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

The intake of ultra-processed foods and homocysteine levels in women with(out) overweight and obesity: The Rotterdam Periconceptional Cohort

PURPOSE

Today's diet consists of a substantial proportion of ultra-processed foods (UPF), especially in women with overweight and obesity in the reproductive period. High UPF intake results in an inadequate and unbalanced diet leading to derangements of several metabolic pathways detrimental to pregnancy and birth outcomes. Therefore, we aim to investigate whether UPF intake in the periconceptional period affects total homocysteine plasma levels (tHcy).

METHODS

1532 participants were included from the prospective Rotterdam Periconceptional Cohort. UPF intake was calculated using Food Frequency Questionnaires including items classified as 4 in the Nova classification, and tHcy was measured by using liquid chromatography-tandem mass spectrometry system, with an interassay coefficient of variation of < 5.5%. Multivariable linear regression modeling was used and adjusted for covariates and significant interaction terms.

RESULTS

Women with overweight or obesity showed significantly higher percentage of UPF intake (respectively, 50.3 and 51.3%) and higher tHcy (respectively, 6.6 and 6.3 µmol/L, Kruskal-Wallis test; respectively, p < 0.001 and p = 0.04) compared to women with normal BMI (UPF intake: 46.8%, tHcy: 6.1 µmol/L). A 10% higher intake of UPF was associated with an increase in tHcy (adjusted: β = 1.31, 95% CI = 0.38-2.23). Analysis stratified for BMI classification showed comparable associations in normal weight participants (adjusted: β = 1.07, 95% CI = 0.06-2.07); however, no significant association in participants with overweight (adjusted: β = 0.06, 95% CI = - 0.95-1.07) and obesity (adjusted: β = 1.70, 95% CI = - 0.52-3.92) was shown.

CONCLUSION

This study showed that a higher intake of UPF is associated with increased tHcy. Better knowledge and awareness of the nutritional quality of the diet in the periconceptional period may contribute to 1-CM and subsequently improve pregnancy course and outcome.

TRIAL REGISTRATION NUMBER AND DATE

NTR4356, November 2010.

CYP19A1 Expression Is Controlled by mRNA Stability of the Upstream Transcription Factor AP-2γ in Placental JEG3 Cells

CYP19A1 encodes aromatase, which converts testosterone to estrogen, and is induced during placental maturation. To elucidate the molecular mechanism underlying this function, histone methylation was analyzed using the placental cytotrophoblast cell line, JEG3. Treatment of JEG3 cells with 3-deazaneplanocin A, an inhibitor of several methyltransferases, resulted in increased CYP19A1 expression, accompanied by removal of the repressive mark H3K27me3 from the CYP19A1 promoter. However, this increase was not observed in cells treated with GSK126, another specific inhibitor for H3K27me3 methylation. Expression of TFAP2C, which encodes AP-2γ, a transcription factor that regulates CYP19A1, was also elevated on 3-deazaneplanocin A treatment. Interestingly, TFAP2C messenger RNA (mRNA) was readily degraded in JEG3 cells but protected from degradation in the presence of 3-deazaneplanocin A. TFAP2C mRNA contained N6-methyladenosines, which were reduced on drug treatment. These observations indicate that the TFAP2C mRNA undergoes adenosine methylation and rapid degradation, whereas 3-deazaneplanocin A suppresses methylation, resulting in an increase in AP-2γ levels. We conclude that the increase in AP-2γ expression via stabilization of the TFAP2C mRNA is likely to underlie the increased CYP19A1 expression.

Assessment of blood one-carbon metabolism indexes during mid-to-late pregnancy in 397 Chinese pregnant women

Objectives

One-carbon metabolism (OCM) significantly influences fetal growth and neurodevelopment through transferring methyl group to biomolecules, during which folate, methionine, choline and betaine function as methyl donor nutrients, while vitamin B2, B6, B12 function as enzyme cofactors, and homocysteine (Hcy) and S-adenosyl methionine (SAM) are functional metabolites. This study aimed to assess blood OCM index levels and explore their relationships among Chinese pregnant women.

Methods

Data were obtained from the baseline of the Mother-Child Nutrition and Health Cohort Study. Pregnant women, voluntarily recruited from September 2020 to June 2022 during antenatal examinations in five Chinese cities at 24-32 gestational weeks, provided fasting venous blood samples. Measurements included RBC and serum folate, serum vitamin B2, B6, B12, choline, betaine, methionine, total Hcy (tHcy), and plasma SAM. Sociodemographic characteristics and pregnancy-related conditions were collected via a self-designed questionnaire.

Results

Of 397 participants, 82.6% were in mid-pregnancy (24-27 gestational weeks) and 17.4% were in late-pregnancy (28-32 gestational weeks). Serum folate, vitamin B6, and B12 deficiencies were 2.5, 1.3, and 8.3%, respectively. Elevated tHcy (≥10 μmol/L) was observed in 1.8% of pregnant women. Elderly pregnant women (aged 35 and above) exhibited significantly lower serum methionine levels (p < 0.05), while multiparous women had lower RBC folate levels (p < 0.05), and lower serum methionine and vitamin B12 levels (p < 0.10, not statistically significant). Partial correlation analysis revealed positive associations between RBC folate and cofactor vitamin B12 (r = 0.244, p < 0.05) in the folate cycle, as well as significant correlations between two methyl donor paths [serum folate was significantly related to serum choline (r = 0.172) and betaine (r = 0.193)]. As functional biomarkers of OCM, serum tHcy exhibited negative associations with RBC folate (β = -0.330, p < 0.05) and vitamin B6 (β = -0.317, p < 0.05), and plasma SAM displayed a positive association with serum betaine (β = 0.610, p < 0.05), while negatively associated with serum vitamin B6 (β = -0.181, p < 0.05).

Conclusion

The blood OCM exhibited imbalances during mid-to-late pregnancy, characterized by lower levels of folate, vitamin B6, and B12, alongside elevated tHcy levels. Adequate folate and vitamin B6 emerged as significant predictors of lower tHcy levels. Additionally, serum betaine showed a positive correlation with plasma SAM. This suggests the importance of not only ensuring sufficient folate but also optimizing other OCM-related nutrients throughout pregnancy.

Platelet counts affect the association between hyperhomocysteinemia and pregnancy complications

BACKGROUND

The joint effect of platelet and other modifiers on the risk of pregnancy complications is unknown. This study investigated whether platelet count (PC) and total homocysteine (tHcy) level have a synergistic effect on the incidence of pregnancy complications in a Chinese population.

METHODS

Total 11,553 consecutive pregnant women who received whole blood cell and biochemical tests at the time of admission for labor in Changzhou Maternal and Child Health Care Hospital were analyzed. The primary outcome was the prevalence of pregnancy complications: gestational diabetes mellitus (GDM), intrahepatic cholestasis of pregnancy (ICP), pre-eclampsia (PE), and pregnancy induced hypertension (PIH).

RESULTS

The prevalence of GDM, ICP, PE, and PIH was 8.4%, 6.2%, 3.4%, and 2.1%, respectively. The highest rate of ICP (28.6%) was observed in women with high tHcy (> 15 μmol/L) and low PC (quartile 1); and the lowest rate of GDM (0.6%) was found in women with high tHcy and high PC (quartiles 2 to 4). In low PC group, the prevalence of ICP in women with high tHcy was significantly higher than that in women with low tHcy (≤ 15 μmol/L) (28.6% vs. 8.4%), representing an absolute risk increment of 20.2% and a relative risk increment of 3.3-fold (OR: 3.34; 95% CI: 1.55, 7.17; P = 0.002), whereas no joint effect was observed among high PC group.

CONCLUSIONS

Among Chinese pregnant women, one subgroup (high tHcy and low PC) has the highest risk of ICP and another (high tHcy and high PC) has the lowest risk of GDM; tHcy and platelet could be used as indicators to identify the women with high risk of ICP or low risk of GDM.

Raised Maternal Homocysteine Levels in Antenatal Women at 10 to 14 Weeks of Gestation and Placenta-Mediated Complications: A Cohort Study

Background Placenta-mediated complications, such as preeclampsia, placental abruption, and fetal growth restriction, can indeed lead to significant maternal and perinatal morbidity and mortality. Early detection and management of these conditions are crucial to ensuring optimal outcomes for both the mother and baby. However, there have been inconsistent correlations found between maternal homocysteine levels and placenta-related problems in various studies. Therefore, prospective research based on data pointing to a role for hyperhomocysteinemia in placenta-mediated complications will open doors for early detection and management of these complications. Thus, this study aims to determine if a higher risk of placenta-mediated problems is connected with a higher maternal plasma homocysteine content between 10 and 14 weeks of gestation. Methodology An observational prospective cohort study was conducted in the Department of Obstetrics and Gynecology, consisting of all the antenatal women between 10 and 14 weeks of gestation attending outpatient departments or inpatients admitted in labor rooms or wards having singleton pregnancies. Along with socio-demographic information and detailed history, a clinical examination was performed, and blood samples were collected to determine plasma homocysteine levels. Results As per the receiver operating characteristic curve (ROC curve), the cut-off value taken was <5 for the low level of serum homocysteine, 5 to 15 micromol/L for the normal value, and >15 micromol/L for a raised serum homocysteine level. The cutoff value for our study was 45 micromol/L with a sensitivity of 78.33%, a specificity of 91.67%, a positive predictive value of 90.38%, and a negative predictive value of 80.88% with a diagnostic accuracy of 85%. This means that, for most of the women included in the present study, those who developed placenta-mediated complications had serum blood homocysteine levels of 45 micromol/L or more at 10-14 weeks of gestation. Conclusion Women with high homocysteine levels in the late first trimester had more placenta-mediated complications, such as abruption, pre-eclampsia, restricted fetal growth, and recurrent pregnancy losses, compared to women with a normal level of homocysteine in the late first trimester. Therefore, measuring blood homocysteine levels in pregnancy may be helpful as a diagnostic test for the early detection of high-risk individuals for placenta-mediated complications.

Factors associated with poorer childbirth outcomes in pregnant women diagnosed with placenta previa

OBJECTIVE

Placenta previa is a health issue during pregnancy when the placenta wholly or partially covers the opening of the uterus. It can result in bleeding during pregnancy or after delivery, and preterm delivery. This study aimed to investigate the risk factors correlated with poorer childbirth outcomes of placenta previa.

MATERIALS AND METHODS

Between May 2019 and January 2021, pregnant women diagnosed with placenta previa in our hospital were enrolled. Outcomes were postpartum hemorrhage after childbirth, and lower Apgar score and preterm delivery of the neonate. Laboratory blood examination data preoperatively were collected from medical records.

RESULTS

A total of 131 subjects were included, with a median age 31 years. Multivariate analysis showed that fibrinogen reduced risk for postpartum hemorrhage (adjusted odds ratio (aOR): 0.45, 95% confidence interval (CI): 0.26-0.79, p = 0.005). Homocysteine (aOR: 0.73, 95% CI: 0.54-0.99, p = 0.04) reduced the risk while D-dimer (aOR: 1.19, 95% CI: 1.02-1.37, p = 0.02) increased the risk for low Apgar score. Age (aOR: 0.86, 95% CI: 0.77-0.96, p = 0.005) decreased the risk but history of full-term pregnancy more than twice (aOR: 8.58, 95% CI: 2.32-31.71, p = 0.001) increased the risk for preterm delivery.

CONCLUSION

The findings suggest that poorer childbirth outcomes in pregnant women with placenta previa are associated with young age, history of full-term pregnancy, and preoperative concentrations of low fibrinogen, low homocysteine and high D-dimer. This provides obstetricians adjunctive information for early screening of high-risk population and relevant treatment arrangement in advance.

Significance of Hyperhomocysteinemia in Immediate As Well As Long-Term Health Risk/s in Women with Polycystic Ovary Syndrome: a Probabilistic Model Using Dynamic Bayesian Network Analysis

Polycystic ovary syndrome (PCOS) is a heterogeneous entity comprising broad spectra of ovarian disorders with trademark features of metabolic syndrome like insulin resistance, obesity, and dyslipidaemia to name a few. Hyperhomocysteinemia, an independent risk factor of metabolic syndrome, has been suggested as a causative factor in spontaneous miscarriage in PCOS. However, it is yet to be resolved whether hyperhomocysteinemia has a contributory role in the pathogenesis or could direct long-term sequences of the syndrome. A total of 2355 women with history of one or more first trimester abortions were screened and 1539 were selected for the study. Selected patients were initially divided by the presence or absence of PCOS, while subsequent stratification was based on hyperhomocysteinemia, insulin resistance, and/or obesity. The miscarriage population/s was mostly represented by hyperhomocysteinemia in both the cohorts (PCOS: 69.08% vs. non-PCOS: 56.68%). ROC-AUC values suggest increased predisposition of hyperhomocysteinemia-mediated miscarriage (hyperhomocysteinemia: 0.778; insulin resistance: 0.601; BMI: 0.548). A probabilistic causal model was designed using dynamic Bayesian network to evaluate the time-series data points before, during, and after pregnancy which revealed a possibility of 32.24% (n = 79) of PCOS cohort developing hypertension, 26.94% (n = 66) of onset of diabetes and 4.49% cardiovascular disease 3 years following pregnancy. We conclude hyperhomocysteinemia may possibly contribute to spontaneous miscarriage and related to metabolic derailments later in life.

Maternal Hyperhomocysteinemia as a Predictor of Placenta-Mediated Pregnancy Complications: A Two-Year Novel Study

Background Placenta-mediated pregnancy complications (PMPCs) are a significant contributor to adverse maternal and fetal outcomes. Though the exact cause of the array of pregnancy-related vascular disorders is still unknown, increased maternal serum homocysteine (Hct) levels have been linked to the pathophysiology. Hyperhomocysteinemia (HHct) has been strongly linked with the risk of developing PMPCs such as preeclampsia (PE), fetal growth restriction (FGR), intrauterine fetal death (IUFD), preterm births and placental abruption. Methodology The present observational study was carried out on 810 low-risk antenatal women in their early second trimester (13-20 weeks gestation age) in the department of obstetrics and gynecology of a tertiary care rural hospital to identify the significance of abnormally raised maternal serum Hct level in developing PMPCs. Results Of the 810 participants studied, 224 (27.65%) had raised Hct levels whereas the rest of the 586 (72.35%) participants had normal Hct levels. The mean Hct level of raised homocysteine group (18.59 ± 2.46 micromol/L) was substantially raised than the normal Hct group (8.64 ± 3.1 micromol/L). It was observed that women with elevated serum Hct levels developed PMPCs significantly more than women with normal serum Hct levels (p-value <0.05). Among HHct subjects, 65.18% developed PE, 34.38% had FGR, 28.13% had a preterm delivery, 4.02% had abruptio placentae and 3.57% had IUFD. Conclusions The focus of the current study is on an easy and quick intervention such as assessing the often-ignored levels of Hct during pregnancy that can help predict and prevent PMPCs. It also highlights the necessity for well-thought-out large-scale studies and trials to further examine the phenomena, as pregnancy may be the only time when rural women will have the opportunity to receive advice and to be tested for HHct.

Plasma Homocysteine, Folic Acid and Vitamin B12 in Abruptio Placentae: A Cross-Sectional Study of Their Role and Feto-Maternal Outcome

Background Out of the many causes of abruptio placentae, the micronutrient association with its occurrence and severity has not been researched extensively till now. We aim to measure the serum levels of homocysteine, folic acid and vitamin B12 in patients with abruptio placentae in the third trimester of pregnancy and compare the levels with those without the complication. We also propose to compare the feto-maternal outcome between the groups. Methods The cross-sectional study was undertaken in 50 pregnant women with abruption before or during delivery and 50 controls with uncomplicated pregnancy over 28 weeks of gestation. Serum levels of homocysteine, folic acid, and vitamin B12 were determined and feto-maternal outcome was compared between the groups Results Mean age of the cases and controls are 26.82 ± 5.5 and 28.82 ± 4.88 years respectively. Obstetric characteristics have significant difference between the groups in terms of gravidity, mode of delivery, timing of delivery, proportion of stillbirths and blood transfusion. The mean concentration of homocysteine and vitamin B12 between the groups also have a significant difference . The serum level of homocysteine is significantly correlated with serum vitamin B12 level (Pearson correlation= -0.601, P=0.000). However, folic acid concentration between the groups remains comparable. Conclusion Hence we conclude that vitamin B12 and homocysteine are significant determinants of abruptio placentae in pregnant women. Supplementation with the vitamin in the high-risk Indian population can avert a number of obstetric complications occurring due to raised homocysteine.

Higher Than Recommended Folic Acid Intakes is Associated with High Folate Status Throughout Pregnancy in a Prospective French-Canadian Cohort

BACKGROUND

Folate and vitamin B12 status during pregnancy are important for maternal and neonatal health. Maternal intake and prepregnancy body mass index (ppBMI) can influence biomarker status.

OBJECTIVES

This study aimed to, throughout pregnancy; 1) assess folate and B12 status including serum total folate, plasma total vitamin B12, and homocysteine (tHcy); 2) examine how these biomarkers are associated with intakes of folate and B12 and with ppBMI; and 3) determine predictors of serum total folate and plasma total vitamin B12.

METHODS

In each trimester (T1, T2, and T3), food and supplement intakes of 79 French-Canadian pregnant individuals were assessed by 3 dietary recalls (R24W) and a supplement use questionnaire. Fasting blood samples were collected. Serum total folate and plasma total vitamin B12 and tHcy were assessed by immunoassay (Siemens ADVIA Centaur XP).

RESULTS

Participants were 32.1 ± 3.7 y and had a mean ppBMI of 25.7 ± 5.8 kg/m². Serum total folate concentrations were high (>45.3 nmol/L, T1: 75.4 ± 55.1, T2: 69.1 ± 44.8, T3: 72.1 ± 52.1, P = 0.48). Mean plasma total vitamin B12 concentrations were >220 pmol/L (T1: 428 ± 175, T2: 321 ± 116, T3: 336 ± 128, P < 0.0001). Mean tHcy concentrations were <11 μmol/L across trimesters. Most participants (79.6%-86.1%) had a total folic acid intake above the Tolerable Upper Intake Level (UL, >1000 μg/d). Supplement use accounted for 71.9%-76.1% and 35.3%-41.8% of total folic acid and vitamin B12 intakes, respectively. The ppBMI was not correlated with serum total folate (P > 0.1) but was weakly correlated with and predicted lower plasma total vitamin B12 in T3 (r = -0.23, P = 0.04; r² = 0.08, standardized beta [sβ] = -0.24, P = 0.01). Higher folic acid intakes from supplements predicted higher serum total folate (T1: r² = 0.05, sβ = 0.15, P = 0.04, T2: r² = 0.28, sβ = 0.56, P = 0.01, T3: r² = 0.19, sβ = 0.44, P < 0.0001).

CONCLUSIONS

Most pregnant individuals had elevated serum total folate concentrations, reflecting total folic acid intakes above the UL driven by supplement use. Vitamin B12 concentrations were generally adequate and differed by ppBMI and pregnancy stage.

Association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms with vitamin B12 deficiency and adverse perinatal outcomes among pregnant women of rural South India - a cross sectional longitudinal study

OBJECTIVES

To determine the occurrence of MTHFR gene polymorphisms and to study their association with vitamin B12 deficiency and adverse perinatal outcomes among a cohort of pregnant women from Kaniyambadi block, Tamil Nadu.

METHODS

120 consecutive pregnant women who were ≤20 weeks of gestational age from the 82 villages of Kaniyambadi block were recruited. Genomic DNA was isolated from the peripheral blood. PCR amplification was done followed by Sangers sequencing. Maternal and neonatal outcomes were extracted. Data was entered and analysed.

RESULTS

Our study found the occurrence of c.1298A>C variant in homozygous state in 14.2% and c.677C>T heterozygous state in 15%. Sanger sequencing of exon 7 identified another pathogenic variant c.1262G>T in heterozygous state in two of them. Both the mothers who harboured that variant had preterm delivery and one of them gave birth to a low-birth-weight neonate. In the entire cohort, 5% of the mothers had abortion, 4.2% of them had preterm delivery and 8.8% of the neonates had low birth weight. Presence of c.1298A>C or c.677C>T variants were associated with vitamin B12 deficiency [Pearson Chi squared value (χ²)=7.9 and 7.6 respectively; p=0.02]. Heterozygous pathogenic variant c.1262G>T was associated with both adverse maternal [χ²=11.5; p=0.001] and neonatal [χ²=18.3; p=0.009] outcomes.

CONCLUSIONS

MTHFR gene polymorphisms could be associated with several adverse perinatal outcomes and vitamin B12 deficiency. Further larger studies are needed to prove the pathogenicity of c.1262G>T variant on pregnancy.

The Association Between Serum Homocysteine Levels and Placenta-Mediated Complications: A Narrative Review

The most extremely unfavourable outcome of pregnancy is the death of the mother and newborn. Negative outcomes for mothers or babies can occur as a result of complications or issues during pregnancy, birth or the post-partum period. Early elevated maternal homocysteine (Hct) levels during pregnancy have been linked to altered placental development. There is evidence that suggests an elevated maternal blood Hct level is the new obstetrical risk factor, and the association between hyperhomocysteinemia (HHct) and numerous obstetrical problems was recently recognised. Hct is an essential amino acid, which contains sulphur and is formed from the metabolism of methionine. HHct has several known aetiologies, including genetic anomalies; a deficiency in folic acid, vitamin B6 and vitamin B12; hypothyroidism; old age; and renal illnesses. Vascular problems, coronary artery disease, atherosclerosis and embolic illnesses can all occur as a result of high blood levels of Hct. Hct levels are lower in normal pregnancies than it is in women who are not pregnant. Many pregnancy-related problems, including pre-eclampsia (PE), recurrent pregnancy loss (RPL), placental abruption, premature delivery and foetal growth restriction (FGR) have been connected to HHct in recent research. We looked for pertinent literature using a thorough and systematic search from PubMed, Medline, Embase, Cochrane Library, Google, etc., and articles that were published before August 2022 based on serum Hct levels and various placenta-mediated complications for this review. In this review, we described the synthesis and metabolism of Hct in humans, Hct levels at various phases of normal pregnancy and the association between Hct and placenta-mediated pregnancy complications. The outcomes discovered can help obstetricians increase the likelihood of a successful pregnancy in cases where placenta-mediated issues are present. Lowering Hct levels with a high dose of folic acid tablets during the subsequent pregnancy may be useful for women who experienced these difficulties in prior pregnancies as a result of HHct.

Distribution and Determinants of Plasma Homocysteine Levels in a Preconception Population: A Retrospective Single-Center Study

BACKGROUND Raised plasma homocysteine (Hcy) levels have been associated with various diseases and pregnancy complications. Preconception is the primary prevention period to prevent birth defects. This retrospective study aimed to investigate the distribution of plasma Hcy levels among men and women at preconception and further evaluate the factors influencing plasma Hcy levels in a Southern China population. MATERIAL AND METHODS Sex, age, serum folate levels, plasma Hcy levels, and the time of Hcy and folate detection were obtained by medical records. Univariate analysis and multi-factor mixed virtual linear regression were used to explore the distribution and determinants of plasma Hcy levels. RESULTS A total of 3031 participants (1091 men [35.99%] and 1940 women [64.01%]) were included. The average levels of Hcy and the rates of hyperhomocysteinemia (HHcy) in men were higher than those in women (P<0.05). Hcy levels were observed to be lowest during autumn and highest during winter (P<0.05). In the normal Hcy (NHcy) group, serum folate levels were higher than in the HHcy group (P<0.05). Regression analysis suggested that sex, season, and serum folate levels had an effect on Hcy levels, but age was not an influencing factor of Hcy level in the preconception population. CONCLUSIONS This retrospective study showed that Hcy levels are higher in men and in the winter season. Sex, season, and serum folate levels were the influencing factors of Hcy in the preconception population.

Elevated homocysteine activates unfolded protein responses and causes aberrant trophoblast differentiation and mouse blastocyst development

Hyperhomocysteinemia may arise from folate/vitamin B12 deficiency, genetic polymorphisms, kidney disease, or hypothyroidism. It is associated with an increased risk of early pregnancy loss and placenta-related complications of pregnancy, including pre-eclampsia and fetal growth restriction. While the majority of studies of hyperhomocysteinemia focus on epigenetic changes secondary to metabolic disruption, the effects of homocysteine toxicity on placental development remain unexplored. Here, we investigated the influence of hyperhomocysteinemia on early blastocyst development and trophoblast differentiation. Exposure of cultured blastocysts to high homocysteine levels reduces cell number in the trophectoderm layer, most likely through increased apoptosis. Homocysteine also promotes differentiation of a trophoblast stem cell line. Both effects diminish the stem cell pool, and are mediated in an endoplasmic reticulum (ER) unfolded protein response (UPRER )-dependent manner. Targeted alleviation of UPRER may therefore provide a new therapeutic intervention to improve pregnancy outcome in women with hyperhomocysteinemia.

High level of homocysteine is associated with pre-eclampsia risk in pregnant woman: a meta-analysis

OBJECTIVE

We aimed to investigate the correlation between blood homocysteine (Hcy) levels and pre-eclampsia (PE) risk in pregnant women.

METHODS

Related articles were searched using PubMed, Embase, and Web of Science databases. Methodological quality of included studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale (NOS). Cochran's Q and I² tests were used to evaluate heterogeneity. Egger's test was used to evaluate publication bias. A sensitivity analysis was performed to test stability of the results using a one-by-one elimination method. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to assess certainty of evidence.

RESULTS

Nine studies (4384 PE and 26021 non-PE patients) were included in the meta-analysis. The methodology of them was of good quality, with NOS scores of 5-8. However, there was a significant heterogeneity among included studies. Therefore, the random effect model was generated and combined results suggested a significant association between increased level of Hcy in pregnant women and PE risk. Although a significant publication bias was found in the current study with a P value of 0.006 in the Egger test, sensitivity analysis showed that the combined results were stable and did not vary significantly from any single study. However, the GRADE evidence quality was very low, which may lower the recommendation of pooled results.

CONCLUSIONS

Increased levels of Hcy in maternal blood were significantly associated with the risk of PE, but low certainty of evidence need to be improved by more high-quality studies.

First Trimester Maternal Homocysteine and Embryonic and Fetal Growth: The Rotterdam Periconception Cohort

Homocysteine is a marker for derangements in one-carbon metabolism. Elevated homocysteine may represent a causal link between poor maternal nutrition and impaired embryonic and fetal development. We sought to investigate associations between reference range maternal homocysteine and embryonic and fetal growth. We enrolled 1060 singleton pregnancies (555 natural and 505 in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) pregnancies) from November 2010 to December 2020. Embryonic and fetal body and head growth was assessed throughout pregnancy using three-dimensional ultrasound scans and virtual reality techniques. Homocysteine was negatively associated with first trimester embryonic growth in the included population (crown-rump length B −0.023 mm, 95% CI −0.038,−0.007, p = 0.004, embryonic volume B −0.011 cm3, 95% CI −0.018,−0.004, p = 0.003). After stratification for conception mode, this association remained in IVF/ICSI pregnancies with frozen embryo transfer (crown-rump length B −0.051 mm, 95% CI −0.081,−0.023, p < 0.001, embryonic volume B −0.024 cm3, 95% CI −0.039,−0.009, p = 0.001), but not in IVF/ICSI pregnancies with fresh embryo transfer and natural pregnancies. Homocysteine was not associated with longitudinal measurements of head growth in first trimester, nor with second and third trimester fetal growth. Homocysteine in the highest quartile (7.3−14.9 µmol/L) as opposed to the lowest (2.5−5.2 µmol/L) was associated with reduced birth weight in natural pregnancies only (B −51.98 g, 95% CI −88.13,−15.84, p = 0.005). In conclusion, high maternal homocysteine within the reference range is negatively associated with first trimester embryonic growth and birth weight, and the effects of homocysteine are dependent on conception mode.

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.

Folic Acid Supplementation in Early Pregnancy, Homocysteine Concentration, and Risk of Gestational Diabetes Mellitus

We used a prospective cohort of pregnant women at 12 to 20 weeks gestation between 2002 and 2008 in Ottawa and Kingston to evaluate the impact of early pregnancy folic acid supplementation on the risk of gestational diabetes mellitus. Among 7552 eligible women, 84 (1.11%) were diagnosed of gestational diabetes mellitus. Non-significant associations were observed between gestational diabetes mellitus and folate supplementation, homocysteine levels, and methylenetetrahydrofolate reductase 677 TT genotype. Although we found no significant associations between folic acid supplementation and the risk of gestational diabetes mellitus, genetic associations were not confounded by lifestyle or socioeconomic factors, which may have biased previous studies.

The Role of High Concentrations of Homocysteine for the Development of Fetal Growth Restriction

OBJECTIVE

 To assess homocysteine (Hcy) levels in the three trimesters of pregnancy in women with fetal growth restriction (FGR) and to evaluate the role of Hcy as a possible predictor of FGR.

METHODS

 A total of 315 singleton pregnant women were included in the present prospective cohort study and were monitored since the 1^st trimester of pregnancy before delivery. Newborns were monitored for the first 7 days of life. Patients who had risk factors for FGR were excluded. Fetal growth restriction was defined according to uterine fundal height (< 10 percentile), ultrasound fetometry (< 5 percentile), and anthropometry of newborns (< 5 percentile). The concentrations of Hcy were detected at between 10 and 14, between 20 and 24, and between 30 and 34 weeks of pregnancy by enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristics (ROC) curve test and diagnostic odds ratio (DOR) were performed to evaluate the results of ELISA.

RESULTS

 The concentration of Hcy in patients with FGR was 19.65 umol/L at between 10 and 14 weeks, compared with 9.28 umol/L in patients with normal fetal growth (p < 0.0001). The optimal cut-off level for Hcy in the 1^st trimester of pregnancy was > 13.9 umol/L with AUC 0.788, sensitivity of 75%, specificity of 83.6%, and DOR of 15.2.

CONCLUSION

 Assessment of serum Hcy concentration may be used as a predictor of FGR, with the highest diagnostic utility in the 1^st trimester of pregnancy.

Exposure to chemical components of fine particulate matter and ozone, and placenta-mediated pregnancy complications in Tokyo: a register-based study

BACKGROUND

Maternal exposure to fine particulate matter (PM_2.5) was associated with pregnancy complications. However, we still lack comprehensive evidence regarding which specific chemical components of PM_2.5 are more harmful for maternal and foetal health.

OBJECTIVE

We focused on exposure over the first trimester (0-13 weeks of gestation), which includes the early placentation period, and investigated whether PM_2.5 and its components were associated with placenta-mediated pregnancy complications (combined outcome of small for gestational age, preeclampsia, placental abruption, and stillbirth).

METHODS

From 2013 to 2015, we obtained information, from the Japan Perinatal Registry Network database, on 83,454 women who delivered singleton infants within 23 Tokyo wards (≈627 km²). Using daily filter sampling of PM_2.5 at one monitoring location, we analysed carbon and ion components, and assigned the first trimester average of the respective pollutant concentrations to each woman.

RESULTS

The ORs of placenta-mediated pregnancy complications were 1.14 (95% CI = 1.08-1.22) per 0.51 μg/m³ (interquartile range) increase of organic carbon and 1.11 (1.03-1.18) per 0.06 μg/m³ increase of sodium. Organic carbon was also associated with four individual complications. There was no association between ozone and outcome.

SIGNIFICANCE

There were specific components of PM_2.5 that have adverse effects on maternal and foetal health.

Periconceptional maternal and paternal homocysteine levels and early utero-placental (vascular) growth trajectories: The Rotterdam periconception cohort

INTRODUCTION

Maternal elevated plasma total homocysteine (tHcy) is involved in the origin of several placenta-related pregnancy complications. The first trimester is the most sensitive period for placentation influenced by maternal and paternal health. The aim is to study associations between periconceptional parental tHcy levels and utero-placental growth trajectories in the first trimester of pregnancy.

METHODS

Pregnant women and their partners were enrolled before 10 weeks of gestation in the Virtual Placenta study as subcohort of the Rotterdam periconception cohort (Predict study). A total of 190 women with a singleton pregnancy, of which 109 conceived naturally and 81 after IVF/ICSI treatment, were included. We measured serial utero-placental vascular volumes (uPVV) and placental volumes (PV) at 7, 9 and 11 weeks of gestation. First-trimester trajectories of PV were also measured in 662 pregnancies from the total Predict study.

RESULTS

Comparing all participants of the virtual placenta study, no association between maternal tHcy and uPVV was observed. However, in IVF/ICSI pregnancies sub-analyses showed significantly negative associations between maternal tHcy in the 3rd and 4th quartile and uPVV trajectories (beta: -0.38 (95%CI -0.74 to -0.02) and beta: -0.42 (95% CI -0.78 to -0.05), respectively) with the 1st quartile as reference. Analysis in the total Predict cohort showed similar negative associations for the total study population.

DISCUSSION

Periconceptional high maternal tHcy levels are associated with smaller placental growth trajectories depicted as PV and uPVV in the first trimester of pregnancy. The stronger negative associations with uPVV in IVF/ICSI pregnancies underline the need for further investigation.

Hyperhomocysteinemia and low vitamin B12 are associated with the risk of early pregnancy loss: A clinical study and meta-analyses

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.

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.

The impact of micronutrient deficiency on pregnancy complications and development origin of health and disease

Due to the spread of the western style diet, which is characterized by high intake of processed food, micronutrients (vitamins and minerals) deficiency is increasing in the Japanese population of all ages and genders. During pregnancy, the elevated demand for micronutrients put pregnant women at even higher risk of micronutrients deficiency. Some micronutrients are relatively famous such that women with reproductive age are recommended to take folic acid supplementation for the prevention of neural tube defect. However, it is not generally known that folate is also important for fetal growth throughout the pregnancy course and for prevention of pregnancy complications, and that pregnant women should continue to take supplementation during pregnancy and lactation. The types of micronutrients and the duration of supplementation are both important factors to maintain normal pregnancies. This review focused on four micronutrients that are commonly deficient in Japanese pregnant women, folate, vitamin B12, vitamin D, calcium, and magnesium. The detrimental effects of homocysteine accumulation associated with the above micronutrient defects and its link to catechol-o-methyltransferase insufficiency are described. We also discussed possible molecular mechanisms of pregnancy complications and the development origin of health and disease (DOHaD) regarding micronutrient deficiencies from the point of view of one carbon metabolism.

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.

MTHFR 1298A>C Substitution is a Strong Candidate for Analysis in Recurrent Pregnancy Loss: Evidence from 14,289 Subjects

We undertook meta-analyses on MTHFR 1298A>C substitution for critically evaluating its association with recurrent pregnancy loss (RPL). MTHFR genotype data for 5888 cases and 8401 controls from 39 studies were pooled to perform this meta-analyses. Genotype data were screened, scrutinized, pooled, analysed and subjected to sensitivity analysis to carefully evaluate the association between MTHFR 1298A>C and recurrent pregnancy loss. Genetic associations were sought using dominant, recessive and co-dominant models of genetic testing with odds ratio and 95% Confidence interval (CI) as the effect measures. Further analyses were undertaken by classifying the studies into Caucasian and East Asian sub-groups. Genetic heterogeneity was tested before pooling the data across studies. For assessing publication bias, Egger's intercept test was undertaken. We found a significant association of 1298A>C substitution with increased risk of RPL in the dominant (P=0.000; OR = 1.58; 95% CI =1.25-1.99) as well as recessive (P=0.000; OR = 1.66; 95% CI =1.25-2.20) models. In sub-group analysis, we observed a significant association of the polymorphism with RPL in the Caucasian populations using dominant (P=0.000; OR = 1.98; 95% CI =1.42-2.76) and recessive (P=0.000; OR = 2.20; 95% CI =1.49-3.24) models. However, this substitution showed no association with RPL in the East Asian populations (P=0.149; OR = 1.187; 95% CI =0.94-1.50). MTHFR 1298A>C substitution shows association with the risk of recurrent pregnancy loss. The association is in a population-specific manner with the substitution being a strong risk factor only in the Caucasian populations.