vitamin-b-12 and Abortion--Spontaneous

One-carbon metabolism is crucial for the maintenance of healthy pregnancy and alterations in this pathway have been associated with various pregnancy-related complications. Therefore, the present study was conducted to test the hypothesis that the altered folic acid, vitamin B12 and homocysteine levels are associated with the risk of early pregnancy loss (EPL). Plasma folic acid, vitamin B12 and homocysteine levels were analyzed in 83 females with EPL and 70 healthy pregnant females in their first trimester. Further, meta-analyses of folic acid, vitamin B12 and homocysteine were also performed involving various eligible studies. Results from our case-control study and meta-analysis showed that folic acid deficiency is not associated with the risk of EPL. On the other hand, low vitamin B12 and hyperhomocysteinemia were individually found to be significant risk factors for EPL in the present study (P < .01, P < .05, respectively) and meta-analysis as well (P < .001, P < .05, respectively). Vitamin B12 deficiency in combination with hyperhomocysteinemia was a more serious risk factor for EPL (Odds Ratio = 4.98, P = 0.002). Therefore, we conclude that vitamin B12 deficiency and elevated homocysteine levels are independent risk factors for EPL, and of higher risk when combined. The assessment of vitamin B12 and homocysteine levels may serve as a good screening marker for EPL risk.

Topics: Abortion, Spontaneous; Adult; Case-Control Studies; Female; Folic Acid; Folic Acid Deficiency; Homocysteine; Humans; Hyperhomocysteinemia; Maternal Nutritional Physiological Phenomena; Meta-Analysis as Topic; Nutritional Status; Odds Ratio; Pregnancy; Pregnancy Complications; Risk Factors; Vitamin B 12; Vitamin B 12 Deficiency; Young Adult

The importance of folate in reproduction can be appreciated by considering that the existence of the vitamin was first suspected from efforts to explain a potentially fatal megaloblastic anemia in young pregnant women in India. Today, low maternal folate status during pregnancy and lactation remains a significant cause of maternal morbidity in some communities. The folate status of the neonate tends to be protected at the expense of maternal stores; nevertheless, there is mounting evidence that inadequate maternal folate status during pregnancy may lead to low infant birthweight, thereby conferring risk of developmental and long-term adverse health outcomes. Moreover, folate-related anemia during childhood and adolescence might predispose children to further infections and disease. The role of folic acid in prevention of neural tube defects (NTD) is now established, and several studies suggest that this protection may extend to some other birth defects. In terms of maternal health, clinical vitamin B12 deficiency may be a cause of infertility or recurrent spontaneous abortion. Starting pregnancy with an inadequate vitamin B12 status may increase risk of birth defects such as NTD, and may contribute to preterm delivery, although this needs further evaluation. Furthermore, inadequate vitamin B12 status in the mother may lead to frank deficiency in the infant if sufficient fetal stores of vitamin B12 are not laid down during pregnancy or are not available in breastmilk. However, the implications of starting pregnancy and lactation with low vitamin B12 status have not been sufficiently researched.

Topics: Abortion, Spontaneous; Child Development; Child Nutritional Physiological Phenomena; Child, Preschool; Congenital Abnormalities; Female; Folic Acid; Folic Acid Deficiency; Humans; Infant; Infant, Low Birth Weight; Infant, Newborn; Maternal Nutritional Physiological Phenomena; Neural Tube Defects; Nutritional Status; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Prenatal Nutritional Physiological Phenomena; Vitamin B 12; Vitamin B 12 Deficiency; Women's Health

The pathogenesis of human spontaneous abortion involves a complex interaction of several genetic and environmental factors. The firm association between increased homocysteine concentration and neural tube defects (NTD) has led to the hypothesis that high concentrations of homocysteine might be embryotoxic and lead to decreased fetal viability. There are several genetic polymorphisms that are associated with defects in folate- and vitamin B12-dependent homocysteine metabolism. The methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C polymorphisms cause elevated homocysteine concentration and are associated with an increased risk of NTD. Additionally, low concentration of vitamin B12 (cobalamin) or transcobalamin that delivers vitamin B12 to the cells of the body leads to hyperhomocysteinemia and is associated with NTD. This effect involves the transcobalamin (TC) 776C>G polymorphism. Importantly, the biochemical consequences of these polymorphisms can be modified by folate and vitamin B12 supplementation. In this review, I focus on recent studies on the role of hyperhomocysteinemia-associated polymorphisms in the pathogenesis of human spontaneous abortion and discuss the possibility that periconceptional supplementation with folate and vitamin B12 might lower the incidence of miscarriage in women planning a pregnancy.

Topics: Abortion, Spontaneous; Animals; Embryonic Development; Folic Acid; Homocysteine; Humans; Methylenetetrahydrofolate Reductase (NADPH2); Polymorphism, Genetic; Transcobalamins; Vitamin B 12

The fetus, the neonate, and the pregnant woman have a greater requirement for folic acid and vitamin B12 and are more likely to suffer from a deficiency of these vitamins. This article reviews the source, requirement, absorption, and metabolism of these vitamins and discusses the problems attributed to their deficiency in pregnancy and in the neonatal period.

Topics: Abortion, Spontaneous; Anemia; Congenital Abnormalities; Female; Folic Acid; Folic Acid Deficiency; Humans; Infant, Newborn; Infant, Premature; Intellectual Disability; Neural Tube Defects; Pregnancy; Pregnancy Complications; Pregnancy Complications, Hematologic; Vitamin B 12; Vitamin B 12 Deficiency

Adequate vitamin A is essential for healthy pregnancy, but high levels may be teratogenic. We present a patient who underwent bariatric surgery, prior to child bearing, and suffered maternal and foetal complications during eleven pregnancies, possibly associated with vitamin A deficiency, amongst multiple micronutrient deficiencies and risk factors including smoking and obesity. Maternal complications included visual disturbance, night blindness and recurrent infections. Recurrent foetal pulmonary hypoplasia and microphthalmia led to foetal and neonatal loss, not previously described in the medical literature. Current guidance on vitamin A deficiency in pregnancy is focused on developing countries where aetiology of vitamin A deficiency is different to that of women in developed countries. We describe nutritional management of the micronutritient deficiencies, focusing on vitamin A, during her last pregnancy. The need for specific antenatal nutritional guidance for pregnant women post-bariatric surgery is becoming more urgent as more mothers and offspring will be affected.

Topics: Abortion, Spontaneous; Adult; Anemia, Iron-Deficiency; Biliopancreatic Diversion; Diet; Female; Fetal Diseases; Gestational Age; Humans; Infant, Newborn; Iron; Micronutrients; Obesity; Perinatal Death; Pregnancy; Pregnancy Complications; Premature Birth; Smoking; Vitamin A; Vitamin A Deficiency; Vitamin B 12

Hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) gene mutation have been postulated as a possible cause of recurrent miscarriage (RM). There is a wide variation in the prevalence of MTHFR polymorphisms and homocysteine (Hcy) plasma levels among populations around the world. The present study was undertaken to investigate the possible association between hyperhomocysteinemia and its causative genetic or acquired factors and RM in Catalonia, a Mediterranean region in Spain.. Sixty consecutive patients with ≥ 3 unexplained RM and 30 healthy control women having at least one child but no previous miscarriage were included. Plasma Hcy levels, MTHFR gene mutation, red blood cell (RBC) folate and vitamin B12 serum levels were measured in all subjects.. No significant differences were observed neither in plasma Hcy levels, RBC folate and vitamin B12 serum levels nor in the prevalence of homozygous and heterozygous MTHFR gene mutation between the two groups studied.. In the present study RM is not associated with hyperhomocysteinemia, and/or the MTHFR gene mutation.

Topics: Abortion, Spontaneous; Adult; Case-Control Studies; Erythrocytes; Female; Folic Acid; Genotype; Heterozygote; Homocysteine; Homozygote; Humans; Hyperhomocysteinemia; Methylenetetrahydrofolate Reductase (NADPH2); Mutation; Odds Ratio; Polymorphism, Single Nucleotide; Spain; Vitamin B 12

Pregnancy losses must be categorised into biochemical loss, early embryonic loss, late foetal loss and stillbirth cases. No haemostasis-related investigations are necessary for biochemical losses. Antiphospholipid antibodies must be checked for three early losses or one late loss. A complete blood count will reveal the rare essential thrombocytemias, a functional fibrinogen assay the exceptional dysfibrinogenemia cases. Vitamin B12 and intracellular folates levels must be checked in case of clinical or biological suspicion. Constitutive thrombophilias must not be routinely assessed because a therapeutic option is not definitively demonstrated. Screening for constitutive thrombophilias should be only indicated for clinical research purposes, only for late foetal loss and stillbirth cases.

Topics: Abortion, Spontaneous; Antibodies, Antiphospholipid; Biomarkers; Blood Cell Count; Female; Folic Acid; Hemostasis; Humans; Pregnancy; Pregnancy Complications, Hematologic; Risk Factors; Thrombophilia; Vitamin B 12; Vitamin B Complex

Maternal vitamin status contributes to clinical spontaneous abortion, but the role of B-vitamin and homocysteine status in subclinical early pregnancy loss is unknown. Three-hundred sixty-four textile workers from Anqing, China, who conceived at least once during prospective observation (1996-1998), provided daily urine specimens for up to 1 year, and urinary human chorionic gonadotropin was assayed to detect conception and early pregnancy loss. Homocysteine, folate, and vitamins B6 and B12 were measured in preconception plasma. Relative to women in the lowest quartile of vitamin B6, those in the third and fourth quartiles had higher adjusted proportional hazard ratios of conception (hazard ratio (HR)=2.2, 95% confidence interval (CI): 1.3, 3.4; HR=1.6, 95% CI: 1.1, 2.3, respectively), and the adjusted odds ratio for early pregnancy loss in conceptive cycles was lower in the fourth quartile (odds ratio=0.5, 95% CI: 0.3, 1.0). Women with sufficient vitamin B6 had a higher adjusted hazard ratio of conception (HR=1.4, 95% CI: 1.1, 1.9) and a lower adjusted odds ratio of early pregnancy loss in conceptive cycles (odds ratio=0.7, 95% CI: 0.4, 1.1) than did women with vitamin B6 deficiency. Poor vitamin B6 status appears to decrease the probability of conception and to contribute to the risk of early pregnancy loss in this population.

Topics: Abortion, Spontaneous; Adult; China; Chorionic Gonadotropin; Female; Fertilization; Folic Acid; Homocysteine; Humans; Odds Ratio; Preconception Care; Pregnancy; Prospective Studies; Risk Assessment; Risk Factors; Vitamin B 12; Vitamin B 6

To understand the correlation of lower serum folate, and red blood cell (RBC) folate level with birth defects including unexplained recurrent pregnancy loss, and to evaluate the role of RBC folate level as a suitable marker for folate supplement.. Two hundred and ninety-nine non-pregnant women at child-bearing age with a birth defect history were selected as birth defect group. The levels of serum and RBC folate, and serum vitamin B(12) were determined. By comparing with the group of non-pregnant women at child-bearing age without any birth defect history (control group), we evaluated the correlation between lower serum folate, RBC folate level and main kinds of birth defects including unexplained recurrent pregnancy loss. And the levels of serum and RBC folate of birth defect group were also determined and compared before and after oral folate intake (5 mg/d) for one month.. The serum folate level of birth defect group was not different from the control group (17 - 26 vs 14 nmol/L, P > 0.05). The RBC folate level of birth defect group except the urinary defect was significantly lower compared with the control group (233 - 547 vs 689 nmol/L, P < 0.05). After the oral folate intake (5 mg/d), the serum folate level of unexplained recurrent pregnancy loss group and neural tube defects group were significantly increased than before [(22 +/- 9) vs (27 +/- 12) nmol/L, (19 +/- 10) vs (25 +/- 18) nmol/L; P < 0.05]. The RBC folate level of unexplained recurrent pregnancy loss group and congenital heart defect group were significantly increased than before [(374 +/- 275) vs (567 +/- 397) nmol/L, (322 +/- 205) vs (527 +/- 351) nmol/L, P < 0.05].. RBC folate level is more closely correlated than serum folate level with the incidence of main birth defect.

Topics: Abortion, Spontaneous; Adult; Congenital Abnormalities; Erythrocytes; Female; Folic Acid; Folic Acid Deficiency; Heart Defects, Congenital; Humans; Infant, Newborn; Nutritional Requirements; Pregnancy; Pregnancy Outcome; Vitamin B 12

Chronic exposure to ambient nitrous oxide levels found in dental offices may pose unrecognized health risks, among them, increased incidence of spontaneous abortion or infertility among female workers. Vitamin B12 supplements can reverse some of the effects of chronic N2O exposure.

Topics: Abortion, Spontaneous; Dental Staff; Female; Humans; Infertility, Female; Nitrous Oxide; Occupational Diseases; Pregnancy; Vitamin B 12

The purpose of this study was to examine whether women with first trimester uterine bleeding and low serum folate have a higher incidence of spontaneous abortions and adverse perinatal outcome compared with women whose folate levels are normal. Serum folate and vitamin B12 levels were obtained on 225 women who presented with first trimester vaginal bleeding; pregnancy outcomes of those whose folate or vitamin B12 levels were low were compared with those with normal levels using the chi-square test. Of the 151 women included, 52 had low folate levels (less than 4.0 ng/ml). Their spontaneous abortion rate and perinatal outcomes were similar to those whose folate levels were normal. We concluded that in pregnancies complicated by first trimester vaginal bleeding, low folate levels do not appear to be associated with an increased risk of pregnancy loss and adverse outcome.

Topics: Abortion, Spontaneous; Adult; Case-Control Studies; Female; Folic Acid; Folic Acid Deficiency; Humans; Pregnancy; Pregnancy Complications, Cardiovascular; Pregnancy Outcome; Pregnancy Trimester, First; Uterine Hemorrhage; Vitamin B 12

Topics: Abortion, Habitual; Abortion, Spontaneous; Female; Ferritins; Folic Acid; Folic Acid Deficiency; Follow-Up Studies; Hematocrit; Hemoglobins; Humans; Longitudinal Studies; Nutritional Status; Pregnancy; Pregnancy Outcome; Reference Values; Vitamin B 12; Zinc

To investigate maternal and fetal folate and vitamin B12 concentrations in pregnancies affected by neural tube defects (NTD).. Measurement of folate and vitamin B12 concentrations in amniotic fluid, fetal blood and maternal blood samples in midgestation.. 32 women undergoing termination of pregnancy at 14-21 weeks gestation for social reasons (n = 24) or for fetuses with neural tube defects (n = 8).. Fetoscopy before intra-amniotic injection of prostaglandins.. In normal pregnancies there was a positive correlation between maternal and fetal serum folate, and the fetal serum and red blood cell folate concentrations were higher than the maternal. There were no differences in amniotic fluid, maternal blood or fetal blood folate concentrations between pregnancies with NTD and normal pregnancies. Although amniotic fluid vitamin B12 was lower in pregnancies with NTD, maternal serum vitamin B12 concentration was not reduced.. In this small group of pregnancies with NTD at mid-gestation there is no evidence to suggest folate or vitamin B12 deficiency.

Topics: Abortion, Spontaneous; Amniotic Fluid; Female; Fetal Blood; Folic Acid; Humans; Neural Tube Defects; Pregnancy; Pregnancy Complications; Pregnancy Trimester, Second; Vitamin B 12

Topics: Abortion, Spontaneous; Air Pollutants; Anesthetics; Animals; Female; Gases; Humans; Nitrous Oxide; Operating Rooms; Oxidation-Reduction; Polyneuropathies; Pregnancy; Rats; Vitamin B 12

Topics: Abnormalities, Drug-Induced; Abortion, Spontaneous; Anesthetics; Animals; Cell Division; Cells, Cultured; Chromosome Aberrations; Environmental Exposure; Female; Health Occupations; Humans; Nitrous Oxide; Occupational Diseases; Pregnancy; Rats; Vitamin B 12

Topics: Abortion, Spontaneous; Anemia, Macrocytic; Blood Transfusion; Congenital Abnormalities; Female; Folic Acid; Folic Acid Deficiency; Humans; Placenta Diseases; Pregnancy; Pregnancy Complications; Prognosis; Vitamin B 12

Topics: Abortion, Spontaneous; Anemia; Animals; Body Weight; Congenital Abnormalities; Diet; Female; Germ-Free Life; Kidney; Liver; Pregnancy; Rats; Vitamin B 12; Vitamin B 12 Deficiency

Topics: Abortion, Spontaneous; Anemia, Hemolytic, Congenital; Animals; Ascorbic Acid; Ergocalciferols; Female; Humans; Hydrocephalus; Infant, Newborn; Infant, Newborn, Diseases; Jaundice, Neonatal; Maternal-Fetal Exchange; Osteomalacia; Pregnancy; Pregnancy, Prolonged; Pyridoxine; Rats; Scurvy; Seizures; Skull; Vitamin A; Vitamin B 12; Vitamin E; Vitamin K; Vitamins

Topics: Abortion, Induced; Abortion, Spontaneous; Anaphylaxis; Female; Humans; Pregnancy; Vitamin B 12; Vitamins

Topics: Abortion, Criminal; Abortion, Induced; Abortion, Spontaneous; Corrinoids; Criminals; Female; Humans; Pregnancy; Quinine; Vitamin B 12

Topics: Abortion, Habitual; Abortion, Induced; Abortion, Spontaneous; Blood Group Antigens; Female; Humans; Intercellular Signaling Peptides and Proteins; Peptides; Pregnancy; Vitamin B 12