The Ottawa and Kingston (OaK) Birth Cohort: development and achievements

Methionine in embryonic development: metabolism, redox homeostasis, epigenetic modification and signaling pathway

Methionine, an essential sulfur-containing amino acid, plays a critical role in methyl metabolism, folate metabolism, polyamine synthesis, redox homeostasis maintenance, epigenetic modification and signaling pathway regulation, particularly during embryonic development. Animal and human studies have increasingly documented that methionine deficiency or excess can negatively impact metabolic processes, translation, epigenetics, and signaling pathways, with ultimate detrimental effects on pregnancy outcomes. However, the underlying mechanisms by which methionine precisely regulates epigenetic modifications and affects signaling pathways remain to be elucidated. In this review, we discuss methionine and the metabolism of its metabolites, the influence of folate-mediated carbon metabolism, redox reactions, DNA and RNA methylation, and histone modifications, as well as the mammalian rapamycin complex and silent information regulator 1-MYC signaling pathway. This review also summarizes our present understanding of the contribution of methionine to these processes, and current nutritional and pharmaceutical strategies for the prevention and treatment of developmental defects in embryos.

Engaging, recruiting, and retaining pregnant people from marginalized communities in environmental health cohort studies: a scoping review

OBJECTIVES

To identify barriers to and strategies for improving the representation of pregnant people from marginalized communities in pregnancy cohort studies that measure environmental chemicals.

METHODS

Guided by the Arksey O'Malley and Levac Frameworks, we conducted a scoping review of peer-reviewed literature published between 2000 and 2022. Included studies discussed barriers and/or strategies related to engaging, recruiting, and retaining pregnant participants or participants of reproductive age from marginalized communities into environmental health research.

RESULTS

Twenty-nine peer-reviewed articles were included in the review. Overall, 31% (9/29) of the studies reported on engagement, recruitment, and retention of participants from racialized communities, 10% (3/29) reported on involvement of participants identifying as Indigenous, and 10% (3/29) of studies reported on participants living in households or areas of low socioeconomic status. We identified four key barriers: participant burden, social inequities, lack of trust, and lack of cultural relevance. We reported identified strategies to mitigate these barriers.

CONCLUSION

Although there is limited coverage in the literature on strategies to effectively engage people from marginalized communities in environmental health pregnancy cohort studies, our findings suggest that applying a health equity and social justice lens to research may help address barriers that exist at the individual, interpersonal, community, institutional, and policy levels. Findings from this review may have important implications for planning future pregnancy cohort studies and ensuring that communities who are disproportionately affected by environmental chemical exposures may be better represented in research and considered in policy decisions.

Maternal folic acid supplementation to prevent preeclampsia: a systematic review and meta-analysis

OBJECTIVE

The purpose of this systematic review was to examine the association between folic acid supplementation during pregnancy and the risk of preeclampsia.

METHODS

Relevant studies were included by searching Embase, PubMed, Scope, Web of science, Cochrane Library databases. Studies were reviewed according to prespecified inclusion and exclusion criteria. Study characteristics were summarized, and study quality was assessed. Risk ratios (RR) and 95% confidence intervals (CI) were used as indicators of effect to assess the relationship between folic acid supplementation and risk of preeclampsia.

RESULTS

The protocol of this study was prospectively registered with the PROSPERO (registration No. CRD42022380636). A total of nine studies were included, divided into three groups according to the type of study, containing a total of 107 051 and 105 222 women who were supplemented and not supplemented with folic acid during pregnancy. The results showed that folic acid supplementation during pregnancy could not be proven to reduce the risk of preeclampsia.

CONCLUSION

The results of the study suggest that folic acid supplementation alone is not associated with a decreased risk of pre-eclampsia,but the inferences are somewhat limited by the low methodological quality of the included literature, and therefore higher quality studies are needed to prove this point.

The influence of maternal and paternal education on birth outcomes: an analysis of the Ottawa and Kingston (OaK) birth cohort

BACKGROUND

Education is considered one of the most robust determinants of health. However, it is unclear whether maternal education and paternal education have differential impacts on perinatal health outcomes. We assess maternal and paternal education differences and their association with adverse birth outcomes in a large birth cohort from Ontario, Canada.

METHODS

The OaK Birth Cohort recruited patients from Ontario, Canada, between October 2002 and April 2009. We recruited mothers were recruited between 12 and 20 weeks' gestation and collected both mother and infant data. The final sample size of the cohort was 8,085 participants. We use logistic regression to model the probability of preterm birth (less than 34 and 37 weeks' gestation), small-for-gestational-age (SGA), or stillbirth as a function of maternal and paternal educational attainment. We adjust for household-level income, maternal and paternal race and ethnicity, and compare the strength of the association between maternal and paternal education on outcomes using Wald tests.

RESULTS

7,928 mother-father-offspring triads were available for the current analysis. 75% of mothers and fathers had college or university level education, and 8.7% of mothers experienced preterm delivery. Compared to mothers with college or university education, mothers with a high school education had an odds ratio of 1.37 (95% CI: 1.01-1.87) for SGA. Paternal education was not associated with infant outcomes. Comparing the odds ratios for maternal education and paternal education showed a stronger association than paternal education at the high school level for SGA birth (difference in odds ratio: 1.95, 95% CI: 1.13-3.36, p = .016) among women at least 25 years old.

CONCLUSION

Maternal education was associated with SGA, and this effect was more robust than paternal education, but both associations were weaker than previously reported.

Receptiveness to participating in cannabis research in pregnancy: a survey study at The Ottawa Hospital

Background: The prevalence of cannabis use among pregnant individuals in Canada is increasing. In the design of new cohort studies to evaluate the patterns and outcomes of cannabis use in pregnancy, consideration must be given to the factors influencing participation, data sharing, and contribution of biological samples. Our objective was to assess the willingness of pregnant individuals to participate in prospective research during pregnancy. Methods: We surveyed pregnant individuals receiving obstetrical care through The Ottawa Hospital in Ottawa, Canada. The survey consisted of 23 dichotomous (yes/no), multiple-choice, Likert scale, and open-ended questions. Individuals were provided with a hypothetical research scenario and asked to report on the likelihood of their participation, use and storage of personal health information and contribution of maternal and newborn samples. Individuals provided motivating and deterring factors related to research participation. Descriptive statistics included frequencies (n) and percentages (%) for categorical variables. Continuous variables were described using means and standard deviations. Results: A total of 84 survey responses were collected. The mean age of respondents was 32.6(±5.3) years. Respondents were predominantly Caucasian (79%), college/university educated (85%) with a household income of ≥$100,000 (64%). There was a high degree of willingness to participate in prospective research by sharing data and biological samples. The most commonly cited motivating and deterring factors for participating in future research were a desire to contribute to science and health information (79%) and fear of privacy invasion (17%), respectively. Conclusions: Pregnant individuals receiving care at The Ottawa Hospital are willing to participate in prospective research studies, including those related to cannabis use. Survey respondents were predominantly of higher socioeconomic status, and few individuals reported cannabis use during pregnancy. Future studies should accommodate multiple recruitment strategies and flexible study designs to encourage enrollment from and retention across diverse sociodemographic communities.

Recruitment and retention of pregnant women in prospective birth cohort studies: A scoping review and content analysis of the literature

Longitudinal cohort studies present unique methodological challenges, especially when they focus on vulnerable populations, such as pregnant women. The purpose of this review is to synthesize the existing knowledge on recruitment and retention (RR) of pregnant women in birth cohort studies and to make recommendations for researchers to improve research engagement of this population. A scoping review and content analysis were conducted to identify facilitators and barriers to the RR of pregnant women in cohort studies. The search retrieved 574 articles, with 38 meeting eligibility criteria and focused on RR among English-speaking, adult women, who are pregnant or in early postpartum period, enrolled in birth cohort studies. Selected studies were birth cohort (including longitudinal) (n = 20), feasibility (n = 14), and other (n = 4) non-interventional study designs. The majority were from low-risk populations. Abstracted data were coded according to emergent theme clusters. The majority of abstracted data (79%) focused on recruitment practices, with only 21% addressing retention strategies. Overall, facilitators were reported more often (75%) than barriers (25%). Building trusting relationships and employing diverse recruitment methods emerged as major recruitment facilitators; major barriers included heterogeneous participant reasons for refusal and cultural factors. Key retention facilitators included flexibility with scheduling, frequent communication, and culturally sensitive practices, whereas participant factors such as loss of interest, pregnancy loss, relocation, multiple caregiver shifts, and substance use/psychiatric problems were cited as major barriers. Better understanding of facilitators and barriers of RR can help enhance the internal and external validity of future birth/pre-birth cohorts. Strategies presented in this review can help inform investigators and funding agencies of best practices for RR of pregnant women in longitudinal studies.

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.

Nutraceuticals and Hypertensive Disorders in Pregnancy: The Available Clinical Evidence

The aim of the present critical review is to summarize the available clinical evidence supporting the use of some dietary supplements that have been shown to lower blood pressure in hypertensive pregnant women. A systematic search strategy was carried out to identify trials in MEDLINE (National Library of Medicine, Bethesda, Maryland, MD, USA; January 1980 to September 2019) and the Cochrane Register of Controlled Trials (The Cochrane Collaboration, Oxford, UK). The terms 'nutraceuticals', 'dietary supplements', 'pregnancy', 'pre-eclampsia', 'clinical trial', and 'human' were incorporated into an electronic search strategy. The references of the identified studies and review articles were reviewed to look for additional studies of interest. We preferably selected papers that reported recent comprehensive reviews or meta-analysis, or original clinical trials of substances with blood pressure-lowering or vascular protective effect in pregnancy. There is a relative body of evidence that supports the use of calcium, vitamin D, folic acid, and resveratrol in preventing the development of hypertensive disorders in pregnancy, and evidence supporting drug treatment too. Further clinical research is advisable to identify the dosage and timing of the supplementation, the group of women that might benefit the most from this approach, and the nutraceuticals with the best cost-effectiveness and risk-benefit ratio for widespread use in clinical practice.

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.

Prevention of pre-eclampsia after infertility treatment: Preconceptional minimalisation of risk factors

Although an increased risk of pre-eclampsia in pregnancies conceived after infertility treatment has been reported, it remains unknown whether preconceptional minimalisation of known risk factors would help in preventing pre-eclamsia. Obesity and preconceptional blood pressure are discussed as major risks for the development of pre-eclampsia and low doses of aspirins, folic acid, statins and metformin are discussed as potential preventive treatments to decrease the risk of pre-eclampsia. In the present review we discuss whether present-day reproductive medicine could progress towards complication-free pregnancy.

Association between prophylactic low-molecular-weight heparin use in pregnancy and macrosomia: analysis of the Ottawa and Kingston birth cohort

Essentials Low-molecular-weight heparin (LMWH) is used to prevent venous thromboembolism (VTE) in pregnancy. We evaluated the association between LMWH and large for gestational age (LGA) infants. We found no significant associations between LMWH use and LGA. LMWH does not appear to increase the risk for the delivery of an LGA infant. SUMMARY: Background Low-molecular-weight heparin (LMWH), an anticoagulant, is the recommended drug for thromboprophylaxis and treatment of venous thromboembolism (VTE) in pregnancy. During pregnancy, LMWH is routinely prescribed to mothers with an increased risk of VTE or with a history of thrombosis. Although clinical reports of larger offspring born to women administered LMWH have been noted, no studies to date have evaluated or associated the use of LMWH and large for gestational age (LGA) infants. Objectives To determine whether there is an association between LMWH usage in mothers and the prevalence of LGA. Patients/Methods We performed an analysis of the Ottawa and Kingston (OaK) Birth Cohort and report characteristics of LMWH and association LGA (> 10%ile). We used coarsened exact matching (CEM) methods to account for bias and confounding. Results A total of 7519 women from the OaK Birth Cohort were included; 59 were administered LMWH during pregnancy (0.78%). Mothers prescribed LMWH had significantly greater BMI (P = 0.0001), age (P = 0.0001) and parity (P = 0.02). Gestational length was shorter among women administered LMWH compared to those without treatment (37.7 ± 2.0 vs. 39.2 ± 2.0, P < 0.0001), an iatrogenic finding. The odds ratio of an LGA delivery among women administered LMWH was 1.02 (95% confidence interval [CI], 0.48-2.16; P = 0.96) in unadjusted analyses and was 1.15 (95% CI, 0.49-2.71) in the matched sample adjusted for maternal age, BMI and gestational age. Conclusions These results, although exploratory, provide indirect evidence of no increased risk of LGA infants among women prescribed LMWH.

Effect of high dose folic acid supplementation in pregnancy on pre-eclampsia (FACT): double blind, phase III, randomised controlled, international, multicentre trial

OBJECTIVE

To determine the efficacy of high dose folic acid supplementation for prevention of pre-eclampsia in women with at least one risk factor: pre-existing hypertension, prepregnancy diabetes (type 1 or 2), twin pregnancy, pre-eclampsia in a previous pregnancy, or body mass index ≥35.

DESIGN

Randomised, phase III, double blinded international, multicentre clinical trial.

SETTING

70 obstetrical centres in five countries (Argentina, Australia, Canada, Jamaica, and UK).

PARTICIPANTS

2464 pregnant women with at least one high risk factor for pre-eclampsia were randomised between 2011 and 2015 (1144 to the folic acid group and 1157 to the placebo group); 2301 were included in the intention to treat analyses.

INTERVENTION

Eligible women were randomised to receive either daily high dose folic acid (four 1.0 mg oral tablets) or placebo from eight weeks of gestation to the end of week 16 of gestation until delivery. Clinicians, participants, adjudicators, and study staff were masked to study treatment allocation.

MAIN OUTCOME MEASURE

The primary outcome was pre-eclampsia, defined as hypertension presenting after 20 weeks' gestation with major proteinuria or HELLP syndrome (haemolysis, elevated liver enzymes, low platelets).

RESULTS

Pre-eclampsia occurred in 169/1144 (14.8%) women in the folic acid group and 156/1157 (13.5%) in the placebo group (relative risk 1.10, 95% confidence interval 0.90 to 1.34; P=0.37). There was no evidence of differences between the groups for any other adverse maternal or neonatal outcomes.

CONCLUSION

Supplementation with 4.0 mg/day folic acid beyond the first trimester does not prevent pre-eclampsia in women at high risk for this condition.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN23781770 and ClinicalTrials.gov NCT01355159.

Comparison of risk factors and outcomes of gestational hypertension and pre-eclampsia

Background

It remains an enigma whether gestational hypertension (GH) and pre-eclampsia (PE) are distinct entities or different spectrum of the same disease. We aimed to compare the risk factors and outcomes between GH and PE.

Method

A total of 7,633 pregnant women recruited between 12 and 20 weeks of gestation in the Ottawa and Kingston Birth Cohort from 2002 to 2009 were included in the analysis. Cox proportional hazards model was used to identify and compare the risk factors for GH and PE by treating gestational age at delivery as the survival time. Logistic regression model was used to compare outcome. Subgroup analysis was performed for early- and late-onset PE.

Results

GH and PE shared most risk factors including overweight and obesity, nulliparity, PE history, type 1 and 2 diabetes, and twin birth. Effect size of PE history (RR = 14.1 for GH vs. RR = 6.4 for PE) and twin birth (RR = 4.8 for GH vs. RR = 10.3 for PE) showed substantial difference. Risk factors modified gestational age at delivery in patients with GH and PE in similar pattern. Subgroup analysis showed that early- and late-onset PE shared some risk factors with different effect sizes, whereas folic acid supplementation showed protective effect for early-onset PE only. PE was strongly associated with several adverse outcomes including cesarean section, placental abruption, small for gestational age, preterm birth, and 5 min Apgar score < 7, whereas GH was associated with increased risk of preterm birth only.

Conclusions

GH and PE shared common risk factors. Differences in effect sizes of risk factors and outcomes indicate that the conditions may have different pathophysiology and mechanism.

Generation and validation of a universal perinatal database and biospecimen repository: PeriBank

OBJECTIVE

There is a dearth of biospecimen repositories available to perinatal researchers. In order to address this need, here we describe the methodology used to establish such a resource.

STUDY DESIGN

With the collaboration of MedSci.net, we generated an online perinatal database with 847 fields of clinical information. Simultaneously, we established a biospecimen repository of the same clinical participants.

RESULTS

The demographic and clinical outcomes data are described for the first 10 000 participants enrolled. The demographic characteristics are consistent with the demographics of the delivery hospitals. Quality analysis of the biospecimens reveals variation in very few analytes. Furthermore, since the creation of PeriBank, we have demonstrated validity of the database and tissue integrity of the biospecimen repository.

CONCLUSION

Here we establish that the creation of a universal perinatal database and biospecimen collection is not only possible, but allows for the performance of state-of-the-science translational perinatal research and is a potentially valuable resource to academic perinatal researchers.

Maternal supplementation of omega-3 fatty acids and micronutrients reduces cardiometabolic variables in pregnancy induced hypertension rats

AIMS

Reports indicate that during pregnancy hypertension is known to have long term adverse effects both in the mother and offspring. However, the effect of maternal micronutrient supplementation on this association of in utero exposure and risk of non-communicable diseases in the later life remains unclear. The present study examines the effect of maternal micronutrient and omega-3 fatty acid supplementation either individual or in combination on cardiometabolic risk factors both in the mother and offspring using an animal model of hypertension.

MAIN METHODS

Pregnant Wistar rats were randomly assigned to the following groups; control, PIH (Pregnancy induced hypertention) Induced, PIH+vitamin B12, PIH+ folic acid, PIH+omega-3 fatty acids and PIH+combined smicronutrient supplementation (vitamin B12+folic acid + omega-3 fatty acids). The dams and their offspring were shifted to a control diet after delivery and the offspring continued on these diets till 3mo of age. Hypertension during pregnancy was induced using l-Nitroarginine methylester (50mg/kgbody weight/day).

KEY FINDINGS

Omega-3 fatty acid supplementation during pregnancy demonstrated lower levels (p<0.05) of plasma cholesterol while a combined supplementation of folic acid, vitamin B12 and omega 3 fatty acids demonstrated lower (p<0.05) triglyceride levels as compared to PIH induced dams. PIH induction increased (p<0.01) the triglyceride levels in the offspring at 3mo of age and maternal supplementation of either individual or combined micronutrients demonstrated lower (p<0.01) triglyceride levels.

SIGNIFICANCE

Our findings have implications for planning intervention studies in women with pregnancy induced hypertension.

Serum and red-blood-cell folate demonstrate differential associations with BMI in pregnant women

Objective

To examine the association between BMI and folate concentrations in serum and red blood cells (RBC) in pregnant women.

Design

A cross-sectional comparison of folate concentrations in serum and RBC sampled simultaneously from the same individual.

Setting

The Ottawa Hospital and Kingston General Hospital, Ontario, Canada.

Subjects

Pregnant women recruited between 12 and 20 weeks of gestation.

Results

A total of 869 pregnant women recruited from April 2008 to April 2009 were included in the final analysis. Serum folate was inversely associated and RBC folate positively associated with BMI, after adjusting for folic acid supplementation, age, gestational age at blood sample collection, race, maternal education, annual income, smoking and MTHFR 677C→T genotype. In stratified analyses, this differential association was significant in women with the MTHFR CC variant. In women with the CT and TT variants, the differential associations were in the same direction but not significant. Folic acid supplementation during pregnancy did not alter the differential association of BMI with serum and RBC folate concentration. This indicates that the current RBC folate cut-off approach for assessing risk of neural tube defects in obese women may be limited.

Conclusions

BMI is inversely associated with serum folate and positively associated with RBC folate in pregnant women, especially for those with the MTHFR CC variant.

A combined supplementation of omega-3 fatty acids and micronutrients (folic acid, vitamin B12) reduces oxidative stress markers in a rat model of pregnancy induced hypertension

Objectives

Our earlier studies have highlighted that an altered one carbon metabolism (vitamin B₁₂, folic acid, and docosahexaenoic acid) is associated with preeclampsia. Preeclampsia is also known to be associated with oxidative stress and inflammation. The current study examines whether maternal folic acid, vitamin B₁₂ and omega-3 fatty acid supplementation given either individually or in combination can ameliorate the oxidative stress markers in a rat model of pregnancy induced hypertension (PIH).

Materials and Methods

Pregnant Wistar rats were assigned to control and five treatment groups: PIH; PIH + vitamin B₁₂; PIH + folic acid; PIH + Omega-3 fatty acids and PIH + combined micronutrient supplementation (vitamin B₁₂ + folic acid + omega-3 fatty acids). L-Nitroarginine methylester (L-NAME; 50 mg/kg body weight/day) was used to induce hypertension during pregnancy. Blood Pressure (BP) was recorded during pregnancy and dams were dissected at d20 of gestation.

Results

Animals from the PIH group demonstrated higher (p<0.01 for both) systolic and diastolic BP; lower (p<0.01) pup weight; higher dam plasma homocysteine (p<0.05) and dam and offspring malondialdehyde (MDA) (p<0.01), lower (p<0.05) placental and offspring liver DHA and higher (p<0.01) tumor necrosis factor–alpha (TNF–ά) levels as compared to control. Individual micronutrient supplementation did not offer much benefit. In contrast, combined supplementation lowered systolic BP, homocysteine, MDA and placental TNF-ά levels in dams and liver MDA and protein carbonyl in the offspring as compared to PIH group.

Conclusion

Key constituents of one carbon cycle (folic acid, vitamin B₁₂ and DHA) may play a role in reducing oxidative stress and inflammation in preeclampsia.

Prevention of congenital malformations and other adverse pregnancy outcomes with 4.0 mg of folic acid: community-based randomized clinical trial in Italy and the Netherlands

BACKGROUND

In 2010 a Cochrane review confirmed that folic acid (FA) supplementation prevents the first- and second-time occurrence of neural tube defects (NTDs). At present some evidence from observational studies supports the hypothesis that FA supplementation can reduce the risk of all congenital malformations (CMs) or the risk of a specific and selected group of them, namely cardiac defects and oral clefts. Furthermore, the effects on the prevention of prematurity, foetal growth retardation and pre-eclampsia are unclear.Although the most common recommendation is to take 0.4 mg/day, the problem of the most appropriate dose of FA is still open.The aim of this project is to assess the effect a higher dose of peri-conceptional FA supplementation on reducing the occurrence of all CMs. Other aims include the promotion of pre-conceptional counselling, comparing rates of selected CMs, miscarriage, pre-eclampsia, preterm birth, small for gestational age, abruptio placentae.

METHODS/DESIGN

This project is a joint effort by research groups in Italy and the Netherlands. Women of childbearing age, who intend to become pregnant within 12 months are eligible for the studies. Women are randomly assigned to receive 4 mg of FA (treatment in study) or 0.4 mg of FA (referent treatment) daily. Information on pregnancy outcomes are derived from women-and-physician information.We foresee to analyze the data considering all the adverse outcomes of pregnancy taken together in a global end point (e.g.: CMs, miscarriage, pre-eclampsia, preterm birth, small for gestational age). A total of about 1,000 pregnancies need to be evaluated to detect an absolute reduction of the frequency of 8%. Since the sample size needed for studying outcomes separately is large, this project also promotes an international prospective meta-analysis.

DISCUSSION

The rationale of these randomized clinical trials (RCTs) is the hypothesis that a higher intake of FA is related to a higher risk reduction of NTDs, other CMs and other adverse pregnancy outcomes. Our hope is that these trials will act as catalysers, and lead to other large RCTs studying the effects of this supplementation on CMs and other infant and maternal outcomes.

TRIAL REGISTRATION

Italian trial: ClinicalTrials.gov Identifier: NCT01244347.Dutch trial: Dutch Trial Register ID: NTR3161.

Is thrombophilia associated with placenta-mediated pregnancy complications? A prospective cohort study

BACKGROUND

Case control studies suggest that genetic thrombophilias increase the risk of placenta-mediated pregnancy complications (pregnancy loss, small for gestational age (SGA), preeclampsia and/or placental abruption). Cohort studies have not supported this association but were underpowered to detect small effects.

OBJECTIVE

To determine if factor V Leiden (FVL) or the prothrombin gene mutation (PGM) were associated with placenta-mediated pregnancy complications.

PATIENTS/METHODS

A prospective cohort of unselected, consenting pregnant women at three Canadian tertiary care hospitals had blood drawn in the early second trimester and were genotyped for FVL and PGM after delivery. The main outcome measure was a composite of pregnancy loss, SGA < 10th percentile, preeclampsia or placental abruption.

RESULTS

Complete primary outcome and genetic data were available for 7343 women. Most were Caucasian (77.7%, n = 5707), mean age was 30.4 (± 5.1) years, and half were nulliparous. There were 507 (6.9%) women with FVL and/or PGM; 11.64% had a placenta-mediated pregnancy complication. Of the remaining 6836 women, 11.23% experienced a complication. FVL and/or PGM was associated with a relative risk of 1.04 (95% CI, 0.81-1.33) for the composite outcome, with similar results after adjustment for important covariates.

CONCLUSIONS

Carriers of FVL or PGM are not at significantly increased risk of these pregnancy complications.

Validation of Canadian mothers' recall of events in labour and delivery with electronic health records

Background

Maternal report of events that occur during labour and delivery are used extensively in epidemiological research; however, the validity of these data are rarely confirmed. This study aimed to validate maternal self-report of events that occurred in labour and delivery with data found in electronic health records in a Canadian setting.

Methods

Data from the All Our Babies study, a prospective community-based cohort of women’s experiences during pregnancy, were linked to electronic health records to assess the validity of maternal recall at four months post-partum of events that occurred during labour and delivery. Sensitivity, specificity and kappa scores were calculated. Results were stratified by maternal age, gravidity and educational attainment.

Results

Maternal recall at four months post-partum was excellent for infant characteristics (gender, birth weight, gestational age, multiple births) and variables related to labour and delivery (mode of delivery, epidural, labour induction) (sensitivity and specificity >85%). Women who had completed a university degree had significantly better recall of labour induction and use of an epidural.

Conclusion

Maternal recall of infant characteristics and events that occurred during labour and delivery is excellent at four months post-partum and is a valid source of information for research purposes.

The All Our Babies pregnancy cohort: design, methods, and participant characteristics

Background

The prospective cohort study design is ideal for examining diseases of public health importance, as its inherent temporal nature renders it advantageous for studying early life influences on health outcomes and research questions of aetiological significance. This paper will describe the development and characteristics of the All Our Babies (AOB) study, a prospective pregnancy cohort in Calgary, Alberta, Canada designed to examine determinants of maternal, infant, and child outcomes and identify barriers and facilitators in health care utilization.

Methods

Women were recruited from health care offices, communities, and through Calgary Laboratory Services before 25 weeks gestation from May 2008 to December 2010. Participants completed two questionnaires during pregnancy, a third at 4 months postpartum, and are currently being followed-up with questionnaires at 12, 24, and 36 months. Data was collected on pregnancy history, demographics, lifestyle, health care utilization, physical and mental health, parenting, and child developmental outcomes and milestones. In addition, biological/serological and genetic markers can be extracted from collected maternal and cord blood samples.

Results

A total of 4011 pregnant women were eligible for recruitment into the AOB study. Of this, 3388 women completed at least one survey. The majority of participants were less than 35 years of age, Caucasian, Canadian born, married or in a common-law relationship, well-educated, and reported household incomes above the Calgary median. Women who discontinued after the first survey (n=123) were typically younger, non-Caucasian, foreign-born, had lower education and household income levels, were less likely to be married or in a common-law relationship, and had poor psychosocial health in early pregnancy. In general, AOB participants reflect the pregnant and parenting population at local and provincial levels, and perinatal indicators from the study are comparable to perinatal surveillance data.

Conclusions

The extensive and rich data collected in the AOB cohort provides the opportunity to answer complex questions about the relationships between biology, early experiences, and developmental outcomes. This cohort will contribute to the understanding of the biologic mechanisms and social/environmental pathways underlying associations between early and later life outcomes, gene-environment interactions, and developmental trajectories among children.