神经管缺陷的诊断

神经管缺陷(NTD)是指无脑畸形、开放性脊柱裂以及脑膨出。是最常见又严重的围产期新生儿畸形之一，其中又以无脑和脊柱裂为重要，发病率高，死亡率更高，地理分布差异较大。据我国1986～1987年资料，围产儿出生缺陷发生率为13．01%，其中NTD占全部缺陷儿的21%，居首位。1987年我国人口统计资料出生2258万新生儿，若按上述发生率推算，     

神经管缺陷的诊断

神经管缺陷(NTD)是指无脑畸形、开放性脊柱裂以及脑膨出。是最常见又严重的围产期新生儿畸形之一，其中又以无脑和脊柱裂为重要，发病率高，死亡率更高，地理分布差异较大。据我国1986～1987年资料，围产儿出生缺陷发生率为13．01%，其中NTD占全部缺陷儿的21%，居首位。1987年我国人口统计资料出生2258万新生儿，若按上述发生率推算，     

同型半胱氨酸与神经管畸形发生关系的研究进展

神经管畸形(NTDs)是由于在胚胎发育过程中,神经管闭合不全所引起的一组缺陷,包括无脑畸形、脑膨出、脊柱裂、脑脊膨出等,其发生率高,后果严重.世界范围内神经管畸形发病率为0.05％-0.2％[1].我国是神经管畸形的高发国家,每年大约有8万-10万例神经管畸形患儿出生,其中山西省发生率最高达1.02％[2].NTDs是多因素疾病,是由遗传和环境因素共同作用而导致的.研究表明,高同型半胱氨酸血症与神经管畸形的发生密切相关,已有报道,NTDs患儿母亲血浆同型半胱氨酸浓度明显升高[3].同型半胱氨酸(Hcy)是人体必需氨基酸甲硫氨酸的中间代谢产物[3],Hcy 是一种含硫氨基酸,在体内经蛋氨酸脱甲基化生成.     

超声诊断胎儿神经管畸形的应用价值

胎儿神经管畸形是一组主要包括无脑畸形和脊柱裂、脑膨出等疾病的严重出生缺陷,我国北方高于南方,神经管缺陷是临床最常见的先天畸形,约占全部畸形的1/4,我院查出112例胎儿异常中,神经管畸形发生率最高。因此,产前筛查出胎儿神经管畸形,对临床尽早进行干预,降低围产儿死亡率及避免此类患儿出生都有十分重要的意义。1资料与方法1.1资料2010年1月～2011年11月在我院接受系统性胎儿超声检查及常规胎儿超声检查的孕妇中共检出112例胎儿异常,其中32例神经管畸形,全部病例     

重庆市部分地区2009～2011年度出生缺陷人群监测结果分析

目的收集2008年10月1日至2011年9月30日重庆市以人群为基础的出生缺陷监测数据,描述围产儿出生缺陷的流行病学特征及其动态变化趋势。方法采用以人群为基础的监测方法收集资料。调查对象为孕28周至生后42d随访的围产儿,包括活产、死胎和死产。结果共收集围产儿22 250例,出生缺陷儿166例。围产儿出生缺陷总发生率为74.61/万。男性发生率为83.75/万,女性为61.65/万;城市为97.00/万,农村为69.20/万。出生缺陷儿中早产儿占15.06%,低出生体质量儿占16.27%,围产期病死率为12.05%。结论加强孕产妇孕期保健和产前检查是降低出生缺陷发生率的有效措施;合理配置农村医疗保健资源,提高基层人员的产前诊断水平,加强基层监测人员生后诊断能力的培训对出生缺陷人群监测的开展有着非常重要的意义。     

神经管缺陷的病因及危险因素综述

神经管缺陷(Neural Tube Defects.NTD)是指一组先天性的中枢神经系统畸形,包括无脑畸形、开放性脊柱裂、脑膨出、脑脊膜膨出。国外文献记载其发生率为0.62—10.4‰,国内为0.66—10.55‰。NTD在全部出生缺陷中约占12—36％,是引起围产儿死亡、影响人口素质的重要疾病。国内外医务工作者曾对其病因及致病危险因素做过多方面的研究,现将其综述如下。     

中国围产儿畸胎瘤的流行病学特征

目的：利用1987－1992年中国出生缺陷监测网收集的资料，描述围产儿畸胎瘤的发生水平和流行病学特征，方法：采用以医院为基础的监测方法收集资料，调查对象为孕28周到产后7天住院分娩的围产儿，包括活产，死胎和死产。结果：共收集围产儿4489692例；畸胎瘤238例，其中单发198例，合并有其他畸形者40例，中国人围产儿畸胎瘤发生率为0．53／万，单发畸胎瘤发生率为0．44／万，合并其他畸形者发生率为0．09／万。城市发生率为0．46／万，乡村发生率为0．66／万；男性围产儿畸胎瘤发生率为0．27／万，女性为0．80／万，畸胎瘤儿性别比为1：2．76。畸胎瘤围产儿病死率为55．0％，结论：中国围产儿畸胎瘤以单发为主，发生率变化无长期趋势。乡村发生率高于城镇，女性发生率高于男性，畸胎瘤儿病死率高，应进一步加强产前诊断和围产期管理。     

叶酸与神经管缺陷

约2%～3%的新生儿会出现严重的先天性畸形,常见的有神经管缺陷(NTDs)、唇腭裂和心脏畸形。神经管缺陷是一组影响神经系统发育的、严重的出生缺陷,包括无脑畸形、脊柱裂和脑膨出。出生记录显示美国每年约有2500名婴儿(或1‰～2‰)发生这些出生缺陷,一些受此影响的妊娠自然流产或选择性流产,95%以上的妇女此前并无家     

2003年福建省出生缺陷监测情况分析

目的了解福建省出生缺陷监测情况，为提高出生人口素质提供可靠依据。方法按全国出生缺陷监测方案要求，以医院为单位监测2003年孕28周-产后7d的围产儿。结果2003年监测围产儿41527人，出生缺陷发生率为97．53／万，不同年龄组先天缺陷发生率不同，差异有显著性（P〈0．05）。唐氏综合征、尿道下裂和外耳道缺陷城市发生率高于农村；神经管缺陷、无脑儿、脊柱裂、先天性脑积水、联体双胎农村发生率高于城市。唇裂合并腭裂、尿道下裂、直肠闭锁男性发病率高于女性，差异均有显著性（P〈0．05）。结论应系统对围产期孕妇监测，以做到早发现、早诊断，减少有生理缺陷儿出生。     

中国围产儿畸胎瘤的流行病学特征

目的　利用 1987～ 1992年中国出生缺陷监测网收集的资料 ,描述围产儿畸胎瘤的发生水平和流行病学特征。方法　采用以医院为基础的监测方法收集资料。调查对象为孕 2 8周到产后 7天住院分娩的围产儿 ,包括活产、死胎和死产。结果　共收集围产儿 44 896 92例 ;畸胎瘤 2 38例 ,其中单发 198例 ,合并有其他畸形者40例。中国人围产儿畸胎瘤发生率为 0 .5 3/万 ,单发畸胎瘤发生率为 0 .44 /万 ,合并其他畸形者发生率为 0 .0 9/万。城市发生率为 0 .46 /万 ,乡村发生率为 0 .6 6 /万 ;男性围产儿畸胎瘤发生率为 0 .2 7/万 ,女性为 0 .80 /万 ;畸胎瘤儿性别比为 1∶ 2 .76。畸胎瘤围产儿病死率为 5 5 .0 %。结论　中国围产儿畸胎瘤以单发为主 ,发生率变化无长期趋势。乡村发生率高于城镇 ,女性发生率高于男性。畸胎瘤儿病死率高 ,应进一步加强产前诊断和围产期管理     

中国30个县(市)1993～2000年神经管畸形在出生人群中的患病率及变动趋势分析

目的:描述中国30个县(市)1993至2000年神经管畸形(neural tube defects,NTD)在出生人群中的患病率及变动趋势.方法:资料来源于"中美预防出生缺陷和残疾合作项目"中出生缺陷监测的常规报告.研究对象为1993～2000年所有孕满20周的总出生人群(包括活产和死胎、死产).利用线性回归分析神经管畸形率按年变动的趋势.结果:在1993～2000年间,共监测到1 189 126个活产儿和死胎、死产儿出生,其中有明确诊断的神经管畸形儿1 264例;总出生人群中的神经管畸形率为10.63/10 000,1993年的畸形率最高(18.99/10 000), 1998年最低(6.05/10 000);无脑儿、脊柱裂和脑膨出在每10 000个出生儿中的患病率分别为4.71、4.39和1.53.在所有神经管畸形病例中,无脑儿和脊柱裂占的比例较高,分别为44.3% 和41.3% ,而脑膨出仅占14.4%.在神经管畸形病例中有 69.3% 为死胎、死产;而死胎、死产在无脑儿、脊柱裂和脑膨出中所占的比例分别为95.4% 、 43.7% 和 62.6%.线性回归分析结果显示,神经管畸形率从1993至2000年呈显著下降趋势(F=11.818,β=-0.814,P<0.05);而对3种畸形单独分析发现,无脑儿和脊柱裂率也呈显著下降趋势(P分别为0.004和0.026),没有发现脑膨出有显著的年度变化(P=0.227).与国外的9个监测地区比较结果显示,中国的神经管畸形率最高,约为英格兰和威尔士(最低)的7倍.结论:中国30个县(市)的神经管畸形率从1993至2000年呈显著下降趋势;然而中国的神经管畸形率仍然较高.     

Structural birth defects associated with neural tube defects in Hawai'i from 1986 until 2001

Using birth defects registry data, this study identified birth defects associated with anencephaly, spina bifida, and encephalocele. Musculoskeletal defects were associated with anencephaly; central nervous system defects, gastrointestinal atresia/stenosis, genitourinary system defects, and musculoskeletal system defects with spina bifida; and central nervous system defects, respiratory defects, oral clefts, genitourinary system defects, and musculoskeletal system defects with encephalocele.     

Prevalence and prenatal diagnosis of neural tube defects in Nova Scotia in 1980-84.

A survey of the records of all hospitals with obstetric services in Nova Scotia revealed that during 1980-84 there were 122 pregnancies involving a neural tube defect. The mean rate was 2/1000 births. Of the affected fetuses or infants 54% had spina bifida, 35% had anencephaly and 11% had encephalocele. The records showed that in the early part of the period studied at least one prenatal ultrasonographic examination had been performed in 60% of the pregnancies; in 1984 the rate was 74%. When examinations done before 16 weeks' gestation were excluded, the overall detection rates at the first ultrasonographic examination were 100% for anencephaly and 73% for spina bifida and encephalocele; the rates improved toward the end of the study period.     

Impact of folic acid fortification of the US food supply on the occurrence of neural tube defects.

CONTEXT: Daily consumption of 400 microg of folic acid before conception and during early pregnancy dramatically reduces the occurrence of neural tube defects (NTDs). Before food fortification, however, only an estimated 29% of US reproductive-aged women were taking a supplement containing 400 microg of folic acid daily. The US Food and Drug Administration authorized addition of folic acid to enriched grain products in March 1996, with compliance mandatory by January 1998. OBJECTIVE: To evaluate the impact of food fortification with folic acid on NTD birth prevalence. DESIGN, SETTING, AND POPULATION: National study of birth certificate data for live births to women in 45 US states and Washington, DC, between January 1990 and December 1999. MAIN OUTCOME MEASURE: Birth certificate reports of spina bifida and anencephaly before fortification (October 1995 through December 1996) compared with after mandatory fortification (October 1998 through December 1999). RESULTS: The birth prevalence of NTDs reported on birth certificates decreased from 37.8 per 100 000 live births before fortification to 30.5 per 100 000 live births conceived after mandatory folic acid fortification, representing a 19% decline (prevalence ratio [PR], 0.81; 95% confidence interval [CI], 0.75-0.87). During the same period, NTD birth prevalence declined from 53.4 per 100 000 to 46.5 per 100 000 (PR, 0.87; 95% CI, 0.64-1.18) for women who received only third-trimester or no prenatal care. CONCLUSIONS: A 19% reduction in NTD birth prevalence occurred following folic acid fortification of the US food supply. However, factors other than fortification may have contributed to this decline.     

Potential impact of pregnancy outcome on the completeness of diagnosis of birth defects, Hawai'i, 1986-2001

Using data from a birth defects registry, this study investigated whether pregnancy outcome influences completeness of diagnosis ascertainment for cases with seven selected birth defects. For anencephaly, spina bifida, encephalocele, trisomy 21, trisomy 13, and trisomy 18, the proportion of isolated cases was higher among elective terminations than among live births. This was not the situation for omphalocele.     

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.     

神经管缺陷重现危险的初步估计

对１９９０年７月至１９９３年６月全国２８省（市、自治区）（天津、浙江未参加）２３３所医院住院分娩，且分娩神经管缺陷儿的产妇２１５９例进行回顾性调查。结果发现：神经管缺陷的重现率为６．８６％；神经管缺陷重现率与畸形率密切相关，畸形率高的地区，重现率也高，全国神经管缺陷的高发区的重现率最高，为８．３２％，中发区为４．５０％，低发区为３．７０％；神经管缺陷的重现以出现相同的畸形的机率最大。     

Epidemiology of neural tube defects in China

During a period of 12 months (Oct. 1986 to Sep. 1987), 1,243,284 live and still births from 28 weeks of gestation to a period within 7 days after delivery were monitored in 945 hospitals of 29 provinces, cities and autonomous regions of China. A total of 3,404 cases of neural tube defects were recorded, among which there were 1,891 cases of anencephaly (55.6%), 1,050 cases of spina bifida (30.9%) and 463 cases of encephalocele (13.6%). The incidence of neural tube defects in China varied from 6.6 to 105.5 with a mean of 27.4 per 10,000. A female preponderance (35.7 per 10,000) over the male (19.2 per 10,000) was noted (P less than 0.01). The incidence of neural tube defects in the rural area (51.7 per 10,000) is higher than that in the urban area (15.5 per 10,000), (P less than 0.01).     

Effect of Pathoanatomic Diagnosis on the Quality of Birth Defects Surveillance in China1

Objective To provide evidence for more accurate diagnosis of birth defects based on the pathoanatomy of congenital malformations. Methods Data used in this study were obtained from Luliang City Hospital and three county hospitals of Shanxi province between February 2004 and March 2006. Autopsy and pathological examination of 160 dead fetuses and stillbirths were performed. Photos of dead fetuses and stillbirths were taken, tissues were cut into sections for pathological examination under microscope, all pathological information was recorded, and percentage of birth defects was calculated.Results The proportion of dead fetuses and stillbirths with or without congenital malformations was 84.4% (135/160) and 15.6% (25/160), respectively. There were 16 categories of major external and internal birth defects in 135 cases of such defects.Congenital heart defects, anencephaly and spina bifida had a higher prevalence rate in the study period. The prevalence rate of non-malformation death and birth defects < 28 gestational weeks and internal anomalies≥ 28 gestational weeks was 14.61% (61/4175) and 17.25% (72/4175), respectively. A total of 413 in situ anomalies were found in 135 cases of autopsy. Spina bifida,anencephaly, congenital heart defects, aplasia or accessory lobe of lung, renal agenesis and dysplasis and congenital hydrocephaly were more closely associated with severe malformations than with mitis malformations. The cases of dead fetuses and stillbirths with multiple malformations (≥ 2 in situ anomalies) had a higher proportion (74.1%), whereas those with isolated malformations had a lower proportion (25.93%). Conclusion The occurrence of congenital malformations in different embryonic developmental stages affects multiple organs. Postmortem examination of internal and multiple malformations of fetal deaths and stillbirths can provide more accurate diagnostic information for birth defects.     

Decline in the incidence of neural tube defects after the national fortification of flour (1997-2005)

OBJECTIVE: To evaluate the effect of flour fortification with folic acid on the incidence of neural tube defects (NTDs) in babies. We also report the pattern of NTDs, and we compare it with those reported previously. METHODS: All babies who were born with NTDs at King Abdul-Aziz University Hospital (KAUH), Jeddah, Kingdom of Saudi Arabia between 1997 and 2005 were included in the study. The incidence of NTDs was compared between the eras before flour fortification (1997-2000) and the eras after fortification. RESULTS: We have observed a decline in NTD incidence in the last decade from 1.9/1000 live births (1997-2000) to 0.76/1000 live births (2001-2005). Forty-two babies were born with NTDs with a male to female ratio of 1.1:1. Sixty percent received folic acid during pregnancy, but none pre-conception. Eighty-three percent of the cases had myelomeningocele (MMC), 12% had encephalocele, 2.5% had meningocele, and another 2.5% had anencephaly. Ninety-one percent of MMC patients had severe physical disability. Thirty-two children (91%) had hydrocephalus, which required shunting in the neonatal period and 22 children (63%) had clubfeet. CONCLUSION: After folic acid flour fortification, there was an apparent decline in the incidence of NTDs in babies born at KAUH. However, the incidence is still high and associated with serious morbidity. This stresses the need for innovative programs to increase folic acid consumption by women of childbearing age, to reduce NTDs.