MTHFD1 is critical for the negative regulation of retinoic acid receptor signalling in anencephaly.

Neural tube defects are the most severe congenital malformations that result from failure of neural tube closure during early embryonic development, and the underlying molecular mechanisms remain elusive. Retinoic acid, an active derivative of vitamin A, is critical for neural system development, and retinoic acid receptor (RAR) signalling malfunctions have been observed in human neural tube defects. However, retinoic acid-retinoic acid receptor signalling regulation and mechanisms in neural tube defects are not fully understood. The mRNA expression of RARs and retinoid X receptors in the different human neural tube defect phenotypes, including 11 pairs of anencephaly foetuses, 10 pairs of hydrocephalus foetuses and nine pairs of encephalocele foetuses, was investigated by NanoString nCounter technology. Immunoprecipitation-mass spectrometry was performed to screen the potential interacting targets of retinoic acid receptor γ. The interactions between proteins were confirmed by co-immunoprecipitation and immunofluorescence laser confocal microscopy. Luciferase and chromatin immunoprecipitation with quantitative real-time polymerase chain reaction assays were used to clarify the underlying mechanism. Moreover, a neural tube defect animal model, constructed using excess retinoic acid, was used for further analysis with established molecular biology technologies. We report that level of retinoic acid receptor γ (RARγ) mRNA was significantly upregulated in the brain tissues of human foetuses with anencephaly. To further understand the actions of retinoic acid receptor γ in neural tube defects, methylenetetrahydrofolate dehydrogenase 1 was identified as a specific retinoic acid receptor γ target from IP-MS screening. Additionally, methylenetetrahydrofolate dehydrogenase 1 negatively regulated retinoic acid receptor γ transcription factor activity. Furthermore, low expression of methylenetetrahydrofolate dehydrogenase 1 and activation of retinoic acid receptor signalling were further determined in human anencephaly and a retinoic acid-induced neural tube defect mouse model. This study reveals that methylenetetrahydrofolate dehydrogenase 1, the rate-determining enzyme in the one-carbon cycle, might be a specific regulator of retinoic acid receptors; these findings provide new insights into the functional linkage between nuclear folate metabolism and retinoic acid receptor signalling in neural tube defect pathology.

Clinical presentation and outcomes of neonates born with neural tube defects- an experience from a level III B NICU in Western India.

PURPOSE: Neural tube defects (NTDs) are one of the most common congenital anomalies and a cause of chronic disability. The study was done to study outcomes of neural tube defects admitted at a tertiary level neonatal intensive care unit (NICU) from 2018 to 2022, a period of 4 years that also coincided with the COVID pandemic. The secondary outcome was to study the clinical presentation, associated anomalies and epidemiological features. METHODS: It was a retrospective observational study; data of infants was obtained from medical records and analysis was done. RESULTS: Thirty-four neonates were enrolled, of which there were 16 (47%) males and 18 (53%) females. History of pre-pregnancy maternal folate intake was present in 4 (11.7%) cases. 33 (97%) babies were diagnosed with meningomyelocele (MMC) and one each had anencephaly, iniencephaly and encephalocele, of which one had frontal and two had occipital encephalocele. The median age of surgery was 16 days of life with primary repair being the most common procedure followed by MMC repair with VP shunt. Twenty babies (58.8%) were discharged successfully, while 9 (26.5%) expired and 5 (14.7%) were discharged against medical advice; which can be attributed to the financial problems of the patients in a developing country. The overall deaths in our series were four (26.5%) which is slightly higher than other studies which may be due to the fact that this study was conducted during the COVID era with lesser rates of folate supplementation, reduced access to prenatal diagnosis coupled with poor follow-up and compliance of patients post-surgical repair. CONCLUSION: This study emphasizes the importance of periconceptional folic acid supplementation, prenatal diagnosis, early surgery and meticulous follow-up as being pivotal to improving outcomes in children with NTDs.

Post-cesarean section laparoscopic cholecystectomy: a case report.

BACKGROUND: Laparoscopic cholecystectomy at the time of cesarean section is novel in medicine. It is safe, feasible, and cost-effective. CASE PRESENTATION: A 29-year-old G3P2 + 0 woman had two previous cesarean sections. She was pregnant at 32 weeks. The fetus had anencephaly. She had acute cholecystitis. Laparoscopic cholecystectomy done at the time of termination of pregnancy by cesarean section. CONCLUSIONS: In a critical period, such as acute cholecystitis, the combination of laparoscopic cholecystectomy immediately post cesarean section is effective if the surgeon is highly qualified and experienced.

Neural tube defects: a review of global prevalence, causes, and primary prevention.

Neural tube defects (NTDs) are common birth defects and contribute to life-long disabilities, high medical care costs, and perinatal and child mortality. This review is a primer on prevalence, causes, and evidence-based prevention strategies for NTDs. The estimated average global prevalence of NTDs is two cases per 1000 births, amounting to approximately 214,000-322,000 affected pregnancies worldwide annually. Prevalence and associated adverse outcomes are disproportionately high in developing countries. NTDs have multiple risk factors including genetic and non-genetic (i.e., maternal nutritional status, pre-pregnancy diabetes, early pregnancy exposure to valproic acid (anti-epileptic medication), and a previous pregnancy affected by a NTD) factors. Maternal folate insufficiency before and during early pregnancy is the most common risk factor and is preventable. Folic acid (vitamin B9) is required for formation of the neural tube early in pregnancy, around 28 days after conception, when most women are unaware of their pregnancies. Current guidelines recommend that all women planning or capable of pregnancy take a daily supplement containing 400-800 µg of folic acid. Mandatory folic acid fortification of staple foods (e.g., wheat flour, maize flour, rice) is safe, economical, and the effective intervention for primary prevention of NTDs. Currently, about 60 countries are implementing mandatory folic acid fortification of staple foods, preventing just a quarter of all preventable NTD cases worldwide. There is an urgent need for active champions, including neurosurgeons and other healthcare providers, to generate political will and promote effective mandatory food fortification with folic acid, and reach equitable primary prevention of NTDs in all countries.

Transitioning care for adolescents with spina bifida in the US: challenges for management.

Open spina bifida (OSB) is a common neural tube defect. Medical and surgical care involves addressing the baseline orthopedic, urologic, and neurological dysfunction as well as the changes or declines that may occur as the patient ages. Given the complexity of this disease, coordinated, multidisciplinary care involving specialists in neurosurgery, orthopedics, urology, rehabilitation and physical medicine, pediatrics, and psychology is necessary to establish and optimize baseline function. Traditionally in the US, pediatric multispecialty spina bifida clinics have provided the patient with a coordinated medical support system. Unfortunately, this coordinated, medical home has been difficult to establish during the transition from pediatric to adult care. Medical professionals must have a strong understanding of OSB to properly manage the disease and detect and prevent associated complications. In this manuscript, we (1) describe the changing needs and challenges of people living with OSB over a lifespan, (2) delineate current practices in the transition of care for people with OSB from childhood to adulthood, and (3) provide recommendations for best practices in navigating the transition process for clinicians who provide care for those afflicted with this most complex congenital abnormality of the nervous system compatible with long term survival.

Barriers and facilitators to the implementation of mandatory folate fortification as an evidence-based policy to prevent neural tube defects.

BACKGROUND: Neural tube defects continue to be one of the main congenital malformations affecting the development of the nervous system and a significant cause of disability and disease burden to individuals living with these conditions. Mandatory food fortification with folic acid is, by far, one of the most efficacious, safe, and cost-effective interventions to prevent neural tube defects. However, most countries fail to effectively fortify staple foods with folic acid, impacting public health and healthcare systems and generating dismal disparities. AIM: This article discusses the main barriers and facilitators for implementing mandatory food fortification as an evidence-based policy to prevent neural tube defects worldwide. METHODS: A comprehensive review of the scientific literature allowed the identification of the determinant factors acting as barriers or facilitators for the reach, adoption, implementation, and scaling up of mandatory food fortification with folic acid as an evidence-based policy. RESULTS: We identified eight barriers and seven facilitators as determinant factors for food fortification policies. The identified factors were classified as individual, contextual, and external, inspired by the Consolidated Framework for Implementation of Research (CFIR). We discuss mechanisms to overcome obstacles and seize the opportunities to approach this public health intervention safely and effectively. CONCLUSIONS: Several determinant factors acting as barriers or facilitators influence the implementation of mandatory food fortification as an evidence-based policy worldwide. Notoriously, policymakers in many countries may lack knowledge of the benefits of scaling up their policies to prevent folic acid-sensitive neural tube defects, improve the health status of their communities, and promote the protection of many children from these disabling but preventable conditions. Not addressing this problem negatively affects four levels: public health, society, family, and individuals. Science-driven advocacy and partnerships with essential stakeholders can help overcome the barriers and leverage the facilitators for safe and effective food fortification.

A Revised Moral Appraisal of Early Induction of Labor in Cases of Anencephaly.

The central concern of this article is whether early induction of labor for an anencephalic fetus can ever be morally justified, particularly by a Catholic healthcare ethics committee. By revisiting and refining arguments in articles by Drane (1992) and Bole (1992) published in this journal, a revised argument - consistent with the Catholic moral tradition - can seemingly be constructed that a Catholic healthcare ethics committee might use to justify early induction of labor in some pregnancies involving an anencephalic fetus. Such a revised argument depends upon two central claims; first, that the anencephalic fetus in question is necessarily in the process of dying when early induction of labor occurs, and second, that the fetus is judged to be undergoing extraordinary or disproportionate means of preserving their life as a result of receiving ongoing maternal support of a mother's womb. The revised argument developed in this article aims to utilize the doctrine of double effect in conjunction with these two central claims to justify early induction of labor for anencephalic fetal persons in some circumstances. Unfortunately, the revised argument - if successful - would be at odds with a stance taken in the United States Conference of Catholic Bishops (USCCB) 1996 statement "Moral Principles Concerning Infants with Anencephaly." However, there is reason to believe the revised argument offered in this article is well aligned with other guidance from the USCCB, contained in the publication Ethical and Religious Directives for Catholic Healthcare Services (2018). This article concludes by noting some important limitations of the argument and offering hope that consideration of the argument ultimately helps to strengthen the Catholic moral tradition.

Neural tube defects.

Neural tube defects (NTDs), including spina bifida and anencephaly, are severe birth defects of the central nervous system that originate during embryonic development when the neural tube fails to close completely. Human NTDs are multifactorial, with contributions from both genetic and environmental factors. The genetic basis is not yet well understood, but several nongenetic risk factors have been identified as have possibilities for prevention by maternal folic acid supplementation. Mechanisms underlying neural tube closure and NTDs may be informed by experimental models, which have revealed numerous genes whose abnormal function causes NTDs and have provided details of critical cellular and morphological events whose regulation is essential for closure. Such models also provide an opportunity to investigate potential risk factors and to develop novel preventive therapies.

Birth prevalence of neural tube defects in eastern Africa: a systematic review and meta-analysis.

BACKGROUND: Neural tube defects (NTDs) are associated with high rates of neonatal mortality and morbidity worldwide. The promotion of folic acid fortification and supplementation in pregnant women by the Food and Drug Administration significantly decreased the incidence of NTDs in the United States. This practice is not widely adopted in Eastern Africa countries. We hypothesized that these countries experience a higher burden of NTDs than countries that promote the use of folic acid. We aimed to estimate the birth prevalence of NTDs in the United Nations (UN) Eastern African region. METHODS: PubMed (Medline), Embase, and Cochrane Library databases were systematically searched from inception to December 17, 2021. We included randomized controlled trials or observational studies that reported the prevalence estimates of NTDs in Eastern Africa. Random effects model was used to pool the effect estimates. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach was used to assess the certainty of the evidence. Outcome measures were overall and specific (spina bifida, anencephaly, encephalocele) rates of NTDs per 10,000 births, including live and stillborn cases. RESULTS: The meta-analysis included 20 studies consisting of 752,936 individuals. The pooled prevalence of all NTDs per 10,000 births in Eastern Africa was 33.30 (95% CI: 21.58 to 51.34). Between-study heterogeneity was high (I2 = 97%, p < 0.0001), The rate was highest in Ethiopia (60 per 10,000). Birth prevalence of spina bifida (20 per 10,000) was higher than anencephaly (9 per 10,000) and encephalocele (2.33 per 10,000). No studies on NTDs were identified in 70% of the UN Eastern Africa region. Birth prevalence increased by 4% per year from 1983 to 2018. The level of evidence as qualified with GRADE was moderate. CONCLUSION: The birth prevalence of NTDs in the United Nations region of Eastern Africa is 5 times as high as observed in Western countries with mandatory folic acid supplementation in place. Therefore, mandatory folic acid supplementation of stable foods may decrease the risk of NTDs in Eastern Africa.

Global prevalence of congenital anencephaly: a comprehensive systematic review and meta-analysis.

BACKGROUND: Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Timely preventive measures can be taken by knowing the exact prevalence of this common neural tube defect; thus, carried out through systematic review and meta-analysis, the present study was conducted to determine the worldwide prevalence, incidence and mortality of anencephaly. METHODS: Cochran's seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of "AND" and "OR" operators with no time limit to 2021. The I2 test was used to calculate study heterogeneity, and Begg and Mazumdar rank correlation tests were employed to assess the publication bias. Data were analyzed by Comprehensive Meta-Analysis software (Version 2). RESULTS: In this study, the statements of Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) were used. In the first stage, 1141 articles were found, of which 330 duplicate studies were omitted. 371 articles were deleted based on the inclusion and exclusion criteria by reviewing the title and abstract of the study. 58 articles were removed by reviewing the full text of the article because it was not relevant to the research. 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7-5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5-9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8-15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7-9.5 per ten thousand births). CONCLUSION: The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Cochran's seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of "AND" and "OR" operators with no time limit to 2021. Out of 1141 initial articles found, and after excluding repetitive ones in various databases and those irrelevant to inclusion criteria, 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7­5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5­9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8­15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7­9.5 per ten thousand births). The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Unraveling the complex genetics of neural tube defects: From biological models to human genomics and back.

Neural tube defects (NTDs) are a classic example of preventable birth defects for which there is a proven-effective intervention, folic acid (FA); however, further methods of prevention remain unrealized. In the decades following implementation of FA nutritional fortification programs throughout at least 87 nations, it has become apparent that not all NTDs can be prevented by FA. In the United States, FA fortification only reduced NTD rates by 28-35% (Williams et al., 2015). As such, it is imperative that further work is performed to understand the risk factors associated with NTDs and their underlying mechanisms so that alternative prevention strategies can be developed. However, this is complicated by the sheer number of genes associated with neural tube development, the heterogeneity of observable phenotypes in human cases, the rareness of the disease, and the myriad of environmental factors associated with NTD risk. Given the complex genetic architecture underlying NTD pathology and the way in which that architecture interacts dynamically with environmental factors, further prevention initiatives will undoubtedly require precision medicine strategies that utilize the power of human genomics and modern tools for assessing genetic risk factors. Herein, we review recent advances in genomic strategies for discovering genetic variants associated with these defects, and new ways in which biological models, such as mice and cell culture-derived organoids, are leveraged to assess mechanistic functionality, the way these variants interact with other genetic or environmental factors, and their ultimate contribution to human NTD risk.

Food Fortification With Folic Acid for Prevention of Spina Bifida and Anencephaly: The Need for a Paradigm Shift in Evidence Evaluation for Policy-Making.

Context-specific evidence evaluation is advocated in modern epidemiology to support public health policy decisions, avoiding excessive reliance on experimental study designs. Here we present the rationale for a paradigm shift in evaluation of the evidence derived from independent studies, as well as systematic reviews and meta-analyses of observational studies, applying Hill's criteria (including coherence, plausibility, temporality, consistency, magnitude of effect, and dose-response) to evaluate food fortification as an effective public health intervention against folic acid-preventable (FAP) spina bifida and anencephaly (SBA). A critical appraisal of evidence published between 1983 and 2020 supports the conclusion that food fortification with folic acid prevents FAP SBA. Policy-makers should be confident that with mandatory legislation, effective implementation, and periodic evaluation, food fortification assures that women of reproductive age will safely receive daily folic acid to significantly reduce the risk of FAP SBA. Current evidence should suffice to generate the political will to implement programs that will save thousands of lives each year in over 100 countries.

Magnitude and determinants of neural tube defect in Africa: a systematic review and meta-analysis.

BACKGROUND: Neural tube defects (NTDs) are a group of disorders that arise from the failure of the neural tube close between 21 and 28 days after conception. About 90% of neural tube defects and 95% of death due to these defects occurs in low-income countries. Since these NTDs cause considerable morbidity and mortality, this study aimed to determine the prevalence and associated factors of NTDs in Africa. METHODS: The protocol of this study was registered in the International Prospective Register of Systematic Reviews (PROSPERO number: CRD42020149356). All major databases such as PubMed/MEDLINE, EMBASE, CINAHL, Web of Science, African Journals Online (AJOL), and Google Scholar search engine were systematically searched. A random-effect model was used to estimate the pooled prevalence of NTDs in Africa, and Cochran's Q-statistics and I2 tests were used to assess heterogeneity between included studies. Publication bias was assessed using Begg 's tests, and the association between determinant factors and NTDs was estimated using a random-effect model. RESULTS: Of the total 2679 articles, 37 articles fulfilled the inclusion criteria and were included in this systematic review and meta-analysis. The pooled prevalence of NTDs in Africa was 50.71 per 10,000 births (95% CI: 48.03, 53.44). Folic acid supplementation (AOR: 0.40; 95% CI: 0.19-0.85), maternal exposure to pesticide (AOR: 3.29; 95% CI: 1.04-10.39), mothers with a previous history of stillbirth (AOR: 3.35, 95% CI: 1.99-5.65) and maternal exposure to x-ray radiation (AOR 2.34; 95% CI: 1.27-4.31) were found to be determinants of NTDs. CONCLUSIONS: The pooled prevalence of NTDs in Africa was found to be high. Maternal exposure to pesticides and x-ray radiation were significantly associated with NTDs. Folic acid supplementation before and within the first month of pregnancy was found to be a protective factor for NTDs.

Examining the Vanishing Twin Hypothesis of Neural Tube Defects: Application of an Epigenetic Predictor for Monozygotic Twinning.

Strong associations between neural tube defects (NTDs) and monozygotic (MZ) twinning have long been noted, and it has been suggested that NTD cases who do not present as MZ twins may be the survivors of MZ twinning events. We have recently shown that MZ twins carry a strong, distinctive DNA methylation signature and have developed an algorithm based on genomewide DNA methylation array data that distinguishes MZ twins from dizygotic twins and other relatives at well above chance level. We have applied this algorithm to published methylation data from five fetal tissues (placental chorionic villi, kidney, spinal cord, brain and muscle) collected from spina bifida cases (n = 22), anencephalic cases (n = 15) and controls (n = 19). We see no difference in signature between cases and controls, providing no support for a common etiological role of MZ twinning in NTDs. The strong associations therefore continue to await elucidation.

Craniorachischisis with Exencephaly.

BACKGROUND: Neural tube defects can be as mild as spina bifida, to as severe as anencephaly, with only a fraction of these cases presenting as both craniorachischisis and exencephaly. Case report: The G3, P1011 mother was 25-years old, who at an estimated fetal gestational age of 17 weeks had a fetal diagnosis of anencephaly based on a sonogram, resulting in elective pregnancy termination. The female fetus had an open neural tube defect, consisting of craniorachischisis and exencephaly. No abnormalities were noted in any other organs. Conclusion: Although mostly associated with anencephaly, craniorachischisis can also be associated with exencephaly in early pregnancy.

Laboratory screening and diagnosis of open neural tube defects, 2019 revision: a technical standard of the American College of Medical Genetics and Genomics (ACMG).

Open neural tube defects (ONTDs) include open spina bifida (OSB) and anencephaly. These defects are caused by incomplete closure of the neural tube at about 4 weeks of pregnancy. Levels of early second-trimester maternal serum (ms) alpha-fetoprotein (AFP) are sufficiently elevated in affected pregnancies to be used as a population-based screening test. The basic screening methodology was described in the late 1970s and screening programs were active a few years later. By identifying pregnancies with the highest msAFP levels, about 80% of OSB and 95% of anencephaly can be identified as early as 16 weeks gestation. The interpretation of msAFP levels is complicated by the need to consider multiple factors such as gestational age, maternal weight, maternal race, multiple gestations, and more. Testing for AFP and acetylcholinesterase in amniotic fluid and/or identification of the lesion by targeted ultrasound is considered diagnostic of ONTD. When a diagnosis is made, options include termination, surgery after delivery, or in utero surgery, depending on factors such as location and size of the defect, and the presence of any additional anomalies. Screening for ONTD should be performed as part of a comprehensive program linking primary obstetrical care providers, laboratorians, and high-risk clinicians.

Lower rates of neural tube defects in Israel following folic acid supplementation policy.

Neural tube defects (NTDs) are common and disabling congenital malformations that remain a public health challenge despite prevention efforts. In 2000, The Israeli Ministry of Health published recommendations on daily folic acid (FA) supplementation for women of reproductive age and established a national NTD registry. This study aims to evaluate the long-term impact of the FA supplementation policy on NTD rates in Israel and the need for further intervention. In this descriptive report, we present the rate of NTD-affected pregnancies recorded in the registry between 2000 and 2012, their subtype (anencephaly, spina bifida or other), outcome (live birth, stillbirth or pregnancy termination), ethnic group (Jewish, Bedouin and non-Bedouin Muslim) and years of maternal education. The final analysis included 2374 NTD cases reported between 2000 and 2012, compared with 1,668,073 live births. During this period NTD rates decreased from 20.3 to 11.2 cases per 10,000 live births, a 45% reduction. Reductions were seen in rates of spina bifida, anencephaly and encephalocele. NTD rates decreased in all pregnancy outcomes and in all ethnic groups, though rates among Bedouins remain high. Women with higher levels of education tended to have lower NTD rates, and were more prone to choose termination of an affected pregnancy. Following the institution of FA supplementation in Israel, a substantial reduction was seen in NTD rates. Nonetheless, Israeli NTD rates remain higher than in other developed countries. FA interventions should continue to be vigorously implemented, especially in vulnerable populations. The global success of mandatory fortification of grain strongly advocates its consideration in Israel.

Maternal exposure to ambient particulate matter 10 µm or less in diameter before and after pregnancy, and anencephaly risk: A population-based case-control study in China.

BACKGROUND: There is no epidemiological evidence on the effects of maternal exposure to ambient particulate matter 10 µm or less in diameter (PM10) and anencephaly risk in offspring. METHODS: We conducted a population-based case-control study in Liaoning Province, China. The case group consisted of 663 cases with anencephaly and the control group consisted of 7950 healthy infants from the Maternal and Child Health Certificate Registry of Liaoning Province that were born between 2010 and 2015. Daily PM10 concentrations were obtained from 77 monitoring stations located within the study area. A multivariable logistic regression model was established to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Maternal PM10 exposure was significantly associated with an increased risk of anencephaly at three months before conception (highest versus lowest tertile: OR = 1.74, 95% CI: 1.29-2.34; per 10 µg/m3 increment: OR = 1.13, 95% CI: 1.06-1.20) and three months after conception (highest versus lowest tertile: OR = 1.93, 95% CI: 1.44-2.60; per 10 µg/m3 increment: OR = 1.01, 95% CI: 0.95-1.08). The evaluation of shorter exposure windows revealed similar associations for PM10 exposure from the third month before pregnancy to the third month after pregnancy. CONCLUSIONS: Maternal PM10 exposure is positively associated with anencephaly risk during the critical period of neural system development.

Prenatal diagnosis of fetal microhydranencephaly: a case report and literature review.

BACKGROUND: The prenatal diagnosis of microhydranencephaly is important and needs to be distinguished from anencephaly, because unlike anencephaly, fetuses with microhydranencephaly can survive after birth. Herein, we report a case of microhydranencephaly that was diagnosed and distinguished from anencephaly prenatally. CASE PRESENTATION: The patient was an 18-year-old woman, 2 gravida nullipara, who presented at 15 weeks of gestation. Ultrasonography showed a normal biparietal diameter (BPD) and no major anomalies. At 23 weeks of gestation, an ultrasound examination revealed a BPD of 40 mm (-5.3 standard deviation, SD). At 29 weeks, anencephaly was suspected despite difficulty in visually examining the fetal head above the orbit. At 34 weeks, insertion of a metreurynter made it possible to observe the skull. Three-dimensional computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the presence of the fetal skull, a prominent occipital bone, sloping forehead, marked microcephaly, cerebral loss, and excess cerebrospinal fluid. This allowed differentiation between microhydranencephaly and anencephaly. She delivered vaginally at 37 weeks, and the child had a birth weight of 2342 g and a head circumference of 24 cm (-5.4 SD). The baby's head was flat above the forehead, with a suspected partial head defect. The baby received desmopressin acetate due to central diabetes insipidus 6 months after birth. CONCLUSIONS: The use of multiple imaging modalities and physical manipulation of the fetal head are required to accurately differentiate between microhydranencephaly and anencephaly.

An Unusual First-Trimester Ultrasound Presentation of the Acrania-Anencephaly Sequence: The "Turkish Turban" Sign.

A previously unrecognized first-trimester presentation of the acrania-anencephaly sequence is described. Ultrasound features included a constriction ring around the external base of the developing skull and an enlarged globular head, resembling a Turkish turban, with large cystic spaces replacing the brain. This constellation of findings was noted in 3 first-trimester fetuses. In 2 of them, it was possible to identify the amniotic membrane attached to the constriction ring. One case presented with anencephaly and fetal demise at 16 weeks. The other 2 women terminated the pregnancies and aborted anencephalic fetuses. This subtype of the acrania-anencephaly sequence could represent an earlier segmental rupture of the amnion, which subsequently entraps the developing fetal skull.