Effect of homocysteine concentration in early pregnancy on gestational hypertensive disorders and other pregnancy outcomes

Association of serum homocysteine with vitamin B12 and folate levels in women with pre-eclampsia in a tertiary health care center in Nepal

BACKGROUND

Pre-eclampsia is a syndrome that chiefly includes the development of new-onset hypertension and proteinuria after 20 weeks of pregnancy. Pre-eclampsia is one of the major causes of mortality and morbidity in Nepal. Hyperhomocysteinemia may be a cause of the endothelial dysfunction provoked by oxidative stress in pre-eclampsia. This study was designed to evaluate the association of homocysteine with Vitamin B12 and folate in patients with pre-eclampsia.

METHOD

An observational cross sectional study was performed in the Gynecology and Obstetrics Department of TUTH involving seventy two subjects with pre-eclampsia. Blood pressure, urinary protein levels, serum homocysteine, Vitamin B12 and folate levels were compared in both mild and severe forms of pre-eclampsia. Concentration of Vitamin B12 and folate were measured using Vitros ECI and homocysteine was measured using CLIA. SPSS 23.0 was used to analyze the data. Tests were performed with Mann Whitney Test and Spearman's rank correlation test. A p-value < 0.05 was considered statistically significant.

RESULTS

This study showed no significant difference in age and weeks of gestation in both mild and severe forms of pre-eclampsia. Mean concentration of homocysteine was higher (13.1 ± 6.4 micromol/L) in severe Pre-eclampsia as compared to mild cases (7.6 ± 2.8 micromol/L). Mean concentration of folate was lower in severe cases (35.4 ± 24.1 micromol/L) when compared with mild cases of pre-eclampsia (57 ± 23.4 micromol/L).

CONCLUSION

Homocysteine levels were increased in severe Pre-eclampsia when compared with mild pre-eclampsia and this finding can be used to predict and prevent complications in patients with pre-eclampsia.

Trimester-specific reference intervals of serum homocysteine levels for pregnant women: a longitudinal study in China

OBJECTIVE

To investigate the physiological changes of serum homocysteine (Hcy) levels and to establish trimester-specific reference intervals of serum Hcy levels for Chinese pregnant women.

METHOD

According to the guideline of the Clinical and Laboratory Standards Institute (CLSI) C28-A3 document, 476 healthy women were recruited in West China Second University Hospital, Sichuan University from January 2021 to October 2021. Among them, 120 were non-pregnant, 118 were in the first trimester, 120 were in the second and 118 were in the third trimester of gestation. The enzymatic cycling method was performed to detect serum Hcy levels. Non-parametric percentiles (2.5th percentile and 97.5th percentile) were calculated to establish the reference intervals for non-pregnant women and pregnant women in different trimester of gestation.

RESULTS

There was a significant statistical difference for serum Hcy levels between non-pregnant women and pregnant women (p < 0.05), and serum Hcy levels in the first, second, and third trimesters of gestation were statistically different (p < 0.05). The trimester-specific reference intervals of serum Hcy levels were 4.35 ∼ 10.16 μmol/L, 3.38 ∼ 8.60 μmol/L, and 3.75 ∼ 11.17 μmol/L for pregnant women in the first, second, and third trimester of gestation, respectively.

CONCLUSIONS

Compared to non-pregnant women, serum Hcy levels physiologically decreased after pregnancy, and the physiological changes in serum Hcy levels during pregnancy were also found. Establishing trimester-specific reference intervals of serum Hcy levels for pregnant women was valuable for clinical practice.

Impact of Homocysteine as a Preconceptional Screening Factor for In Vitro Fertilization and Prevention of Miscarriage with Folic Acid Supplementation Following Frozen-Thawed Embryo Transfer: A Hospital-Based Retrospective Cohort Study

Homocysteine is an amino acid naturally produced in the body and metabolized via the methionine cycle. High homocysteine levels can increase the risk of infertility and pregnancy complications, such as preeclampsia, preterm delivery, miscarriage, and low birth weight. Preconceptional homocysteine levels may be reduced by taking folic acid supplements to reduce the risk of such complications. This cross-sectional, hospital-based study was conducted to examine the role of homocysteine in 1060 infertile women with a history of IVF/intracytoplasmic sperm injection (ICSI) failure. We analyzed whether folic acid intervention altered homocysteine levels and influenced reproductive outcome. We found that a higher homocysteine level was statistically associated with a lower fertilization rate in patients with a history of IVF/ICSI failure. There was an inverse relationship between homocysteine levels and serum 25(OH)VD, and a trend towards lower anti mullerian hormone in the group with higher homocysteine levels. This is the first interventional study to identify that folic acid supplementation improved pregnancy outcomes following freeze embryo transfer (FET) in women with a history of FET failure by monitoring the reduction in homocysteine levels. Therefore, folic acid supplementation and homocysteine level monitoring may constitute a novel intervention for improving IVF/ICSI pregnancy outcomes.

Is Maternal Serum Homocysteine a Novel Diagnostic Biomarker for Predicting Placenta-Mediated Disorders?

Background Uteroplacental insufficiency and related disorders, though a significant cause of undesirable maternal and fetal outcomes, are complex and poorly understood. The newer screening modalities are expensive and difficult to procure for day-to-day use in developing countries. This study aimed to examine the association of mid-trimester maternal serum homocysteine levels with maternal and neonatal outcomes. Methodology This was a prospective cohort study involving 100 participants between 18 and 28 weeks of gestation. The study was conducted at a tertiary care center in south India from July 2019 to September 2020. Maternal blood samples were analyzed for serum homocysteine levels and correlated with the third-trimester pregnancy outcomes. Statistical analysis was done, and diagnostic measures were computed. Results The mean age was found to be 26.8 ± 4.8 years. Of the participants, 15% (n = 15) were diagnosed with hypertensive disorders during pregnancy, while 7% (n = 7) had fetal growth restriction (FGR) and 7% (n = 7) were complicated by preterm birth. An elevated maternal serum homocysteine level was positively associated with adverse pregnancy outcome measures such as hypertensive disorders (p = 0.001), with sensitivity and specificity of 27% and 99%, respectively, and FGR (p = 0.03) with sensitivity and specificity of 28.6% and 98.6%, respectively. Moreover, a statistically significant outcome was noted with preterm birth before 37 weeks (p = 0.001) and a low Apgar score (p = 0.02). No association was established with spontaneous preterm labor (p = 1.00), neonatal birth weight (p = 0.42), and special care unit admission (p = 1.00). Conclusions Such a simple and affordable investigation has the potential to go a long way in the early diagnosis and management of placenta-mediated disorders in pregnancy during the antenatal period, especially in low-resource settings.

Homocysteine Metabolism in Pregnancy and Developmental Impacts

Homocysteine is a metabolite generated by methionine cycle metabolism, comprising the demethylated derivative of methionine. Homocysteine can be metabolised by the transsulphuration pathway to cystathionine, which requires vitamin B6, or can undergo remethylation to methionine. Homocysteine remethylation to methionine is catalysed by methionine synthase activity which requires vitamin B12, regenerating methionine to allow synthesis of the universal methyl donor S-adenosylmethionine required for methylation and gene transcription regulation. The methyl-group donated for homocysteine remethylation comes from 5-methyltetrahydrofolate generated by the folate cycle, which allows tetrahydrofolate to be returned to the active folate pool for nucleotide biosynthesis. Therefore the integrated actions of the methionine and folate cycles, required to metabolise homocysteine, also perpetuate methylation and nucleotide synthesis, vitally important to support embryonic growth, proliferation and development. Dysregulated activities of these two interdependent metabolic cycles, arising from maternal suboptimal intake of nutrient co-factors such as folate and vitamin B12 or gene polymorphisms resulting in reduced enzymatic activity, leads to inefficient homocysteine metabolic conversion causing elevated concentrations, known as hyperhomocysteinemia. This condition is associated with multiple adverse pregnancy outcomes including neural tube defects (NTDs). Raised homocysteine is damaging to cellular function, binding to proteins thereby impairing their function, with perturbed homocysteine metabolism impacting negatively on embryonic development. This review discusses the "cross-talk" of maternal-fetal homocysteine interrelationships, describes the placental transport of homocysteine, homocysteine impacts on pregnancy outcomes, homocysteine and methylation effects linking to NTD risk and proposes a putative pathway for embryonic provision of folate and vitamin B12, homocysteine-modulating nutrients that ameliorate NTD risk.

Estimation of homocysteine concentration as an indicator of foetal death in pregnant Chinese women with preeclampsia: A case-control study

Introduction

This study evaluated whether changes in homocysteine concentrations in pregnant women with preeclampsia (PE) might be useful for predicting foetal death.

Materials and methods

This study evaluated 1,368 PE women at two Chinese centres. Medical records were reviewed to collect data regarding maternal age, homocysteine concentrations and other clinical parameters.

Results

Maternal serum homocysteine concentrations were significantly higher in the group with PE than control. Significant differences (p < 0.05) were also observed between the foetal death and survival groups in terms of body mass index, neonatal weight, previous deliveries, gestation length and adverse pregnancy history. Multivariate logistic regression analysis revealed that upper‐quartile homocysteine concentration was a significant risk factor of foetal death in the group with PE, and overall survival rate of patients with high homocysteine concentrations during pregnancy was significantly lower than those with low level (p < 0.05).

Conclusions

Our results indicate that foetal death was associated with upper‐quartile homocysteine concentrations in the group with PE, it can be an indicator of foetal death throughout the pregnancy.

Infertility, Miscarriage, Stillbirth, and the Risk of Stroke Among Women: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Stroke is one of the leading causes of mortality, and women are impacted more from stroke than men in terms of their absolute number and in having worse outcomes. A growing number of studies have explored the association between pregnancy complications, pregnancy outcomes, and stroke. Limited studies, however, have investigated links involving infertility, miscarriage, and stillbirth, which could plausibly be associated via a background of endocrine conditions, endothelial dysfunction, and chronic systematic inflammation. This review aims to summarize current evidence and provide up-to-date information on the associations of infertility, miscarriage, and stillbirth, with stroke incidence.

METHODS

A comprehensive literature search was conducted for cohort and case-control studies on associations between infertility, miscarriage, stillbirth, and stroke up to September 26, 2020. Seven databases were searched: PubMed, Embase, Cochrane, CINIHL, PsyclNFO, Wanfang, and CNKI. Random-effects models were used to estimate the pooled hazard ratios (HRs) and 95% CIs.

RESULTS

Sixteen cohort studies and 2 case-control studies enrolling 7 808 521 women were included in this meta-analysis. Women who had experienced miscarriage or stillbirth were at higher risk of stroke (miscarriage: HR, 1.07 [95% CI, 1.00-1.14]; stillbirth: HR, 1.38 [95% CI, 1.11-1.71]) than other women. The HRs of stroke for each additional miscarriage and stillbirth were 1.13 (95% CI, 0.96-1.33) and 1.25 (95% CI, 1.06-1.49), respectively. In subgroup analysis, increased risk of stroke was associated with repeated miscarriages and stillbirths (miscarriage ≥3: HR, 1.42 [95% CI, 1.05-1.90]; stillbirth ≥2: HR, 1.14 [95% CI, 1.04-1.26]). Associations between infertility and stroke were inconsistent and inconclusive (HR, 1.07 [95% CI, 0.87-1.32]).

CONCLUSIONS

Miscarriage and stillbirth are associated with increased risk of stroke among women, which could be used as a contributing risk factor to help identify women at higher risk of stroke.

Homocysteine and female fertility, pregnancy loss and offspring birthweight: a two-sample Mendelian randomization study

BACKGROUND/OBJECTIVES

Observational studies link elevated homocysteine concentrations (Hcy) with female fertility, pregnancy loss, and low offspring birthweight. Maternal rs1801133, a functional variant in MTHFR strongly associated with lifelong elevated Hcy, is associated with recurrent pregnancy loss and offspring birthweight in Asian women. We investigated if genetically elevated Hcy is associated with fertility, pregnancy loss, and offspring birthweight in European women.

SUBJECTS/METHODS

We performed a two-sample Mendelian randomization (MR) study using publicly available data. We obtained 18 genetic variants (five involved in Hcy metabolism) explaining up to 5.9% of the variance in Hcy from a genome-wide association meta-analysis of 44,147 European individuals (82% women). We investigated fertility (including age at menopause), pregnancy loss, and offspring birthweight in the UK Biobank (N = 194,174), EGG (N = 190,406), and ReproGen (N = 69,360-252,514) consortia using summary statistics. We calculated inverse-variance weighted, and several sensitivity MR regression statistics.

RESULTS

rs1801133 was associated with a 7.45 months (95% CI: 4.09, 10.80) increase in age at menopause and 29.69 (12.87, 46.51) g decrease in offspring birthweight per SD increase in Hcy in the UK biobank, and confirmed in EGG and ReproGen. MR for Hcy metabolism alone (five variants in MTHFR, MTR, CBS) showed similar results for offspring birthweight across consortia. However, using all 18 variants resulted in no association for any of the outcomes across consortia.

CONCLUSION

Hcy and suggestively vitamin B variants are most likely the drug targets for folate supplementation in pregnant women on the offspring birthweight, while Hcy variants related to renal function or diabetes are not involved.

Provision of folic acid for reducing arsenic toxicity in arsenic-exposed children and adults

BACKGROUND

Arsenic is a common environmental toxin. Exposure to arsenic (particularly its inorganic form) through contaminated food and drinking water is an important public health burden worldwide, and is associated with increased risk of neurotoxicity, congenital anomalies, cancer, and adverse neurodevelopment in children. Arsenic is excreted following methylation reactions, which are mediated by folate. Provision of folate through folic acid supplements could facilitate arsenic methylation and excretion, thereby reducing arsenic toxicity.

OBJECTIVES

To assess the effects of provision of folic acid (through fortified foods or supplements), alone or in combination with other nutrients, in lessening the burden of arsenic-related health outcomes and reducing arsenic toxicity in arsenic-exposed populations.

SEARCH METHODS

In September 2020, we searched CENTRAL, MEDLINE, Embase, 10 other international databases, nine regional databases, and two trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the provision of folic acid (at any dose or duration), alone or in combination with other nutrients or nutrient supplements, with no intervention, placebo, unfortified food, or the same nutrient or supplements without folic acid, in arsenic-exposed populations of all ages and genders.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included two RCTs with 822 adults exposed to arsenic-contaminated drinking water in Bangladesh. The RCTs compared 400 µg/d (FA400) or 800 µg/d (FA800) folic acid supplements, given for 12 or 24 weeks, with placebo. One RCT, a multi-armed trial, compared FA400 plus creatine (3 g/d) to creatine alone. We judged both RCTs at low risk of bias in all domains. Due to differences in co-intervention, arsenic exposure, and participants' nutritional status, we could not conduct meta-analyses, and therefore, provide a narrative description of the data. Neither RCT reported on cancer, all-cause mortality, neurocognitive function, or congenital anomalies. Folic acid supplements alone versus placebo Blood arsenic. In arsenic-exposed individuals, FA likely reduces blood arsenic concentrations compared to placebo (2 studies, 536 participants; moderate-certainty evidence). For folate-deficient and folate-replete participants who received arsenic-removal water filters as a co-intervention, FA800 reduced blood arsenic levels more than placebo (percentage change (%change) in geometric mean (GM) FA800 -17.8%, 95% confidence intervals (CI) -25.0 to -9.8; placebo GM -9.5%, 95% CI -16.5 to -1.8; 1 study, 406 participants). In one study with 130 participants with low baseline plasma folate, FA400 reduced total blood arsenic (%change FA400 mean (M) -13.62%, standard error (SE) ± 2.87; placebo M -2.49%, SE ± 3.25), and monomethylarsonic acid (MMA) concentrations (%change FA400 M -22.24%, SE ± 2.86; placebo M -1.24%, SE ± 3.59) more than placebo. Inorganic arsenic (InAs) concentrations reduced in both groups (%change FA400 M -18.54%, SE ± 3.60; placebo M -10.61%, SE ± 3.38). There was little to no change in dimethylarsinic acid (DMA) in either group. Urinary arsenic. In arsenic-exposed individuals, FA likely reduces the proportion of total urinary arsenic excreted as InAs (%InAs) and MMA (%MMA) and increases the proportion excreted as DMA (%DMA) to a greater extent than placebo (2 studies, 546 participants; moderate-certainty evidence), suggesting that FA enhances arsenic methylation. In a mixed folate-deficient and folate-replete population (1 study, 352 participants) receiving arsenic-removal water filters as a co-intervention, groups receiving FA had a greater decrease in %InAs (within-person change FA400 M -0.09%, 95% CI -0.17 to -0.01; FA800 M -0.14%, 95% CI -0.21 to -0.06; placebo M 0.05%, 95% CI 0.00 to 0.10), a greater decrease in %MMA (within-person change FA400 M -1.80%, 95% CI -2.53 to -1.07; FA800 M -2.60%, 95% CI -3.35 to -1.85; placebo M 0.15%, 95% CI -0.37 to 0.68), and a greater increase in %DMA (within-person change FA400 M 3.25%, 95% CI 1.81 to 4.68; FA800 M 4.57%, 95% CI 3.20 to 5.95; placebo M -1.17%, 95% CI -2.18 to -0.17), compared to placebo. In 194 participants with low baseline plasma folate, FA reduced %InAs (%change FA400 M -0.31%, SE ± 0.04; placebo M -0.13%, SE ± 0.04) and %MMA (%change FA400 M -2.6%, SE ± 0.37; placebo M -0.71%, SE ± 0.43), and increased %DMA (%change FA400 M 5.9%, SE ± 0.82; placebo M 2.14%, SE ± 0.71), more than placebo. Plasma homocysteine: In arsenic-exposed individuals, FA400 likely reduces homocysteine concentrations to a greater extent than placebo (2 studies, 448 participants; moderate-certainty evidence), in the mixed folate-deficient and folate-replete population receiving arsenic-removal water filters as a co-intervention (%change in GM FA400 -23.4%, 95% CI -27.1 to -19.5; placebo -1.3%, 95% CI -5.3 to 3.1; 1 study, 254 participants), and participants with low baseline plasma folate (within-person change FA400 M -3.06 µmol/L, SE ± 3.51; placebo M -0.05 µmol/L, SE ± 4.31; 1 study, 194 participants). FA supplements plus other nutrient supplements versus nutrient supplements alone In arsenic-exposed individuals who received arsenic-removal water filters as a co-intervention, FA400 plus creatine may reduce blood arsenic concentrations more than creatine alone (%change in GM FA400 + creatine -14%, 95% CI -22.2 to -5.0; creatine -7.0%, 95% CI -14.8 to 1.5; 1 study, 204 participants; low-certainty evidence); may not change urinary arsenic methylation indices (FA400 + creatine: %InAs M 13.2%, SE ± 7.0; %MMA M 10.8, SE ± 4.1; %DMA M 76, SE ± 7.8; creatine: %InAs M 14.8, SE ± 5.5; %MMA M 12.8, SE ± 4.0; %DMA M 72.4, SE ±7.6; 1 study, 190 participants; low-certainty evidence); and may reduce homocysteine concentrations to a greater extent (%change in GM FA400 + creatinine -21%, 95% CI -25.2 to -16.4; creatine -4.3%, 95% CI -9.0 to 0.7; 1 study, 204 participants; low-certainty evidence) than creatine alone.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that FA supplements may benefit blood arsenic concentration, urinary arsenic methylation profiles, and plasma homocysteine concentration versus placebo. There is low-certainty evidence that FA supplements plus other nutrients may benefit blood arsenic and plasma homocysteine concentrations versus nutrients alone. No studies reported on cancer, all-cause mortality, neurocognitive function, or congenital anomalies. Given the limited number of RCTs, more studies conducted in diverse settings are needed to assess the effects of FA on arsenic-related health outcomes and arsenic toxicity in arsenic-exposed adults and children.

History of Pregnancy Loss as a Risk Factor for Myocardial Infarction

Introduction

There are few cardiovascular risk factors that are unique to females, such as after menopause, lipid profiles change unfavorably. Another risk factor that might be associated with an increased risk of cardiovascular diseases in women is the incidence of miscarriages and abortions. In this study, we will determine the association between the previous history of pregnancy loss and myocardial infarction (MI).

Methods

This case-control study was conducted from December 2019 to January 2021. We enrolled 600 female patients with a confirmed diagnosis of MI from the outpatient department (OPD) of the cardiology and internal medicine unit of a tertiary care hospital in Pakistan. Another 600 female participants without the diagnosis of MI were enrolled from the OPD as the control group. Participants were asked about the history of pregnancy, including the number of miscarriages, abortions, and stillbirths.

Results

Participants with myocardial infarction had experienced greater than one miscarriage compared to participants without MI (25.1% vs. 13.6%; p-value: <0.0001). Similarly, participants with MI had significantly more participants with stillbirth compared to participants without MI (12.0% vs. 6.66%; p-value: 0.0017).

Conclusion

Pregnancy loss is associated with MI in the future. Women with a history of pregnancy loss must undergo regular cardiovascular screening to protect themselves from cardiovascular events.

Functional inhibition of redox regulated heme proteins: A novel mechanism towards oxidative stress induced by homocysteine

Homocysteine (Hcy) is a sulfur containing non-protein toxic amino acid synthesized from methionine. Elevated level of Hcy is associated with cardiovascular complications and neurodegeneration. Hcy is believed to induce organ damage and apoptosis via oxidative stress. The pro-oxidant nature of Hcy is considered to originate from the metal-induced oxidation of thiol group-containing molecules forming disulfides (Hcy-Hcy, Hcy-cysteine, Hcy-glutathione, etc) or with free cysteine residues of proteins (a process called protein S-homocysteinylation). Formation of such disulfides indeed results in the generation of reactive oxygen species (ROS) which eventually leads to loss of cellular integrity. In the present manuscript, we performed systematic investigation of the effect of Hcy on iron containing proteins. We discover a novel mechanism of Hcy toxicity wherein Hcy oxidation is linked with the functional loss of the protein with iron as cofactors. Our results indicate that redox regulated heme proteins might be primarily involved in the Hcy toxicity and associated oxidative stress.

The association of physical activity on homocysteine in pregnant women

INTRODUCTION

Women with high levels of physical activity have improved pregnancy, labor, and delivery outcomes related to cardiovascular health. Hyperhomocysteinemia, which predicts cardiovascular disease risk, is associated with maternal vascular complications during pregnancy, such as placental abruption and preeclampsia. However, studies are lacking on whether physical activity impacts homocysteine in pregnant women, pointing to a potential mechanism behind the improved cardiovascular health in women who exercise during pregnancy. The purpose of this study was to examine if women with high levels of physical activity have lower levels of homocysteine compared to women with low levels of physical activity.

METHODS

This study was a secondary analysis using data from the 2003 to 2006 National Health and Nutrition Examination Survey. A total of 257 pregnant women were included. Physical activity was assessed objectively over seven days with accelerometers. High and low groups based on moderate-to-vigorous physical activity (MVPA) and steps/day were defined. Homocysteine and related laboratory biomarkers (vitamin B12, folate, pyridoxal 5'-phosphate) were assessed through blood draws. Data assembly was performed using SAS and analysis via SPSS Complex Samples.

RESULTS

Only an estimated 17.7 ± 4.7% of women met guidelines to achieve at least 150 min per week of MVPA. Plasma homocysteine was not different between pregnant women with high and low levels of moderate-to-vigorous physical activity (4.39 ± 0.21 and 4.44 ± 0.17 µmol/L; p > .05) or between those with high and low levels of steps (3.95 ± 0.26 and 4.62 ± 0.27 µmol/L; p > .05) when the data was split into two quantiles by the median. These results were similar when using log-transformed values for homocysteine to normalize the distribution of data. Pregnant women in the group of the high steps tended to have higher vitamin B12, folate, and pyridoxal 5'-phosphate than those in the group of the low steps. Sensitivity analyses revealed that homocysteine was not different between the upper 25% (4.04 ± 0.22 µmol/L) and lower 25% (4.17 ± 0.26 µmol/L) MVPA (p = .716) but that it was statistically higher in the low (<5000 steps/day) (4.99 ± 0.20 µmol/L) steps/day group compared to high (>7500 steps/day) steps/day (3.99 ± 0.23 µmol/L) (p = .003) after excluding individuals with hypertension and thyroid/kidney issues.

CONCLUSION

Maternal steps/day, but not MVPA, appear to be associated with homocysteine (albeit weakly) in the present study after excluding potential factors which impact homocysteine. The volume of physical activity appears to be an important indicator as this difference was not revealed until the physical activity was more distinctly separated.

A Novel Review of Homocysteine and Pregnancy Complications

Homocysteine (Hct) is a substance produced in the metabolism of methionine. It is an essential type of amino acid gained from the daily diet. Methylenetetrahydrofolate reductase (MTHFR) gene mutation is related to elevated total homocysteine (tHct) expressions, in particular, among women with low folate intake. Hyperhomocysteinemia (HHct) is caused by numerous factors, such as genetic defects, lack of folic acid, vitamin B₆ and B₁₂ deficiency, hypothyroidism, drugs, aging, and renal dysfunction. Increased Hct in peripheral blood may lead to vascular illnesses, coronary artery dysfunction, atherosclerotic changes, and embolic diseases. Compared to nonpregnant women, the Hct level is lower in normal pregnancies. Recent studies have reported that HHct was associated with numerous pregnancy complications, including recurrent pregnancy loss (RPL), preeclampsia (PE), preterm delivery, placental abruption, fetal growth restriction (FGR), and gestational diabetes mellitus (GDM). Besides, it was discovered that neonatal birth weight and maternal Hct levels were negatively correlated. However, a number of these findings lack consistency. In this review, we summarized the metabolic process of Hct in the human body, the levels of Hct in different stages of normal pregnancy reported in previous studies, and the relationship between Hct and pregnancy complications. The work done is helpful for obstetricians to improve the likelihood of a positive outcome during pregnancy complications. Reducing the Hct level with a high dosage of folic acid supplements during the next pregnancy could be helpful for females who have suffered pregnancy complications due to HHct.

Evaluation of Zinc and Homocysteine Status in Pregnant Women and Their Association with Pre-eclampsia in Jordan

Pre-eclampsia (PE) is considered a major complication of pregnancy. Hyperhomocyteinemia (H-Hcy) has been proposed to be associated with a number of placenta-mediated diseases, such as PE. Zinc (Zn) is involved in the regulation of total homocysteine (Hcy) levels. A case-control study design was used to examine serum Zn and Hcy statuses, and their association to PE risk. Thirty pregnant women with PE 21∼35 years of age, and 30 matched healthy pregnant women were recruited from Amman, Jordan. Plasma Hcy was measured using liquid chromatography-mass spectrometry, and Zn was measured using atomic absorption. Hcy levels were significantly higher among women with PE compared with controls (16.35±0.43 and 7.25±0.21 μmol/L, respectively; P<0.05). However, there was no significant difference in Zn levels between women with PE and controls (65.37±1.27 and 63.71±1.24 μg/dL, respectively; P>0.05). Blood levels of Hcy (μmol/L) were positively associated with systolic and diastolic blood pressure (β=3.54 and β=1.81, respectively; P<0.05), and Zn levels [odds ratios (OR)=0.84; 95% confidence intervals (CI): 0.71∼0.98] were significantly associated with PE risk (P<0.05). Although women with PE had significantly higher Hcy levels than controls, H-Hcy was not associated with increased PE risk. However, there was a strong association between severity of hypertension and serum Hcy levels, and serum Zn levels were inversely associated with H-Hcy. The likelihood of PE was significantly higher in women who were Zn deficient compared with healthy controls. To conclude, early management of H-Hcy and associated risk factors may be effective in decreasing the incidence of PE.

Health outcomes associated with vegetarian diets: An umbrella review of systematic reviews and meta-analyses

BACKGROUND

Several meta-analyses evaluated the association between vegetarian diets and health outcomes. To integrate the large amount of the available evidence, we performed an umbrella review of published meta-analyses that investigated the association between vegetarian diets and health outcomes.

METHODS

We performed an umbrella review of the evidence across meta-analyses of observational and interventional studies. PubMed, Embase, Cochrane Database of Systematic Reviews, and ISI Web of Knowledge. Additional articles were retrieved from primary search references. Meta-analyses of observational or interventional studies that assessed at least one health outcome in association with vegetarian diets. We estimated pooled effect sizes (ESs) using four different random-effect models: DerSimonian and Laird, maximum likelihood, empirical Bayes, and restricted maximum likelihood. We assessed heterogeneity using I2 statistics and publication bias using funnel plots, radial plots, normal Q-Q plots, and the Rosenthal's fail-safe N test.

RESULTS

The umbrella review identified 20 meta-analyses of observational and interventional research with 34 health outcomes. The majority of the meta-analyses (80%) were classified as moderate or high-quality reviews, based on the AMSTAR2 criteria. By comparison with omnivorous diets, vegetarian diets were associated with a significantly lower concentration of blood total cholesterol (pooled ES = -0.549 mmol/L; 95% CI: -0.773 to -0.325; P < 0.001), LDL-cholesterol (pooled ES = -0.467 mmol/L; 95% CI: -0.600 to -0.335); P < 0.001), and HDL-cholesterol (pooled ES = -0.082 mmol/L; 95% CI: -0.095 to -0.069; P < 0.001). In comparison to omnivorous diets, vegetarian diets were associated with a reduced risk of negative health outcomes with a pooled ES of 0.886 (95% CI: 0.848 to 0.926; P < 0.001). In comparison to omnivores, Seventh-day Adventists (SDA) vegetarians had a significantly reduced risk of negative health outcomes with a pooled ES of 0.721 (95% CI: 0.625 to 0.832; P < 0.001). Non-SDA vegetarians had no significant reduction of negative health outcomes when compared to omnivores (pooled ES = 0.973; 95% CI: 0.873 to 1.083; P = 0.51). Vegetarian diets were associated with harmful outcomes on one-carbon metabolism markers (lower concentrations of vitamin B12 and higher concentrations of homocysteine), in comparison to omnivorous diets.

CONCLUSIONS

Vegetarian diets are associated with beneficial effects on the blood lipid profile and a reduced risk of negative health outcomes, including diabetes, ischemic heart disease, and cancer risk. Among vegetarians, SDA vegetarians could represent a subgroup with a further reduced risk of negative health outcomes. Vegetarian diets have adverse outcomes on one-carbon metabolism. The effect of vegetarian diets among pregnant and lactating women requires specific attention. Well-designed prospective studies are warranted to evaluate the consequences of the prevalence of vitamin B12 deficiency during pregnancy and infancy on later life and of trace element deficits on cancer risks.

PROSPERO REGISTRATION NUMBER

CRD42018092470.

Association between maternal serum homocysteine concentrations in early pregnancy and adverse pregnancy outcomes

Background

There is still conflicting evidence on the extent to which maternal hyperhomocysteinemia is a risk factor for pregnancy complications.

Aims

The study aimed to investigate the impact of elevated maternal homocysteine concentrations on adverse pregnancy outcomes among Nigerian women in Lagos.

Materials and Methods

This was a prospective cohort study conducted at the Lagos University Teaching Hospital, Idi-Araba, Lagos, Nigeria. Participants were enrolled during the first trimester of pregnancy following which relevant data were obtained by the interview. Fasting blood samples were collected for the measurement of maternal homocysteine concentration using the enzyme-linked immunosorbent assay method. Pregnancy outcomes and complications were obtained by abstracting the antenatal, delivery, and newborn medical records. Preterm births, low-birth weight (LBW), and antepartum fetal death were used as confirmatory outcome variables in the final analysis. Descriptive statistics for all data were computed using SPSS version 22.0. The associations between the variables were tested and multivariate analyses were used to study the effects of the major baseline characteristics on the pregnancy outcome. P < 0.05 was considered statistically significant.

Conclusions

The prevalence of hyperhomocysteinemia among mothers in Lagos was relatively low. The associations between hyperhomocysteinemia and adverse pregnancy outcomes could have implications in future for the prevention of these adverse outcomes.

Results

Hyperhomocysteinemia was recorded in 41 (24.6%) patients. Women with a high homocysteine concentration and those with a normal homocysteine level did not differ significantly in terms of age (P = 0.684), level of education (P = 0.866), and parity (P = 0.647). Women with hyperhomocysteinemia had an approximately twelve-fold higher risk of preterm birth (P = 0.001) and a ten-fold higher risk of delivering a term neonate with LBW (P = 0.004), but had no risk of antepartum fetal death (P = 0.118) compared to women with a normal homocysteine concentration.

Stillbirth is associated with increased risk of long-term maternal renal disease: a nationwide cohort study

Background

Stillbirth is a devastating adverse pregnancy outcome that may occur without any obvious reason or may occur in the context of fetal growth restriction, preeclampsia, or other obstetric complications. There is increasing evidence that women who experience stillbirths are at greater risk of long-term cardiovascular disease, but little is known about their risk of chronic kidney disease and end-stage renal disease. We conducted the largest study to date to investigate the subsequent risk of maternal chronic kidney disease and end-stage renal disease following stillbirth.

Objective

To identify whether pregnancy complicated by stillbirth is associated with subsequent risk of maternal chronic kidney disease and end-stage renal disease, independent of underlying medical or obstetric comorbidities.

Study Design/Methods

We conducted a population-based cohort study using nationwide data from the Swedish Medical Birth Register, National Patient Register, and Swedish Renal Register. We included all women who had live births and stillbirths from 1973 to 2012, with follow-up to 2013. Women with preexisting renal disease were excluded. Cox proportional hazard regression models were used to estimate adjusted hazard ratios and 95% confidence intervals for associations between stillbirth and maternal chronic kidney disease and end-stage renal disease respectively. We controlled for maternal age, year of delivery, country of origin, parity, body mass index, smoking, gestational diabetes, preeclampsia, and small for gestational age deliveries. Women who had a history of medical comorbidities, which may predispose to renal disease (prepregnancy cardiovascular disease, hypertension, diabetes, lupus, systemic sclerosis, hemoglobinopathy, or coagulopathy), were excluded from the main analysis and examined separately.

Results

There were 1,941,057 unique women who had 3,755,444 singleton pregnancies, followed up over 42,313,758 person-years. The median follow-up time was 20.7 years (interquartile range, 9.9–30.0 years). 13,032 women (0.7%) had at least 1 stillbirth. Women who had experienced at least 1 stillbirth had a greater risk of developing chronic kidney disease (adjusted hazard ratio, 1.26; 95% confidence interval, 1.09–1.45) and end-stage renal disease (adjusted hazard ratio, 2.25; 95% confidence interval, 1.55–3.25) compared with women who only had live births. These associations persisted after removing all stillbirths that occurred in the context of preeclampsia, and small for gestational age or congenital malformations (for chronic kidney disease, adjusted hazard ratio, 1.33; 95% confidence interval, 1.13–1.57; for end-stage renal disease, adjusted hazard ratio, 2.95; 95% confidence interval, CI 1.86–4.68). There was no significant association observed between stillbirth and either chronic kidney disease or end-stage renal disease in women who had preexisting medical comorbidities (chronic kidney disease, adjusted hazard ratio, 1.13; 95% confidence interval, 0.73–1.75 or end-stage renal disease, adjusted hazard ratio, 1.49; 95% confidence interval, 0.78–2.85).

Conclusion

Women who have a history of stillbirth may be at increased risk of chronic kidney disease and end-stage renal disease compared with women who have only had live births. This association persists independently of preeclampsia, and small for gestational age, maternal smoking, obesity, and medical comorbidities. Further research is required to determine whether affected women would benefit from closer surveillance and follow-up for future renal disease.

Folic Acid Supplement Use and Increased Risk of Gestational Hypertension

Current results regarding the effect of folic acid (FA) supplement use on gestational hypertension (GH) and preeclampsia are limited and inconsistent. We aimed to investigate whether FA supplement use was associated with GH and preeclampsia. Participants from the Tongji Maternal and Child Health Cohort with information on periconceptional FA supplement use and diagnosis of GH/preeclampsia were included (n=4853). Robust Poisson regression was used to assess the association of FA supplement use and GH and preeclampsia. Among the 4853 participants in this study, 1161 (23.9%) and 161 (3.3%) women were diagnosed with GH and preeclampsia, respectively. The risk ratio of developing GH was higher in women who used ≥800 µg/d FA supplement from prepregnancy through midpregnancy than nonusers (risk ratio, 1.33 [1.08–1.65]). After adjusting for social-demographic, reproductive, lifestyle factors, family history of hypertension, other supplement use, and gestational weight gain, the adverse association remained significant (risk ratio, 1.32 [1.06–1.64]). Restricting the analysis among women with normal weight, without family history of hypertension, and without gestational diabetes mellitus, the positive FA-GH association still existed. We did not find any significant association between FA supplement use and preeclampsia regardless of adjustment. High-dose (≥800 µg/d) FA supplement use from prepregnancy through midpregnancy was associated with increased risk of GH. Attention should be given to avoid the potential risk of GH due to inappropriate FA supplement use in women who are planning or capable of pregnancy.

Critical review of nutrition, blood pressure and risk of hypertension through the lifecycle: do B vitamins play a role?

Hypertension is the leading cause of preventable mortality worldwide, contributing to over 9 million deaths per annum, predominantly owing to cardiovascular disease. The association of obesity, physical inactivity and alcohol with elevated blood pressure (BP) is firmly established. Weight loss or other dietary strategies, such as the Dietary Approaches to Stop Hypertension (DASH) diet, have been shown to be effective in lowering BP. Additionally, specific nutrients are recognised to contribute to BP, with higher sodium intake linked with an increased risk of hypertension, while potassium is associated with a reduced risk of hypertension. Of note, emerging evidence has identified a novel role for one-carbon metabolism and the related B vitamins, particularly riboflavin, in BP. Specifically in adults genetically at risk of developing hypertension, owing to the common C677T polymorphism in MTHFR, supplemental riboflavin (co-factor for MTHFR) was shown in randomised trials to lower systolic BP by up to 13 mmHg. A BP response to intervention of this magnitude could have important clinical impacts, given that a reduction in systolic BP of 10 mmHg is estimated to decrease stroke risk by 40%. This review aims to explore the factors contributing to hypertension across the lifecycle and to critically evaluate the evidence supporting a role for nutrition, particularly folate-related B vitamins, in BP and risk of hypertension. In addition, gaps in our current knowledge that warrant future research in this area, will be identified.

The determinants of maternal homocysteine in pregnancy: findings from the Ottawa and Kingston Birth Cohort

OBJECTIVE

Observational studies have linked elevated homocysteine to vascular conditions. Folate intake has been associated with lower homocysteine concentration, although randomised controlled trials of folic acid supplementation to decrease the incidence of vascular conditions have been inconclusive. We investigated determinants of maternal homocysteine during pregnancy, particularly in a folic acid-fortified population.

DESIGN

Data were from the Ottawa and Kingston Birth Cohort of 8085 participants. We used multivariable regression analyses to identify factors associated with maternal homocysteine, adjusted for gestational age at bloodwork. Continuous factors were modelled using restricted cubic splines. A subgroup analysis examined the modifying effect of MTHFR 677C>T genotype on folate, in determining homocysteine concentration.

SETTING

Participants were recruited in Ottawa and Kingston, Canada, from 2002 to 2009.

PARTICIPANTS

Women were recruited when presenting for prenatal care in the early second trimester.

RESULTS

In 7587 participants, factors significantly associated with higher homocysteine concentration were nulliparous, smoking and chronic hypertension, while factors significantly associated with lower homocysteine concentration were non-Caucasian race, history of a placenta-mediated complication and folic acid supplementation. Maternal age and BMI demonstrated U-shaped associations. Folic acid supplementation of >1 mg/d during pregnancy did not substantially increase folate concentration. In the subgroup analysis, MTHFR 677C>T modified the effect of folate status on homocysteine concentration.

CONCLUSIONS

We identified determinants of maternal homocysteine relevant to the lowering of homocysteine in the post-folic acid fortification era, characterised by folate-replete populations. A focus on periconceptional folic acid supplementation and improving health status may form an effective approach to lower homocysteine.

Homocysteine: Its Possible Emerging Role in At-Risk Population Groups

Increased plasma homocysteine is a risk factor for several pathological disorders. The present review focused on the role of homocysteine (Hcy) in different population groups, especially in risk conditions (pregnancy, infancy, old age), and on its relevance as a marker or etiological factor of the diseases in these age groups, focusing on the nutritional treatment of elevated Hcy levels. In pregnancy, Hcy levels were investigated in relation to the increased risk of adverse pregnancy outcomes such as small size for gestational age at birth, preeclampsia, recurrent abortions, low birth weight, or intrauterine growth restriction. In pediatric populations, Hcy levels are important not only for cardiovascular disease, obesity, and renal disease, but the most interesting evidence concerns study of elevated levels of Hcy in autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). Finally, a focus on the principal pathologies of the elderly (cardiovascular and neurodegenerative disease, osteoporosis and physical function) is presented. The metabolism of Hcy is influenced by B vitamins, and Hcy-lowering vitamin treatments have been proposed. However, clinical trials have not reached a consensus about the effectiveness of vitamin supplementation on the reduction of Hcy levels and improvement of pathological condition, especially in elderly patients with overt pathologies, suggesting that other dietary and non-dietary factors are involved in high Hcy levels. The importance of novel experimental designs focusing on intra-individual variability as a complement to the typical case-control experimental designs and the study of interactions between different factors it should be emphasized.

Evidence of a Role for One-Carbon Metabolism in Blood Pressure: Can B Vitamin Intervention Address the Genetic Risk of Hypertension Owing to a Common Folate Polymorphism?

Hypertension in adulthood is recognized as the leading risk factor contributing to mortality worldwide, primarily from cardiovascular disease, whereas hypertension in pregnancy leads to serious adverse fetal and maternal outcomes. This article explores the under-recognized role of one-carbon metabolism in blood pressure (BP) and the potential for folate-related B vitamins to protect against hypertension. Genome-wide association studies and clinical studies provide evidence linking the 677C→T polymorphism in the gene encoding methylenetetrahydrofolate reductase (MTHFR) with BP and increased risk of hypertension and hypertension in pregnancy. A novel role for riboflavin (the MTHFR cofactor) has recently emerged, however, with evidence from randomized trials that supplemental riboflavin can lower BP specifically in adults with the variant MTHFR 677TT genotype. Further studies are required to elucidate the biological mechanisms linking one-carbon metabolism with BP and explore the effect of riboflavin in modulating the genetic risk of hypertension in early and later life.

Preconception folate status and reproductive outcomes among a prospective cohort of folate-replete women

BACKGROUND

Most studies of folate metabolism and reproduction have been conducted after pregnancy and in folate-deficient populations. However, measurement of maternal folate status preconceptionally may be most relevant to certain folate-linked early processes preceding a successful pregnancy, and there has been a major increase in folate concentrations in women of childbearing age in high resource settings.

OBJECTIVE

To examine associations between preconceptional biomarkers of maternal folate status (folate and homocysteine) and reproductive outcomes in folate-replete women.

STUDY DESIGN

Cohort nested within the Effects of Aspirin in Gestation and Reproduction trial, a block-randomized, double-blind, placebo-controlled trial whereby women were randomized to daily low-dose aspirin (81 mg/day) or placebo and all women received folic acid (400 μg/day). In total, 1228 women with 1-2 previous pregnancy losses and no documented infertility were recruited from 4 clinical sites in the United States (2006-2012) and were attempting pregnancy for up to 6 menstrual cycles. Log-binomial regression models were used to estimate relative risks and 95% confidence intervals between preconception serum folate and plasma homocysteine for anovulation, pregnancy, and pregnancy loss.

RESULTS

Greater plasma homocysteine was nonlinearly associated with greater risks of pregnancy loss only among women with 2 previous losses: a relative risk of 1.43 (95% confidence interval, 1.08-1.89) was found for plasma homocysteine concentrations at the study median of 8.0 μmol/L compared with a US population median of 6.0 μmol/L. No meaningful relationships were found between serum folate and any reproductive outcome or between plasma homocysteine and anovulation or becoming pregnant.

CONCLUSION

These data justify further study of the role of folate and homocysteine metabolism in normal and abnormal early pregnancy.

The Role of Nitric Oxide, ADMA, and Homocysteine in The Etiopathogenesis of Preeclampsia-Review

Preeclampsia is a serious, pregnancy-specific, multi-organ disease process of compound aetiology. It affects 3–6% of expecting mothers worldwide and it persists as a leading cause of maternal and foetal morbidity and mortality. In fact, hallmark features of preeclampsia (PE) result from vessel involvement and demonstrate maternal endothelium as a target tissue. Growing evidence suggests that chronic placental hypoperfusion triggers the production and release of certain agents that are responsible for endothelial activation and injury. In this review, we will present the latest findings on the role of nitric oxide, asymmetric dimethylarginine (ADMA), and homocysteine in the etiopathogenesis of preeclampsia and their possible clinical implications.

Pregnancy loss and risk of later dementia: A nationwide cohort study, Denmark, 1977-2017

INTRODUCTION

Pregnancy losses may be associated with increased risks of dementia.

METHODS

We conducted a register-based cohort study in 1,243,957 women with ≥1 pregnancy in Denmark in the period 1977-2015. Using Cox regression, we estimated hazard ratios (HRs) comparing risks of dementia in women with and without pregnancy losses.

RESULTS

During 21,672,433 person-years of follow-up, 261,279 women experienced a pregnancy loss, and 2188 women were diagnosed with dementia. Stillbirth was associated with an 86% increased risk of dementia overall (HR 1.86, 95% confidence interval [CI] 1.28-2.71). By contrast, miscarriage was not associated with later risk of dementia overall (single miscarriage, HR 0.99, 95% CI 0.87-1.12; recurrent miscarriages, HR 1.06, 95% CI 0.84-1.35). Adjustment for cardiovascular disease, hypertension, and diabetes did not meaningfully alter the association magnitudes.

DISCUSSION

Stillbirth and dementia may share underlying mechanisms, suggesting that a history of stillbirth should be considered when assessing dementia risk in women.

The role of maternal homocysteine concentration in placenta-mediated complications: findings from the Ottawa and Kingston birth cohort

Background

Homocysteine is an intermediate metabolite implicated in the risk of placenta-mediated complications, including preeclampsia, placental abruption, fetal growth restriction, and pregnancy loss. Large cohort and case-control studies have reported inconsistent associations between homocysteine and these complications. The purpose of this study was to investigate whether elevated maternal plasma homocysteine concentration in the early to mid-second trimester is associated with an increased risk of placenta-mediated complications. We examined the following potential moderating factors that may explain discrepancies among previous studies: high-risk pregnancy and the MTHFR 677C>T polymorphism.

Methods

We analyzed data from participants recruited to the Ottawa and Kingston (OaK) Birth Cohort from 2002 to 2009 in Ottawa and Kingston, Canada. The primary outcome was a composite of any placenta-mediated complication, defined as a composite of small for gestational age (SGA) infant, preeclampsia, placental abruption, and pregnancy loss. Secondary outcomes were, individually: SGA infant, preeclampsia, placental abruption, and pregnancy loss. We conducted multivariable logistic regression analyses with homocysteine as the primary continuous exposure, adjusting for gestational age at the time of bloodwork and explanatory maternal characteristics. The functional form, i.e., the shape of the homocysteine association with the outcome was examined using restricted cubic splines and information criteria (Akaike’s/Bayesian Information Criterion statistics). Missing data were handled with multiple imputation.

Results

7587 cohort participants were included in the study. Maternal plasma homocysteine concentration was significantly associated (linearly) with an increased risk of both the composite outcome of any placenta-mediated complication (p = 0.0007), SGA (p = 0.0010), severe SGA, and marginally with severe preeclampsia, but not preeclampsia, placental abruption and pregnancy loss. An increase in homocysteine concentration significantly increased the odds of any placenta-mediated complication (odds ratio (OR) for a 5 μmol/L increase: 1.63, 95% Confidence Interval (CI) 1.23–2.16) and SGA (OR 1.76, 95% CI 1.25–2.46). Subgroup analyses indicated some potential for modifying effects of the MTHFR 677C>T genotype and high-risk pregnancy, although the interaction was not statistically significant (high-risk subgroup OR 2.37, 95% CI 1.24–4.53, p-value for interaction =0.14).

Conclusions

Our results suggest an independent effect of early to mid-pregnancy elevated maternal homocysteine on placenta-mediated pregnancy complications.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2219-5) contains supplementary material, which is available to authorized users.

Association of Cystathionine β-Synthase Gene Polymorphisms With Preeclampsia

Preeclampsia (PE) is a pregnancy disorder that increases maternal and fetal morbidity and mortality worldwide. High plasma levels of homocysteine (Hcy) are a risk factor for several cardiovascular diseases. Cystathionine β-synthase (CBS) plays an important role in Hcy homeostasis catalyzing the irreversible degradation of Hcy to cystathionine, protecting the endothelium from injury caused by hypoxia. Several mutations and polymorphisms may alter the expression of the CBS gene, resulting in variable levels of Hcy. The purpose of this study was to investigate the association of CBS gene polymorphisms with PE in Mexican women. A case–control study consisting of 129 pregnant women with PE (37 severe and 92 mild) and 173 women with uncomplicated pregnancies was performed. Polymorphisms, such as G797A, C785T, T833C, G919A, T959C, C1105T, and 844ins68 base pair, in the CBS gene were genotyped. The polymorphism G797A was monomorphic in cases with the presence of only G797A-G allele. Allele C785T-T and genotype C785T-C/T were associated with susceptibility in severe and mild PE. Alleles G797A-G and T959C-T were associated with susceptibility only in severe PE. Haplotype TGTWGTC was of susceptibility for severe PE and of protection for mild PE. Haplotypes CGTWGCC and CATWGTC seem to be protective for severe PE, but the latter is related to susceptibility in mild PE. The results suggest that C785T, G797A, and T959C mutations are contributing in different ways in severe and mild PE in our population and could be count as another related factor for this disease.

Effect of homocysteine on pregnancy: A systematic review

Research purpose was to put together the available pieces of present scientific data and to close the gap in the knowledge of Hcy levels in pregnancy and its association with some pregnancy complications. Scientific data were taken from research papers published between January 1990 and December 2017, and found on the Internet (PubMed, ClinicalKey and Embase databases) by the following tags entered in English, Russian, French and German languages: pregnancy, homocysteine, pregnancy complications, pregnancy loss, preeclampsia, intrauterine growth restriction, and placental abruption. The review showed that Hcy levels range in uncomplicated pregnancy. Upon that, Hcy level tends to decrease during the second and third trimesters. Some studies have revealed a link between polymorphism and abortion. Sufficient data were obtained indicating the relationship between HHcy and PE. Placental abruption was also associated with high Hcy levels increasing the risk 5.3-fold, but still there are data not supporting the hypothesis that Hcy levels correlate with placental abruption.

Preeclampsia biomarkers: An assessment of maternal cardiometabolic health

Preeclampsia is a serious pregnancy condition defined as new-onset hypertension and proteinuria, commonly characterized as either early, 'placental', or late onset, 'maternal', using a cut-off of 34 weeks gestation. However, it may be more useful to differentiate between the vascular remodelling and placental invasion vs. inflammation and metabolic pathophysiology that underlie these forms of preeclampsia. Due to rising rates of obesity, the late-onset, maternal form is increasingly occurring earlier in pregnancy. Predictive tests for preeclampsia typically include biophysical markers such as maternal body mass index and mean arterial pressure, indicating the importance of cardiovascular and metabolic health in its pathophysiology. In contrast, the placental, inflammatory, endothelial and/or metabolic biomarkers used in these tests are generally thought to indicate an abnormal response to placentation and predict the disease. However, many of these non-placental biomarkers are known to predict impaired metabolic health in non-pregnant subjects with obesity (metabolically unhealthy obesity) and coronary artery disease or stroke in people at risk for cardiovascular events. Similarities between the performance of these markers in the prediction of cardiovascular and metabolic health outside of pregnancy suggests that they may be more indicative of maternal health than predictive for preeclampsia. This paper reviews the biophysical and biochemical markers in preeclampsia prediction and compares their performance to tests assessing metabolic health and risk of cardiovascular disease, particularly in the obese population.

Screening for fetal growth restriction using fetal biometry combined with maternal biomarkers

Fetal growth restriction is a major determinant of perinatal morbidity and mortality. Screening for fetal growth restriction is a key element of prenatal care but it is recognized to be problematic. Screening using clinical risk assessment and targeting ultrasound to high-risk women is the standard of care in the United States and United Kingdom, but the approach is known to have low sensitivity. Systematic reviews of randomized controlled trials do not demonstrate any benefit from universal ultrasound screening for fetal growth restriction in the third trimester, but the evidence base is not strong. Implementation of universal ultrasound screening in low-risk women in France failed to reduce the risk of complications among small-for-gestational-age infants but did appear to cause iatrogenic harm to false positives. One strategy to making progress is to improve screening by developing more sensitive and specific tests with the key goal of differentiating between healthy small fetuses and those that are small through fetal growth restriction. As abnormal placentation is thought to be the major cause of fetal growth restriction, one approach is to combine fetal biometry with an indicator of placental dysfunction. In the past, these indicators were generally ultrasonic measurements, such as Doppler flow velocimetry of the uteroplacental circulation. However, another promising approach is to combine ultrasonic suspicion of small-for-gestational-age infant with a blood test indicating placental dysfunction. Thus far, much of the research on maternal serum biomarkers for fetal growth restriction has involved the secondary analysis of tests performed for other indications, such as fetal aneuploidies. An exemplar of this is pregnancy-associated plasma protein A. This blood test is performed primarily to assess the risk of Down syndrome, but women with low first-trimester levels are now serially scanned in later pregnancy due to associations with placental causes of stillbirth, including fetal growth restriction. The development of "omic" technologies presents a huge opportunity to identify novel biomarkers for fetal growth restriction. The hope is that when such markers are measured alongside ultrasonic fetal biometry, the combination would have strong predictive power for fetal growth restriction and its related complications. However, a series of important methodological considerations in assessing the diagnostic effectiveness of new tests will have to be addressed. The challenge thereafter will be to identify novel disease-modifying interventions, which are the essential partner to an effective screening test to achieve clinically effective population-based screening.

Correlation of Maternal Serum Homocysteine in the First Trimester with the Development of Gestational Hypertension and Preeclampsia

Background

This study investigated the relationship of serum homocysteine in early pregnancy with the risk of gestational hypertension (GH) and preeclampsia (PE) and with the severity of preeclampsia.

Material/Methods

In a retrospective cohort study, we identified 147 confirmed cases of preeclampsia (103 with mild PE and 44 with severe PE) and 147 confirmed cases of GH; 4418 women who remained normotensive and nonproteinuric throughout pregnancy served as controls. Maternal blood samples were collected at between 11 and 13 weeks of gestation to test serum concentrations of homocysteine (Hcy), folic acid, and VitB12. A logistic regression model was used to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

Results

Women who subsequently developed GH and PE were older and had higher body mass indexes (BMIs) than those in the control group. Compared with the control group, women who developed PE were less educated (P=0.031), and more of those who developed GH were primiparas (P=0.012). The serum levels of Hcy in severe PE were significantly higher than those in the control group (median: 8.50 μmol/L vs. 7.33 μmol/L, P<0.001). After logistic regression analyses for potential confounding factors, the adjusted odds ratios (aORs) of Hcy was 1.12 for severe PE (95% CI 1.06–1.20). The serum concentrations of folic acid and VitB12 in those with GH and PE were not significantly different from controls.

Conclusions

A high level of Hcy in the first trimester is an independent risk factor for severe PE, although it is not a useful marker for the subsequent development of GH and mild PE.

Maternal serum homocysteine and uterine artery Doppler as predictors of preeclampsia and poor placentation

PURPOSE

The aim of this study was to evaluate the role of maternal serum total Homocysteine (tHcy) and uterine artery (Ut-A) Doppler as predictors of preeclampsia (PE), intrauterine growth restriction (IUGR), and other complications related to poor placentation.

PATIENTS AND METHODS

A prospective cohort study was conducted on 500 women with spontaneous pregnancies. tHcy was measured at 15-19 weeks, and then, Ut-A Doppler was performed at 18-22 weeks of pregnancy.

RESULTS

453 pregnant women completed the follow-up of the study. The tHcy and Ut-A resistance index were significantly higher in women who developed PE, IUGR, and other complications when compared to controls (tHcy: 7.033 ± 2.744, 6.321 ± 3.645, and 6.602 ± 2.469 vs 4.701 ± 2.082 μmol/L, respectively, p value <0.001 and Ut-A resistance index: 0.587 ± 0.072, 0.587 ± 0.053, and 0.597 ± 0.069 vs 0.524 ± 0.025, respectively, p value <0.001). The use of both tHcy assessment and Ut-A Doppler improved the sensitivity of prediction of PE relative to the use of each one alone (85.2 relative to 73.33 and 60%, respectively).

CONCLUSION

The use of elevated homocysteine and uterine artery Doppler screening are valuable in prediction of preeclampsia, IUGR, and poor placentation disorders. CLINCALTRIAL.

GOV ID

NCT02854501.

Associations of Maternal Vitamin B12 Concentration in Pregnancy With the Risks of Preterm Birth and Low Birth Weight: A Systematic Review and Meta-Analysis of Individual Participant Data

Vitamin B12 (hereafter referred to as B12) deficiency in pregnancy is prevalent and has been associated with both lower birth weight (birth weight <2,500 g) and preterm birth (length of gestation <37 weeks). Nevertheless, current evidence is contradictory. We performed a systematic review and a meta-analysis of individual participant data to evaluate the associations of maternal serum or plasma B12 concentrations in pregnancy with offspring birth weight and length of gestation. Twenty-two eligible studies were identified (11,993 observations). Eighteen studies were included in the meta-analysis (11,216 observations). No linear association was observed between maternal B12 levels in pregnancy and birth weight, but B12 deficiency (<148 pmol/L) was associated with a higher risk of low birth weight in newborns (adjusted risk ratio = 1.15, 95% confidence interval (CI): 1.01, 1.31). There was a linear association between maternal levels of B12 and preterm birth (per each 1-standard-deviation increase in B12, adjusted risk ratio = 0.89, 95% CI: 0.82, 0.97). Accordingly, B12 deficiency was associated with a higher risk of preterm birth (adjusted risk ratio = 1.21, 95% CI: 0.99, 1.49). This finding supports the need for randomized controlled trials of vitamin B12 supplementation in pregnancy.

Determinants of vitamin D status in pregnant women and neonates

OBJECTIVES

Evidence suggests a beneficial effect of vitamin D on perinatal health; however, low vitamin D status is prevalent in pregnant women and neonates. The objective was to determine factors that are associated with vitamin D status of mothers in early pregnancy and neonates.

METHODS

The study comprised 1,635 pregnant women from Quebec City and Halifax, Canada, 2002-2010. Vitamin D status was based on the concentration of 25-hydroxy-vitamin D [25(OH)D] determined with a chemiluminescence immunoassay in maternal sera collected at a median of 15 weeks' gestation and in neonatal cord sera at delivery. A questionnaire with information on potential determinants was completed midpregnancy.

RESULTS

A total of 44.8% of mothers and 24.4% of neonates had 25(OH)D concentrations &lt;50 nmol/L. Adjusted mean (95% confidence interval) maternal 25(OH)D levels were higher in summer than in winter by 16.1 nmol/L (13.6-18.7), and in those in the highest versus the lowest category of education by 6.1 nmol/L (0.5-11.8), in BMI &lt;25 kg/m2 versus BMI ≥35 kg/m2 by 8.2 nmol/L (4.0-12.3), and in the highest versus the lowest physical activity category by up to 9.5 nmol/L (2.9-16.1). Determinants of neonatal 25(OH)D levels were similar but also included maternal age, dairy intake, supplement use and 25(OH)D level.

CONCLUSION

This study suggests that vitamin D status of pregnant women and/or neonates might be improved through supplementation, adequate dairy intake, a move towards a healthy pre-pregnancy body weight, and participation in physical activity. Controlled studies are needed to determine the effectiveness of interventions aimed at these factors.

Conformational status of cytochrome c upon N-homocysteinylation: Implications to cytochrome c release

One of the proposed mechanisms of homocysteine (Hcy) toxicity is the post-translational modification of proteins by its metabolite, homocysteine thiolactone (HTL). Incubation of proteins with HTL has been shown to form covalent adducts with ε-amino group of lysine residues of protein (called N-homocysteinylation) which ultimately results in structural and functional alterations of the modified proteins. In the present study, the effects of HTL on the conformational and heme status of cytochrome c (cyt c) were investigated. Spectroscopic analyses revealed that HTL-modified cyt c undergoes certain conformational alterations leading to disturbed heme-Trp distance and packing of the apolar groups. These alterations were accompanied with the reduction of the heme moiety and activation of peroxidase-like function of cyt c, which is known to be a crucial event for initiation of the intrinsic apoptotic pathway. Further structural characterization revealed that disruption of the heme-Met80 interaction, thereby converting the hexa-coordinate cyt c to a penta-coordinate species (with a free heme ligand), was responsible for the activation of the peroxidase activity. The study provides insights for the possible role of cyt c N-homocysteinylation in eliciting its toxicity and cell death.

The evaluation of serum homocysteine, folic acid, and vitamin B12 in patients complicated with preeclampsia

Introduction

Increased plasma homocysteine may be associated with adverse pregnancy outcomes, such as preeclampsia. The aim of this study was to determine the plasma homocysteine, serum folate, and vitamin B12 levels in preeclamptic pregnant women.

Methods

This case-control study was conducted in 2016 in Ahwaz on 51 pregnant women with preeclampsia and 51 healthy pregnant women of the same gestational age, who served as controls. The case group also was subdivided into severe and non-severe preeclampsia. Patients’ data were collected through a questionnaire and medical records. Serum homocysteine, folic acid, and vitamin B12 were analyzed using chemiluminescent assay. The results were compared between two groups. Statistical analyses were done using IBM-SPSS 20.0. A Kolmogorov-Smirnov test, independent samples t-test, Mann-Whitney test, and Chi-square test were used for data analysis.

Results

No different demographic characteristics were found among the groups. Pregnant women complicated with preeclampsia displayed significantly higher serum homocysteine levels (p < 0.001) and lower serum folate (p = 0.005) and vitamin B12 levels (p < 0.001) compared to controls. A statistically significant inverse correlation was evident between serum homocysteine and serum folate levels in preeclamptic patients (p = 0.005; r = −0.389). In addition, an inverse correlation was identified between homocysteine and serum vitamin B12, but it was not statistically significant (p = 0.160; r = −0.200). Significant differences occurred in serum homocysteine and folate levels between the severe and non-severe subgroups (p < 0.001, p < 0.001).

Conclusion

Women complicated with preeclampsia displayed higher maternal serum homocysteine and lower serum folate and vitamin B12. Further studies are needed to confirm if the prescription of folic acid and vitamin B12 in women with a deficiency of these vitamins could decrease the level of serum homocysteine and, therefore, reduce the risk of preeclampsia or, if it occurred, its severity.

Homocysteine augments BK channel activity and decreases exocytosis of secretory granules in rat GH3 cells

In this study, we investigated the effects of L-homocysteine (Hcy) on maxi calcium-activated potassium (BK) channels and on exocytosis of secretory granules in GH3 rat pituitary-derived cells. A major finding of our study indicates that short-term application of Hcy increased the open probability of oxidized BK channels in inside-out recordings. Whole-cell recordings show that extracellular Hcy also augmented BK currents during long-term application. Furthermore, Hcy decreased the exocytosis of secretory granules. This decrease was partially prevented by the BK channel inhibitor paxilline and fully prevented by N-acetylcysteine, a reactive oxygen species scavenger. Taken together, our data show that elevation of cellular Hcy level induces oxidative stress, increases BK channel activity, and decreases exocytosis of secretory granules. These findings may provide insight into some of the developmental impairments and neurotoxicity associated with Hyperhomocysteinemia (HHcy), a disease arising due to abnormally elevated levels of Hcy in the plasma.

Maternal and Neonatal Markers of the Homocysteine Pathway and Fetal Growth: The Generation R Study

BACKGROUND

Suboptimal dietary intake during pregnancy may have long-term health implications in children. These effects may be mediated by fetal growth. We investigated the associations of early pregnancy and umbilical cord total homocysteine (tHcy), folate, and total and active vitamin B12 concentrations with fetal growth parameters repeatedly measured in pregnancy and at birth.

METHODS

This study was performed in 5890 pregnant women, participating in a population-based prospective cohort study. Blood samples were obtained from women in early pregnancy and from the umbilical vein at delivery. Fetal size parameters were repeatedly measured by ultrasound. Information about birth anthropometrics was retrieved from medical records.

RESULTS

High early pregnancy maternal tHcy (≥8.31 μmol/L), as compared with low maternal homocysteine (≤5.80 μmol/L), and low early pregnancy maternal folate (≤9.10 nmol/L), as compared with high maternal folate (≥25.81 nmol/L) concentrations, were associated with reduced weight growth patterns throughout pregnancy, resulting in birthweight differences of -102.3 g (95% CI -139.6, -65.0) and -113.0 g (95% CI -159.6, -66.3), respectively. Low umbilical cord folate concentrations (≤15.20 nmol/L) as compared with high umbilical cord folate concentrations (≥28.41 nmol/L) were also associated with a lower birthweight and birth length (P < 0.001). Interestingly, compared with higher umbilical cord vitamin B12 , lower vitamin B12 concentrations were associated with a higher weight, length, and head circumference at birth (P < 0.01).

CONCLUSION

Early pregnancy maternal and umbilical cord markers of the homocysteine pathway are significantly associated with fetal growth patterns. These differences arise from mid-pregnancy onwards.

Vitamin D Status and Gestational Diabetes: Effect of Smoking Status during Pregnancy

BACKGROUND

Vitamin D status, as measured by serum 25-hydroxyvitamin D (25(OH)D), has been shown in some studies to be inversely associated with gestational diabetes risk. Recently, it has been suggested that maternal smoking status may modify this relationship. We explored the association between 25(OH)D concentration and gestational diabetes and determined if there was an interaction between smoking and 25(OH)D.

METHODS

A nested case-control study was conducted in Halifax, Nova Scotia and Quebec City, Quebec. Women were recruited before 20 weeks gestation and 25(OH)D was measured. Cases were women who developed gestational diabetes and controls were frequency matched to cases on study site, gestational age at blood draw, and season and year of blood draw. Logistic regression models estimated adjusted odds ratios (aOR) and 95% confidence intervals (CI). Models were tested for multiplicative and additive interaction, which was estimated by relative excess risk due to interaction (RERI).

RESULTS

The study included 395 gestational diabetes cases and 1925 controls. Women who smoked during pregnancy and had 25(OH)D concentrations <30 nmol/L had an aOR = 3.73 [95% CI 1.95, 7.14] compared to non-smokers with 25(OH)D concentrations ≥50 nmol/L. Additive interaction was detected between smoking status and 25(OH)D [RERI = 2.44, 95% CI 0.03, 4.85].

CONCLUSION

Our study supports the inverse association of vitamin D status with gestational diabetes risk, particularly among women who smoke during pregnancy. More research is needed to confirm this finding and, if confirmed, to determine the mechanism by which the combined effect of smoking and low vitamin D status increases the risk of developing gestational diabetes.

Folic acid supplementation: what is new? Fetal, obstetric, long-term benefits and risks

The association between folic acid supplementation, prior to conception and/or during pregnancy and pregnancy outcomes, has been the subject of numerous studies. The worldwide recommendation of folic acid is at least 0.4 mg daily for all women of reproductive age, and 4–5 mg in high-risk women. In addition, evidence shows that folic acid supplementation could modulate other adverse pregnancy outcomes, specifically, in pregnancies complicated by seizure disorders, preeclampsia, anemia, fetal growth restriction and autism. This review summarizes the available national and international guidelines, concerning the indications and dosage of folic acid supplementation during pregnancy. In addition, it describes the potential preventive benefits of folic acid supplementation on multiple maternal and fetal outcomes, as well as potential risks.

Placental NRP1 and VEGF expression in pre-eclamptic women and in a homocysteine-treated mouse model of pre-eclampsia

OBJECTIVES

To investigate the expression levels of neuropilin 1 (NRP1) and vascular endothelial growth factor (VEGF) in the placentas of women with pre-eclampsia (PE), determine whether homocysteine (Hcy) contributes to the development of PE in mice, and detect alterations in placental NRP1 and VEGF in Hcy-treated mice.

STUDY DESIGN

Placental tissue samples were obtained from 16 patients with and without PE. Using reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, the expression levels of NRP1 and VEGF in PE and control placental tissues were examined. Immunohistochemical (IHC) assay was used to detect the localization of NRP1 and VEGF proteins. Pregnant mice were treated with DL-Hcy on embryonic day 7.5. The symptoms of the treated mice were examined. The expression levels of Ddah1, Ddah2, eNos, Cbs and Cse were determined by quantitative RT-PCR to study the possible mechanism of hyperhomocysteinemia (HHcy). Nrp1 and Vegf expression levels in the placentas of treated mice were measured by quantitative RT-PCR, western blot analysis and IHC.

RESULTS

NRP1 and VEGF were expressed at lower levels in women with PE compared with control women. The immunoreactivity of NRP1 was detected in villous trophoblast cells and villous capillary endothelial cells (ECs). Immunoreactive VEGF was observed mainly in vascular ECs within the villi. The pregnant mice treated with DL-Hcy showed PE-like symptoms such as higher systolic blood pressure and proteinuria in late pregnancy. Compared with the control mice, Ddah1, Ddah2 and eNos mRNA were expressed at lower levels, and Cbs and Cse mRNA were expressed at significantly higher levels in the placentas of the Hcy-treated group. Expression levels of Nrp1 and Vegf in mice placentas were decreased in the Hcy-treated group.

CONCLUSIONS

DL-Hcy can induce PE-like symptoms in mice. Both placental NRP1 and VEGF were expressed at lower levels in women with PE and Hcy-treated mice, which may contribute to endothelial damage.

The association between physical activity and maternal and neonatal outcomes: a prospective cohort

Some evidence, but not enough to be conclusive, suggests that physical activity in pregnancy reduces the risk of perinatal complications. Our objective was to examine if physical activity in the year before pregnancy and in the first half of pregnancy is associated with maternal and neonatal outcomes. Associations between physical activity and maternal and neonatal outcomes were examined in a prospective cohort (n = 1,749) in Halifax, Canada. The Kaiser Physical Activity Survey, completed at approximately 20 weeks' gestation, requested information regarding physical activity during the year before the pregnancy and the first 20 weeks of pregnancy. Outcomes were assessed by medical chart review. Multiple logistic regression was used to estimate odds ratios (OR) with 95 % confidence intervals (CI). Women with prepregnancy physical activity levels in the middle and highest tertiles were more likely to have high gestational weight gain relative to women in the lowest tertile [OR (CI): 1.40 (1.06-1.85) and 1.57 (1.18-2.09), respectively]. Higher physical activity in the first half of pregnancy decreased the odds of delivering a macrosomic infant (p trend = 0.005). Associations were not observed between total physical activity and gestational diabetes, gestational hypertension, pre-eclampsia, preterm birth, and low birth weight. Physical activity before, but not in the first half of pregnancy, is associated with high gestational weight gain. Physical activity in the first half of pregnancy may reduce the occurrence of macrosomia without affecting preterm birth or low birth weight.

Folic acid supplementation in early pregnancy and the risk of preeclampsia, small for gestational age offspring and preterm delivery

OBJECTIVE

To assess whether folic acid intake during the first trimester of pregnancy is related to pregnancy outcomes preeclampsia, low birth weight or preterm birth.

STUDY DESIGN

Prospective cohort study of 3647 women who were followed from the first trimester of pregnancy. Detailed information on quantity of folic acid intake before and during the first three months of pregnancy was recorded. Pregnancy outcome data were abstracted from obstetric records.

RESULTS

Lean mothers who used folic acid supplementation the month before pregnancy had a 40% reduced risk of developing preeclampsia. The adjusted odds ratio (OR) with 95% confidence intervals (95%CI) for preeclampsia in lean mothers (BMI<25) who used folic acid supplements the month before pregnancy was 0.6 (95% CI 0.4-1.0). Obese mothers who used folic acid supplementation in the first trimester had an increased, but not statistically significant risk for preterm birth (adjusted OR 1.9 with 95% CI 0.9-4.0). There were no significant associations between folic acid supplementation and low birth weight.

CONCLUSION

Our study supports a possible protective effect of folate intake in early pregnancy on preeclampsia in lean mothers. There was no support for any beneficial effect of folic acid use on preterm birth or low birth weight, and we found no evidence of any harmful effects of folate use for the outcomes included in our study.

Periconceptional folic acid fortification for the risk of gestational hypertension and pre-eclampsia: a meta-analysis of prospective studies

Published literatures report controversial results about the association of folic acid-containing multivitamins with gestational hypertension and pre-eclampsia. A comprehensive search was performed to identify related prospective studies to assess the effect of folic acid fortification on gestational hypertension and pre-eclampsia. The Q test and I(2) statistic were used to examine between-study heterogeneity. Fixed or random effects models were selected based on study heterogeneity. A funnel plot and modified Egger linear regression test were used to estimate publication bias. Eleven studies conformed to the criteria. Pooled results indicated that folic acid fortification alone was not associated with the occurrence of gestational hypertension [relative risk (RR) = 1.03, 95% confidence interval (CI): 0.98-1.09, P = 0.267] and pre-eclampsia (RR = 0.99, 95% CI: 0.90-1.08, P = 0.738). However, supplementation of multivitamins containing folic acid could prevent gestational hypertension (RR = 0.57, 95% CI: 0.43-0.76, P < 0.001) and pre-eclampsia (RR = 0.64, 95% CI: 0.48-0.84, P = 0.001). The difference between folic acid fortification alone and multivitamins containing folic acid was significant. This meta-analysis suggests that periconceptional multivitamin supplementation with appropriate dose, not folic acid alone, is an appropriate recommendation for pregnant women. The effect should be further confirmed by conducting large-scale randomised controlled trials.

Vitamin D status in early pregnancy and risk of preeclampsia

OBJECTIVE

We sought to examine the association between maternal serum 25-hydroxyvitamin D (25[OH]D) concentration in early pregnancy and the subsequent diagnosis of preeclampsia (PE).

STUDY DESIGN

This was a nested case-control study from 2 prospective Canadian cohorts conducted in Quebec City, Quebec, and Halifax, Nova Scotia, from 2002 through 2010. Participants were pregnant women (n = 169 cases with PE and 1975 controls). Maternal serum was drawn <20 weeks of gestation, and 25(OH)D measurement was performed. Cases were ascertained from medical records. Logistic regression analysis was used to estimate adjusted odds ratios with 95% confidence intervals.

RESULTS

Women who developed PE had a significantly lower 25(OH)D concentration at a mean gestational age of 14 weeks compared with women in the control group (mean ± SD 25[OH]D 47.2 ± 17.7 vs 52.3 ± 17.2 nmol/L, P < .0001). Women with 25(OH)D <30 nmol/L compared to those with at least 50 nmol/L had a greater risk of developing PE (adjusted odds ratio, 2.23; 95% confidence interval, 1.29-3.83) after adjustment for prepregnancy body mass index, maternal age, smoking, parity, season and year of blood collection, gestational week at blood collection, and cohort site. Exploratory analysis with cubic splines demonstrated a dose-response relationship between maternal 25(OH)D and risk of PE, up to levels around 50 nmol/L, where the association appeared to plateau.

CONCLUSION

Maternal vitamin D deficiency early in pregnancy defined as 25(OH)D <30 nmol/L may be an independent risk factor for PE. The relevance of vitamin D supplementation for women of childbearing age should be explored as a strategy for reducing PE and for promoting a healthier pregnancy.

Folic acid supplementation and dietary folate intake, and risk of preeclampsia

BACKGROUND/OBJECTIVES

Folic acid supplementation has been suggested to reduce the risk of preeclampsia. However, results from few epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of preeclampsia.

SUBJECTS/METHODS

A birth cohort study was conducted in 2010-2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. A total of 10,041 pregnant women without chronic hypertension or gestational hypertension were enrolled.

RESULTS

Compared with nonusers, folic acid supplement users had a reduced risk of preeclampsia (OR=0.61, 95% CI: 0.43-0.87). A significant dose-response of duration of use was observed among women who used folic acid supplemention during pregnancy only (P-trend=0.007). The reduced risk associated with folic acid supplement was similar for mild or severe preeclampsia and for early- or late-onset preeclampsia, although the statistical significant associations were only observed for mild (OR=0.50, 95% CI: 0.30-0.81) and late-onset (OR=0.60, 95% CI: 0.42-0.86) preeclampsia. The reduced risk associated with dietary folate intake during pregnancy was only seen for severe preeclampsia (OR=0.52, 95% CI: 0.31-0.87, for the highest quartile of dietary folate intake compared with the lowest).

CONCLUSIONS

Our study results suggest that folic acid supplementation and higher dietary folate intake during pregnancy reduce the risk of preeclampsia. Future studies are needed to confirm the associations.

N-homocysteinylation induces different structural and functional consequences on acidic and basic proteins

One of the proposed mechanisms of homocysteine toxicity in human is the modification of proteins by the metabolite of Hcy, homocysteine thilolactone (HTL). Incubation of proteins with HTL has earlier been shown to form covalent adducts with ε-amino group of lysine residues of protein (called N-homocysteinylation). It has been believed that protein N-homocysteinylation is the pathological hallmark of cardiovascular and neurodegenerative disorders as homocysteinylation induces structural and functional alterations in proteins. In the present study, reactivity of HTL towards proteins with different physico-chemical properties and hence their structural and functional alterations were studied using different spectroscopic approaches. We found that N-homocysteinylation has opposite consequences on acidic and basic proteins suggesting that pI of the protein determines the extent of homocysteinylation, and the structural and functional consequences due to homocysteinylation. Mechanistically, pI of protein determines the extent of N-homocysteinylation and the associated structural and functional alterations. The study suggests the role of HTL primarily targeting acidic proteins in eliciting its toxicity that could yield mechanistic insights for the associated neurodegeneration.