World Health Organization Systematic Review of the Literature and Multinational Nutritional Survey of Calcium Intake During Pregnancy

Abstract

In 1999, the US Food and Nutrition Board revised the Adequate Intake (AI) for calcium in pregnancy and recommended 1000 mg/day for adult pregnant women and 1300 mg/day for adolescent women (<19 years). Our interest, from the perspective of an international health organization, was to assess if pregnant women globally meet those requirements. This is particularly important because, among the various biological functions of calcium, the potential protective effect of adequate calcium intake in pregnancy on the risk of pre-eclampsia may have major public health implications, pre-eclampsia being one of the most important causes of maternal and perinatal mortality world-wide. Therefore, we conducted a systematic review of studies, published from 1991 to 2004, that assessed calcium dietary intake in pregnant women. In addition, we conducted a multicentre survey of calcium dietary intake during pregnancy among nulliparous women attending antenatal care in developing countries. This survey was conducted before starting a large calcium supplementation multicentre trial: the WHO Calcium Supplementation Trial in Low Calcium Intake Women for the Prevention of Pre-eclampsia. This article presents the results of the systematic review and of the multicentre survey.

World Health Organisation multicentre randomised trial of supplementation with vitamins C and E among pregnant women at high risk for pre‐eclampsia in populations of low nutritional status from developing countries

“…Although we reached a sample size 20% smaller than planned, the higher than anticipated pre-eclampsia rate observed, provided sufficient power (88%) to detect the difference between groups projected in the protocol. The high rates of pre-eclampsia (24% compared with 16% in the United Kingdom trial also among high-risk women 5 ), may reflect the low socio-economic and nutritional status including very low calcium intake 10,11 of our study populations that were, in addition, being provided with a very intense antenatal care followup, seldom offered to such high-risk women. The incidence of pre-eclampsia (74%) among women who had preeclampsia in a previous pregnancy was also high, but similar to recently reported recurrence risk.…”

“…This assessment was based on data collected by us in these same clinics 10,11,18 focusing on calories, protein and calcium intake. We assumed that vitamin C and E intake follows the pattern of the other major nutrients.…”

“…The study groups' low nutritional intake was based on the evaluation of the pregnant population served by these clinics and not by a direct evaluation of the intake of the actual women randomised. This assessment was based on data collected by us in these same clinics 10,11,18 focusing on calories, protein and calcium intake. We assumed that vitamin C and E intake follows the pattern of the other major nutrients.…”

“…A multicentre, randomised, placebo-controlled, double-blind trial was performed between October 2004 and December 2006, at antenatal clinics that served populations with low socio-economic status and had evidence of overall low nutritional status from a previous WHO survey. 11 These clinics, located in Nagpur, India; Lima and Trujillo, Peru; Cape Town, South Africa; and Ho Chi Minh City, Viet Nam form part of the WHO Maternal and Perinatal Research Network--all having extensive experience in conducting large multicentre randomised trials. The trial followed the research protocol used in the recently completed United Kingdom based multicentre trial of vitamins C and E (the VIP trial) 5 with only minor adaptations to accommodate local resources.…”

Should women be advised to use calcium supplements during pregnancy? A decision analysis

“…Comparable results can be expected for other high-income countries. In low-income countries, particularly those in which inadequate dietary calcium intake is more prevalent or baseline risk of PE is higher, health and economic effects may be more favorable (Khan, Wojdyla, Say, Gulmezoglu, & Van Look, 2006;Merialdi et al, 2005;Saleem et al, 2014). Our model can be used for the calculation of country-specific effects by making use of local point estimates and plausible ranges.…”