Possible dietary measures in the prevention of pre-eclampsia and eclampsia

The impact of salt intake during and after pregnancy

Although high blood pressure before pregnancy is associated with a risk of gestational hypertension and preeclampsia, no convincing evidence has been produced to show that dietary salt reduction helps in the prevention and treatment of hypertension during pregnancy. Thus the current guidelines do not recommend a sodium restriction during pregnancy to prevent gestational hypertension and the development of preeclampsia. However, the long-term impact of hypertensive disorders of pregnancy for life-threatening diseases later in life is a critical issue. Gestational hypertension could contribute to the risk of developing hypertension later in life, and recent studies have suggested that gestational hypertension and preeclampsia are linked to cardiovascular complications. In this article, we provide an overview of the current perspectives on the salt intake of pregnant women and consider both the short-term influence and the impact beyond the perinatal period.

Impact of singlehood during pregnancy on dietary intake and birth outcomes- a study in the Norwegian Mother and Child Cohort Study

Background

Little attention has been given to the impact of singlehood during pregnancy. The aim of this study was to examine the impact of marital status on diet during pregnancy and pregnancy outcome.

Methods

The study population comprised 62,773 women participating in the Norwegian Mother and Child Cohort Study. Marital status was categorised into singles living alone, singles living with parents and married/cohabiting (reference group). Participants answered a general health questionnaire in gestational week 15–17 and a food frequency questionnaire in gestational week 22. We used nonparametric tests to compare dietary intakes by marital status, and multiple logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for infants being small for gestational age (SGA), large for gestational age (LGA), and preterm delivery (defined as delivery before gestational week 37).

Results

Single women living with parents had lower intakes of fruits and vegetables, higher intake of total energy, higher proportion of energy from added sugar, and lower intake of fibre than the reference group. Singles living alone also had a higher intake of added sugar. In both of the single groups, daily smoking was more prevalent than in women living with a partner. In analyses adjusted for maternal age, pre-pregnancy BMI, energy intake, energy contributed by protein, education, income, parity and nausea, single women living alone had increased risk of SGA with OR = 1.27 (95% CI: 1.05, 1.55). When smoking was included among the confounding variables, the association was no longer significant. Likewise, singles living alone had increased risk of preterm delivery, with OR = 1.32 (95% CI: 1.01, 1.72) in a partly adjusted model, but the association did not remain significant in a model fully adjusted for confounding variables.

Conclusions

Single mothers had lower dietary quality and included more smokers than women who lived with a partner. Single mothers living alone had higher prevalence of SGA and preterm delivery, but the associations with adverse pregnancy outcomes were confounded by other variables. This study shows that single mothers should be given special attention during antenatal care and counselling.

Evidence for compromised aldosterone synthase enzyme activity in preeclampsia

BACKGROUND

In normal pregnancy, an increased aldosterone (Aldo) concentration coincides with volume expansion. In preeclampsia, Aldo levels are low despite intravascular volume depletion. The present investigation aimed to characterize the compromised Aldo synthesis in preeclampsia, and to identify the molecular basis hereof.

METHODS

We recruited 66 pregnant women (24 uneventful, 42 preeclamptic). Genomic DNA was isolated from peripheral blood leukocytes. Urine samples were obtained for gas chromatography-mass spectroscopic measurements of steroid hormones reflecting apparent Aldo synthase (CYP11B2) and 11-hydroxylase (CYP11B1) activities. Polymerase chain reaction (PCR)-based screening for CYP11B2 mutations was performed by SSCP, restriction analysis, and sequencing.

RESULTS

CYP11B1 activity was unaltered, but reduction of mean tetrahydro (TH)-Aldo excretion by a factor of 3.9 indicated a diminished CYP11B2 activity in preeclampsia. Accordingly, the ratios of (TH-11-dehydrocorticosterone [A]+TH-corticosterone [B]+5alpha-THB) to (TH-cortisone +TH-cortisol [F]+5alpha-THF) and of 18-OH-THA to THAldo were increased in preeclampsia 2.6- and 15.2-fold, respectively, indicating reduced Aldo synthesis due to diminished methyl oxidase (MO) activity. A lower percentage of women with normal pregnancies had CYP11B2 mutations when compared to preeclamptic women (P < 0.05). Eight polymorphisms were detected, two of which were non-amino acid conserving. Of those, the mutation V386A, earlier found to jeopardize MO activity, was exclusively observed in preeclampsia (0% vs. 17%; P < 0.05).

CONCLUSION

Aldo deficiency due to a compromised MO step of Aldo synthesis favors extracellular volume depletion, and may account for an increased risk of placental hypoperfusion and consecutive development of preeclampsia. The sole presence of mutation V386A in preeclamptic mothers may identify a subgroup with an increased risk to develop preeclampsia during pregnancy.

Serum calcium and serum magnesium in normal and preeclamptic pregnancy

OBJECTIVE

The aims of this study were to measure serum levels of calcium and magnesium in preeclamptic pregnancies and to compare them with those in normal pregnancies.

MATERIALS AND METHODS

We collected venous serum samples from 40 preeclamptic pregnant women and 40 normal pregnant women. The blood samples were analyzed for calcium and magnesium, using a colorimetric analyzer. The data were analyzed using the Student's t-test, chi2-test or Fisher exact tests when appropriate.

RESULTS

The serum calcium concentration in preeclamptic pregnant women is significantly lower than that in normal pregnant women (9.0 +/- 0.4 mg/dl vs. 9.7 +/- 0.7 mg/dl, p < 0.0001). Like serum calcium, serum magnesium concentration in preeclamptic women is significantly lower than that in normal pregnant women (0.77 +/- 0.08 mmol/l vs. 0.85 +/- 0.09 mmol/l, p = 0.001).

CONCLUSION

This study shows that both serum calcium and serum magnesium levels in preeclamptic pregnant women are lower than in normal pregnant women. These findings support the hypothesis that hypocalcemia and hypomagnesemia are possible etiologies of preeclampsia.

Nutrient intake and hypertensive disorders of pregnancy: Evidence from a large prospective cohort

OBJECTIVE

The objective of this analysis was to prospectively determine the effects of nutrient intakes on the incidences of preeclampsia and pregnancy-associated hypertension among women enrolled in the Calcium for Preeclampsia Prevention study.

STUDY DESIGN

This was a prospective observational cohort study of women in a randomized clinical trial that included women seeking prenatal care at university medical centers and affiliated clinics and hospitals in 5 US communities. A total of 4589 nulliparous women were recruited between 13 and 21 weeks' gestation. Preeclampsia and pregnancy-associated hypertension were the main outcome measures.

RESULTS

Preeclampsia was noted in 326 (7.6%) of the 4314 women with known pregnancy outcomes followed up until > or =20 weeks' gestation, and pregnancy-associated hypertension was noted in 747 (17.3%). As previously reported, there was no significant difference in these outcomes between cohorts randomly assigned to supplementation with calcium or placebo. By means of logistic regression a baseline risk model was constructed for preeclampsia and pregnancy-associated hypertension. After adjustment for treatment and clinical site, body mass index >26 kg/m(2) and race were significantly associated with an increased risk of preeclampsia. Body mass index > or =35 kg/m(2), race, and never smoking were significantly associated with an increased risk of pregnancy-associated hypertension. After adjustment for baseline risks, none of the 28 nutritional factors analyzed were significantly related to either preeclampsia or pregnancy-associated hypertension.

CONCLUSION

We found no evidence in this study for a significant association of hypertensive disorders of pregnancy with any of the 23 nutrients measured.

Dietary calcium and mineral/vitamin supplementation: a controversial problem

There is a consensus that adequate calcium intake during bone development, and possibly in adulthood and senescence, helps to prevent bone resorption and osteoporosis. The uptake of dietary calcium should be sufficient to maintain both normal serum calcium concentrations and parathyroid hormone levels in the low normal range throughout the day, otherwise, increased bone resorption occurs. Calcium intake varies with race and with environmental and dietary conditions. Estimating the appropriate amount of calcium to be added to dietary sources for an optimal supplementation regimen is therefore difficult. Few intervention studies have evaluated the dose-effect relationship for calcium supplementation conclusively. The mechanisms regulating fractional calcium absorption as a function of intake suggest that very high daily doses are probably useless. They may be unsafe in the long term because of the risks of hypercalciuria and kidney stones, and of an imbalance in the ratio of calcium to magnesium. Concomitant supplementation with limited amounts of magnesium may reduce this risk and improve mineralization. Dietary intake is 500-600 mg/day in most studies, making 400 mg/day an appropriate supplementary dose for most premenopausal women (RDA 1000 mg/day). After the menopause and during lactation (RDA 1200-1500 mg/day), 800 mg/day is probably appropriate, particularly if low doses of vitamin D are taken concomitantly.