Blood Pressure Responses to Dietary Sodium Manipulation During Normotensive Human Pregnancy

McEniery, P. J.; Hunyor, Stephen N.; Cooper, Karen; Gallery, Eileen D.M.; Györy, Á. Z.; Boyce, E. S.

doi:10.1111/j.1440-1681.1985.tb02654.x

Cited by 8 publications

(9 citation statements)

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“…The non-significant differences in changes in systolic and diastolic blood pressure over pregnancy between the I-and C-groups were only 1 and 0 mmHg in the sitting position and 2 and 1 mmHg in the left lateral recumbent position, indicating that the low-Na diet had no effect on the course of blood pressure during pregnancy. This is in line with three recent studies in which no effect of salt restriction in pregnancy on blood pressure was found (McEniery et al 1985;Brown et al 1987;Steegers et al 1991). However, in the study of Brown et al (1987) subjects who developed hypertension were excluded and in the study of McEniery et al (1985) compliance was not controlled.…”

Section: Effect Of a Low-sodium Diet During Pregnancy On Blood Pressuresupporting

confidence: 90%

Low-sodium diet in pregnancy: effects on blood pressure and maternal nutritional status

et al. 1997

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In ninety-four Dutch nulliparous women the effects of a low-Na diet in pregnancy on blood pressure, energy and nutrient intake, Ca metabolism, Zn and Mg status and body composition were studied longitudinally. The women were randomly divided into an intervention group (n 41), which used a low-Na diet (mean urinary Na excretion 61 mmoV24 h) from week 14 of pregnancy until delivery and a control group (n 53; mean urinary Na excretion 142 mmoV24 h). No effect of the diet on blood pressure was observed. The use of a low-Na diet resulted in significantly reduced intakes of energy, protein, carbohydrates, fat, Ca, Zn, Mg, Fe and cholesterol. However, the women on the low-Na diet appeared to be able to adapt quite well to the reduced intake since Ca, Zn and Mg homeostasis was maintained. In the case of Ca and Mg this was probably due to the observed reduced urinary excretions of these nutrients. Non-significant reductions in weight gain (1-5 kg) and fat-mass gain (0.9 kg) over pregnancy were found in the women on the low-Na diet. No significant effects of the diet on birth weight or placental weight were observed. Pregnancy: Sodium: Blood pressure: Nutritional statusThe present study was part of a multicentre controlled randomized study, in which the prophylactic effect of a low-Na diet during pregnancy on hypertensive disorders was evaluated (B. J. A. Van Buul, E. A. P. Steegers, G. D. Van der Maten and T. K. A. B. Eskes, unpublished results). Thus far not much consideration has been given to the (patho)-physiological consequences of a change in Na intake for mother and fetus. Therefore, each centre also studied different possible side-effects of the low-Na diet. In the present study the results for the additional variables studied at the hospital Groot Ziekengasthuis are described. The aim of the study was to investigate, besides an effect on blood pressure, the effects of a low-Na diet in pregnancy on maternal energy and nutrient intake, Ca metabolism, Zn and Mg status, weight gain and body-fat storage. Since there are indications that nutrition, mineral and trace element status and body composition are related to pregnancy outcome, in affecting these variables a low-Na diet may have implications for the health of the mother and fetus (Institute of Medicine, 1990 SUBJECTS AND METHODS Study designNinety-four nulliparous women visiting the antenatal clinic of the hospital Groot Ziekengasthuis were studied longitudinally from early pregnancy until 6 weeks postpartum. Pregnancies were dated using the first day of the last menstrual period. After baseline measurements, at week 13 of pregnancy, the women were randomly assigned (by closed envelope system) to an intervention group (I-group), which used a low-Na diet from week 14 of pregnancy onwards until delivery, and a control group (C-group), which continued its ad libitum dietary intake. Blood pressure, heart rate, food consumption, blood and urinary analyses, body weight and skinfold thicknesses were measured during pregnancy and post-partum. In addition, infant birth...

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Section: Effect Of a Low-sodium Diet During Pregnancy On Blood Pressuresupporting

confidence: 90%

Low-sodium diet in pregnancy: effects on blood pressure and maternal nutritional status

et al. 1997

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“…This suggested that the decreased sensitivity to vasoconstrictor normally observed in pregnancy is reversed, and this could explain the absence of decreased blood pressure. McEniery et al (25) demonstrated that normotensive 18-wk pregnant women receiving a high-sodium diet (300 mmol sodium per day) for 7-10 days had no blood pressure change compared with pregnant women on a regular diet. The discrepancy with our results and other animal studies (3,26) with those of the women of McEniery study could be explained by the level of sodium loading.…”

Section: Discussionmentioning

confidence: 99%

High-sodium intake prevents pregnancy-induced decrease of blood pressure in the rat

Beauséjour

Auger

St‐Louis

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

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Brochu. High-sodium intake prevents pregnancy-induced decrease of blood pressure in the rat. Am J Physiol Heart Circ Physiol 285: H375-H383, 2003; 10.1152/ ajpheart.01132.2002.-Despite an increase of circulatory volume and of renin-angiotensin-aldosterone system (RAAS) activity, pregnancy is paradoxically accompanied by a decrease in blood pressure. We have reported that the decrease in blood pressure was maintained in pregnant rats despite overactivation of RAAS following reduction in sodium intake. The purpose of this study was to evaluate the impact of the opposite condition, e.g., decreased activation of RAAS during pregnancy in the rat. To do so, 0.9% or 1.8% NaCl in drinking water was given to nonpregnant and pregnant SpragueDawley rats for 7 days (last week of gestation). Increased sodium intakes (between 10-and 20-fold) produced reduction of plasma renin activity and aldosterone in both nonpregnant and pregnant rats. Systolic blood pressure was not affected in nonpregnant rats. However, in pregnant rats, 0.9% sodium supplement prevented the decreased blood pressure. Moreover, an increase of systolic blood pressure was obtained in pregnant rats receiving 1.8% NaCl. The 0.9% sodium supplement did not affect plasma and fetal parameters. However, 1.8% NaCl supplement has larger effects during gestation as shown by increased plasma sodium concentration, hematocrit level, negative water balance, proteinuria, and intrauterine growth restriction. With both sodium supplements, decreased AT1 mRNA levels in the kidney and in the placenta were observed. Our results showed that a high-sodium intake prevents the pregnancy-induced decrease of blood pressure in rats. Nonpregnant rats were able to maintain homeostasis but not the pregnant ones in response to sodium load. Furthermore, pregnant rats on a high-sodium intake (1.8% NaCl) showed some physiological responses that resemble manifestations observed in preeclampsia. sodium supplement; renin-angiotensin-aldosterone system; preeclampsia PREGNANCY, IN HUMANS AND RATS, is associated with important hemodynamic, hormonal, biochemical, and molecular changes. During normal pregnancy, plasma volume expands. In humans, it appears as early as the sixth week of pregnancy. Thereafter, blood volume increases by 40% until the thirtieth week to reach plateau, which is maintained until term (14). In pregnant rats, the increase in blood volume occurs during the last week of gestation (4, 31). Plasma renin activity (PRA), plasma ANG II, and aldosterone levels are increased during pregnancy (37). In humans, by the eighth week of pregnancy, PRA and aldosterone levels are higher than baseline and increase gradually until the end of pregnancy (42). In pregnant rats, aldosterone increases gradually from day 15 to 22 of gestation (9, 16). Despite blood volume expansion and activation of the renin-angiotensin-aldosterone system (RAAS), normal pregnancy is paradoxically accompanied by a significant fall in arterial blood pressure in women (28) and rats (36). However, the fall in blood press...

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“…McEniery and colleagues studied the effects of short-term manipulations of dietary sodium on blood pressure in pregnancy. 27 In their small study, 22 normal pregnant women, of whom eight were primigravid, were recruited at approximately 18 weeks gestation and allocated to a randomly selected series of three diets, each for 7-10 days: a low sodium (10 mmol per day), a high sodium (300 mmol per day) and the womens' regular diet with ad libitum sodium intake. These short-term dietary manipulations produced no changes in blood pressure or heart rate.…”

Section: Discussionmentioning

confidence: 99%

Sodium–blood pressure interrelationship in pregnancy

Franx¹,

Steegers

Boo³

et al. 1999

J Hum Hypertens

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In non-pregnant individuals, a strong positive association of sodium intake with blood pressure has been established, but the relationship between sodium intake and blood pressure in human pregnancy remains obscure up to date. The aim of this prospective observational cohort study was to assess the relationship between urinary sodium excretion (as a measure for intake) and blood pressure from the early second trimester onwards throughout pregnancy. The study group consisted of 667 low-risk women with singleton pregnancies, of whom 350 were nulliparous and 317 parous. Blood pressure was measured in a standardised fashion at predetermined intervals from the first antenatal visit prior to 16 weeks gestation until delivery. Urinary sodium excretion was measured in 24-h urine collections on at least four occasions between 16 and 38 weeks gestation. Main outcome measures were the

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Blood Pressure Responses to Dietary Sodium Manipulation During Normotensive Human Pregnancy

Cited by 8 publications

References 28 publications

Low-sodium diet in pregnancy: effects on blood pressure and maternal nutritional status

Low-sodium diet in pregnancy: effects on blood pressure and maternal nutritional status

High-sodium intake prevents pregnancy-induced decrease of blood pressure in the rat

Sodium–blood pressure interrelationship in pregnancy

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