Association of maternal serum homocysteine concentration levels in late stage of pregnancy with preterm births: a nested case-control study

Choline in pregnant women: a systematic review and meta-analysis

CONTEXT

Choline is a critical nutrient. Inadequate choline intake during pregnancy increases the risk of adverse maternal and offspring health.

OBJECTIVE

A systematic review and meta-analysis were conducted to examine the current recommendations for choline intake by pregnant women, estimate the overall prevalence of pregnant women with adequate choline intake, and explore associations between maternal choline level and adverse pregnancy outcomes (APOs).

METHODS

Choline recommendations for pregnant women were assessed from eight nutrient guidelines of the United States, United Kingdom, Canada, Australia, Asia, International Federation of Gynecology and Obstetrics, and World Health Organization. Data on the prevalence of pregnant women with adequate choline intake and the association between maternal choline level and APOs were collected from 5 databases up to May 2023. Meta-analyses with random effects and subgroup analyses were performed for the pooled estimate of prevalence and association.

RESULTS

Five recent nutrition guidelines from the United States (United States Department of Agriculture), United States (Food and Drug Administration), Canada, Australia, and the International Federation of Gynecology and Obstetrics have emphasized the importance of adequate choline intake for pregnant women. Of 27 publications, 19 articles explored the prevalence and 8 articles explored the association. Meta-analysis of 12 prevalence studies revealed a concerning 11.24% (95% confidence interval, 6.34-17.26) prevalence of pregnant women with adequate choline intake recommendations. A meta-analysis of 6 studies indicated a significant association between high maternal choline levels and a reduced risk of developing APOs, with an odds ratio of 0.51 (95% confidence interval, 0.40-0.65).

CONCLUSION

The existing guidelines highlight the importance of choline in supporting maternal health and fetal development during pregnancy. Furthermore, a high maternal choline level was likely to be associated with a lower risk of APOs. However, 88.76% of pregnant women do not achieve the optimal choline intake. Therefore, specific policies and actions may be necessary to improve choline intake in pregnant women's care and support the well-being of pregnant women.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CDR42023410561.

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.

Polymorphisms in vitamin B12 and folate metabolising genes and their association with adverse pregnancy outcome: secondary analysis of a population based case control study

Vitamin B12 and folate deficiency leads to accumulation of homocysteine that increases the risk of adverse pregnancy outcomes like preterm birth and low birth weight (LBW) of the neonate. We explored the association of genetic variants of key vitamin B12 and folate metabolising enzymes (MTHFR C677T and A1298C, MTR A2756G, TCN-2 C776G) with preterm birth and LBW in South Indian women. MTHFR A1298C heterozygotes (AC) were at higher risk for preterm delivery, whereas TCN-2 C776G heterozygotes (CG) were at higher risk for both preterm delivery and LBW. MTHFR C677T, A1298C and MTR A2756G haplotype CAG was protective for preterm delivery (p=.036, OR = 0.475; 95% CI: 0.233-0.97), whereas, haplotype CCG increasing the risk of preterm birth by 1.8 folds (p=.018, OR = 1.81; 95% CI: 1.09-2.98). These results underscore the significance of vitamin B12 and folate in the pathophysiology of preterm birth and LBW.Impact StatementWhat is already known on this subject? Polymorphisms of vitamin B12 and folate metabolising genes have been reported to influence preterm birth and LBW, but the reports are not consistent.What do the results of this study add? We observed a relationship of MTHFR A1298C and TCN-2 C776G with preterm birth, and significant association of TCN-2 C776G with LBW in infants.What are the implications of these findings for clinical practice and/or further research? Identification of women carrying these polymorphic risk alleles may benefit from early nutritional modifications.

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.

Dietary Choline Intake during Pregnancy and PEMT rs7946 Polymorphism on Risk of Preterm Birth: A Case-Control Study

INTRODUCTION AND AIMS

Choline-metabolizing genetic variation may interact with choline intake on fetal programming and pregnancy outcome. This case-control study aims to explore the association of maternal choline consumption and phosphatidylethanolamine N-methyltransferase (PEMT) gene polymorphism rs7946 with preterm birth risk.

METHODS

145 Han Chinese women with preterm delivery and 157 Han Chinese women with term delivery were recruited in Shanghai. Dietary choline intake during pregnancy was assessed using a validated food frequency questionnaire. Additionally, DNA samples were genotyped for PEMT rs7946 (G5465A) with plasma homocysteine (Hcy) levels measured.

RESULTS

Compared with the lowest quartile of choline intake, women within the highest consumption quartile had adjusted odds ratio (aOR) for preterm birth of 0.48 (95% confidence interval, CI [0.24, 0.95]). There was a significant interaction between maternal choline intake and PEMT rs7946 (p for interaction = 0.04), where the AA genotype carriers who consumed the energy-adjusted choline <255.01 mg/day had aOR for preterm birth of 3.75 (95% CI [1.24, 11.35]), compared to those with GG genotype and choline intake >255.01 mg/day during pregnancy. Additionally, the greatest elevated plasma Hcy was found in the cases with AA genotype and choline consumption <255.01 mg/day (p < 0.001).

CONCLUSION

The AA genotype of PEMT rs7946 may be associated with increased preterm birth in these Han Chinese women with low choline intake during pregnancy.

Association of pre-pregnancy body mass index with adverse pregnancy outcome among first-time mothers

Background

Studies have reported an increased risk of adverse pregnancy outcome associated with pre-pregnancy body mass index (BMI). However, the data on such associations in urban areas of southern Chinese women is limited, which drive us to clarify the associations of pre-pregnancy BMI and the risks of adverse pregnancy outcomes (preterm birth (PTB) and low birth weight (LBW)) and maternal health outcomes (gestational hypertension and cesarean delivery).

Methods

We performed a hospital-based case-control study including 3,864 Southern Chinese women who gave first birth to a live singleton infant from January 2015 to December 2015. PTB was stratified into three subgroups according to gestational age (extremely PTB, very PTB and moderate PTB). Besides, we combined birth weight and gestational age to dichotomise as being small for gestational age (SGA, less than the tenth percentile of weight for gestation) and non-small for gestational age (NSGA, large than the tenth percentile of weight for gestation), gestational week was also classified into categories of term, 34-36 week and below 34 week.. We then divided newborns into six groups: (1) term and NSGA; (2) 34–36 week gestation and NSGA; (3) below 34 week gestation and NSGA; (4) term and SAG; (5) 34–36 week gestation and SAG; (6) below 34 week gestation and SAG. Adjusted logistic regression models was used to estimate the odds ratios of adverse outcomes.

Results

Underweight women were more likely to give LBW (AOR = 1.44, 95% CI [1.11–1.89]), the similar result was seen in term and SAG as compared with term and NSAG (AOR = 1.78, 95% CI [1.45–2.17]), whereas underweight was significantly associated with a lower risk of gestational hypertension (AOR = 0.45, 95% CI [0.25–0.82) and caesarean delivery (AOR = 0.74, 95% CI [0.62–0.90]). The risk of extremely PTB is relatively higher among overweight and obese mothers in a subgroup analysis of PTB (AOR = 8.12, 95% CI [1.11–59.44]; AOR = 15.06, 95% CI [1.32–172.13], respectively). Both maternal overweight and obesity were associated with a greater risk of gestational hypertension (AOR = 1.71, 95% CI [1.06–2.77]; AOR = 5.54, 95% CI [3.02–10.17], respectively) and caesarean delivery (AOR = 1.91, 95% CI [1.53–2.38]; AOR = 1.85, 95% CI [1.21–2.82], respectively).

Conclusions

Our study suggested that maternal overweight and obesity were associated with a significantly higher risk of gestational hypertension, caesarean delivery and extremely PTB. Underweight was correlated with an increased risk of LBW and conferred a protective effect regarding the risk for gestational hypertension and caesarean delivery for the first-time mothers among Southern Chinese.

Effects of hyperhomocysteinaemia and metabolic syndrome on reproduction in women with polycystic ovary syndrome: a secondary analysis

RESEARCH QUESTION

What is the association between hyperhomocysteinaemia (HHCY), metabolic syndrome, and reproductive outcomes among women with polycystic ovary syndrome (PCOS).

DESIGN

A secondary analysis of PCOSAct with 21 sites in China. A total of 1000 women with PCOS were enrolled; 936 women with baseline homocysteine (HCY) were analysed.

RESULTS

Higher HCY was associated with higher body mass index, free testosterone and lower FSH, fasting glucose (P < 0.001; P < 0.001; P = 0.005; P < 0.001) and ovulation rate among all participants (OR 0.59, 95% CI 0.41 to 0.86; OR 0.57, 95% CI 0.39 to 0.83 tertiles 2 and 3 versus tertile 1, respectively). The HHCY group had lower oestradiol and higher free testosterone (P = 0.04; P < 0.001) than the controls. In the metabolic syndrome group, LH, LH-FSH ratio and sex hormone-binding globulin were lowest in the metabolic syndrome group (all P < 0.001). In the HHCY group, ovulation rate decreased and the second or third trimester pregnancy loss rate increased compared with controls (OR 1.678, 95% CI 1.04 to 2.70; OR 0.03, 95% CI 0.00 to 0.42) with treatment adjustment. Compared with the controls, ovulation, conception, pregnancy, second or third trimester pregnancy loss and live birth rates were statistically lower in the metabolic syndrome group after adjusting treatment (OR 1.76, 95% CI 1.15 to 2.70; OR 1.75, 95% CI 1.15 to 2.65; OR 2.09, 95% CI 1.27 to 3.44; OR 0.02, 95% CI 0.00 to 0.33; OR 2.42 95% CI 1.42 to 4.10), and pregnancy, pregnancy loss and live birth rates remained significantly different after adjusting for treatment and sex-hormone factors (OR 1.77, 95% CI 1.05 to 2.99; OR 0.14, 95% CI 0.02 to 0.82; OR 2.02, 95% CI 1.16 to 3.50).

CONCLUSIONS

In women with PCOS, HHCY contributes to increased pregnancy loss and reduced ovulation, and metabolic syndrome was related to defects in ovulation, conception, pregnancy, pregnancy loss and live birth, indicating that the two conditions lead to defects at various reproductive stages.

Association of induced abortion with preterm birth risk in first-time mothers

Women who have previously had an induced abortion (IA) before their first birth have been associated with preterm birth (PTB). However, previous studies on the PTB are inconsistent. Therefore, the aim of this study was to clarify the association between IA and PTB and low birth weight (LBW) for first-time mothers. A total of 3,684 Southern Chinese women who gave birth for the first time to a live singleton infants were recruited between January 2015 and December 2015 in the province of Guangdong, China. Univariable and multivariable analyses were conducted to determine whether IA was associated with PTB and LBW. Previous IA was not associated with increased risks of PTB or LBW, adjusted odds ratios were 0.80 (95% CI = 0.53 to 1.20) and 0.86 (95% CI = 0.57 to 1.31), respectively. Additionally, no significant associations were observed for infants born at before 37, before 32, and before 28 gestational weeks. And no significant associations were also observed for LBW measuring lower than 2500 grams and also measuring lower than 1500 grams. Our study suggested that a previous IA, as compared with women who reported no previous IA, does not increase the risk of PTB or LBW in subsequent pregnancy for the first-time mothers among Southern Chinese women.