Dietary supplementation with primrose oil or fish oil does not change urinary excretion of prostacyclin and thromboxane metabolites in pre-eclamptic women

The effect of Oenothera biennis (Evening primrose) oil on inflammatory diseases: a systematic review of clinical trials

BACKGROUND

Evening primrose oil (EPO), extracted from the seeds of Oenothera biennis, has gained attention for its therapeutic effects in various inflammatory conditions.

METHOD

We performed a systematic search in multiple databases and defined the inclusion criteria based on the following PICOs: P: Patients with a form of inflammatory condition, I: EPO, C: Placebo or other therapeutic interventions, O: changes in inflammatory markers or patients' symptoms; S: randomized controlled trials. The quality of the RCTs was evaluated using Cochrane's RoB tool.

RESULTS

Several conditions were investigated in the literature. In rheumatoid arthritis, mixed results were observed, with some studies reporting significant improvements in symptoms while others found no significant impact. EPO showed some results in diabetes mellitus, atopic eczema, menopausal hot flashes, and mastalgia. However, it did not demonstrate effectiveness in chronic hand dermatitis, tardive dyskinesia, psoriatic arthritis, cystic fibrosis, hepatitis B, premenstrual syndrome, contact lens-associated dry eyes, acne vulgaris, breast cyst, pre-eclampsia, psoriasis, or primary Sjogren's syndrome. Some results were reported from multiple sclerosis after EPO consumption. Studies in healthy volunteers indicated no significant effect of EPO on epidermal atrophy, nevertheless, positive effects on the skin regarding hydration and barrier function were achieved.

CONCLUSION

Some evidence regarding the potential benefits of EPO in inflammatory disorders were reported however caution is due to the limitations of the current survey. Overall, contemporary literature is highly heterogeneous and fails to provide strong recommendations regarding the efficacy of EPO on inflammatory disorders. Further high-quality studies are necessitated to draw more definite conclusions and establish O. biennis oil effectiveness as an assuring treatment option in alleviating inflammatory conditions.

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.

Omega-3 supplementation during pregnancy to prevent recurrent intrauterine growth restriction: systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the efficacy of omega-3 supplementation during pregnancy in preventing intrauterine growth restriction (IUGR) in women with apparently uncomplicated singleton pregnancy and previous IUGR pregnancy.

METHODS

For this systematic review, the research protocol was designed a priori. Searches were performed in electronic databases for studies published from inception of each database to December 2014. A combination of search terms was used including 'fish oil', 'long chain polyunsaturated fatty acids', 'intrauterine growth restriction', 'small for gestational age' and 'omega-3'. We included all randomized controlled trials (RCTs) of women with an uncomplicated singleton pregnancy and a prior IUGR pregnancy who were randomized to receive prophylactic treatment with omega-3 supplementation or either placebo or no treatment (control). Trials that included women with multiple gestations and those with only biochemical outcomes available were excluded. Pooled estimates were based on relative risk (RR) with 95% CI. Primary outcome was incidence of IUGR as defined in the RCTs.

RESULTS

Three RCTs including 575 women with uncomplicated singleton pregnancy with prior IUGR were analyzed. Women who received omega-3 supplementation during pregnancy had the same incidence of IUGR, defined as estimated fetal weight < 5(th) or < 3(rd) centiles, as had controls (22.8% vs 20.2%, respectively; RR, 1.13 (95% CI, 0.83-1.54)). Compared to controls, women who received omega-3 supplementation delivered later (mean difference, 1.4 (95% CI, 1.28-1.63) weeks), had a longer latency (mean difference, 2 (95% CI, 1.73-2.08) weeks), had a similar incidence of perinatal death (2.1% vs 3.3%, respectively; RR, 0.60 (95% CI, 0.15-2.42)) and similar birth weight (mean difference, 50 g (95% CI, -26 to 246 g)).

CONCLUSIONS

Omega-3 supplementation during pregnancy does not prevent recurrence of IUGR in women with uncomplicated singleton pregnancy and a previous IUGR pregnancy.

Omega-3 long-chain polyunsaturated fatty acids and fish oil supplementation during pregnancy: which evidence?

OBJECTIVE

The aim of this study was to provide evidence-based recommendations for omega-3 supplementation during pregnancy through a systematic review of level-1 data published on this topic.

METHODS

We reviewed all randomized-controlled trials (RCTs) including women who were randomized to treatment with either omega-3 supplementation or control (placebo or no treatment) during pregnancy and analyzed all the outcomes reported in the trials, separately. We planned to evaluate the effect of omega-3 on: preterm birth (PTB); pre-eclampsia (PE) and intrauterine growth restriction (IUGR); gestational diabetes; perinatal mortality; small for gestational age (SGA) and birth weight; infant eye and brain development; and postpartum depression.

RESULTS

We identified 34 RCTs including 14 106 singletons and 2578 twins. These level-1 data showed that omega-3 was not associated with prevention of PTB, PE, IUGR, gestational diabetes, SGA, post-partum depression or better children development. Data about birth weight, perinatal mortality and childhood cognitive outcome were limited. Women with gestational diabetes who received omega-3 had significantly lower serum C-reactive protein concentrations, low incidence of hyperbilirubinemia in newborns and decreased newborns' hospitalization rate.

CONCLUSIONS

There was not enough evidence to support the routine use of omega-3 supplementation during pregnancy. Given the 73% significant decrease in perinatal death in the singleton gestations who started omega-3 supplementation ≤ 20 weeks, further research is needed. Large RCTs in multiple gestations and longer follow-up are also required.

Omega-3 supplementation to prevent recurrent preterm birth: a systematic review and metaanalysis of randomized controlled trials

The purpose of this study was to evaluate the efficacy of omega-3 supplementation for the prevention of recurrent preterm birth (PTB) in asymptomatic singleton gestations with previous PTB. We searched fish oil, long chain polyunsaturated fatty acids, pregnancy, and omega-3 in MEDLINE, OVID, Scopus, ClinicalTrials.gov, the PROSPERO International Prospective Register of Systematic Reviews, EMBASE, and the Cochrane Central Register of Controlled Trials from inception of each database to December 2014 with no limit for language. In addition the reference lists of all identified articles were examined to identify studies that were not captured by electronic searches. We performed a metaanalysis of randomized controlled trials of asymptomatic singleton gestations with previous PTB who were assigned randomly to prophylactic omega-3 supplementation vs control (either placebo or no treatment). The primary outcome was predefined as PTB at <37 weeks of gestation. The pooled results were reported as relative risk (RR) with 95% confidence interval (95% CI). The protocol of this review was registered with PROSPERO (registration number: CRD42015016371). Two randomized controlled trials that included 1080 women were analyzed. The mean gestational age at randomization was approximately 134 days in both groups (mean difference, 0.01 days; 95% CI, -0.13 to 0.14). Women who received omega-3 had similar rates of PTB at <37 weeks of gestation (34.5% vs 39.8%; RR, 0.81; 95% CI, 0.59-1.12) and PTB at <34 weeks of gestation (12.0% vs 15.4%; RR, 0.62; 95% CI, 0.26-1.46) compared with control subjects. The omega-3 groups had a statistically significantly longer latency (mean difference, 2.10 days; 95% CI, 1.98-2.22) and higher birthweight (mean difference, 102.52 g; 95% CI, 20.09-184.95) compared with control subjects; the other secondary outcomes (which included gestational age at delivery, spontaneous PTB at <37 and 34 weeks of gestation, admission to the intensive care unit, intraventricular hemorrhage, necrotizing enterocolitis, sepsis, and perinatal death) were similar. Omega-3 supplementation during pregnancy does not prevent recurrent PTB in asymptomatic singleton gestations with previous PTB. The benefits in longer latency and higher birth weight may deserve further study.

Omega-3 long chain polyunsaturated fatty acids to prevent preterm birth: a systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of omega-3 in reducing the incidence of preterm birth.

DATA SOURCES

Searches were performed in MEDLINE, OVID, Scopus, ClinicalTrials.gov, the PROSPERO International Prospective Register of Systematic Reviews, EMBASE, and the Cochrane Central Register of Controlled Trials with the use of a combination of keywords related to "fish oil," "pregnancy," and "omega-3."

METHODS OF STUDY SELECTION

We included all randomized controlled trials of asymptomatic women with singleton gestations who were randomized to prophylactic treatment with either omega-3 supplementation or control (either placebo or no treatment). Exclusion criteria included trials in women with multiple gestations, intrauterine growth restriction, gestational hypertension or preeclampsia at randomization, prior preterm birth, and trials with polyunsaturated fatty acids as control.

TABULATION, INTEGRATION, AND RESULTS

Nine randomized trials including 3,854 eligible women were identified. Women who received omega-3 had a similar rate of preterm birth before 37 weeks of gestation compared with women in the control group (7.7% compared with 9.1%, respectively; relative risk 0.90, 95% confidence interval [CI] 0.72-1.11). There were no significant differences in birth weight, neonatal intensive care unit admission, necrotizing enterocolitis, sepsis, or perinatal death in the omega-3 compared with control groups, respectively. There were no significant differences in the subgroup analyses, except for the rate of perinatal death, which was lower (0.3% compared with 1.2%; relative risk 0.27, 95% CI 0.09-0.80) in the women who received omega-3 before 21 weeks of gestation and in trials with low risk of bias (0.3% compared with 1.0%; relative risk 0.28, 95% CI 0.09-0.89) compared with women in the control group. However, in no randomized controlled trial was perinatal death the primary outcome.

CONCLUSION

Omega-3 supplementation during pregnancy does not reduce the incidence of preterm birth or improve neonatal outcome.

Effect of supplementation of women in high-risk pregnancies with long-chain polyunsaturated fatty acids on pregnancy outcomes and growth measures at birth: a meta-analysis of randomized controlled trials

It is hypothesized that the intake of long-chain PUFA (LC-PUFA) throughout pregnancy could protect against pre-eclampsia, pregnancy-induced hypertension or intra-uterine growth retardation, and is essential for optimal neural development. The objective of the present study was to systematically evaluate the effect of LC-PUFA supplementation of high-risk pregnant women's diets on pregnancy outcomes and growth measures at birth. We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library through March 2006 and references in reviewed articles for randomized controlled trials (RCT) comparing LC-PUFA supplementation with placebo or no supplementation in women with high-risk pregnancies. We found no evidence that supplementation influenced the duration of pregnancy or the percentage of preterm deliveries < 37 weeks of gestation. However, compared with controls, supplementation was associated with a significantly lower rate of early preterm delivery ( < 34 weeks of gestation) (two RCT; n 291; relative risk 0.39 (95 % CI 0.18, 0.84)). There was no significant difference in the infant birth weight, the rate of low birth weight ( < 2500 g or < 10th percentile) and the recurrence of intra-uterine growth retardation. Other pregnancy outcomes (for example, the rate of pregnancy-induced hypertension, the rate of pre-eclampsia and the rate of Caesarean section) were also similar in both groups. In conclusion, the present data suggest that supplementation with n-3 LC-PUFA in women with high-risk pregnancies reduced the risk of early preterm delivery in the fatty acid-supplemented group compared with the placebo group, while no other effects on pregnancy outcomes were detected.

Marine oil, and other prostaglandin precursor, supplementation for pregnancy uncomplicated by pre-eclampsia or intrauterine growth restriction

BACKGROUND

Population studies have shown that higher intakes of marine foods during pregnancy are associated with longer gestations, higher infant birthweights and a low incidence of pre-eclampsia. It is suggested that the fatty acids of marine foods may be the underlying cause of these associations.

OBJECTIVES

To estimate the effects of marine oil, and other prostaglandin precursor, supplementation during pregnancy on the risk of pre-eclampsia, preterm birth, low birthweight and small-for-gestational age.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (December 2005), The Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 2) and MEDLINE (1966 to April 2005).

SELECTION CRITERIA

All randomised trials comparing oral marine oil, or other prostaglandin precursor, supplementation during pregnancy with either placebo or no treatment. Trials were excluded if their aim was to treat women with established pre-eclampsia or suspected intrauterine growth restriction.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, data extraction and trial quality.

MAIN RESULTS

Six trials, involving 2783 women, are included in this review. Three of these were rated as high quality, including the largest trial with 1477 women. Women allocated a marine oil supplement had a mean gestation that was 2.6 days longer than women allocated to placebo or no treatment (weighted mean difference (WMD), 2.55 days, 95% confidence interval (CI) 1.03 to 4.07 days; 3 trials, 1621 women). This was not reflected in a clear difference between the two groups in the relative risk (RR) of birth before 37 completed weeks, although women allocated marine oil did have a lower risk of giving birth before 34 completed weeks' gestation (RR 0.69, 95% CI 0.49 to 0.99; 2 trials, 860 women). Birthweight was slightly greater in infants born to women in the marine oil group compared with control (WMD 47 g, 95% CI 1 g to 93 g; 3 trials, 2440 women). However, there were no overall differences between the groups in the proportion of low birthweight or small-for-gestational age babies. There was no clear difference in the relative risk of pre-eclampsia between the two groups.

AUTHORS' CONCLUSIONS

There is not enough evidence to support the routine use of marine oil, or other prostaglandin precursor, supplements during pregnancy to reduce the risk of pre-eclampsia, preterm birth, low birthweight or small-for-gestational age.

Preeclampsia and Eclampsia Revisited

Hypertensive disorders during pregnancy, which account for approximately 15% of pregnancy-related deaths, represent the second-leading cause of morbidity and mortality in the United States. New classifications recommended by the National Institutes of Health's Working Group on High Blood Pressure in Pregnancy have decreased the confusion often associated with these disorders. The cause of preeclampsia-eclampsia still remains elusive, but continued research has provided hope with regard to screening, improved diagnosis, and management. Risk factors that have recently gained attention include inherited thrombophilias, inherited metabolic disorders, and lipid disorders. Treatment and management of the hypertensive disorders of pregnancy have not changed substantially in the past 50 years. Prevention of preeclampsia-eclampsia has been unsuccessful, and recurrence risks remain high. Careful diagnosis, classification, and further investigation of the causes of hypertensive disorders in pregnancy are needed to achieve optimal management of affected women and their fetuses.

Preeclampsia. Part 1: clinical and pathophysiologic considerations

Preeclampsia-eclampsia is still one of the leading causes of maternal and fetal morbidity and mortality. Despite active research for many years, the etiology of this disorder exclusive to human pregnancy is an enigma. Recent evidence suggests there may be several underlying causes or predispositions leading to the signs of hypertension, proteinuria, and edema, findings that allow us to make the diagnosis of the "syndrome" of preeclampsia. Despite improved prenatal care, severe preeclampsia and eclampsia still occur. Although understanding of the pathophysiology of these disorders has improved, treatment has not changed significantly in over 50 years. Although postponement of delivery in selected women with severe preeclampsia improves fetal outcome to a degree, this is not done without risk to the mother. In the United States, magnesium sulfate and hydralazine are the most commonly used medications for seizure prophylaxis and hypertension in the intrapartum period. The search for the underlying cause of this disorder and for a clinical marker to predict those women who will develop preeclampsia-eclampsia is ongoing, with its prevention the ultimate goal. This review begins with the clinical and pathophysiologic aspects of preeclampsia-eclampsia (Part 1). In Part 2, the experimental observations, the search for predictive factors, and the genetics of this disorder will be reviewed.

Complexity and complicity in eclampsia: barriers or bridges?

The aetiology of pre-eclampsia-eclampsia remains largely unclarified, despite over 100 years of systematic study. The assumption that the triggering event is linear and amenable to reductionist techniques has characterized these efforts. The main purpose of this paper is to show that complexity and complicity characterize most pathophysiological processes in pre-eclampsia-eclampsia, a situation suggesting that similar mechanisms must exist at the origin of the disease. The unique configuration of the intervillous space and the intensity of energy transference through the fetomaternal interface offer many dysfunctional possibilities, even in clinically normal pregnancies. The most characteristic seem to be: the shedding and deportation of trophoblast, the fragmentation of villi, the escape of fetal blood, and events associated with trophoblast damage, degeneration and death. The pathogenic potential of these natural processes seems to depend on the association with amplifiers and permissive factors, which vary from person to person and from time to time. Thus, considering the convergence of multiple factors and the presence of nonlinearity in some of their interactions as a plausible working hypothesis, further exploration on this subject should adhere to the rules of this different reality. To find the best possible method of inquiry and to recognize its limitations will be the surest way to avoid failure.