSAFP) values are used primarily but not solely to predict the occurrence of open neural tube defects in the fetus; their use for prediction of Down's syndrome is a new initiative under investigation. The test is a good one, as far as such a test can be, but it is imperfect, because false-negative and false-positive results both occur. In other words, it is not an infallible test. To use the test as effectively as is currently possible requires a program capable of supplying baseline values in sufficient number and the follow-up procedures necessary for interpretation of positive tests. In other words, it is not simply an office test. Because there is no effective treatment to relax the burden of neural tube defects in the large majority of patients, prevention of disease involves termination of pregnancy at present. In other words, use of the test is value laden and controversial for some sectors of society. Despite its imperfections, the need for an elaborate societal structure to apply it, and its value-laden context the test is considered by many as a necessary procedure to maintain normal standards of practice. Indeed, the American College of Obstetricians and Gynecologists issued a statement advising its fellows to be aware of the availability of MSAFP testing and to discuss such testing with patients. It is natural that confusion about protocol and anxiety about practice and its consequences are prevalent in this context. The American Society of Human Genetics (ASHG) offers here a statement about issues that affect MSAFP testing and the attendant pitfalls.     

Maternal serum alpha-fetoprotein screening: report of a Canadian pilot project.

A pilot project of maternal serum alpha-fetoprotein (MSAFP) screening was carried out in Ontario from 1982 to 1985 to examine the feasibility and acceptability of screening a prenatal population for open fetal neural tube defects. A total of 8140 patients at low genetic risk were screened. Patient acceptance was excellent. Blood samples were taken at 16 to 18 weeks' gestation. If the MSAFP level was elevated, the assay was repeated and an ultrasound examination performed. Amniocentesis was offered to 67 women with unexplained persistently elevated levels. The outcome of pregnancy was known in 7473 patients (91.8%). Seven of nine known open fetal neural tube defects were detected. All were confirmed, and no unaffected fetuses were aborted on the basis of the screening results. The rates of perinatal death (6.7%), intrauterine growth retardation (11.7%) and prematurity (23.3%) were significantly higher among the patients with unexplained elevated MSAFP levels than among those with normal levels (p less than 0.001). Of 20 patients with unexplained low levels, 10 subsequently had spontaneous abortions and 10 gave birth to term appropriate-for-gestational-age infants. Seven of nine patients who gave birth to infants with autosomal trisomy had MSAFP values below the median. The findings indicate that MSAFP screening is feasible, accurate and acceptable in a low-risk area.     

Impact of maternal serum alpha-fetoprotein screening on antenatal diagnosis

An analysis has been made of indications for amniocentesis in the Edinburgh area from 1979 to 1981. About 5% of all mothers underwent the procedure. Among 2137 amniocenteses, 37% were performed on mothers 35 years old or more, and 30% on patients with raised serum alpha-fetoprotein. The total number of amniocenteses and the categories have been stable for the past three years. As a result of amniocentesis 104 pregnancies were terminated, 66 of which (63%) followed a raised maternal serum alpha-fetoprotein indication, while only 10 (9.6%) were in mothers aged 35 or more. There were a further 12 terminations based on raised serum alpha-fetoprotein but where no amniocentesis had been thought necessary. Even when figures for anencephaly are excluded from the analysis, maternal serum alpha-fetoprotein screening was responsible for detecting 35 out of 63 (56%) abnormal fetuses. This constitutes a strong case for the continuation of alpha-fetoprotein screening programmes.     

Prenatal fetal karyotyping and maternal serum alpha-fetoprotein screening

Prenatal karyotyping was undertaken in 569 consecutive amniotic fluid samples where the indication for amniocentesis was two sequential raised maternal serum alpha-fetoprotein concentrations. In 475 successful cultures five chromosome abnormalities were found--four constitutional anomalies (47,XXY; 47,XYY; an inherited inv(8) (p23q11); and a de-novo translocation t(6;7) (p11;p22) and a culture-derived anomaly (trisomy 2) found in amniotic fluid cells but not in the fetus aborted because it had spina bifida. Of the pregnancies complicated by constitutional abnormalities, only the pregnancy in which the de-novo translocation was detected was terminated. No chromosome abnormalities were detected in the 17 pregnancies which miscarried after amniocentesis. These results provide little justification for including fetal karyotyping as an essential part of maternal serum alpha-fetoprotein screening programmes.     

唐氏综合症孕中期母血筛查及羊水诊断分析

目的 探讨检测孕中期母血清中AFP，β-HCG浓度对筛壹唐氏综合症胎儿的作用。方法 利用微粒子酶免疫技术检测血清中甲胎蛋白（AFP）和绒毛膜促性腺激素（β-HCG）的浓度，结合各种影响因素，利用分析软件进行风险评估，再经羊水细胞染色体核型分析确诊。结果 3617例孕中期孕妇接受筛查，唐氏综合症高危者219例。阳性率6．1％。219例高危者中的178例接受羊水染色体检查。共查出染色体异常6例，其中唐氏综合证3例。结论 孕中期母血清中AFP，β-HCG的测定是一种无创性检测手段，对筛查唐氏综合症胎儿，减少其出生有重要意义。     

母血、羊水中胰岛素样生长因子测定及羊膜腔内给药早期诊治胎儿生长

目的 探讨胰岛素样生长因子(IGFs)与胎儿生长受限(FGR)的关系以及胎儿生长受限早期治疗的方法。方法 挑选FGR孕妇44例和正常孕妇36例,抽取中、晚期母血及羊膜腔穿刺术抽取羊水检测IGF-Ⅰ、IGF-Ⅱ水平。同时将44名FGR孕妇随机分为治疗组和对照组,FGR治疗组行羊膜腔内输注小儿氨基酸治疗,而FGR对照组采用孕妇静脉滴注复方氨基酸治疗,并运用多参数B超比较其疗效。结果 (1)FGR孕妇母血中IGF-Ⅰ水平、羊水中IGF-Ⅰ、IGF-Ⅱ水平显著低于同期正常孕妇(P<0.01),而两组孕妇母血中IGF-Ⅱ水平无显著性差异(P>0.05)。(2)经治疗后,FGR治疗组羊水中IGF-Ⅰ、IGF-Ⅱ水平显著升高(P<0.01),母血IGF-Ⅰ水平也明显升高(P<0.01);而FGR对照组IGF水平无明显改变(P>0.05)。(3)FGR治疗组羊水中IGF-Ⅰ、IGF-Ⅱ水平,母血IGF-Ⅰ水平较FGR对照组显著升高(P<0.01);FGR治疗组孕妇宫高、腹围,胎儿双顶径、股骨长度净增长值及新生儿出生体重均显著高于对照组(P<0.01),且治疗组胎儿出生体重接近正常水平。结论 检测母血IGF-Ⅰ及羊水中IGF-Ⅰ、IGF-Ⅱ水平可早期诊断FGR及监测胎儿宫内生长。羊膜腔内输注小儿氨基酸是治疗FGR的有效方法。     

母血、羊水中胰岛素样生长因子测定及羊膜腔内给药早期诊治胎儿生长

目的探讨胰岛素样生长网子（IGFs）与胎儿生长受限（FGR）的关系以及眙儿生长受限早期治疗的方法。方法挑选FGR孕妇44例和正常孕妇36例，抽取中、晚期母血及羊膜腔穿刺术抽取羊水检测IGF—Ⅰ、IGF-Ⅱ水平。同时将44名FGR孕妇随机分为治疗组和对照组，FGR治疗组行羊膜腔内输注小儿氨基酸治疗，而FGR对照组采用孕妇静脉滴注复方氨基酸治疗．并运用多参数B超比较其疗效。结果（1）FGR孕妇母血中IGF—Ⅰ水平、羊水中IGF—Ⅰ、IGF-Ⅱ水平显著低于同期正常孕妇（P〈0．01），而两组孕妇母血中IGF-Ⅱ水平无显著性差异（P〉0．05）。（2）经治疗后，FGR治疗组羊水中IGF—Ⅰ、IGF-Ⅱ水平显著升高（P〈0．01），母血IGF—Ⅰ水平也明显升高（P〈0．01）；而FGR对照组IGF水平无明显改变（P〉0．05）。（3）FGR治疗组羊水中IGF—Ⅰ、IGF-Ⅱ水平，母血IGF-Ⅰ水平较FGR对照组显著升高（P〈0．01）；FGR治疗组孕妇宫高、腹围，胎儿双顶径．股骨长度净增长值及新生儿出生体重均显著高于对照组（P〈0．01），且治疗组胎儿出生体重接近正常水平。结论检测母血IGF—Ⅰ及羊水中IGF—Ⅰ、IGF-Ⅱ水平可早期诊断FGR及监测胎儿宫内生长。羊膜腔内输注小儿氨基酸是治疗FGR的有效方法。     

Results and benefits of a maternal serum alpha-fetoprotein screening program

Maternal serum alpha-fetoprotein (MSAFP) screening was offered in a private suburban practice to 21,000 nondiabetic and 442 diabetic women with apparently normal pregnancies. Using 2.5 or greater multiples of the median as the normal upper limit, 249 (1.2%) had a raised MSAFP level. There were 25 neural tube defects (NTDs) (1.2/1,000 births); 18 were detected by screening and two by ultrasound scanning. Three had closed spina bifida lesions. Two had anencephaly with normal MSAFP levels, but were studied at more than 24 weeks' gestation. An additional 13 with raised MSAFP levels had other congenital defects. One in 400 women screened had a recommended amniocentesis; 26.4% of them had a fetus with an NTD or major malformation. Our detection efficiency before 24 weeks' gestation for anencephaly was 85.7% (12/14), 62.5% (5/8) for open and closed spina bifida, and 1/1 for encephalocele. A raised MSAFP level occurred in ten (2.3%) of the 442 diabetic women, four (0.9%) of whom had a fetus with an open NTS. A screening program should be established only where there is linked excellent interdisciplinary support among obstetrician, laboratory, clinical geneticist, ultrasonographer, and an identified program coordinator.     

羊水栓塞发病机理及诊治进展

羊水栓塞（amniotic Fluid embolism，AFE）是指羊水物质进入母血循环引起肺栓塞、休克、弥漫性血管内凝血（disseminated intravascular coagulation，DIC）等一系列严重症状的综合征。Clark报道AFE发病率约1：8000，80000，死亡率高达80％以上。AFE引起死亡的孕产妇数占孕产妇死亡总数的10％，20％。近年孕产妇病死率显著下降，而导致产妇直接死因的AFE一直未改变。可见AFE是一种发病率低，病死率高，但又不可预料且极其凶险的产科并发症。近年来通过临床病例的总结、研究，对AFE的发病原因及相关因素有了新的认识，并对早期诊断及治疗也有了新的进展。     

羊水栓塞诊断与治疗新进展

羊水栓塞是比较罕见的严重产科并发症,在1941年首先由Steiner和Luschbaugh描述,他们在一组分娩时死亡孕妇的肺循环中发现了来自胎儿的组织碎片.羊水栓塞的发生率为1:5000～1:80 000,分娩过程中发生占70%,产后发生的占30%,死亡率可以高达70%～80%.在孕产妇死亡原因的顺位中,一般会排在前5位,随着地区的不同和年份的不同,其顺位会有上升或下降.以上海为例,羊水栓塞在孕产妇死亡的顺位中1995年排第4位,1996年,1997年排第3,1998年排第2.     

细胞因子在子痫前期血清及羊水中的表达变化

目的探讨子痫前期中细胞因子的变化。方法随机选取患者120例,其中对照组40例,子痫前期患者80例。采用EHSA法检测分娩前、分娩后7d血清及羊水TNF—α、IL-1β水平。结果子痫前期患者的血清及羊水TNF—α、IL-1β水平明显高于对照组（t=1．358,P〈0．01）。患者产后7d的血清TNF-α、IL-1β水平较产前下降（t=1．358,P〈0．01）。结论细胞因子TNF—α、IL-1β在子痫前期中表达异常,提示子痫前期的发病可能与炎症有关。     

分娩启动宫缩时产妇血清及羊水中糖皮质激素改变

分娩启动是一个十分复杂的生理过程,包括子宫体肌细胞及子宫内膜等在内的诸多因素已经被广为研究.大量研究表明,糖皮质激素是启动分娩的重要激素[1],成人血清中的糖皮质激素有着周期性的变化,本研究探讨足月妊娠妇女分娩启动宫缩时血清及羊水中糖皮质激素的变化.     

Prenatal diagnosis of mucopolysaccharidosis by continuous, monodimensional electrophoresis of amniotic fluid glycosaminoglycans.

A continuous dimensional electrophoretic method was used in 15 urine samples of clinically diagnosed mucopolysaccharidoses I or IV. Twelve of the 15 were glycosaminoglycans band positive. Of the 12 one was KS band positive but methyl toluidine blue test was negative. The other 11 were positive with both methods. Prenatal diagnosis was done in 10 cases during their next pregnancy with the same method on the amniotic fluid. Two affected fetuses were diagnosed and proved, one after induced abortion and the other after full-term delivery.

     

足月妊娠临产前后羊水、母血和胎盘中TNF-α的表达

目的 探讨TNF—α在足月妊娠临产前后的变化和意义。方法 将足月妊娠60例，分为临产组30例和未临产组30例，应用放射免疫法测定母血、羊水中TNF—α，免疫组化SABC法对胎盘中TNF—α进行定位和定量检测。结果 临产组羊水中TNF—α水平较未临产组升高（P=0．000），胎盘中TNF—α定位于胎盘滋养细胞，且临产组较未临产组升高（P=0．000）。两组母血中TNF—α水平无变化（P=0．109）。结论 临产后羊水、胎盘中TNF—α发生了变化，而母血中的TNF—α无变化，足月妊娠局部组织的TNF—α升高可能导致了分娩发动。     

7例羊水栓塞诊断与抢救的临床分析

目的 分析7例羊水栓塞的临床诊断与抢救,提供临床诊治羊水栓塞的参考,以提高抢救成功率。方法选取2011年1月～2019年10月于本院住院治疗的7例羊水栓塞的产妇临床资料、救治措施、预后及有无并发症进行回顾性分析。结果 7例羊水栓塞患者中,4例行剖宫产术,3例阴道分娩,经多学科合作积极抢救,4例抢救成功,1例有肺挫裂伤、胸骨、肋骨骨折,其余3例无并发症,1例植物人状态,2例死亡(死于严重的DIC、多器官功能衰竭)。结论 羊水栓塞起病急骤、表现不一、进展快,死亡率高,因此早期识别、积极治疗,多学科合作,必要时及时行子宫切除术,可提高抢救成功率,改善预后、减少并发症的发生。