Effects of calcium supplementation on uteroplacental and fetoplacental blood flow in low-calcium-intake mothers: a randomized controlled trial (original) (raw)
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Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems
The Cochrane database of systematic reviews, 2000
BACKGROUND Calcium supplementation may prevent high blood pressure through a number of mechanisms and may help to prevent preterm labour. OBJECTIVES The objective of this review was to assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child adverse outcomes. SEARCH STRATEGY We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register and we contacted study authors. Date of last search: February 2000. SELECTION CRITERIA Randomised trials comparing at least one gram daily of calcium during pregnancy with placebo. DATA COLLECTION AND ANALYSIS Eligibility and trial quality were assessed. Data extraction was carried out and double entered. MAIN RESULTS Ten studies were included, all of good quality. There was a modest reduction in high blood pressure with calcium supplementation (relative risk 0.81, 95% confidence interval 0.74 to 0.89). The effect was great...
American Journal of Obstetrics and Gynecology, 2006
Objective: The purpose of this trial was to determine whether calcium supplementation of pregnant women with low calcium intake reduces preeclampsia and preterm delivery. Study design: Randomized placebo-controlled, double-blinded trial in nulliparous normotensive women from populations with dietary calcium !600 mg/d. Women who were recruited before gestational week 20 received supplements (1.5 g calcium/d or placebo) throughout pregnancy.
Medical Hypotheses, 1995
Pregnancy-induced hypertension (PIH) remains a common cause of maternal and fetal morbidity and mortality. During the past 7 years, some progress has been made in the prevention of PIH. Specifically, clinical studies have shown that supplementation with calcium can significantly reduce the frequency of PIH, specially in populations with a low calcium intake. We have suggested that, in such a population, calcium supplementation is a safe and effective measure for reducing the frequency of PIH. Thus, the purpose of this article is to advance a hypothesis about the mechanism by which calcium supplementation reduces the risk of PIH. We propose that dietary calcium supplementation reduces the frequency of PIH by maintaining the serum ionized calcium level which is crucial for the production of endothelial nitric oxide, the increased generation of which maintains the vasodilatation that is characteristic of normal pregnancy.
Annals of the New York Academy of Sciences, 2022
Most low-and middle-income countries present suboptimal intakes of calcium during pregnancy and high rates of mortality due to maternal hypertensive disorders. Calcium supplementation during pregnancy is known to reduce the risk of these disorders and associated complications, including preeclampsia, maternal morbidity, and preterm birth, and is, therefore, a recommended intervention for pregnant women in populations with low dietary calcium intake (e.g., where ≥25% of individuals in the population have intakes less than 800 mg calcium/day). However, this intervention is not widely implemented in part due to cost and logistical issues related to the large dose and burdensome dosing schedule (three to four 500-mg doses/day). WHO recommends 1.5-2 g/day but limited evidence suggests that less than 1 g/day may be sufficient and ongoing trials with low-dose calcium supplementation (500 mg/day) may point a path toward simplifying supplementation regimens. Calcium carbonate is likely to be the most cost-effective choice, and it is not necessary to counsel women to take calcium supplements separately from iron-containing supplements. In populations at highest risk for preeclampsia, a combination of calcium supplementation and food-based approaches, such as food fortification with calcium, may be required to improve calcium intakes before pregnancy and in early gestation.
Australian and New Zealand Journal of Obstetrics and Gynaecology, 1999
A multicentre, randomized controlled double-blind trial in 5 maternity hospitals in Australia assessed the effect of a daily supplement of calcium (1.8g oral calcium or an oral placebo) taken daily until delivery, from less than 24 weeks' gestation, on the frequency of pregnancy-induced hypertension, preeclampsia and preterm birth (< 37 weeks' gestation) in 456 nulliparas with a singleton pregnancy. Treatment with calcium reduced the risk of preeclampsia (relative risk 0.44 [95% CI, 0.21-0.90], p = 0.02) and the risk of preterm birth (relative risk 0.44 [95% CI, 0.21-0.90], p = 0.02). No significant differences were seen between the 2 groups in the frequency of pregnancy-induced hypertension, although the study only had statistical power to detect large differences in this outcome. An updated systematic review of the 9 randomized trials of calcium supplementation in pregnancy shows a significant reduction in the risk of hypertension and preeclampsia although no effect on preterm birth. Calcium supplementation during pregnancy reduced the risk of preeclampsia and preterm birth in this nulliparous population. The available evidence for systematic review of all the randomized trials of calcium supplementation shows benefit in reducing the risk of hypertension and preeclampsia.
Relationship Of Calcium Levels To Hypertension In Pregnancy
Pregnancy-induced hypertension often progresses to pre-eclampsia as one of the biggest contributors to maternal mortality. Mineral and nutritional factors have an important role in the etiology of pregnancy-induced hypertension, especially pre-eclampsia. A mineral factor associated with hypertension is calcium. This study attempts to analyze the relationship between calcium levels and the occurance of pregnancy-induced hypertension. A crosssectional study design was used to measure or observe independent variables (calcium levels) and dependent variables (hypertension in pregnancy). The number of samples was 43 second-trimester pregnant women taken by consecutive sampling technique. This study used primary data by examining blood pressure and calcium levels contained in the blood serum of pregnant women. Univariate analysis results showed that 30% of pregnant women experienced pregnancy-induced hypertention, and 44% of pregnant women had insufficient calcium levels. The results of t...
Calcium Supplementation For The Prevention Of Pregnancy Induced Hypertension/Preeclampsia
2022
Background: Pregnancy induced hypertension (PIH) and preeclampsia (PE) contribute significantly to maternal and perinatal morbidity and mortality. The role of calcium supplementation towards preventing PIH/PE however remains unclear. Objective: To assess the efficacy of calcium supplementation in prevention of PIH and PE. Materials and methods: An open label, randomized controlled trial conducted at the antenatal clinic of University of Abuja Teaching Hospital between July 2014 and June 2015. A total of 484 nulliparous women 16 weeks or less gestation and with normal blood pressures were randomly assigned to either receive 1200mg of calcium tablet daily (N=242) or not to receive calcium tablets (N=242) from 16weeks until delivery. Primary outcome measure was development of PIH or PE and secondary outcome measure was preterm birth. Results: The incidence of PIH was 7.7% among the intervention group compared to 13.7% in the control, p=0.039 and calcium supplementation reduced the risk of PIH (RR=0.56 (95% CI: 0.32-0.98)), but not PE. It also prolonged the duration of pregnancy in women who developed PIH (p=0.02). Incidence of preeclampsia was not significant, RR-0.56 (95% CI: 0.21-1.52) so also was the incidence of preterm delivery between the two groups (RR-0.65 (95% CI: 0.32-1.31)). No serious maternal side effects of treatment were recorded. Conclusion: Calcium supplementation during pregnancy reduced the risk of PIH and thus may have a role in the prevention of PIH amongst nulliparous women. Its role in the absolute prevention of PE was not demonstrated in this study.