Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Neural Tube Defects”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35Linked to original sources
PubMed2002

Knowledge, use, and education regarding folic acid supplementation: continuation study of women in Colorado who had a pregnancy affected by a neural tube defect.

BACKGROUND: This study was conducted to: (1) determine whether women who have had a neural tube defect (NTD) affected pregnancy know about recommendations for NTD recurrence prevention; (2) educate them about the recommendations; and (3) ensure that they have access to folic acid prior to another pregnancy. METHODS: Colorado women who had an NTD affected pregnancy in 1999 or later were interviewed about their knowledge and use of folic acid, provided with verbal information about folic acid and NTD prevention, and offered written information and a voucher for free folic acid. RESULTS: Thirty-two of 68 women who had an NTD affected pregnancy were interviewed. Of these, 22 (69%) were aware of the 0.4 mg. folic acid recommendation for women of child bearing age who have not had an NTD affected pregnancy (MMWR, '91). Only 15 (47%) of the women knew about the U.S. Public Health Service recommendation (MMWR, '92) to consume 4.0 mg of folic acid prior to another pregnancy for NTD recurrence prevention. Twenty-five (78%) of the women reported taking a multivitamin or folic acid daily. CONCLUSIONS: Nine years after national folic acid recommendations, a majority of interviewed women (53%) with NTD affected pregnancies did not know about the recommendation to consume 4.0 mg of folic acid for NTD recurrence prevention. This sample of women are receptive to information about folic acid. Health care providers and public health officials should ensure that education about folic acid is provided in an effective and timely manner to women with NTD-affected pregnancies.

Colorado↗
PubMed1984

Amniotic fluid gamma-glutamyl transferase activity in trisomy 21 and neural tube defects.

The amniotic fluid gamma-glutamyl transferase (gamma GT) has been measured in normal pregnancies (n = 128), six pregnancies associated with trisomy 21 and 12 pregnancies involving a foetus with a neural tube defect. In normal pregnancies, the amniotic fluid gamma GT activity falls during the second trimester, the level at 20 wk being 60% of that at 14 wk. In the six cases of trisomy 21 and 8 of the 12 cases with neural tube defects, the gamma GT levels were below the 95% confidence limit.

Amniotic Fluid↗
PubMed1994

Maternal hyperhomocysteinemia: a risk factor for neural-tube defects?

The maternal vitamin status, especially of folate, is involved in the pathogenesis of neural-tube defects (NTDs). Maternal folate administration can prevent these malformations. The precise metabolic mechanism of the beneficial effect of folate is unclear. In this study we focus on homocysteine accumulation, which may derive from abnormalities of metabolism of folate, vitamin B12, and vitamin B6. We studied nonpregnant women, 41 of whom had given birth to infants with NTDs and 50 control women who previously had normal offspring. The determinations included the plasma total homocysteine both in the fasting state and 6 hours after the ingestion of a methionine load. In addition, we measured the fasting blood levels of folate, vitamin B12, and vitamin B6. The mean values for both basal homocysteine and homocysteine following a methionine load were significantly increased in the group of women who previously had infants with NTDs. In nine of these subjects and two controls, the values after methionine ingestion exceeded the mean control by more than 2 standard deviations. Cystathionine synthase levels in skin fibroblasts derived from these methionine-intolerant women were within the normal range. Our findings suggest a disorder in the remethylation of homocysteine to methionine due to an acquired (ie, nutritional) or inherited derangement of folate or vitamin B12 metabolism. Increased homocysteine levels can be normalized by administration of vitamin B6 or folate. Therefore, we suggest that the prevention of NTDs by periconceptional folate administration may effectively correct a mild to moderate hyperhomocysteinemia.

Adult↗
PubMed1980

Amniotic fluid acetylcholinesterase isoenzyme patterns in the diagnosis of neural tube defects.

Acetylcholinesterase isoenzyme patterns were determined in amniotic fluid from 140 normal pregnancies and from 68 pregnancies with various fetal abnormalities. A fast acetylcholinesterase isoenzyme was detected in all cases of neural tube defect, exomphalos and intrauterine death. The fast isoenzyme was not seen in any of the normal pregnancies. Blood-contaminated amniotic fluids with false positive elevation of alphafetoprotein gave a single isoenzyme band. The qualitative demonstration of a fast acetylcholinesterase isoenzyme in amniotic fluid provides a useful adjunct to the alphafetoprotein assay in the prenatal diagnosis of neural tube defects.

Acetylcholinesterase↗
PubMed2002

Incidence of open neural tube defects in Nova Scotia after folic acid fortification.

BACKGROUND: With the goal of preventing open neural tube defects (NTDs), recommendations for folic acid supplementation before conception were introduced in Canada in 1994, and by November 1998 Canadian grain products were being fortified with folic acid. We wished to determine whether the annual incidence of open NTDs in Nova Scotia, including those in stillbirths and terminated pregnancies, changed after the introduction of either folic acid supplementation or fortification. METHODS: For the 10-year period from Jan. 1, 1991, to Dec. 31, 2000, we retrospectively extracted the total number of births in Nova Scotia and the number of live births and stillbirths with open NTDs from the Nova Scotia Atlee Perinatal Database as well as the number of terminated pregnancies affected by NTDs from the Fetal Anomaly Database. We determined the total annual incidence of all open NTDs, and of the subgroups spina bifida and anencephaly, per 1000 births in the province during the periods before (1991-1994) and after (1995-1998) folic acid supplementation initiatives were begun but before folic acid fortification of grain products was implemented, and during the periods before (1991-1997) and after (1998-2000) fortification. RESULTS: In the period after supplementation initiatives were begun but before fortification was implemented, the incidence of open NTDs did not change significantly: the mean annual rate was 2.55 per 1000 births during 1991-1994 and 2.61 per 1000 births during 1995-1997 (relative risk [RR] 1.02, 95% confidence interval [CI] 0.77-1.35). After the fortification was implemented the incidence of open NTDs decreased by more than 50%: the mean annual rate was 2.58 per 1000 births during 1991-1997 and 1.17 per 1000 births during 1998-2000 (relative risk 0.46, 95% CI 0.32-0.66). INTERPRETATION: The recommendations for folic acid supplementation alone did not appear to succeed in reducing the incidence of open NTDs in Nova Scotia, whereas the fortification of grain products with folic acid did result in a significant reduction in the incidence.

Adult↗
PubMed2005

Greater maternal weight and the ongoing risk of neural tube defects after folic acid flour fortification.

OBJECTIVE: Maternal obesity is likely a risk factor for neural tube defects (NTDs). By late 1997, it became mandatory in Canada that all refined wheat flour be fortified with folic acid. Because overweight women may consume greater quantities of refined wheat flour, we questioned whether their risk of NTD changed after flour fortification. METHODS: A retrospective population-based study was conducted between 1994 and late 2000. We included all Ontarian women who underwent antenatal maternal screening at 15 to 20 weeks of gestation. Self-declared maternal date of birth, ethnicity, current weight, and the presence of pregestational diabetes mellitus were recorded in a standardized fashion on the maternal screening requisition sheet. The presence of NTDs was systematically detected both antenatally and postnatally. The risk of open NTD was evaluated across maternal weight quartiles and deciles, and an interaction between greater maternal weight and the presence of flour fortification was tested using multiple logistic regression analysis. RESULTS: A total of 292 open NTDs were detected among 420,362 women. The adjusted odds ratio (OR) for NTD was 1.2 (95% confidence interval [CI] 1.1-1.3) per 10-kg incremental rise in maternal weight. Comparing the highest with the lowest quartile of maternal weight, the adjusted OR for NTD was 2.6 (95% CI 1.8-4.0). A similar finding was observed for the highest compared with lowest weight deciles (adjusted OR 3.3, 95% CI 1.7-6.2). The interaction between elevated maternal weight and the presence of folic acid flour fortification was of borderline significance (P = .09). Before fortification, greater maternal weight was associated with a modestly increased risk of NTD (adjusted OR 1.4, 95% CI 1.0-1.8); after flour fortification, this effect was more pronounced (adjusted OR 2.8, 95% CI 1.2-6.6). CONCLUSION: These data emphasize the higher risk of NTD associated with increased maternal weight, even after universal folic acid flour fortification. Beyond periconceptional folic acid use, consideration should be given to testing whether prepregnancy weight reduction is an independent means of preventing NTD. LEVEL OF EVIDENCE: II-2.

Body Constitution↗
PubMed2003

[Folic acid reduces risks of having fetus affected with neural tube defects: dietary food folate and plasma folate concentration].

OBJECTIVES: Risk of having fetus affected with neural tube defects can be reduced by maternal periconceptional folic acid supplementation. The purpose of the present study is to investigate how folate is taken from diets and to measure plasma folate concentrations. SUBJECTS AND METHODS: A total of 222 women comprising 5 groups, i.e., healthy women, mothers of myelodysplastic patients, pregnant women, myelodysplastic patients, nurse students, participated in our study. Food frequency questionnaires kept 3 days were analyzed based on the 5th standard table of food composition in Japan. Plasma folate concentrations were measured by means of chemiluminescent immunoassay method. Changes in plasma folate concentrations and possible adverse effects following the folic acid supplementation for 16 weeks were also investigated. RESULTS: The dietary intake of folate, plasma folate concentration and energy intake averaged 293 micrograms/day, 8.1 ng/ml and 1,857 Kcal, respectively, among the subjects. Pregnant women took the largest amount of folate from diets and demonstrated the highest plasma folate concentration among the groups. The dietary folate in myelodysplastic patients and nurse students was significantly lower compared to that of healthy women. The Recommended Dietary Allowance of folate was not fulfilled in 22% of non-pregnant adult women and 72% of pregnant women. The dietary folate was mainly taken from the 3rd food group but the 4th group of food was consumed most. Mean folate intake was significantly correlated with circulating concentrations of serum folate (p = 0.012 r = 0.186). The consecutive administration of 400 micrograms supplements for 16 weeks increased a baseline plasma value of 8.7 ng/ml to 32.6 but fell down rapidly to 17.3 24 hours later without any adverse effects. CONCLUSIONS: The dietary folate and serum folate concentrations averaged 293 micrograms/day and 8.1 ng/ml, respectively. The former is the first report based on the 5th standard table of food composition in Japan. Majority of pregnant women took less dietary folate than what recommended by the government. Those who are capable of becoming pregnant are recommended to consume much of the 3rd food group and those who are planning to become pregnant are recommended to take 400 micrograms of folic acid supplements from 4 weeks before to 12 weeks after conception.

Adolescent↗
PubMed1993

Recommendations on the use of folic acid supplementation to prevent the recurrence of neural tube defects. Clinical Teratology Committee, Canadian College of Medical Geneticists.

OBJECTIVE: To prevent the recurrence of neural tube defects (NTDs) in families at increased risk of having offspring with NTDs with the use of periconceptional folic acid supplementation. OPTIONS: Genetic counselling and prenatal diagnosis of NTDs. OUTCOMES: NTDs cause stillbirth, neonatal death and severe disabilities. The cost for medical care and rehabilitation in the first 10 years of life of a child with spina bifida cystica was estimated to be $42,507 in 1987. EVIDENCE: The authors reviewed the medical literature, communicated with investigators from key studies, reviewed policy recommendations from other organizations and drew on their own expertise. A recent multicentre randomized controlled trial showed that among women at high risk of having a child with an NTD those who received 4 mg/d of folic acid had 72% fewer cases of NTD-affected offspring than nonsupplemented women. Two previous intervention studies also demonstrated that folic acid supplementation was effective in reducing the rate of NTD recurrence. Several retrospective studies support this conclusion. VALUES: Recommendations are the consensus of the Clinical Teratology Committee of the Canadian College of Medical Geneticists (CCMG) and have been approved by the CCMG Board. The committee believes that primary prevention of NTDs is preferable to treatment or to prenatal detection and abortion. BENEFITS, HARMS AND COSTS: Folic acid supplementation should result in fewer NTDs among infants in Canada and ancillary savings in medical costs. The recommended dosage of folic acid is not known to be associated with adverse effects. Higher dosages of folic acid may make vitamin B12 deficiency difficult to diagnose and may alter seizure frequency in patients with epilepsy due to drug interactions with anticonvulsants. RECOMMENDATIONS: A minimum dosage of folic acid of 0.8 mg/d, not to exceed 5.0 mg/d, is recommended along with a well-balanced, nutritious diet for all women who are at increased risk of having offspring with NTDs and who are planning a pregnancy or may become pregnant. Supplementation should begin before conception and continue for at least 10 to 12 weeks of pregnancy. VALIDATION: These guidelines are similar to those of the Society of Obstetricians and Gynaecologists of Canada, the US Centers for Disease Control and Prevention and the Department of Health in Britain. SPONSORS: These guidelines were developed by the CCMG Clinical Teratology Committee and endorsed by the Board of the CCMG. No funding for the development of these guidelines was obtained from any other sources.

Female↗
PubMed1987

Pregnancies of mothers with a neural tube defect child: outcomes and recurrence risks.

Ninety-four mothers who had been in contact with the Center for Human Genetics of the University of Leuven (Belgium) after the birth of a child with neural tube defect were questioned about the outcomes of their pregnancies. To this end a structured interview and a mailed questionnaire were used. The recurrence rate for neural tube defects after the birth of one affected child was 2.9%. This number is at the lower border of the risk rates (between 3% and 5%) generally given to parents during genetic counseling sessions. The relative amount of miscarriages was larger in the interviewed group than in the Belgian population in general.

Abortion, Spontaneous↗
PubMed1999

Defective neural tube morphogenesis and altered apoptosis in the absence of both JNK1 and JNK2.

Mice lacking both c-Jun-NH(2)-terminal kinases (JNK1 and JNK2) were generated to define their roles in development. Jnk1/jnk2 double mutant fetuses die around embryonic day 11 (E11) and were found to display an open neural tube (exencephaly) at the hindbrain level with reduced apoptosis in the hindbrain neuroepithelium at E9.25. In contrast, a dramatic increase in cell death was observed one day later at E10.5 in both the hindbrain and forebrain regions. Moreover, about 25% of jnk1-/-jnk2+/- fetuses display exencephaly probably due to reduced levels of JNK proteins, whereas jnk1+/-jnk2-/- mice are viable. These results assign both pro- and anti-apoptotic functions for JNK1 and JNK2 in the development of the fetal brain.

Animals↗
PubMed1984

Neural-tube defects and vitamins: the need for a randomized clinical trial.

It has been suggested that taking extra vitamins around the time of conception may reduce the risk of fetal neural-tube defects. We have examined the evidence for this and conclude that there is considerable doubt about the efficacy of such a regimen. Also, it cannot be assumed that the taking of extra vitamins has no adverse medical effects. We give reasons for our view that a large randomized clinical trial is ethical and the only satisfactory way of resolving the matter. The Medical Research Council is currently conducting such a study in centres in Britain and abroad, involving women who have already had a pregnancy with a fetal neural-tube defect. The design of the Medical Research Council study is described briefly.

Anencephaly↗
PubMed1995

Folate metabolism and neural tube defects: a review.

The importance of folate in normal fetal development and wellbeing has been recognized only during the past three decades and knowledge concerned is still far from complete. In man, folate acts as a substrate in the transfer of one-carbon moieties and thereby, plays an essential role in the synthesis of several amino acids such as methionine and nucleic acids. Consequently, folate requirements are related to the amount of tissue growth. Epidemiological, clinical and teratological research showed that this B-vitamin is particularly involved in the prevention and pathogenesis of neural tube defects. Therefore, in this review the metabolism of folate has been outlined. Furthermore, the characteristics of the various genically determined folate 'deficiencies' as well as a possible biochemical explanation of the relationship between folate and neural tube defects are being discussed. Finally, the new recommendations launched in November 1993 by the Dutch Health Council as well as the Food and Nutrition Council with regard to folate supplementation in the prevention of neural tube defects are presented.

Embryonic and Fetal Development↗
PubMed2001

Circletail, a new mouse mutant with severe neural tube defects: chromosomal localization and interaction with the loop-tail mutation.

Circletail (Crc) is a new mouse mutant that exhibits a severe form of neural tube defect, craniorachischisis, in which almost the entire neural tube fails to close. This phenotype is seen in very few other mutants, the best characterized of which is loop-tail (Ltap(Lp), referred to hereafter as Lp). We tested the possibility of allelism between Lp and Crc by intercrossing Lp/+ and Crc/+mice. A proportion of double heterozygotes (Lp/+,Crc/+) exhibit craniorachischisis, revealing failure of complementation. However, genetic analysis shows that Crc is not linked to the markers that flank the Lp locus and cannot, therefore, be an allele of Lp. A genome-wide scan has localized the Crc gene to a region of 8.8 cM on central chromosome 15. Partial penetrance of the craniorachischisis phenotype in Crc/+,Lp/+double heterozygotes suggests the existence of a third, unlinked genetic locus that influences the interaction between Crc and Lp.

Alleles↗
PubMed1981

Quantitative and qualitative assay of amniotic-fluid acetylcholinesterase in the prenatal diagnosis of neural tube defects.

In 110 amniotic fluids the specific acetylcholinesterase was determined quantitatively and qualitatively. In the quantitative assay there were a considerable number of false positives and false negatives, although the mean value of the normal controls differed significantly from that of neural tube defect pregnancies. By the electrophoretic separation of acetylcholinesterase, however, all fluid samples with borderline alpha-fetoprotein levels or fetal blood contamination could be correctly classified. With the exception of one skin-covered spina bifida all neural tube defects in the second trimester could be identified by this method. The second fast-moving band characteristic of the specific acetylcholinesterase was also present in abdominal wall defects and intrauterine death.

Acetylcholinesterase↗
PubMed1989

The role of ultrasonography and amniocentesis in the evaluation of pregnancies at risk for neural tube defects.

To assess the relative efficacy of amniocentesis versus targeted (detailed) ultrasonography, 225 patients referred because of an elevated maternal serum alpha-fetoprotein level (79.6%) or a family history of neural tube defect (20.4%) were evaluated. Ultrasonographic examination alone detected all 26 fetal abnormalities (11 cases of anencephaly, 10 cases of open spina bifida, and five other anomalies). Twenty-eight patients declined amniocentesis; all had normal pregnancy outcomes. Of the 167 patients with apparently normal fetal anatomy by sonography, seven had elevated alpha-fetoprotein levels but no acetylcholinesterase in the amniotic fluid. Six of these pregnancies resulted in normal infants; one infant had congenital nephrosis. The remaining 160 patients had normal sonograms with normal amniotic fluid alpha-fetoprotein levels and no fetal malformations at delivery. Although these results suggest that targeted ultrasonography by experienced personnel is a reasonable alternative to amniocentesis in evaluations for neural tube defects, the availability, cost-effectiveness, and diagnostic accuracy of this approach must be well documented in large prospective studies.

Acetylcholinesterase↗
PubMed2002

Double-positive maternal serum screening results for down syndrome and open neural tube defects: An indicator for fetal structural or chromosomal abnormalities and adverse obstetric outcomes.

OBJECTIVE: The study was designed to evaluate whether double positive maternal serum screening results for Down syndrome and open neural tube defects indicate an increased risk of adverse perinatal outcome. STUDY DESIGN: A retrospective case-control study was conducted. In a cohort of 170,394 women who underwent maternal serum triple screening in Ontario, Canada, between October 1995 and September 1998, 189 women received positive screening results for both Down syndrome and neural tube defects. Each case was matched to 5 control subjects who had negative screening results for test center, maternal age, and specimen date. The risks for adverse perinatal outcomes were compared. RESULTS: Women with double-positive screening results had significantly higher risks of having fetuses with structural abnormalities (odds ratio, 14.5) and chromosomal anomalies (odds ratio, 36.3). They also had higher risks of having preeclampsia (odds ratio, 6.7), small-for-gestational age (odds ratio, 9.7), preterm delivery (odds ratio, 5.9), miscarriage, and intrauterine fetal death (odds ratio, 11.8). CONCLUSION: Double-positive maternal serum screening results are associated with fetal structural and chromosomal abnormalities and/or adverse pregnancy outcomes. Close fetal and maternal surveillance are indicated when such pregnancies are identified.

Case-Control Studies↗
PubMed1991

Vitamins, folic acid and neural tube defects: comments on investigations in the United States.

No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S.

Female↗
PubMed1998

[Dynamic variation of incidence of neural tube defects during 1988 to 1992 in China].

OBJECTIVE: To study the variation trend in incidence of neural tube defects (NTDs) during 1988 to 1992 in China. METHODS: Data were collected by hospital-based monitoring, with women of gestation of 28 weeks to seven days after birth as study subjects. And, 3,246,408 perinates were monitored in the National Birth Defect Monitoring Network in 30 provinces, municipalities and autonomous regions all over the country, and 7,778 cases of NTDs during 1988 to 1992 were recorded and analyzed. RESULTS: Incidence of NTDs was 18.0 per ten thousand in 1992, 28.9% reduction from 25.3 per ten thousand in 1988, and yearly average reduction of 8.2%. Incidence of NTDs decreased by 30.5% and 34.2% in rural and urban areas, respectively, by 30.5% and 27.8% in the north and the south, respectively, and incidence of anencephaly and encephalocele fell by 34.2% and 48.5%, respectively. CONCLUSION: Incidence of NTDs showed a falling trend in China, more decrease in rural area and in the north than in urban areas and in the south, respectively, and incidence of anencephaly and encephalocela fell faster.

Anencephaly↗