Fish consumption, erythrocyte fatty acids, and preterm birth

Development and internal validation of a non-invasive clinical tool to predict sufficient omega-3 levels in early pregnancy

BACKGROUND

Complications from preterm birth (PTB) are the leading cause of death and disability in those under five years. Whilst the role of omega-3 (n-3) supplementation in reducing PTB is well-established, growing evidence suggests supplementation use in those replete may increase the risk of early PTB.

AIM

To develop a non-invasive tool to identify individuals with total n-3 serum levels above 4.3% of total fatty acids in early pregnancy.

METHODS

We conducted a prospective observational study recruiting 331 participants from three clinical sites in Newcastle, Australia. Eligible participants (n = 307) had a singleton pregnancy between 8 and 20 weeks' gestation at recruitment. Data on factors associated with n-3 serum levels were collected using an electronic questionnaire; these included estimated intake of n-3 (including food type, portion size, frequency of consumption), n-3 supplementation, and sociodemographic factors. The optimal cut-point of estimated n-3 intake that predicted mothers with total serum n-3 levels likely above 4.3% was developed using multivariate logistic regression, adjusting for maternal age, body mass index, socioeconomic status, and n-3 supplementation use. Total serum n-3 levels above 4.3% was selected as previous research has demonstrated that mothers with these levels are at increased risk of early PTB if they take additional n-3 supplementation during pregnancy. Models were evaluated using various performance metrics including sensitivity, specificity, area under receiver operator characteristic (AUROC) curve, true positive rate (TPR) at 10% false positive rate (FPR), Youden Index, Closest to (0,1) Criteria, Concordance Probability, and Index of Union. Internal validation was performed using 1000-bootstraps to generate 95% confidence intervals for performance metrics generated.

RESULTS

Of 307 eligible participants included for analysis, 58.6% had total n-3 serum levels above 4.3%. The optimal model had a moderate discriminative ability (AUROC 0.744, 95% CI 0.742-0.746) with 84.7% sensitivity, 54.7% specificity and 37.6% TPR at 10% FPR.

CONCLUSIONS

Our non-invasive tool was a moderate predictor of pregnant women with total serum n-3 levels above 4.3%; however, its performance is not yet adequate for clinical use.

TRIAL REGISTRATION

This trial was approved by the Hunter New England Human Research Ethics Committee of the Hunter New England Local Health District (Reference 2020/ETH00498 on 07/05/2020 and 2020/ETH02881 on 08/12/2020).

ISSFAL statement number 7 - Omega-3 fatty acids during pregnancy to reduce preterm birth

Globally, preterm birth is the leading cause of death in children under the age of 5 years and survivors may suffer life-long consequences. Following many years of investigation, there is strong evidence that a proportion of preterm births can be prevented by increasing maternal dietary omega-3 long chain polyunsaturated fatty acid (LCPUFA) intake during pregnancy. This Statement provides a synthesis of contemporary evidence on the role of omega-3 LCPUFA on prevention of preterm birth and is designed to provide fatty acid-specific knowledge and guidance for medical practitioners, midwives, health services, professional bodies and policy makers to consider for their contextual situations. The evidence synthesis, which underpins this statement, is based on the 2018 Cochrane systematic review with supplemental evidence from RCTs completed since that time as well as other systematic reviews. Heterogeneity between studies was explored to understand how the effect of omega-3 supplementation may vary in different population groups and by dose and type of omega-3 supplementation. Most trials were conducted in upper-middle or high-income countries and the evidence are most applicable in those settings. The evidence synthesis confirmed that omega-3 LCPUFA, particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have an important role to play in determining gestational length in singleton pregnancies. Adequate intake of omega-3 LCPUFA in early pregnancy, consistent with existing nutritional guidelines, is associated with a lower risk of preterm and early preterm births for women with singleton pregnancies. Therefore, women with adequate omega-3 intakes in early pregnancy should maintain these intakes. Women who are low in omega-3 fatty acids will benefit most from omega-3 LCPUFA supplementation to reduce their risk of early birth. In such cases supplementation with a total of about 1000 mg of DHA plus EPA is effective at reducing risk of early birth, preferably with supplementation commencing before 20 weeks' gestation.

Maternal fish and shellfish consumption and preterm birth: a retrospective study in urban China

Preterm birth is the leading cause of perinatal mortality and morbidity. Some prospective cohort studies suggested that fish and shellfish consumption may affect the incidence of preterm birth. However, conflicting evidence exists on the relationship between fish and shellfish consumption and preterm birth. A total of 10 179 women from Gansu province were interviewed after delivery to collect information on their past intake of fish and shellfish using FFQ. Logistic regression models were used to estimate OR and 95 % CI to examine the association between fish and shellfish consumption and preterm birth and its clinical subtypes. Fish and shellfish consumption was associated with reduced risk of preterm birth (OR = 0·65, 95 % CI 0·56, 0·77). Increasing frequency of fish and shellfish consumption, compared with no fish and shellfish consumption, was associated with decreasing odds of preterm birth. Besides, increasing weekly total amount of fish and shellfish consumption, compared with no fish and shellfish consumption, was also associated with decreasing odds of preterm birth. Significant trend effect was also seen between fish and shellfish consumption and very preterm birth (P_{for trend} = 0·001) and spontaneous preterm birth (P_{for trend} = 0·003). Interaction was observed between total fish and shellfish consumption with maternal age (P_{for interaction} = 0·041) and pre-pregnancy BMI underweight (P_{for interaction} = 0·012). Our findings showed that maternal fish and shellfish consumption was associated with lower incidence of preterm birth.We recommend for the national guideline of ≥350 g/week of fish and shellfish consumption among pregnant women.

Evidence based recommendations for an optimal prenatal supplement for women in the US: vitamins and related nutrients

The blood levels of most vitamins decrease during pregnancy if un-supplemented, including vitamins A, C, D, K, B1, B3, B5, B6, folate, biotin, and B12. Sub-optimal intake of vitamins from preconception through pregnancy increases the risk of many pregnancy complications and infant health problems. In the U.S., dietary intake of vitamins is often below recommended intakes, especially for vitamin D, choline and DHA. Many studies suggest that insufficient vitamin intake is associated with a wide range of pregnancy complications (anemia, Cesarean section, depression, gestational diabetes, hypertension, infertility, preeclampsia, and premature rupture of membranes) and infant health problems (asthma/wheeze, autism, low birth weight, congenital heart defects, intellectual development, intrauterine growth restriction, miscarriage, neural tube defects, orofacial defects, and preterm birth). The primary goal of this paper is to review the research literature and propose evidence-based recommendations for the optimal level of prenatal supplementation for each vitamin for most women in the United States. A secondary goal was to compare these new recommendations with the levels of vitamins in over 180 commercial prenatal supplements. The analysis found that prenatal supplements vary widely in content, often contained only a subset of essential vitamins, and the levels were often below our recommendations. This suggests that increasing prenatal vitamin supplementation to the levels recommended here may reduce the incidence of many pregnancy complications and infant health problems which currently occur.

Perceived social support predicts self-reported and objective health and health behaviors among pregnant women

Perinatal health and health behaviors play a crucial role in maternal and neonatal health. Data examining psychosocial factors which predict self-reported health and health behaviors as well as objective indicators downstream of health behaviors among pregnant women are lacking. In this longitudinal study design with 131 pregnant women, perceived social support was examined as a predictor of self-rated health and average levels of sleep quality, health-promoting and health-impairing behaviors, and red blood cell (RBC) polyunsaturated fatty acids across early, mid, and late pregnancy. Participants provided a blood sample and fatty acid methyl esters were analyzed by gas chromatography. Measures included the Multidimensional Scale of Perceived Social Support, Pittsburgh Sleep Quality Index, and Prenatal Health Behavior Scale. Regression models demonstrated that, after adjustment for income, race/ethnicity, age, relationship status, pre-pregnancy body mass index, greater social support was associated with better self-rated health (p = 0.001), greater sleep quality (p = 0.001), fewer health-impairing behaviors (p = 0.02), and higher RBC omega-3 fatty acids (p = 0.003). Associations among social support with health-promoting behaviors, RBC omega-6 fatty acids, or gestational weight gain were not significant. Findings underscore the benefits of perceived social support in the context of pregnancy. Examination of pathways that link social support with these outcomes will be meaningful in determining the ways in which perinatal psychosocial interventions may promote health.

Recent advances in policy and practice translation of the evidence for additional omega-3 fatty acids and prematurity

PURPOSE OF REVIEW

This is a review of the most up-to-date research on the effectiveness of omega-3 fatty acids for reducing the risk of prematurity in well nourished women with access to high-quality obstetric care. It will provide an overview of the translation of the evidence on omega-3 screening into policy, and the latest research on how to implement the policy into practice.

RECENT FINDINGS

Findings of the included clinical studies support that omega-3 supplementation for women with a singleton pregnancy who have a low omega-3 status reduces the risk of early preterm birth.

SUMMARY

There is evidence that screening and providing appropriate advice to women with a singleton pregnancy who have a low omega-3 status can reduce their risk of early preterm birth, and avoiding supplementation for women who are replete will avoid unnecessary supplementation and potential harm.

Translating n-3 polyunsaturated fatty acid status from whole blood to plasma and red blood cells during pregnancy: Translating n-3 status across blood fractions in pregnancy

Women with low n-3 (omega-3) status in pregnancy can reduce their risk of early preterm birth (<34 weeks' gestation) through n-3 long chain polyunsaturated fatty acid (LCPUFA) supplementation. As investigators measure fatty acid status in different blood fractions, equations are needed to compare results across studies. Similarly, derived cut-points for defining low and replete n-3 status are needed to assist clinical interpretation during early pregnancy. Our aims were to develop equations to convert the percentage of total n-3 fatty acids, EPA+DHA and DHA between whole blood, plasma and red blood cells (RBC), and to derive cut-points for defining low and replete total n-3 fatty acid status in plasma and RBC from those already established in whole blood. Using blood samples from 457 pregnant women in a multicentre randomised controlled trial, equations for these interconversions were developed using simple linear regression models. Measures of n-3 fatty acid status in whole blood and plasma were strongly related (R² > 0.85), while more moderate relationships were observed between measures in whole blood and RBC (R² 0.55 - 0.71), or plasma and RBC (R² 0.55 - 0.63). Using the conversion equations, established cut-points for low and replete n-3 status in whole blood (<4.2% and >4.9% of total fatty acids) converted to <3.7% and >4.3% of plasma total fatty acids, and to <7.3% and >8.1% of RBC total fatty acids. Agreement to define low and replete n-3 status was better between whole blood and plasma, rather than between whole blood and RBC. Our data also show that total n-3 fatty acids in plasma and serum are interchangeable. We conclude that either whole blood or plasma total n-3 fatty acids can be used to define low status in pregnancy and identify women who will most benefit from n-3 LCPUFA supplementation to reduce their risk of early birth. Further research is needed to determine the clinical utility of other fatty acid measures in various blood lipid fractions.

Plasma long-chain omega-3 fatty acid status and risk of recurrent early spontaneous preterm birth: a prospective observational study

INTRODUCTION

A 2018 Cochrane review found that omega-3 supplementation in pregnancy was associated with a risk reduction of early preterm birth of 0.58; prompting calls for universal supplementation. Recent analysis suggests the benefit may be confined to women with a low baseline omega-3 fatty acid status. However, the contemporary omega-3 fatty acid status of pregnant women in the UK is largely unknown. This is particularly pertinent for women with a previous preterm birth, in whom a small relative risk reduction would have a larger reduction of absolute risk. This study aimed to assess the omega-3 fatty acid status of a UK pregnant population and determine the association between the long-chain omega-3 fatty acids and recurrent spontaneous early preterm birth.

MATERIAL AND METHODS

A total of 283 high-risk women with previous early preterm birth were recruited to the prospective observational study in Liverpool, UK. Additionally, 96 pregnant women with previous term births and birth ≥39⁺⁰  weeks in the index pregnancy provided a low-risk population sample. Within the high-risk group we assessed the odds ratio of recurrent early preterm birth compared with birth at ≥37⁺⁰  weeks of gestation according to plasma eicosapentaenoic acid plus docosahexaenoic acid (EPA+DHA) at 15-22 weeks of gestation.

RESULTS

Our participants had low EPA+DHA; 62% (143/229) of women with previous preterm birth and 69% (68/96) of the population sample had levels within the lowest two quintiles of a previously published pregnancy cohort. We found no association between long-chain omega-3 status and recurrent early preterm birth (n = 51). The crude odds ratio of a recurrent event was 0.91 (95% CI 0.38-2.15, p = 0.83) for women in the lowest, compared with the highest three quintiles of EPA+DHA.

CONCLUSIONS

In the majority of our participants, levels of long-chain omega-3 were low; within the range that may benefit from supplementation. However, levels showed no association with risk of recurrent early spontaneous preterm birth. This could be because our population levels were too low to show benefit in being omega-3 "replete"; or else omega-3 levels may be of lesser importance in recurrent early preterm birth.

Prenatal Nutritional Strategies to Reduce the Risk of Preterm Birth

Worldwide, around 15 million preterm babies are born annually, and despite intensive research, the specific mechanisms triggering preterm birth (PTB) remain unclear. Cost-effective primary prevention strategies to reduce PTB are required, and nutritional interventions offer a promising alternative. Nutrients contribute to a variety of mechanisms that are potentially important to preterm delivery, such as infection, inflammation, oxidative stress, and muscle contractility. Several observational studies have explored the association between dietary nutrients and/or dietary patterns and PTB, often with contrasting results. Randomized trial evidence on the effects of supplementation with zinc, multiple micronutrients (iron and folic acid), and vitamin D is promising; however, results are inconsistent, and many studies are not adequately powered for outcomes of PTB. Large-scale clinical trials with PTB as the primary outcome are needed before any firm conclusions can be drawn for these nutrients. The strongest evidence to date for a nutritional solution exists for omega-3 long-chain polyunsaturated fatty acids (LCPUFAs), key nutrients in fish. In 2018, a Cochrane Review (including 70 studies) showed that prenatal supplementation with omega-3 LCPUFAs reduced the risk of PTB and early PTB (EPTB) compared with no omega-3 supplementation. However, the largest trial of omega-3 supplementation in pregnancy, the Omega-3 to Reduce the Incidence of Prematurity (ORIP) trial (n = 5,544), showed no reduction in EPTB and a reduction in PTB only in a prespecified analysis of singleton pregnancies. Exploratory analyses from the ORIP trial found that women with low baseline total omega-3 status were at higher risk of EPTB, and that this risk was substantially reduced with omega-3 supplementation. In contrast, women with replete or high baseline total omega-3 status were already at low risk of EPTB and additional omega-3 supplementation increased the risk of EPTB compared to control. These findings suggest that determining an individual woman's PUFA status may be the most precise way to inform recommendations to reduce her risk of PTB.

Omega-3 fatty acid supplementation in pregnancy-baseline omega-3 status and early preterm birth: exploratory analysis of a randomised controlled trial

OBJECTIVE

To identify a polyunsaturated fatty acid (PUFA) biomarker able to detect which women with singleton pregnancies are most likely to benefit from omega-3 supplementation to reduce their risk of early preterm birth.

DESIGN

Exploratory analysis of a randomised controlled trial.

SETTING

Six Australian hospitals.

POPULATION

Women with a singleton pregnancy enrolled in the ORIP trial.

METHODS

Using maternal capillary whole blood collected ~14 weeks' gestation, the fatty acids in total blood lipids were quantified using gas chromatography. Interaction tests examined whether baseline PUFA status modified the effect of omega-3 supplementation on birth outcomes.

MAIN OUTCOME MEASURE

Early preterm birth (<34 weeks' gestation).

RESULTS

A low total omega-3 PUFA status in early pregnancy was associated with a higher risk of early preterm birth. Among women with a total omega-3 status ≤4.1% of total fatty acids, omega-3 supplementation substantially reduced the risk of early preterm birth compared with control (0.73 versus 3.16%; relative risk = 0.23, 95% confidence interval [CI] 0.07-0.79). Conversely, women with higher total omega-3 status in early pregnancy were at lower risk of early preterm birth. Supplementing women with a baseline status above 4.9% increased early preterm birth (2.20 versus 0.97%; relative risk = 2.27, 95% CI 1.13-4.58).

CONCLUSIONS

Women with singleton pregnancies and low total omega-3 PUFA status early in pregnancy have an increased risk of early preterm birth and are most likely to benefit from omega-3 supplementation to reduce this risk. Women with higher total omega-3 status are at lower risk and additional omega-3 supplementation may increase their risk.

TWEETABLE ABSTRACT

Low total omega-3 fat status helps identify which women benefit from extra omega-3 to reduce early prematurity.

Examining the Effect of Fish Oil Supplementation in Chinese Pregnant Women on Gestation Duration and Risk of Preterm Delivery

BACKGROUND

Intervention studies have shown that long-chain (LC) n-3 PUFA intake can prolong gestation but the dose-time-effect relations remain unresolved.

OBJECTIVES

We examined the effect on gestation duration of 2 doses of supplemental LC n-3 PUFAs.

METHODS

We undertook a 3-group parallel randomized controlled trial in areas of China with low (median: 2.1 g/d) and higher (14.3 g/d) fish intake. Unselected women (median: age, 26.2 y; BMI, 20. kg/m2) were randomly assigned at midgestation to take four 0.72-g identical gelatin capsules per day until the last day of the preterm period (<259 days of gestation), when they were asked to stop. Capsules contained fish oil [high fish oil (HFO) group (60% w/w LC n-3 PUFAs)], a 1:3 mixture of fish oil to olive oil [low fish oil (LFO) group (20%)], or olive oil [control (CON) group (0%)], providing 2.0, 0.5, and 0 g/d of LC n-3 PUFAs, respectively. Habitual fish intake was recorded at baseline. Hazard rate ratios (HRRs) for spontaneous delivery <259 days of gestation and <273 days of gestation across groups were estimated by Cox regression.

RESULTS

Among 5531 women randomly assigned, 92.5% were included in analyses (1706/1825, 1695/1851, and 1717/1855, respectively). The groups were similar with respect to hazard rates <259 days of gestation [HRR: 1.04 (95% CI: 0.70, 1.53) for LFO compared with CON and 0.90 (95% CI: 0.60, 1.35) for HFO compared with CON], hazard rates <273 days of gestation [HRR: 1.00 (95% CI: 0.86, 1.18) and 0.91 (95% CI: 0.77, 1.07), respectively], and mean gestation durations [differences: 0.2 d (95% CI: -0.5, 0.8) and 0.6 d (95% CI: -0.06, 1.2), respectively]. Inspection of pregnancy survival curves suggested that LC n-3 PUFAs delayed delivery in low fish consumers by 5-10 d and that this effect ceased rapidly after stopping taking the capsules.

CONCLUSION

This trial could not substantiate that fish oil prevents preterm birth in Chinese women, possibly because statistical power was too low. This trial was registered at clinicaltrials.gov as NCT02770456.

Omega-3 Polyunsaturated Fatty Acids and Their Health Benefits

Omega-3 polyunsaturated fatty acids (PUFAs) include α-linolenic acid (ALA; 18:3 ω-3), stearidonic acid (SDA; 18:4 ω-3), eicosapentaenoic acid (EPA; 20:5 ω-3), docosapentaenoic acid (DPA; 22:5 ω-3), and docosahexaenoic acid (DHA; 22:6 ω-3). In the past few decades, many epidemiological studies have been conducted on the myriad health benefits of omega-3 PUFAs. In this review, we summarized the structural features, properties, dietary sources, metabolism, and bioavailability of omega-3 PUFAs and their effects on cardiovascular disease, diabetes, cancer, Alzheimer's disease, dementia, depression, visual and neurological development, and maternal and child health. Even though many health benefits of omega-3 PUFAs have been reported in the literature, there are also some controversies about their efficacy and certain benefits to human health.

Importance of n-3 PUFA consumption during pregnancy: perception discrepancies between pregnant women and gynaecologists-obstetricians in Belgium

OBJECTIVE

n-3 PUFA during pregnancy have been subject to intense research interest, but also much controversy, creating a situation of confusion among patients and health-care providers. The present study was carried out to explore knowledge, attitude and practices regarding n-3 PUFA in two independent populations of pregnant women and gynaecologists-obstetricians in Belgium and to assess the relationship between the pregnant women's attributes and their n-3 PUFA status measured by the omega-3 index.

DESIGN

Cross-sectional study. Knowledge, attitude and practices were collected by self-administered questionnaires while laboratory data were available for each pregnant woman.

SETTING

During the first antenatal hospital appointment (for the pregnant women) and by email (for the gynaecologists-obstetricians).ParticipantsWomen in early pregnancy (n 122) and gynaecologists-obstetricians (n 67).

RESULTS

Marked discrepancies in perception were evidenced between the pregnant women and health-care providers. While 82 % of the women attached high importance to n-3 PUFA during pregnancy, only a third of the gynaecologists-obstetricians did. About 35 % of the women declared paying particular attention to their consumption of n-3 PUFA. After adjusting for sociodemographic characteristics, these positive dietary practices were significantly associated with higher omega-3 index (P=0·04). Overall, 43·3 % of professionals did not provide any information about n-3 PUFA to their pregnant patients and 46·3 % did not take any preventive actions.

CONCLUSIONS

Evidence-based guidelines, refreshment training and communication tools are needed to improve awareness and clinical practices among caregivers regarding n-3 PUFA to benefit both mothers and their children.

A Prenatal DHA Test to Help Identify Women at Increased Risk for Early Preterm Birth: A Proposal

Fish intake and docosahexaenoic acid (DHA), a nutrient found in fish, have been favorably linked to several pregnancy outcomes. The risk of early preterm birth (ePT, <34 weeks gestation) is associated with low fish intake and DHA blood levels and can be reduced by supplemental DHA. Here, we summarize the evidence linking blood DHA levels with risk for ePT birth, and based on the available studies, propose that women who are pregnant or trying to become pregnant aim for a red blood cell (RBC) DHA value of at least 5% (of total RBC fatty acids). In the US, ~70% of women of childbearing age are likely below this cut-point, and dietary intake data suggest that this group, including pregnant women, consumes ~60 mg/day DHA and that >90% of this group do not take an omega-3 supplement. Since the recommendations for women to consume fish and to take a 200 mg DHA supplement during pregnancy are not being heeded generally, there is a need to motivate practitioners and pregnant women to attend to these recommendations. Having an objective prenatal blood DHA test could provide such motivation. More research is needed to test the clinical utility of this proposed target prenatal DHA level.

Omega-3 fatty acid addition during pregnancy

BACKGROUND

Higher intakes of foods containing omega-3 long-chain polyunsaturated fatty acids (LCPUFA), such as fish, during pregnancy have been associated with longer gestations and improved perinatal outcomes. This is an update of a review that was first published in 2006.

OBJECTIVES

To assess the effects of omega-3 LCPUFA, as supplements or as dietary additions, during pregnancy on maternal, perinatal, and neonatal outcomes and longer-term outcomes for mother and child.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (16 August 2018), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing omega-3 fatty acids (as supplements or as foods, stand-alone interventions, or with a co-intervention) during pregnancy with placebo or no omega-3, and studies or study arms directly comparing omega-3 LCPUFA doses or types. Trials published in abstract form were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data, assessed risk of bias in trials and assessed quality of evidence for prespecified birth/infant, maternal, child/adult and health service outcomes using the GRADE approach.

MAIN RESULTS

In this update, we included 70 RCTs (involving 19,927 women at low, mixed or high risk of poor pregnancy outcomes) which compared omega-3 LCPUFA interventions (supplements and food) compared with placebo or no omega-3. Overall study-level risk of bias was mixed, with selection and performance bias mostly at low risk, but there was high risk of attrition bias in some trials. Most trials were conducted in upper-middle or high-income countries; and nearly half the trials included women at increased/high risk for factors which might increase the risk of adverse maternal and birth outcomes.Preterm birth < 37 weeks (13.4% versus 11.9%; risk ratio (RR) 0.89, 95% confidence interval (CI) 0.81 to 0.97; 26 RCTs, 10,304 participants; high-quality evidence) and early preterm birth < 34 weeks (4.6% versus 2.7%; RR 0.58, 95% CI 0.44 to 0.77; 9 RCTs, 5204 participants; high-quality evidence) were both lower in women who received omega-3 LCPUFA compared with no omega-3. Prolonged gestation > 42 weeks was probably increased from 1.6% to 2.6% in women who received omega-3 LCPUFA compared with no omega-3 (RR 1.61 95% CI 1.11 to 2.33; 5141 participants; 6 RCTs; moderate-quality evidence).For infants, there was a possibly reduced risk of perinatal death (RR 0.75, 95% CI 0.54 to 1.03; 10 RCTs, 7416 participants; moderate-quality evidence: 62/3715 versus 83/3701 infants) and possibly fewer neonatal care admissions (RR 0.92, 95% CI 0.83 to 1.03; 9 RCTs, 6920 participants; moderate-quality evidence - 483/3475 infants versus 519/3445 infants). There was a reduced risk of low birthweight (LBW) babies (15.6% versus 14%; RR 0.90, 95% CI 0.82 to 0.99; 15 trials, 8449 participants; high-quality evidence); but a possible small increase in large-for-gestational age (LGA) babies (RR 1.15, 95% CI 0.97 to 1.36; 6 RCTs, 3722 participants; moderate-quality evidence, for omega-3 LCPUFA compared with no omega-3. Little or no difference in small-for-gestational age or intrauterine growth restriction (RR 1.01, 95% CI 0.90 to 1.13; 8 RCTs, 6907 participants; moderate-quality evidence) was seen.For the maternal outcomes, there is insufficient evidence to determine the effects of omega-3 on induction post-term (average RR 0.82, 95% CI 0.22 to 2.98; 3 trials, 2900 participants; low-quality evidence), maternal serious adverse events (RR 1.04, 95% CI 0.40 to 2.72; 2 trials, 2690 participants; low-quality evidence), maternal admission to intensive care (RR 0.56, 95% CI 0.12 to 2.63; 2 trials, 2458 participants; low-quality evidence), or postnatal depression (average RR 0.99, 95% CI 0.56 to 1.77; 2 trials, 2431 participants; low-quality evidence). Mean gestational length was greater in women who received omega-3 LCPUFA (mean difference (MD) 1.67 days, 95% CI 0.95 to 2.39; 41 trials, 12,517 participants; moderate-quality evidence), and pre-eclampsia may possibly be reduced with omega-3 LCPUFA (RR 0.84, 95% CI 0.69 to 1.01; 20 trials, 8306 participants; low-quality evidence).For the child/adult outcomes, very few differences between antenatal omega-3 LCPUFA supplementation and no omega-3 were observed in cognition, IQ, vision, other neurodevelopment and growth outcomes, language and behaviour (mostly low-quality to very low-quality evidence). The effect of omega-3 LCPUFA on body mass index at 19 years (MD 0, 95% CI -0.83 to 0.83; 1 trial, 243 participants; very low-quality evidence) was uncertain. No data were reported for development of diabetes in the children of study participants.

AUTHORS' CONCLUSIONS

In the overall analysis, preterm birth < 37 weeks and early preterm birth < 34 weeks were reduced in women receiving omega-3 LCPUFA compared with no omega-3. There was a possibly reduced risk of perinatal death and of neonatal care admission, a reduced risk of LBW babies; and possibly a small increased risk of LGA babies with omega-3 LCPUFA.For our GRADE quality assessments, we assessed most of the important perinatal outcomes as high-quality (e.g. preterm birth) or moderate-quality evidence (e.g. perinatal death). For the other outcome domains (maternal, child/adult and health service outcomes) GRADE ratings ranged from moderate to very low, with over half rated as low. Reasons for downgrading across the domain were mostly due to design limitations and imprecision.Omega-3 LCPUFA supplementation during pregnancy is an effective strategy for reducing the incidence of preterm birth, although it probably increases the incidence of post-term pregnancies. More studies comparing omega-3 LCPUFA and placebo (to establish causality in relation to preterm birth) are not needed at this stage. A further 23 ongoing trials are still to report on over 5000 women, so no more RCTs are needed that compare omega-3 LCPUFA against placebo or no intervention. However, further follow-up of completed trials is needed to assess longer-term outcomes for mother and child, to improve understanding of metabolic, growth and neurodevelopment pathways in particular, and to establish if, and how, outcomes vary by different types of omega-3 LCPUFA, timing and doses; or by characteristics of women.

Fish consumption prior to pregnancy and pregnancy outcomes in the National Birth Defects Prevention Study, 1997-2011

OBJECTIVE

To evaluate the relationships between maternal fish consumption and pregnancy outcomes in a large, population-based sample of women in the USA.

DESIGN

We collected average fish consumption prior to pregnancy using a modified version of the semi-quantitative Willett FFQ. We estimated adjusted OR (aOR) and 95 % CI for associations between different levels of fish consumption and preterm birth (&lt;37 weeks), early preterm birth (&lt;32 and &lt;35 weeks) and small-for-gestational-age infants (SGA; &lt;10th percentile).

SETTING

The National Birth Defects Prevention Study (NBDPS).

SUBJECTS

Control mother-infant pairs with estimated delivery dates between 1997 and 2011 (n 10 919).

RESULTS

No significant associations were observed between fish consumption and preterm birth or early preterm birth (aOR = 0·7-1·0 and 0·7-0·9, respectively). The odds of having an SGA infant were elevated (aOR = 2·1; 95 % CI 1·2, 3·4) among women with daily fish consumption compared with women consuming fish less than once per month. No associations were observed between other levels of fish consumption and SGA (aOR = 0·8-1·0).

CONCLUSIONS

High intake of fish was associated with twofold higher odds of having an SGA infant, while moderate fish consumption prior to pregnancy was not associated with preterm or SGA. Our study, like many other studies in this area, lacked information regarding preparation methods and the specific types of fish consumed. Future studies should incorporate information on nutrient and contaminant contents, preparation methods and biomarkers to assess these relationships.

Plasma Concentrations of Long Chain N-3 Fatty Acids in Early and Mid-Pregnancy and Risk of Early Preterm Birth

Background

Fish oil supplementation has been shown to delay spontaneous delivery, but the levels and clinical significance remain uncertain. We examined the association between plasma fatty acids quantified in pregnancy and subsequent risk of early preterm birth.

Methods

In a case-control design nested in the Danish National Birth Cohort, we identified 376 early preterm cases (<34 gestational weeks, excluding preeclampsia cases) and 348 random controls. Plasma eicosapentaenoic acid plus docosahexaenoic acid (EPA+DHA% of total fatty acids), were measured twice in pregnancy, at gestation weeks 9 and 25 (medians). Odds ratios and 95% confidence intervals (CI's) for associations between EPA+DHA and early preterm risk were estimated by logistic regression, adjusted for the woman's age, height, pre-pregnancy BMI, parity, smoking, and socioeconomic factors. Hypotheses and analytical plan were defined and archived a priori.

Findings

Analysis using restricted cubic splines of the mean of 1st and 2nd sample measurements showed a strong and significant non-linear association (p < 0.0001) in which the risk of early preterm birth steeply increased when EPA+DHA concentrations were lower than 2% and flattened out at higher levels. Women in the lowest quintile (EPA+DHA < 1.6%) had 10.27 times (95% confidence interval 6.80–15.79, p < 0.0001) increased risk, and women in the second lowest quintile had 2.86 (95% CI 1.79–4.59, p < 0.0001) times increased risk, when compared to women in the three aggregated highest quintiles (EPA+DHA ≥ 1.8%).

Interpretation

Low plasma concentration of EPA and DHA during pregnancy is a strong risk factor for subsequent early preterm birth in Danish women.

Low omega-3 index values and monounsaturated fatty acid levels in early pregnancy: an analysis of maternal erythrocytes fatty acids

Background

It is unanimously recognized that the maternal nutritional status at the pregnancy onset influence both short-term and long-term health of the mother and offspring. Among several nutrients, LCPUFA, particularly from the omega-3 family, are of utmost importance. This study was carried out to determine fatty acids profile of maternal erythrocyte membranes in early pregnancy and to identify potential determinants impacting on this status.

Methods

A cohort of 122 healthy women with a singleton pregnancy was included. Fatty acids were analyzed using gas chromatography. Because of the lack of cutoff values, reference ranges were used to determine fatty acids categories.

Results

Of concern, our data revealed low monounsaturated and long-chain omega-3 fatty acid status in most participants. More than 75% of Belgian pregnant women exhibited Pal, AO and EPA levels as well as IOM3 values below the laboratory reference ranges. Higher DHA concentrations and IOM3 values were found among foreign-nationality participants, non-smokers and physically active women. With regard to dietary factors, omega-3 supplements and diet seem to be complementary since DHA from supplements (but not from diet) and EPA from diet (but not from supplements) were found to be associated with higher concentrations of DHA and EPA, respectively.

Conclusions

Our study presents evidence demonstrating that the fatty acid status of most early pregnant women is far from being optimal based on the admitted general reference values. Clinicians should be advice to carefully evaluate and improve this status to guarantee the best possible outcome for both the mother and the baby.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0716-6) contains supplementary material, which is available to authorized users.

Maternal obesity, fish intake, and recurrent spontaneous preterm birth

OBJECTIVE

Moderate fish intake in early pregnancy is associated with decreased risk of preterm birth (PTB). Obesity during pregnancy is characterized by inflammation and insufficiency of essential fatty acids. The objective of this study was to measure the association between fish intake during pregnancy and risk of recurrent spontaneous (s) PTB among lean, overweight, and obese women.

DESIGN

This is secondary analysis of a randomized controlled trial of omega-3 fatty acid supplementation for recurrent PTB prevention, 2005-2006. The primary exposure was fish intake at time of enrollment (16-22.9-week gestation). The primary outcomes were sPTB <37 weeks and sPTB <35 weeks. Maternal prepregnancy body mass index was treated as an effect modifier.

SUBJECTS

Eight hundred and fifty-two women were included, 47% were lean, 25% overweight, and 28% obese.

RESULTS

In this cohort, among lean, but not overweight or obese women, ≥1 serving of fish per week was associated with decreased frequency of sPTB <37 weeks compared with <1 serving of fish per week (45.1% versus 27.5%, p = .001) and spontaneous PTB <35 (21.4% versus 11.6%, p = .01). In adjusted models, as fish intake increased, the predicted probability of sPTB decreased in lean women but increased in overweight and obese women (p for interaction < .10).

CONCLUSION

Fish intake was associated with lower probability of sPTB in lean women and higher probability in obese women. These findings warrant further investigation to understand the dietary or metabolic factors associated with obesity that may modulate benefit of fish intake during pregnancy.

Early pregnancy body mass index modifies the association of pre-pregnancy dietary patterns with serum polyunsaturated fatty acid concentrations throughout pregnancy in Brazilian women

Dietary patterns (DPs) have been described as an important factor that may influence polyunsaturated fatty acid (PUFA) concentrations and body mass index (BMI) during pregnancy. We aim to evaluate the association between pre-pregnancy DPs and serum PUFA percentages throughout pregnancy considering early pregnancy BMI as a possible effect modifier. A prospective cohort of 154 pregnant women was followed (5th-13th, 20th-26th, and 30th-36th gestational weeks). Serum PUFA concentrations (total n-3 and total n-6, eicosapentaenoic + docosahexaenoic acids) were measured in each trimester and expressed as percentages. The n-6/n-3 ratio was calculated. Longitudinal linear mixed-effects models including interaction terms between DPs and early pregnancy BMI were employed. Serum PUFA percentages declined, whereas the n-6/n-3 ratio, monounsaturated, and saturated percentages increased throughout pregnancy for all BMI categories. Three pre-pregnancy DPs were identified by principal component analysis (common Brazilian, healthy, and processed). Overweight women with higher adherence to the common-Brazilian and to the healthy DPs presented reduced n-3 PUFA percentage and increased n-6 percentages and n-6/n-3 ratio compared to under or normal weight women. Obese women with higher adherence to the processed DP presented a more pronounced decrease of total n-3 percentage compared to under or normal weight women. Early pregnancy BMI modified the effect of pre-pregnancy DPs on PUFA profile throughout gestation. Higher adherence to the healthy pattern was associated with increased n-3 percentage, except for overweight women. Only for processed DP was the behaviour of PUFA the same for all BMI categories, showing a worse evolution profile, that is, increased n-6 and reduced n-3 fractions.

Assessment of DHA on reducing early preterm birth: the ADORE randomized controlled trial protocol

BACKGROUND

Preterm birth contributes to 0.5 million deliveries in the United States (one of eight pregnancies) and poses a huge burden on public health with costs in the billions. Of particular concern is that the rate of earliest preterm birth (<34 weeks) (ePTB), which has decreased little since 1990 and has the greatest impact on the overall infant mortality, resulting in the greatest cost to society. Docosahexaenoic acid (DHA) supplementation provides a potential high yield, low risk strategy to reduce early preterm delivery in the US by up to 75%. We propose a Phase III Clinical Trial (randomized to low or high dose DHA, double-blinded) to examine the efficacy and safety of high dose DHA supplementation to reduce ePTB. We also plan for a secondary pregnancy efficacy analysis to determine if there is a subset of pregnancies most likely to benefit from DHA supplementation.

METHODS

Between 900 and 1200 pregnant women who are ≥ 18 years old and between 12 and 20 weeks gestation will be recruited from three trial experienced academic medical institutions. Participants will be randomly assigned to two daily capsules of algal oil (totaling 800 mg DHA) or soybean and corn oil (0 mg DHA). Both groups will receive a commercially available prenatal supplement containing 200 mg DHA. Therefore, the experimental group will receive 1000 mg DHA/d and the control group 200 mg DHA/d. We will then employ a novel Bayesian response adaptive randomization design that assigns more subjects to the "winning" group and potentially allows for substantially smaller sample size while providing a stronger conclusion regarding the most effective group. The study has an overall Type I error rate of 5% and a power of 90%. Participants are followed throughout pregnancy and delivery for safety and delivery outcomes.

DISCUSSION

We hypothesize that DHA will decrease the frequency of ePTB <34 weeks. Reducing ePTB is clinically important as these earliest preterm deliveries carry the highest risk of neonatal morbidity, as well as contribute significant stress for families and post a large societal burden.

TRIAL REGISTRATION

This trial was registered with ClinicalTrials.gov (identifier: NCT02626299 ) on December 8, 2015. Additional summary details may be found in Table 1.

Maternal intake of seafood and supplementary long chain n-3 poly-unsaturated fatty acids and preterm delivery

BACKGROUND

Preterm delivery increases the risk of neonatal morbidity and mortality. Studies suggest that maternal diet may affect the prevalence of preterm delivery. The aim of this study was to assess whether maternal intakes of seafood and marine long chain n-3 polyunsaturated fatty acids (LCn-3PUFA) from supplements were associated with preterm delivery.

METHODS

The study population included 67,007 women from the Norwegian Mother and Child Cohort Study. Maternal food and supplement intakes were assessed by a validated self-reported food frequency questionnaire in mid-pregnancy. Information about gestational duration was obtained from the Medical Birth Registry of Norway. We used Cox regression to estimate hazard ratios (HR) with 95% confidence intervals (CI) for associations between total seafood, lean fish, fatty fish, and LCn-3PUFA intakes and preterm delivery. Preterm was defined as any onset of delivery before gestational week 37, and as spontaneous or iatrogenic deliveries and as preterm delivery at early, moderate, and late preterm gestations.

RESULTS

Lean fish constituted 56%, fatty fish 34% and shellfish 10% of seafood intake. Any intake of seafood above no/rare intake (>5 g/d) was associated with lower prevalence of preterm delivery. Adjusted HRs were 0.76 (CI: 0.66, 0.88) for 1-2 servings/week (20-40 g/d), 0.72 (CI: 0.62, 0.83) for 2-3 servings/week (40-60 g/d), and 0.72 (CI: 0.61, 0.85) for ≥3 servings/week (>60 g/d), p-trend <0.001. The association was seen for lean fish (p-trend: 0.005) but not for fatty fish (p-trend: 0.411). The intake of supplementary LCn-3PUFA was associated only with lower prevalence of early preterm delivery (before 32 gestational weeks), while increasing intake of LCn-3PUFA from food was associated with lower prevalence of overall preterm delivery (p-trend: 0.002). Any seafood intake above no/rare was associated with lower prevalence of both spontaneous and iatrogenic preterm delivery, and with lower prevalence of late preterm delivery.

CONCLUSIONS

Any intake of seafood above no/rare consumption was associated with lower prevalence of preterm delivery. The association was stronger for lean than for fatty fish. Intake of supplementary LCn-3PUFA was associated only with early preterm delivery. The findings corroborate the current advice to include fish and seafood as part of a balanced diet during pregnancy.

Pregnancy and Infants' Outcome: Nutritional and Metabolic Implications

Pregnancy is a complex period of human growth, development, and imprinting. Nutrition and metabolism play a crucial role for the health and well-being of both mother and fetus, as well as for the long-term health of the offspring. Nevertheless, several biological and physiological mechanisms related to nutritive requirements together with their transfer and utilization across the placenta are still poorly understood. In February 2009, the Child Health Foundation invited leading experts of this field to a workshop to critically review and discuss current knowledge, with the aim to highlight priorities for future research. This paper summarizes our main conclusions with regards to maternal preconceptional body mass index, gestational weight gain, placental and fetal requirements in relation to adverse pregnancy and long-term outcomes of the fetus (nutritional programming). We conclude that there is an urgent need to develop further human investigations aimed at better understanding of the basis of biochemical mechanisms and pathophysiological events related to maternal-fetal nutrition and offspring health. An improved knowledge would help to optimize nutritional recommendations for pregnancy.

Periconceptional seafood intake and pregnancy complications

OBJECTIVE

To investigate associations of maternal periconceptional shellfish, lean fish and fatty fish intake with risk of pregnancy complications.

DESIGN

In this prospective cohort study, we collected information on intake of seafood subtypes using FFQ. We categorized seafood intake into frequencies of 1 servings/week. We ascertained gestational hypertension, pre-eclampsia, gestational diabetes and preterm birth diagnoses from medical records. Using generalized linear models with a log link, the Poisson family and robust standard errors, we estimated risk ratios and 95 % confidence intervals across seafood intake categories.

SETTING

The Omega study, a study of risk factors for pregnancy complications among women recruited from prenatal clinics in Washington State, USA, 1996-2008.

SUBJECTS

The current study included 3279 participants from the Omega study.

RESULTS

Median (interquartile range) shellfish, lean fish and fatty fish intake was 0·3 (0-0·9), 0·5 (0-1·0) and 0·5 (0·1-1·0) servings/week, respectively. Lean fish intake of >1 servings/week (v. <0·2 servings/month) was associated with a 1·55-fold higher risk of preterm birth (95 % CI 1·04, 2·30) and was not associated with the other pregnancy complications. Higher intake of seafood (total or other subtypes) was not associated with pregnancy complications (separately or combined).

CONCLUSIONS

Higher intake of lean fish, but not fatty fish or shellfish, was associated with a higher risk of preterm birth; these findings may have significance for preterm birth prevention. Studies of mechanisms and potential contributing factors (including seafood preparation and nutrient/contaminant content) are warranted.

Periconceptional Seafood Intake and Fetal Growth

BACKGROUND

Previous reports of associations of maternal seafood intake with fetal growth were inconsistent. Further, little is known whether associations differ across seafood subtypes or fetal growth indices.

METHODS

Among 3141 participants of the Omega study, a pregnancy cohort study, we investigated associations of periconceptional shell, lean, and fatty fish intake with fetal growth indices. We categorised food frequency questionnaire reported seafood intake into frequencies of: <0.2 servings/month, 0.2 servings/month -<0.5 servings/week, 0.5-1 servings/week, and >1 servings/week. We abstracted birthweight, birth length, and head circumference from medical records. Using generalised linear models with a log link, the Poisson family, and robust standard errors, we estimated relative risks and 95% confidence intervals (CI) for low birthweight (LBW, <2500 g) and linear regression models to estimate mean differences for continuous fetal growth indices across seafood intake categories.

RESULTS

Medians (interquartile range) of shell, lean, and fatty fish intake were 0.3 (0-0.9), 0.5 (0-1.0), and 0.5 (0.1-1.0) servings/week, respectively. Lean fish intake of >1 servings/week (vs. <0.2 servings/month) was associated with a 2.2-fold higher risk of LBW (95% CI 1.2, 4.1). Shellfish intake of >1 servings/week (vs. <0.2 servings/month) was associated with a 0.6 kg/m(3) higher mean ponderal index (95% CI 0.0, 1.2 kg/m(3) ). There was no evidence for associations of total seafood or seafood subtype intake with other fetal growth indices.

CONCLUSIONS

Higher intakes of lean fish and shellfish were associated with a higher risk of LBW and higher mean ponderal index, respectively. Findings highlight the importance of considerations of seafood subtype in similar investigations.

The Effect of Omega-3 Docosahexaenoic Acid Supplementation on Gestational Length: Randomized Trial of Supplementation Compared to Nutrition Education for Increasing n-3 Intake from Foods

OBJECTIVE

DHA supplementation was compared to nutrition education to increase DHA consumption from fish and DHA fortified foods.

DESIGN

This two-part intervention included a randomized double-blind placebo controlled DHA supplementation arm and a nutrition education arm designed to increase intake of DHA from dietary sources by 300 mg per day.

SETTING

Denver Health Hospitals and Clinics, Denver, Colorado, USA.

POPULATION

871 pregnant women aged 18-40 were recruited between 16 and 20 weeks of gestation of whom 564 completed the study and complete delivery data was available in 505 women and infants.

METHODS

Subjects received either 300 or 600 mg DHA or olive oil placebo or nutrition education.

MAIN OUTCOME VARIABLE

Gestational length.

RESULTS

Gestational length was significantly increased by 4.0-4.5 days in women supplemented with 600 mg DHA per day or provided with nutrition education. Each 1% increase in RBC DHA at delivery was associated with a 1.6-day increase in gestational length. No significant effects on birth weight, birth length, or head circumference were demonstrated. The rate of early preterm birth (1.7%) in those supplemented with DHA (combined 300 and 600 mg/day) was significantly lower than in controls.

CONCLUSION

Nutrition education or supplementation with DHA can be effective in increasing gestational length.

Efficacy of docosahexaenoic acid-enriched formula to enhance maternal and fetal blood docosahexaenoic acid levels: Randomized double-blinded placebo-controlled trial of pregnant women with gestational diabetes mellitus

BACKGROUND & AIMS

Gestational diabetes mellitus (GDM) compromises the level of docosahexaenoic acid (DHA) in phospholipids of maternal and fetal red blood cells and fetal plasma. This is of some concern because of the importance of DHA for fetal neuro-visual development. We have investigated whether this abnormality could be rectified by supplementation with DHA-enriched formula.

METHODS

Women with GDM (n = 138) recruited from Newham University Hospital, London received two capsules of DHA-enriched formula (active-group) or high oleic acid sunflower seed oil (placebo-group) from diagnosis until delivery. Maternal (baseline and delivery) and fetal (cord blood) red blood cell and plasma phospholipid fatty acid composition, and neonatal anthropometry were assessed.

RESULTS

One hundred and fourteen women (58 active, 56 placebo) completed the trial. The active-group compared with the placebo-group had significantly enhanced level of DHA in plasma phosphatidylcholine (4.5% vs 3.8%, P = 0.011), red blood cell phosphatidylcholine (2.7% vs 2.2%, P = 0.022) and phosphatidylethoanolamine (9.5% vs 7.6%, P = 0.002). There was no difference in cord plasma and red blood cell phospholipid DHA between the two groups. The neonates of the two groups of women had comparable anthropometric measurements at birth.

CONCLUSION

Daily supplementation of 600 mg DHA enhances maternal but not fetal DHA status in pregnancy complicated by GDM. The inefficacy of the supplement to improve fetal status suggests that the transfer of DHA across the placenta maybe impaired in women with the condition. Regardless of the mechanisms responsible for the impairment of the transfer, the finding has implications for the management of neonates of women with GDM because they are born with a reduced level of DHA and the condition is thought to be associated with a risk of neuro-developmental deficits. We suggest that babies of women with GDM, particularly those not suckling, similar to the babies born prematurely require formula milk fortified with a higher level of DHA.

Lower inter-partum interval and unhealthy life-style factors are inversely associated with n-3 essential fatty acids changes during pregnancy: a prospective cohort with Brazilian women

OBJECTIVE

To analyze serum fatty acids concentrations during healthy pregnancy and evaluate whether socioeconomic, demographic, obstetric, nutritional, anthropometric and lifestyle factors are associated with their longitudinal changes.

STUDY DESIGN

A prospective cohort of 225 pregnant women was followed in the 5th-13th, 20th-26th and 30th-36th weeks of gestation. Serum samples were collected in each trimester of pregnancy and analyzed to determine the fatty acids composition using a high-throughput robotic direct methylation method coupled with fast gas-liquid chromatography. The independent variables comprised the subjects' socioeconomic and demographic status, obstetric history, early pregnancy body mass index (BMI), dietary and lifestyle parameters. Analyses were performed using linear mixed-effects models.

RESULTS

The overall absolute concentrations of fatty acids increased from the 1st to the 2nd trimester and slightly increased from the 2nd to the 3rd trimester. Early pregnancy BMI, inter-partum interval and weekly fish intake were the factors associated with changes in eicosapentaenoic + docosahexaenoic acids (EPA+DHA) and total n-3 polyunsaturated fatty acids (PUFAs). Early pregnancy BMI, age and monthly per-capita income were inversely associated with the changes in the n-6/n-3 ratio. Alcohol consumption was positively associated with the n-6/n-3 ratio.

CONCLUSION

Early pregnancy BMI was positively associated with EPA+DHA and total n-3 PUFAs, while presenting a reduced weekly fish intake and a lower inter-partum interval were associated with lower levels of n-3 PUFAs. A lower per-capita family income and a drinking habit were factors that were positively associated with a higher n-6/n-3 ratio.

A randomized longitudinal dietary intervention study during pregnancy: effects on fish intake, phospholipids, and body composition

Background

Fish and meat intake may affect gestational weight gain, body composition and serum fatty acids. We aimed to determine whether a longitudinal dietary intervention during pregnancy could increase fish intake, affect serum phospholipid fatty acids, gestational weight gain and body composition changes during pregnancy in women of normal weight participating in the Pregnancy Obesity Nutrition and Child Health study. A second aim was to study possible effects in early pregnancy of fish intake and meat intake, respectively, on serum phospholipid fatty acids, gestational weight gain, and body composition changes during pregnancy.

Methods

In this prospective, randomized controlled study, women were allocated to a control group or to a dietary counseling group that focused on increasing fish intake. Fat mass and fat-free mass were measured by air-displacement plethysmography. Reported intake of fish and meat was collected from a baseline population and from a subgroup of women who participated in each trimester of their pregnancies. Serum levels of phospholipid arachidonic acid (s-ARA), eicosapentaenoic acid (s-EPA), and docosahexaenoic acid (s-DHA) were measured during each trimester.

Results

Weekly fish intake increased only in the intervention group (n = 18) from the first to the second trimester (median difference 113 g, p = 0.03) and from the first to the third trimester (median difference 75 g, p = 0.01). In the first trimester, fish intake correlated with s-EPA (r = 0.36, p = 0.002, n = 69) and s-DHA (r = 0.34, p = 0.005, n = 69), and meat intake correlated with s-ARA (r = 0.28, p = 0.02, n = 69). Fat-free mass gain correlated with reported meat intake in the first trimester (r = 0.39, p = 0.01, n = 45).

Conclusions

Dietary counseling throughout pregnancy could help women increase their fish intake. Intake of meat in early pregnancy may increase the gain in fat-free mass during pregnancy.

Effect of docosahexaenoic acid-enriched fish oil supplementation in pregnant women with Type 2 diabetes on membrane fatty acids and fetal body composition--double-blinded randomized placebo-controlled trial

AIMS

To test if docosahexaenoic acid-enriched fish oil supplementation rectifies red cell membrane lipid anomaly in pregnant women with Type 2 diabetes and their neonates, and alters fetal body composition.

METHODS

Women with Type 2 diabetes (n = 88; 41 fish oil, 47 placebo) and healthy women (n = 85; 45 fish oil, 40 placebo) were supplemented from the first trimester until delivery. Blood fatty acid composition, fetal biometric and neonatal anthropometric measurements were assessed.

RESULTS

A total of 117 women completed the trial. The women with Type 2 diabetes who took fish oil compared with those who received placebo had higher percentage of docosahexaenoic acid in red cell phosphatidylethanolamine in the third trimester (12.0% vs. 8.9%, P = 0.000) and at delivery (10.7% vs. 7.4%, P = 0.001). Similarly, the neonates of the women with Type 2 diabetes supplemented with the fish oil had increased docosahexaenoic acid in the red cell phosphatidylethanolamine (9.2% vs. 7.7%, P = 0.027) and plasma phosphatidylcholine (6.1% vs. 4.7%, P = 0.020). Docosahexaenoic acid-rich fish oil had no effect on the body composition of the fetus and neonates of the women with Type 2 diabetes.

CONCLUSIONS

A daily dose of 600 mg of docosahexaenoic acid was effective in ameliorating red cell membrane docosahexaenoic acid anomaly in pregnant women with Type 2 diabetes and neonates, and in preventing the decline of maternal docosahexaenoic acid during pregnancy. We suggest that the provision of docosahexaenoic acid supplement should be integrated in the antenatal care of pregnant women with Type 2 diabetes.

Change in mononuclear leukocyte responsiveness in midpregnancy and subsequent preterm birth

OBJECTIVE

To estimate the associations of change in immune response with preterm delivery, omega-3 supplementation, and fish diet.

METHODS

This was an ancillary study to a randomized trial of omega-3 fatty acid supplementation for the prevention of recurrent preterm birth. In vitro maternal peripheral blood mononuclear leukocyte production of the anti-inflammatory cytokine, interleukin-10, and the proinflammatory cytokine, tumor necrosis factor-α, in response to stimulation with lipopolysaccharide, was measured at 16-22 weeks of gestation (baseline) and again at 25-28 weeks of gestation (follow-up) among women with prior spontaneous preterm birth. Changes in concentrations from baseline to follow-up ([INCREMENT]) were compared separately among groups defined by gestational age category at delivery, fish diet history, and omega-3 compared with placebo treatment assignment with Kruskal-Wallis tests.

RESULTS

Interleukin-10 [INCREMENT] differed by gestational age category among 292 women with paired assays. Concentrations increased less in women delivering between 35 and 36 6/7 weeks of gestation (48.9 pg/mL) compared with women delivering at term (159.3 pg/mL) and decreased by 65.2 pg/mL in women delivering before 35 weeks of gestation (P=.01). Tumor necrosis factor-α Δ also differed by gestational age category among 319 women, but the pattern was inconsistent. Those delivering between 35 and 36 6/7 weeks of gestation exhibited decreased concentrations of tumor necrosis factor-α at follow-up compared with baseline (-356.0 pg/mL); concentrations increased among women delivering before 35 weeks of gestation and those delivering at term, 132.1 and 86.9 pg/mL (P=.03). Interleukin-10 Δ and tumor necrosis factor-α Δ were unaffected by either omega-3 supplementation or fish diet.

CONCLUSION

Recurrent preterm birth was associated with decreased peripheral blood mononuclear leukocyte production of interleukin-10 in response to a stimulus during the second trimester.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135902.

LEVEL OF EVIDENCE

II.

Vitamin D status and recurrent preterm birth: a nested case-control study in high-risk women

OBJECTIVE

To determine whether vitamin D status is associated with recurrent preterm birth, and any interactions between vitamin D levels and fish consumption.

DESIGN

A nested case-control study, using data from a randomised trial of omega-3 fatty acid supplementation to prevent recurrent preterm birth.

SETTING

Fourteen academic health centres in the USA.

POPULATION

Women with prior spontaneous preterm birth.

METHODS

In 131 cases (preterm delivery at <35 weeks of gestation) and 134 term controls, we measured serum 25-hydroxyvitamin D [25(OH)D] concentrations by liquid chromatography-tandem mass spectrometry (LC-MS) from samples collected at baseline (16-22 weeks of gestation). Logistic regression models controlled for study centre, maternal age, race/ethnicity, number of prior preterm deliveries, smoking status, body mass index, and treatment.

MAIN OUTCOME MEASURES

Recurrent preterm birth at <37 and <32 weeks of gestation.

RESULTS

The median mid-gestation serum 25(OH)D concentration was 67 nmol/l, and 27% had concentrations of <50 nmol/l. Serum 25(OH)D concentration was not significantly associated with preterm birth (OR 1.33; 95% CI 0.48-3.70 for lowest versus highest quartiles). Likewise, comparing women with 25(OH)D concentrations of 50 nmol/l, or higher, with those with <50 nmol/l generated an odds ratio of 0.80 (95% CI 0.38-1.69). Contrary to our expectation, a negative correlation was observed between fish consumption and serum 25(OH)D concentration (-0.18, P < 0.01).

CONCLUSIONS

In a cohort of women with a prior preterm birth, vitamin D status at mid-pregnancy was not associated with recurrent preterm birth.

Association between intake of artificially sweetened and sugar-sweetened beverages and preterm delivery: a large prospective cohort study

BACKGROUND

Artificially sweetened (AS) and sugar-sweetened (SS) beverages are commonly consumed during pregnancy. A recent Danish study reported that the daily intake of an AS beverage was associated with an increased risk of preterm delivery.

OBJECTIVE

We examined the intake of AS and SS beverages in pregnant women to replicate the Danish study and observe whether AS intake is indeed associated with preterm delivery.

DESIGN

This was a prospective study of 60,761 pregnant women in the Norwegian Mother and Child Cohort Study. Intakes of carbonated and noncarbonated AS and SS beverages and use of artificial sweeteners in hot drinks were assessed by a self-reported food-frequency questionnaire in midpregnancy. Preterm delivery was the primary outcome, and data were obtained from the Norwegian Medical Birth Registry.

RESULTS

Intakes of both AS and SS beverages increased with increasing BMI and energy intake and were higher in women with less education, in daily smokers, and in single women. A high intake of AS beverages was associated with preterm delivery; the adjusted OR for those drinking >1 serving/d was 1.11 (95% CI: 1.00, 1.24). Drinking >1 serving of SS beverages per day was also associated with an increased risk of preterm delivery (adjusted OR: 1.25; 95% CI: 1.08, 1.45). The trend tests were positive for both beverage types.

CONCLUSION

This study suggests that a high intake of both AS and SS beverages is associated with an increased risk of preterm delivery.

Maternal dietary DHA supplementation to improve inflammatory outcomes in the preterm infant

Dietary DHA (22:6n-3) is a long-chain PUFA that has provocative effects on inflammatory signal events that could potentially affect preterm infant health. It is well known that the essential fatty acid of the (n-3) series; α-linolenic acid (18:3n:3) can be desaturated and elongated in the liver endoplasmic reticulum and peroxisome to produce the 22-carbon DHA. Nevertheless, concern exists as to the efficiency of this mechanism in providing the preterm infant with adequate DHA. Activity of the δ-6-desaturase and the δ-5-desaturase necessary for DHA synthesis is decreased by protein deprivation. The combined effects of suboptimal intake of both DHA and protein in the preterm infants could have substantial clinical consequences.