Maternal obesity and pre-pregnancy folic acid supplementation

Contribution of obesity to racial and ethnic disparities in the risk of fetal myelomeningocele: a population-based study

BACKGROUND

Prepregnancy obesity and racial-ethnic disparities has been shown to be associated with meningomyelocele.

OBJECTIVE

This study aimed to investigate the association of maternal periconceptional factors, including race-ethnicity and prepregnancy body mass index, with the prevalence of isolated fetal myelomeningocele.

METHODS

This was a population-based cross-sectional study using Centers for Disease Control and Prevention birth data from 2016 to 2021. Major structural anomalies or chromosomal abnormalities were excluded. Race-ethnicity was classified as non-Hispanic White (reference population), non-Hispanic Black, non-Hispanic Asian, Hispanic, and others. Maternal prepregnancy body mass index was classified as underweight (<18.5 kg/m2), normal (reference group; 18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and class I (30-34.9 kg/m2), class II (35-39.9 kg/m2), and class III obesity (≥40 kg/m2). A chi-square test of independence was performed to identify factors significantly associated with myelomeningocele. These factors were then stratified into 3 adjusted clusters/levels. The prevalence was calculated per 10,000 live births. The Cochran-Armitage test for trend was used to detect any significant increasing or decreasing trends.

RESULTS

A total of 22,625,308 pregnancies with live birth, including 2866 pregnancies with isolated fetal myelomeningocele, were included in the analysis. The prevalence of isolated fetal myelomeningocele per 10,000 live births varied among different racial/ethnic groups, with the highest prevalence found among the non-Hispanic White (1.60 [1.52-1.67]) and lowest among the non-Hispanic Asian (0.50 [0.40-0.64]) population. The prevalence significantly increased with body mass index, with the highest prevalence found in the population with class III obesity (1.88 per 10,000 live births). Subgroup analysis of the associations between the significant variables (obesity, diabetes, hypertension, and education) and each ethnicity in cases with myelomeningocele showed significant variations in prevalence of these variables among different racial/ethnic groups. Following the model with the 3 levels of adjustment described in the Methods section, prepregnancy overweight and class I, II, and III obesity remained significantly associated with the odds of isolated fetal myelomeningocele. The adjusted odds ratios were 1.32 (95% confidence interval, 1.19-1.46; P<.001) for overweight, 1.55 (95% confidence interval, 1.38-1.75; P<.001) for class I obesity, 1.68 (95% confidence interval, 1.45-1.94; P<.001) for class II obesity, and 1.73 (95% confidence interval, 1.47-2.04; P<.001) for class III obesity. Similarly, following the 3-level adjustment model, the obesity-mediated effect of maternal race-ethnicity on the odds of myelomeningocele remained significant (non-Hispanic Black: adjusted odds ratio, 1.03; 95% confidence interval, 1.02-1.05; P<.001; non-Hispanic Asian: adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.03; P<.001; Hispanic: adjusted odds ratio, 1.5; 95% confidence interval, 1.03-1.6; P<.001). The test for trend among different racial/ethnic groups did not show significant results across the past 6 years. However, the test for trend showed a significant increase in the prevalence of isolated myelomeningocele associated with class II and III obesity over the past 6 years.

CONCLUSION

There has been a rising trend of fetal isolated myelomeningocele in pregnancies with maternal class II and III obesity over the past 6 years after adjusting for other covariates. Prepregnancy obesity, a modifiable risk factor, is a significant driver of racial/ethnic disparities in the overall risk for isolated fetal myelomeningocele.

Dietary Intakes of Folate, Vitamin D and Iodine during the First Trimester of Pregnancy and the Association between Supplement Use and Demographic Characteristics amongst White Caucasian Women Living with Obesity in the UK

Folate, vitamin D and iodine are key micronutrients in pregnancy, with deficiency associated with poor maternal and infant outcomes. For folate and vitamin D especially, deficiency is more common amongst women with obesity and recommended intakes and guidance on supplementation varies worldwide. The present study aims to investigate dietary and supplementary intakes of these micronutrients amongst a population of pregnant women with obesity in the United Kingdom, alongside key maternal demographic characteristics. Expectant women (n = 75) with a body mass index ≥ 30 kg/m² at first antenatal appointment were recruited at 12 weeks gestation. Participants were asked about their supplement use preconception and during trimester one in a baseline questionnaire which also asked about demographic characteristics. Women also completed a four day diet diary from which dietary and supplemental intakes of micronutrients intakes were estimated. Folic acid was taken by 96% of women at any point in trimester 1, whilst only 26% of women took the higher 5 mg dose recommended for women with obesity in the UK. For vitamin D and iodine, 56% and 44% of women met the UK RNI, respectively. Maternal age was positively associated with taking supplements of any kind and the 5 mg folic acid supplement, whilst parity was inversely associated with both outcomes. This study strengthens the rationale for further work to be done raising awareness of the need for women with obesity to supplement both with a higher dose of folic acid and vitamin D and to be aware of the role of iodine during pregnancy.

The role of Vitamin B12 and genetic risk factors in the etiology of neural tube defects: A systematic review

Neural tube defects (NTDs) are birth defects that arise during embryogenesis when normal neural tube closure fails to occur. According to the World Health Organization, NTDs are detected annually in approximately 300,000 neonates worldwide. The exact etiology of NTDs remains complex and poorly understood. It is generally agreed that most NTD cases are of multifactorial origin, having a combination of multiple genes and a number of environmental risk factors. The role of folic acid, vitamin B12 deficiency, genetics and other risk factors, in the etiology of NTDs, has also been extensively studied. This knowledge synthesis brings together different types of evidence to update the role of vitamin B12 deficiency, genetics and other risk factors, in the etiology of NTDs. Following a PubMed search and screening for relevant articles, we included 40 studies in our review (30 case-control studies, 3 cross-sectional studies, 5 cohort studies, and 2 case reports). The available data showed that vitamin B12 levels were decreased in mothers and infants in NTD groups compared with control groups. Holo-transcobalamin, the active form of vitamin B12, was also found in lower levels in mothers with NTD-affected infants. Several studies reported elevated homocysteine levels in mothers and infants in NTD groups. Additionally, numerous studies reported links between genetic variants and increased NTD risk. These genes include GIF, LRP2, CUBN, TCb1R, MTHFR, and others. Several maternal factors have also been linked with significant NTD risk such as BMI, maternal diet, air pollutants, low maternal age, and many others. The majority of studies on NTDs have focused on the role of folic acid, hence there is a need for well-designed studies on the role of other risk factors like vitamin B12 deficiency in the etiology of NTDs.

Epidemiology and (Patho)Physiology of Folic Acid Supplement Use in Obese Women before and during Pregnancy

Preconception folic acid supplement use is a well-known method of primary prevention of neural tube defects (NTDs). Obese women are at a higher risk for having a child with a NTD. As different international recommendations on folic acid supplement use for obese women before and during pregnancy exist, this narrative review provides an overview of epidemiology of folate deficiency in obese (pre)pregnant women, elaborates on potential mechanisms underlying folate deficiency, and discusses considerations for the usage of higher doses of folic acid supplements. Women with obesity more often suffer from an absolute folate deficiency, as they are less compliant to periconceptional folic acid supplement use recommendations. In addition, their dietary folate intake is limited due to an unbalanced diet (relative malnutrition). The association of obesity and NTDs also seems to be independent of folate intake, with studies suggesting an increased need of folate (relative deficiency) due to derangements involved in other pathways. The relative folate deficiency, as a result of an increased metabolic need for folate in obese women, can be due to: (1) low-grade chronic inflammation (2) insulin resistance, (3) inositol, and (4) dysbiotic gut microbiome, which plays a role in folate production and uptake. In all these pathways, the folate-dependent one-carbon metabolism is involved. In conclusion, scientific evidence of the involvement of several folate-related pathways implies to increase the recommended folic acid supplementation in obese women. However, the physiological uptake of synthetic folic acid is limited and side-effects of unmetabolized folic acid in mothers and offspring, in particular variations in epigenetic (re)programming with long-term health effects, cannot be excluded. Therefore, we emphasize on the urgent need for further research and preconception personalized counseling on folate status, lifestyle, and medical conditions.

Guideline No. 391-Pregnancy and Maternal Obesity Part 1: Pre-conception and Prenatal Care

OBJECTIVE

This guideline will review key aspects in the pregnancy care of women with obesity. Part I will focus on pre-conception and pregnancy care. Part II will focus on team planning for delivery and Postpartum Care.

INTENDED USERS

All health care providers (obstetricians, family doctors, midwives, nurses, anaesthesiologists) who provide pregnancy-related care to women with obesity.

TARGET POPULATION

Women with obesity who are pregnant or planning pregnancies.

EVIDENCE

Literature was retrieved through searches of Statistics Canada, Medline, and The Cochrane Library on the impact of obesity in pregnancy on antepartum and intrapartum care, maternal morbidity and mortality, obstetrical anaesthesia, and perinatal morbidity and mortality. Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2018. Grey (unpublished) literature was identified through searching the websites of health technology assessment and related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the authors. Then the Maternal-Fetal Medicine Committee peer reviewed the content and submitted comments for consideration, and the Board of the Society of Obstetricians and Gynaecologists of Canada (SOGC) approved the final draft for publication. Areas of disagreement were discussed during meetings, at which time consensus was reached. The level of evidence and quality of the recommendation made were described using the Evaluation of Evidence criteria of the Canadian Task Force on Preventive Health Care.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in these guidelines may increase obstetrical provider recognition of the issues affected pregnant individuals with obesity, including clinical prevention strategies, communication between the health care team, the patient and family as well as equipment and human resource planning. It is hoped that regional, provincial and federal agencies will assist in the education and support of coordinated care for pregnant individuals with obesity.

GUIDELINE UPDATE

SOGC guidelines will be automatically reviewed 5 years after publication. However, authors can propose another review date if they feel that 5 years is too short/long based on their expert knowledge of the subject matter.

SPONSORS

This guideline was developed with resources funded by the SOGC.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Preconception Lifestyle and Weight-Related Behaviors by Maternal Body Mass Index: A Cross-Sectional Study of Pregnant Women

Obesity is a rising global health challenge, particularly for reproductive-aged women. Our cross-sectional study of pregnant women (n = 223) examined associations between preconception body mass index (BMI) and socio-demographics, weight perceptions and lifestyle behaviors. Over half of women were overweight (33.2%) or obese (22.0%), 49.6% of which perceived their weight as normal. High proportions of women reported planning their pregnancies (70.0%) and were actively trying to lose or maintain their weight preconception (72.7%). Weight management approaches varied from reducing discretionary foods (63.7%) to professional support (8.1%). Obese women had significantly greater odds of reducing discretionary foods (odds ratio (OR) = 6.69 95% confidence interval (CI) 2.13–21.00, p = 0.001) and using structured diets (adjusted odds ratio (AOR) = 9.13 95% CI 2.90–28.81, p < 0.001) compared to normal-weight women. After adjusting for socio-demographics, compared to normal-weight women, overweight (AOR = 5.24 95% CI 2.19–12.56, p < 0.001) and obese (AOR = 2.85 95% CI 1.06–7.67, p = 0.04) women had significantly increased odds of exercising for weight management and significantly lower odds of taking folic-acid preconception (overweight: AOR = 0.40 95% CI 0.18–0.90, p = 0.01, obese: AOR = 0.38 95% CI 0.16–0.91, p = 0.03). Large proportions of women planning a pregnancy have an overweight/obese BMI, with associated suboptimal health behaviors and reduced health professional engagement preconception. Further research exploring women’s perspectives regarding preconception lifestyles is needed to inform effective preconception health promotion strategies.

Preconception health behaviours: A scoping review

Preconception health refers to the health of males and females at any point in time prior to a potential pregnancy. A goal of preconception health research is to use preventive behaviour and healthcare to optimize the health of future offspring that result from both planned and unplanned pregnancies. This paper briefly reviews evidence of the importance of various preconception health behaviours, and examines the extent to which specific preconception health behaviours have been included in recent studies of such knowledge, behaviours, and intentions. To describe this recent research in highly developed countries, a scoping review of the literature was completed of studies published within the past seven years. A total of 94 studies on preconception health were identified and reviewed: (a) 15 examined knowledge and attitudes, (b) 68 studied behaviours, (c) 18 examined interventions designed to improve knowledge or behaviour, and (d) no studies examined intentions to engage in preconception health behaviours. Over 40% of studies examining preconception health behaviour focussed exclusively on folic acid. Overall, folic acid, alcohol, and cigarettes have consistently been topics of focus, while exposure to harmful environmental substances, stress, and sleep have been largely neglected. Despite strong evidence for the importance of men's health during the preconception period, only 11% of all studies included male participants. Based on existing gaps in the research, recommendations are provided, such as including men in future research, assessing a wider variety of behaviours, consideration of behavioural intentions, and consideration of the relationships between preconception health knowledge, intentions, and behaviour.

Duration of periconceptional folic acid supplementation in women booking for antenatal care

OBJECTIVE

To provide accurate estimates of the commencement time, duration and dosage of folic acid (FA) supplementation taken by Irish women in the periconceptional period. The study also aimed to establish the factors associated with optimal FA supplementation practices.

DESIGN

Cross-sectional observational study. Women's clinical and sociodemographic details were computerised. Maternal weight and height were measured before calculating BMI. Detailed FA supplementation questionnaires were completed under the supervision of a trained researcher.

SETTING

A large university maternity hospital, Republic of Ireland, January 2014-April 2016.

SUBJECTS

Women (n 856) recruited at their convenience in the first trimester.

RESULTS

While almost all of the women (97 %) were taking FA at enrolment, only one in four women took FA for at least 12 weeks preconceptionally (n 208). Among the 44 % of women who were supplementing with FA preconceptionally, 44 % (162/370) reported taking FA for less than the 12 weeks required to achieve optimal red-blood-cell folate levels for prevention of neural tube defects. On multivariate analysis, only planned pregnancy and nulliparity were associated with taking FA for at least 12 weeks preconceptionally. Among women who only took FA postconceptionally, almost two-thirds commenced it after day 28 of their pregnancy when the neural tube had already closed.

CONCLUSIONS

As the timing of FA was suboptimal both before and after conception, we recommend that current national FA guidelines need to be reviewed.

Pre-pregnancy obesity and non-adherence to multivitamin use: findings from the National Pregnancy Risk Assessment Monitoring System (2009-2011)

BACKGROUND

Although adequate folic acid or multivitamins can prevent up to 70 % of neural tube defects, the majority of U.S. non-pregnant women of childbearing age do not use multivitamins every day. Factors influencing consistent multivitamin use are not fully explored. This study aims to investigate the association between pre-pregnancy body mass index (BMI) and multivitamin use before pregnancy using a large, nationally representative sample of women with recent live births.

METHODS

The national 2009-2011 Pregnancy Risk Assessment Monitoring System data were analyzed. The sample included women with recent singleton live births (N = 104,211). The outcome of interest was multivitamin use which was categorized as no multivitamin use, 1-3 times/week, 4-6 times/week, and daily use. Maternal BMI was examined as underweight (<18.50 kg/m(2)), normal weight (18.50-24.99 kg/m(2)), overweight (25.00-29.99 kg/m(2)), and obese (≥30.00 kg/m(2)). Multinomial logistic regression was conducted, and adjusted odds ratios and 95 % confidence intervals were calculated.

RESULTS

Compared to women with normal weight, overweight and obese women had significantly increased odds of not taking multivitamins after adjusting for confounding factors. Further, the lack of multivitamin use increased in magnitude with the level of BMI (ORoverweight = 1.2, 95 % CI = 1.1-1.3; ORobese = 1.4, 95 % CI = 1.2-1.5).

CONCLUSIONS

Obese and overweight women were less likely to follow the recommendation for preconception multivitamin use compared to normal weight women. All health care professionals must enhance preconception care with particular attention to overweight and obese women. Preconception counseling may be an opportunity to discuss healthy eating and benefits of daily multivitamin intake before pregnancy.

Maternal obesity and the risk of neural tube defects in offspring: A meta-analysis

OBJECTIVES

The aim of this was to access maternal obesity and the risk of neural tube defects (NTDs) in offspring, and establishes a nonlinear dose-response relationship between maternal body mass index (BMI) and risk of NTDs in offspring.

METHODS

PubMed and Web of Science were systematically searched. We compared NTDs risk difference in maternal obesity group vs. normal weight group+overweight group, and maternal obesity group vs. normal weight group. We also examined the dose-response relationship between maternal body mass index and the risk of NTDs in offspring.

RESULTS

A total of 22 studies with 1,758,832 patients included in the meta-analysis. The results showed obesity maternal obesity is an important risk factor for NTDs in offspring. When maternal obesity group compared with normal weight group+overweight group, the summary OR of NTDs was 1.632 (95% CI 1.473-1.808; Z=9.37, P<0.00001); when maternal obesity group compared with normal weight group, the summary OR was 1.682 (95% CI 1.510-1.873; Z=9.44, P<0.00001). No publication biases were found. Dose-response meta-analysis showed statistically significant association between maternal BMI and risk of NTDs in offspring (model χ²=41.49, <0.00001). In linear model, the OR of NTDs in offspring was 1.040 (95% CI 1.027-1.051) for every 1kg/m² BMI increase in mother. In spline model, the OR of NTDs in offspring risk increased rapidly along with maternal BMI, especially when BMI >30kg/m². Sensitivity analyses by only included the studies reported adjusted OR showed the result was robust.

CONCLUSION

Our meta-analysis indicated that maternal obesity is an important risk factor for neural tube defects in offspring.

Pregnancy risks associated with obesity

Obesity has increased dramatically in the United States over the last several decades, with approximately 40% of pregnant women now considered overweight or obese. Obesity has been shown to be associated with numerous poor pregnancy outcomes, including increased rates of preeclampsia, gestational diabetes, fetal macrosomia, stillbirth, postterm pregnancy, and increased rates of cesarean delivery. Many of these complications have been found to increase even further with increasing body mass index in a dose-response fashion. In this review, the association of obesity with maternal, fetal, and pregnancy outcomes is discussed as are the recommendations for caring for the obese gravida.

Preconceptional folic acid-containing supplement use in the National Birth Defects Prevention Study

BACKGROUND

Despite public health campaigns encouraging women to take a daily folic acid supplement, the proportion of reproductive age women, in the United States, who comply with this recommendation is less than optimal. The objective of this analysis was to identify predictors of preconceptional folic acid-containing supplement use to define subgroups of women who may benefit from targeted folic acid campaigns.

METHODS

This study included 6570 mothers of live born infants from the control population of National Birth Defects Prevention Study (1997-2005). Logistic regression analyses were used to identify predictors of preconceptional folic acid supplementation. A classification and regression tree (CART) analysis was used to define subgroups of women with different patterns of preconceptional folic acid supplementation.

RESULTS

Race/ethnicity, education, age at delivery, nativity, employment, income, number of dependents, smoking, and birth control use were significantly associated with preconceptional folic acid-containing supplement use. Based on a CART analysis, education, race/ethnicity, and age were the most distinguishing factors between women with different preconceptional supplementation patterns. Non-white women with <4 years of a college education were the least likely to use folic acid-containing supplements (11%). However, even in the most compliant subgroup (women with ≥4 years of college), only 60% of women supplemented with folic acid.

CONCLUSION

These results demonstrate the need for continued efforts to increase folic acid supplementation among all reproductive aged women. However, the success of such efforts may be improved if maternal characteristics such as education, race/ethnicity, and age, are considered in the development of future interventions.