Pregnant women with a low milk intake have an increased risk of developing preeclampsia

The association between dietary habits and self-care behavior of pregnant women with pregnancy complications

Pregnancy as a sensitive period has a critical effect on the mother and infant's life. It is well understood that dietary habits and mother awareness can improve health status and prevent pregnancy complications such as gestational diabetes, pre-eclampsia, and nausea and vomiting. The current study was conducted to investigate the association between dietary habits and self-care behaviors with pregnancy complications. This cross-sectional study was conducted across 300 pregnant women in their third trimester referred to healthcare centers and Yas hospital in Tehran, Iran. Dietary habits and self-care behaviors were assessed by valid and reliable questionnaires. Dietary intake and physical activity were evaluated using valid and reliable Food Frequency Questionnaires and Pregnancy Physical Activity questionnaires, respectively. Women with self-care behaviors had a lower rate of pre-eclampsia (P = 0.9). Regarding food habits, pregnant women who ate their meals faster had a non-significantly higher rate of gestational diabetes and pre-eclampsia. Pregnant women who consumed red meat on a daily frequency had a significantly higher rate of nausea and vomiting (OR 1.85; 95% CI 1.05-3.28, P = 0.03). Also, there was a significant positive association between the mother's pre-pregnancy BMI and gestational diabetes and pre-eclampsia [(OR 2.03; 95% CI 1.03-3.98, P = 0.03) and (OR 4.23; 95% CI 1.12-16.0, P = 0.03) respectively]. There was no significant association between pregnant women's dietary habits and GDM and pre-eclampsia. However, pregnant women with pre-pregnancy overweight and obesity had increased odds of gestational diabetes and pre-eclampsia significantly.

Determinants of pre-eclampsia among pregnant women attending antenatal care and delivery services at Bahir Dar public hospitals, northwest Ethiopia: A case-control study

Background and Aims

Pre-eclampsia (PE) is a pregnancy-related syndrome that occurs after 20 weeks of pregnancy. The current study was designed to evaluate the determinants of PE in pregnant women following antenatal and delivery services.

Methods

An institution-based case-control study was performed in governmental hospitals of Bahir Dar city. The data were collected using an interview-administered questionnaire and analyzed by SPSS version 20 software. Bivariate and multivariable logistic regression models were utilized for the analysis of variables. A p < 0.05 was used to declare the level of significance.

Results

In this study, the mean ages (in years) of cases and controls were 28.20 ± 5.66 and 27.52 ± 4.70, respectively. Factors such as: being primiparous (adjusted odds ratio [AOR]: 3.19 at 95% confidence interval [CI]: 1.71, 5.97), family history of hypertension (HTN) (AOR: 4.14 at 95% CI: 1.71, 10.05), previous history of PE (AOR: 7.97 at 95% CI: 2.42, 26.63), number of antenatal care (ANC) visits (AOR: 5.43 at 95% CI: 2.86, 10.33), not taking iron and folic acid supplement (AOR: 4.46 at 95% CI: 1.59, 12.48), body mass index ≥25 kg/m² (AOR: 3.47 at 95% CI: 1.78, 6.77), not consuming vegetables (AOR: 1.99 at 95% CI: 1.07, 3.69) and not consuming egg, milk and milk products (AOR: 3.00 at 95% CI: 1.47, 6.11) were the determinants of PE.

Conclusion

In this study, different determinants of PE were identified. Hence, special attention should be given for primiparous women, women having previous history of PE and family history of HTN. Moreover, nutritional counseling should be given for pregnant women during ANC visits. Besides, higher officials should design an appropriate strategy to increase the number of mothers to complete their ANC visits and to take iron and folic acid supplements. Furthermore, to verify the determinants of PE, community-based cohort studies are warranted.

Effects of Xenobiotic Compounds on Preeclampsia and Potential Mechanisms

Preeclampsia (PE) refers to a disease with new hypertension and albuminuria or other end-organ damage after 20 weeks of pregnancy. As a major complication of pregnancy, PE can increase the morbidity and mortality of pregnant women and fetuses and cause serious social burden. Recently, it has been found that exposure to xenobiotic compounds, especially endocrine disruptors in the environment, may contribute to the development of PE. However, the underlying mechanism is still unclear. It is generally believed that PE is related to placental dysplasia, spiral artery remodelling failure, oxidative stress, etc. Therefore, in order to better prevent the occurrence of PE and reduce the damage and impact on mother and fetus, this paper reviews the role and potential mechanism of PE induced by exogenous chemicals and provides an outlook on the environmental etiology of PE.

Occupational Risk Factors and Hypertensive Disorders in Pregnancy: A Systematic Review

Hypertensive disorders in pregnancy (HDP), including gestational hypertension (GH) and preeclampsia (PE), characterize a major cause of maternal and prenatal morbidity and mortality. In this systematic review, we tested the hypothesis that occupational factors would impact the risk for HDP in pregnant workers. MEDLINE, Scopus, and Web of Knowledge databases were searched for studies published between database inception and 1 April 2021. All observational studies enrolling > 10 pregnant workers and published in English were included. Un-experimental, non-occupational human studies were excluded. Evidence was synthesized according to the risk for HDP development in employed women, eventually exposed to chemical, physical, biological and organizational risk factors. The evidence quality was assessed through the Newcastle–Ottawa scale. Out of 745 records identified, 27 were eligible. No definite conclusions could be extrapolated for the majority of the examined risk factors, while more homogenous data supported positive associations between job-strain and HDP risk. Limitations due to the lack of suitable characterizations of workplace exposure (i.e., doses, length, co-exposures) and possible interplay with personal issues should be deeply addressed. This may be helpful to better assess occupational risks for pregnant women and plan adequate measures of control to protect their health and that of their children.

Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems

BACKGROUND

Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth. This is an update of a review last published in 2014.

OBJECTIVES

To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (18 September 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), including cluster-randomised trials, comparing high-dose calcium supplementation (at least 1 g daily of calcium) during pregnancy with placebo. For low-dose calcium we included quasi-randomised trials, trials without placebo, trials with cointerventions and dose comparison trials.

DATA COLLECTION AND ANALYSIS

Two researchers independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Two researchers assessed the evidence using the GRADE approach.

MAIN RESULTS

We included 27 studies (18,064 women). We assessed the included studies as being at low risk of bias, although bias was frequently difficult to assess due to poor reporting and inadequate information on methods.High-dose calcium supplementation (≥ 1 g/day) versus placeboFourteen studies examined this comparison, however one study contributed no data. The 13 studies contributed data from 15,730 women to our meta-analyses. The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: average RR 0.45, 95% CI 0.31 to 0.65; I² = 70%; low-quality evidence). This effect was clear for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) but not those with adequate calcium diets. The effect appeared to be greater for women at higher risk of pre-eclampsia, though this may be due to small-study effects (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42). These data should be interpreted with caution because of the possibility of small-study effects or publication bias. In the largest trial, the reduction in pre-eclampsia was modest (8%) and the CI included the possibility of no effect.The composite outcome maternal death or serious morbidity was reduced with calcium supplementation (four trials, 9732 women; RR 0.80, 95% CI 0.66 to 0.98). Maternal deaths were no different (one trial of 8312 women: one death in the calcium group versus six in the placebo group). There was an anomalous increase in the risk of HELLP syndrome in the calcium group (two trials, 12,901 women: RR 2.67, 95% CI 1.05 to 6.82, high-quality evidence), however, the absolute number of events was low (16 versus six).The average risk of preterm birth was reduced in the calcium supplementation group (11 trials, 15,275 women: RR 0.76, 95% CI 0.60 to 0.97; I² = 60%; low-quality evidence); this reduction was greatest amongst women at higher risk of developing pre-eclampsia (four trials, 568 women: average RR 0.45, 95% CI 0.24 to 0.83; I² = 60%). Again, these data should be interpreted with caution because of the possibility of small-study effects or publication bias. There was no clear effect on admission to neonatal intensive care. There was also no clear effect on the risk of stillbirth or infant death before discharge from hospital (11 trials, 15,665 babies: RR 0.90, 95% CI 0.74 to 1.09).One study showed a reduction in childhood systolic BP greater than 95th percentile among children exposed to calcium supplementation in utero (514 children: RR 0.59, 95% CI 0.39 to 0.91). In a subset of these children, dental caries at 12 years old was also reduced (195 children, RR 0.73, 95% CI 0.62 to 0.87).Low-dose calcium supplementation (< 1 g/day) versus placebo or no treatmentTwelve trials (2334 women) evaluated low-dose (usually 500 mg daily) supplementation with calcium alone (four trials) or in association with vitamin D (five trials), linoleic acid (two trials), or antioxidants (one trial). Most studies recruited women at high risk for pre-eclampsia, and were at high risk of bias, thus the results should be interpreted with caution. Supplementation with low doses of calcium reduced the risk of pre-eclampsia (nine trials, 2234 women: RR 0.38, 95% CI 0.28 to 0.52). There was also a reduction in high BP (five trials, 665 women: RR 0.53, 95% CI 0.38 to 0.74), admission to neonatal intensive care unit (one trial, 422 women, RR 0.44, 95% CI 0.20 to 0.99), but not preterm birth (six trials, 1290 women, average RR 0.83, 95% CI 0.34 to 2.03), or stillbirth or death before discharge (five trials, 1025 babies, RR 0.48, 95% CI 0.14 to 1.67).High-dose (=/> 1 g) versus low-dose (< 1 g) calcium supplementationWe included one trial with 262 women, the results of which should be interpreted with caution due to unclear risk of bias. Risk of pre-eclampsia appeared to be reduced in the high-dose group (RR 0.42, 95% CI 0.18 to 0.96). No other differences were found (preterm birth: RR 0.31, 95% CI 0.09 to 1.08; eclampsia: RR 0.32, 95% CI 0.07 to 1.53; stillbirth: RR 0.48, 95% CI 0.13 to 1.83).

AUTHORS' CONCLUSIONS

High-dose calcium supplementation (≥ 1 g/day) may reduce the risk of pre-eclampsia and preterm birth, particularly for women with low calcium diets (low-quality evidence). The treatment effect may be overestimated due to small-study effects or publication bias. It reduces the occurrence of the composite outcome 'maternal death or serious morbidity', but not stillbirth or neonatal high care admission. There was an increased risk of HELLP syndrome with calcium supplementation, which was small in absolute numbers.The limited evidence on low-dose calcium supplementation suggests a reduction in pre-eclampsia, hypertension and admission to neonatal high care, but needs to be confirmed by larger, high-quality trials.

Serum Calcium, Magnesium, Zinc and Copper Levels in Sudanese Women with Preeclampsia

Background

Although the exact pathophysiology of preeclampsia is not fully understood, several elemental micronutrient abnormalities have been suggested to play a contributory role in preeclampsia.

Aims

To investigate the levels of calcium, magnesium, zinc and copper in women with preeclampsia.

Subjects and Methods

A case—control study was conducted in Omdurman Maternity Hospital, Sudan, during the period of September through December 2014. The cases were women with preeclampsia while healthy pregnant women were the controls. The medical and obstetrics history was gathered using questionnaires. The serum levels of calcium, magnesium, zinc and copper were measured using atomic absorption spectrophotometer.

Results

There was no significant difference between the two groups in their age, gestational age, parity and body mass index. Zinc and copper levels were not significantly different between the two groups. In comparison with the controls, women with preeclampsia had a significantly lower median (inter-quartile) serum calcium [7.6 (4.0─9.6) vs. 8.1 (10.6─14.2), mg/dl, P = 0.032] and higher levels of magnesium [1.9 (1.4─2.5) vs. 1.4 (1.0─1.9) mg/dl; P = 0.003]. In binary logistic regression, lower calcium (OR = 0.73, 95% CI = 0.56 ─ 0.95, P = 0.021) and higher magnesium (OR = 5.724, 95% CI = 1.23 ─ 26.50, P = 0.026) levels were associated with preeclampsia. There were no significant correlations between levels of hemoglobin and these trace elements.

Conclusion

The current study showed significant associations between preeclampsia and serum levels of calcium and magnesium.

The association between dietary factors and gestational hypertension and pre-eclampsia: a systematic review and meta-analysis of observational studies

BACKGROUND

Dietary factors have been suggested to play a role in the prevention of hypertensive disorders of pregnancy (HDP), including gestational hypertension and pre-eclampsia, but inconsistent findings have been reported. A systematic review and meta-analyses were performed to synthesize evidence from observational studies of reproductive-aged women on the association between dietary factors and HDP.

METHODS

MEDLINE and EMBASE were searched to identify studies published until the end of May 2014. Studies were included if they were observational studies of reproductive-age women and reported results on dietary factors (energy, nutrients, foods or overall dietary patterns, alone or in combination with dietary supplements) and gestational hypertension and/or pre-eclampsia. Studies were excluded if they reported on supplements not in combination with dietary intake, or examined a biomarker of dietary intake. Random effects meta-analyses were performed on calculated weighted mean differences (WMD) of dietary intake between cases and non-cases, and effect estimates were pooled.

RESULTS

In total, 23 cohort and 15 case-control studies were identified for systematic review, of which 16 could be included in the meta-analyses. Based on meta-analyses of cohort studies, unadjusted energy intake was higher for pre-eclampsia cases (WMD 46 kcal/day, 95% confidence interval (CI) -13.80 to 106.23; I 2 = 23.9%, P = 0.26), although this was not statistically significant. Unadjusted intakes of magnesium (WMD 8 mg/day, 95% CI -13.99 to -1.38; I 2 = 0.0%, P = 0.41) and calcium (WMD 44 mg/day, 95% CI -84.31 to -3.62, I 2 = 51.1%, P = 0.03) were lower for the HDP cases, compared with pregnant women without HDP. Higher calcium intake consistently showed lower odds for HDP after adjustment for confounding factors (OR = 0.76, 95% CI 0.57 to 1.01, I 2 = 0.0%, P = 0.79). A few studies examining foods and dietary patterns suggested a beneficial effect of a diet rich in fruit and vegetables on pre-eclampsia, although not all the results were statistically significant.

CONCLUSIONS

Based on a limited number of studies, higher total energy and lower magnesium and calcium intake measured during pregnancy were identified as related to HDP. Further prospective studies are required to provide an evidence base for development of preventive health strategies, particularly focusing on dietary factors during pre-pregnancy and early pregnancy.

Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems

BACKGROUND

Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth.

OBJECTIVES

To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 March 2013) and contacted study authors for more data where possible. We updated the search in May 2014 and added the results to the 'Awaiting Classification' section of the review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing high-dose (at least 1 g daily of calcium) or low-dose calcium supplementation during pregnancy with placebo or no calcium.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality, extracted and double-entered data.

MAIN RESULTS

High-dose calcium supplementation (≥1 g/day)We included 14 studies in the review, however one study contributed no data. We included 13 high-quality studies in our meta-analyses (15,730 women). The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a significant reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: RR 0.45, 95% CI 0.31 to 0.65; I² = 70%). The effect was greatest for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) and women at high risk of pre-eclampsia (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42; I² = 0%). These data should be interpreted with caution because of the possibility of small-study effect or publication bias.The composite outcome maternal death or serious morbidity was reduced (four trials, 9732 women; RR 0.80, 95% CI 0.65 to 0.97; I² = 0%). Maternal deaths were not significantly different (one trial of 8312 women: calcium group one death versus placebo group six deaths). There was an anomalous increase in the risk of HELLP (haemolysis, elevated liver enzymes and low platelets) syndrome (two trials, 12,901 women: RR 2.67, 95% CI 1.05 to 6.82; I² = 0%) in the calcium group, however, the absolute number of events was low (16 versus six).The average risk of preterm birth was reduced in the calcium group (11 trials, 15,275 women: RR 0.76, 95% CI 0.60 to 0.97; I² = 60%) and amongst women at high risk of developing pre-eclampsia (four trials, 568 women: average RR 0.45, 95% CI 0.24 to 0.83; I² = 60%), but no significant reduction in neonatal high care admission. There was no overall effect on the risk of stillbirth or infant death before discharge from hospital (11 trials 15,665 babies: RR 0.90, 95% CI 0.74 to 1.09; I² = 0%).One study showed a reduction in childhood systolic BP greater than 95th percentile among children exposed to calcium supplementation in utero (514 children: RR 0.59, 95% CI 0.39 to 0.91). In a subset of these children, dental caries at 12 years old was also reduced (195 children, RR 0.73, 95% CI 0.62 to 0.87). Low-dose calcium supplementation (< 1 g/day)We included 10 trials (2234 women) that evaluated low-dose supplementation with calcium alone (4) or in association with vitamin D (3), linoleic acid (2), or antioxidants (1). Most studies recruited women at high risk for pre-eclampsia, and were at high risk of bias, thus the results should be interpreted with caution. Supplementation with low doses of calcium significantly reduced the risk of pre-eclampsia (RR 0.38, 95% CI 0.28 to 0.52; I² = 0%). There was also a reduction in hypertension, low birthweight and neonatal intensive care unit admission.

AUTHORS' CONCLUSIONS

Calcium supplementation (≥ 1 g/day) is associated with a significant reduction in the risk of pre-eclampsia, particularly for women with low calcium diets. The treatment effect may be overestimated due to small-study effects or publication bias. It also reduces preterm birth and the occurrence of the composite outcome 'maternal death or serious morbidity'. We considered these benefits to outweigh the increased risk of HELLP syndrome, which was small in absolute numbers. The World Health Organization recommends calcium 1.5 g to 2 g daily for pregnant women with low dietary calcium intake.The limited evidence on low-dose calcium supplementation suggests a reduction in pre-eclampsia, but needs to be confirmed by larger, high-quality trials. Pending such results, in settings of low dietary calcium where high-dose supplementation is not feasible, the option of lower-dose supplements (500 to 600 mg/day) might be considered in preference to no supplementation.

First trimester dietary intake, biochemical measures, and subsequent gestational hypertension among nulliparous women

INTRODUCTION

The purpose of this study was to evaluate the relationships between first-trimester dietary factors and biochemical measures and subsequent risk of gestational hypertension.

METHODS

This pilot study used a prospective design utilizing a convenience sample of nulliparous women enrolled at their first prenatal visit. A total of 57 women completed the study. Participants were divided into 2 groups for data analysis: normotensive pregnancy and gestational hypertension.

RESULTS

Nearly one-quarter of study participants (22.8%) developed gestational hypertension, of whom 84.6% had significant proteinuria meeting the criteria for preeclampsia. There were no significant differences in micronutrient or macronutrient dietary intakes between groups. Serum iron and zinc levels were lower for the gestational hypertension group compared with the normotensive pregnancy group (P ≤ .01). Low serum zinc levels were related to a risk of developing gestational hypertension (adjusted odds ratio, 0.930; 95% confidence interval, 0.872-0.992).

DISCUSSION

Ensuring adequate intake of zinc and monitoring serum zinc levels in nulliparous pregnant women may help to prevent or contribute to early detection of gestational hypertension.

Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems

BACKGROUND

Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia through a number of mechanisms, and may help to prevent preterm birth.

OBJECTIVES

To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2010) and contacted study authors.

SELECTION CRITERIA

Randomised trials comparing at least 1 g daily of calcium during pregnancy with placebo.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality, extracted and double-entered data.

MAIN RESULTS

We included 13 studies of good quality (involving 15,730 women). The average risk of high blood pressure was reduced with calcium supplementation rather than placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81). There was also a reduction in the average risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: RR 0.45, 95% CI 0.31 to 0.65). The effect was greatest for high-risk women (five trials, 587 women: RR 0.22, 95% CI 0.12 to 0.42), and those with low baseline calcium intake (eight trials, 10,678 women: RR 0.36, 95% CI 0.20 to 0.65).The average risk of preterm birth was reduced in the calcium group overall (11 trials, 15,275 women: RR 0.76, 95% CI 0.60 to 0.97) and amongst women at high risk of developing pre-eclampsia recruited to four small trials (568 women: RR 0.45, 95% CI 0.24 to 0.83).There was no overall effect on the risk of stillbirth or death before discharge from hospital (11 trials 15,665 babies; RR 0.90, 95% CI 0.74 to 1.09). The composite outcome maternal death or serious morbidity was reduced (four trials, 9732 women; RR 0.80, 95% CI 0.65 to 0.97). Most of the women in these trials were low risk and had a low calcium diet. Maternal deaths were reported in only one trial. One death occurred in the calcium group and six in the placebo group, a difference which was not statistically significant (RR 0.17, 95% CI 0.02 to 1.39).Blood pressure in childhood has been assessed in two studies, only one of which is currently included: childhood systolic blood pressure greater than 95th percentile was reduced (514 children: RR 0.59, 95% CI 0.39 to 0.91).

AUTHORS' CONCLUSIONS

Calcium supplementation appears to approximately halve the risk of pre-eclampsia, to reduce the risk of preterm birth and to reduce the rare occurrence of the composite outcome 'death or serious morbidity'. There were no other clear benefits, or harms.

The role of calcium, magnesium, and zinc in pre-eclampsia

Pre-eclampsia is the most common medical complication of pregnancy associated with increased maternal and infant mortality and morbidity. Its exact etiology is not known, although several evidences indicate that various elements might play an important role in pre-eclampsia. This study was carried out to analyze and to compare the concentration of calcium, magnesium, and zinc in the serum of women with pre-eclampsia and in normal pregnant women. Fifty clinically diagnosed patients with pre-eclampsia (25 with mild and 25 with severe pre-eclampsia) and 50 normal pregnant controls were enrolled in this study. The serum calcium, magnesium, and zinc levels were estimated with an atomic absorption spectrophotometer. The mean serum levels of calcium, magnesium, and zinc in normal pregnant group were 2.45 +/- 0.18 mmol/L, 0.79 +/- 0.13 mmol/L, and 15.64 +/- 2.4 micromol/L, respectively, while in mild pre-eclamptic group, these were 2.12 +/- 0.15 mmol/L, 0.67 +/- 0.14 mmol/L, and 12.72 +/- 1.7 micromol/L, respectively. Serum levels in severe pre-eclamptic group were 1.94 +/- 0.09 mmol/L, 0.62 +/- 0.11 mmol/L, and 12.04 +/- 1.4 micromol/L, respectively. These results indicate that reduction in serum levels of calcium, magnesium, and zinc during pregnancy might be possible contributors in etiology of pre-eclampsia, and supplementation of these elements to diet may be of value to prevent pre-eclampsia.

Role of nutrition in the risk of preeclampsia

Preeclampsia (PE) accounts for about one-quarter of the cases of maternal mortality and ranks second among the causes of pregnancy-associated maternal deaths in Canada and worldwide. The identification of an effective strategy to prevent PE is a priority and a challenge for research in obstetrics. Progress has been hampered by inadequate understanding of the underlying etiology of the disease. The role of maternal diet in the etiology of PE has recently received increased attention. The objective of this paper is to provide an overview of the literature concerning 1) the current understanding of the pathogenesis of PE, 2) the biological plausibility and potential mechanisms underlying the associations between maternal dietary exposures, nutrition, and the risk of PE, and 3) the epidemiological findings of maternal nutrient intake in relation to the risk of PE.

Dietary calcium supplementation for prevention of pre-eclampsia and related problems: a systematic review and commentary

BACKGROUND

Calcium supplementation during pregnancy may reduce the risk of hypertensive disorders of pregnancy.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Central Register of Controlled Trials (March 2006).

SELECTION CRITERIA

Randomised trials comparing at least 1 g of calcium daily during pregnancy with placebo. Eligibility and trial quality were assessed.

DATA COLLECTION AND ANALYSIS

Data were extracted and analysed using Review Manager software.

MAIN RESULTS

Twelve studies (15,528 women) were included, all of good quality. Most women were at low risk and had low dietary calcium. High blood pressure was reduced with calcium supplementation rather than placebo (11 trials, 14,946 women: relative risk [RR] random effects model 0.70; 95% CI 0.57-0.86), as was pre-eclampsia (12 trials, 15,206 women: RR 0.48; 95% CI 0.33-0.69). The effect was greatest for women at high risk (five trials, 587 women: RR 0.22; 95% CI 0.12-0.42) and for those with low baseline calcium intake (seven trials, 10,154 women: RR 0.36; 95% CI 0.18-0.70). There was heterogeneity, with less effect in the larger trials. The composite outcome maternal death or serious morbidity was reduced (four trials, 9732 women: RR 0.80; 95% CI 0.65-0.97). The syndrome of haemolysis, elevated liver enzymes and low platelets was increased (two trials, 12,901 women: RR 2.67; 95% CI 1.05-6.82). There was no overall effect on the risk of preterm birth or stillbirth or death before discharge from hospital.

CONCLUSIONS

Calcium supplementation appears to reduce the risk of pre-eclampsia and to reduce the rare occurrence of the composite outcome 'maternal death or serious morbidity'. There were no other clear benefits or harms.

COMMENTARY

We present the hypothesis that adequate dietary calcium before and in early pregnancy may be needed to prevent the underlying pathology responsible for pre-eclampsia. We suggest that the research agenda be redirected towards calcium supplementation at a community level.

Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems

BACKGROUND

Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia through a number of mechanisms, and may help to prevent preterm labour.

OBJECTIVES

To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (February 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2005, Issue 4), and contacted study authors.

SELECTION CRITERIA

Randomised trials comparing at least one gram daily of calcium during pregnancy with placebo.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality, extracted and double-entered data.

MAIN RESULTS

Twelve studies of good quality were included. The risk of high blood pressure was reduced with calcium supplementation rather than placebo (11 trials, 14,946 women: relative risk (RR) 0.70, 95% confidence interval (CI) 0.57 to 0.86). There was also a reduction in the risk of pre-eclampsia associated with calcium supplementation (12 trials, 15,206 women: RR 0.48, 95% CI 0.33 to 0.69). The effect was greatest for high-risk women (5 trials, 587 women: RR 0.22, 95% CI 0.12 to 0.42), and those with low baseline calcium intake (7 trials, 10,154 women: RR 0.36, 95% CI 0.18 to 0.70). The composite outcome maternal death or serious morbidity was reduced (4 trials, 9732 women; RR 0.80, 0.65 to 0.97). Almost all the women in these trials were low risk and had a low calcium diet. Maternal deaths were reported in only one trial. One death occurred in the calcium group and six in the placebo group, a difference which was not statistically significant (RR 0.17, 95% CI 0.02 to 1.39). There was no overall effect on the risk of preterm birth (10 trials, 14,751 women: RR 0.81, 95% CI 0.64 to 1.03), or stillbirth or death before discharge from hospital (10 trials 15,141 babies; RR 0.89, 95% CI 0.73 to 1.09).Blood pressure in childhood has been assessed in one study: childhood systolic blood pressure greater than 95th percentile was reduced (514 children: RR 0.59, 95% CI 0.39 to 0.91).

AUTHORS' CONCLUSIONS

Calcium supplementation appears to almost halve the risk of pre-eclampsia, and to reduce the rare occurrence of the composite outcome 'death or serious morbidity'. There were no other clear benefits, or harms.

Association of low intake of milk and vitamin D during pregnancy with decreased birth weight

BACKGROUND

Some pregnant women may be advised or choose to restrict milk consumption and may not take appropriate supplements. We hypothesized that maternal milk restriction during pregnancy, which can reduce intakes of protein, calcium, riboflavin and vitamin D, might represent a health risk by lowering infant birth weight.

METHODS

We screened women between the ages of 19 and 45 years who were attending prenatal programs in Calgary, Alberta (51 degrees N) for low milk consumption (< or = 250 mL/d). Using repeat dietary recalls, we compared these women and their offspring with women whose daily milk consumption exceeded 250 mL (1 cup). Birth weight, length and head circumference were obtained from birth records.

RESULTS

Women who consumed < or = 250 mL/d of milk (n = 72) gave birth to infants who weighed less than those born to women who consumed more (n = 207; 3410 g v. 3530 g, respectively; p = 0.07). Infant lengths and head circumferences were similar. Women who restricted milk intake had statistically significantly lower intakes of protein and vitamin D as well. In multivariate analyses controlled for previously established predictors of infant birth weight, milk consumption and vitamin D intake were both significant predictors of birth weight. Each additional cup of milk daily was associated with a 41 g increase in birth weight (95% confidence interval [CI] 14.0-75.1 g); each additional microgram of vitamin D, with an 11 g increase (95% CI 1.2-20.7 g). Neither protein, riboflavin nor calcium intake was found to predict birth weight.

INTERPRETATION

Milk and vitamin D intakes during pregnancy are each associated with infant birth weight, independently of other risk factors.

Relationship between high consumption of marine fatty acids in early pregnancy and hypertensive disorders in pregnancy

OBJECTIVE

To investigate whether there is a relationship between maternal intake of cod-liver oil in early and late pregnancy and hypertensive disorders in pregnancy.

DESIGN

An observational prospective study.

SETTING

Free-living conditions in a community with traditional fish and cod-liver oil consumption.

POPULATION

Four hundred and eighty-eight low-risk pregnant Icelandic women.

METHODS

Maternal use of cod-liver oil, foods and other supplements was estimated with a semiquantitative food frequency questionnaire covering food intake together with lifestyle factors for the previous 3 months. Questionnaires were filled out twice, between 11 and 15 weeks of gestation and between 34 and 37 weeks of gestation. Supplements related to hypertensive disorders in pregnancy, i.e. gestational hypertension and pre-eclampsia, were presented, with logistic regression controlling for potential confounding.

MAIN OUTCOME MEASURES

Gestational hypertension, pre-eclampsia, cod-liver oil and multivitamins.

RESULTS

The odds ratio for developing hypertensive disorders in pregnancy for women consuming liquid cod-liver oil was 4.7 (95% CI 1.8-12.6, P= 0.002), after adjusting for confounding factors. By dividing the amount of n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) into centiles, the odds ratio for hypertensive disorders across groups for n-3 LCPUFA suggested a u-shaped curve (P = 0.008). Similar results were found for gestational hypertension alone. Further, the use of multivitamin supplements without vitamins A and D in late pregnancy doubled the odds of hypertensive disorders (OR 2.4, 95% CI 1.0-5.4, P= 0.044).

CONCLUSIONS

Consumption of high doses of n-3 LCPUFA in early pregnancy, or other nutrients found in liquid cod-liver oil, may increase the risk of developing hypertensive disorders in pregnancy.