The effect of calcium supplementation on blood pressure in non-pregnant women with previous pre-eclampsia: An exploratory, randomized placebo controlled study

BACKGROUND

Epidemiological findings suggest that the link between poverty and pre-eclampsia might be dietary calcium deficiency. Calcium supplementation has been associated with a modest reduction in pre-eclampsia, and also in blood pressure (BP).

METHODS

This exploratory sub-study of the WHO Calcium and Pre-eclampsia (CAP) trial aims to determine the effect of 500mg/day elemental calcium on the blood pressure of non-pregnant women with previous pre-eclampsia. Non-pregnant women with at least one subsequent follow-up trial visit at approximately 12 or 24weeks after randomization were included.

RESULTS

Of 836 women randomized by 9 September 2014, 1st visit data were available in 367 women of whom 217 had previously had severe pre-eclampsia, 2nd visit data were available in 201 women. There was an overall trend to reduced BP in the calcium supplementation group (1-2.5mmHg) although differences were small and not statistically significant. In the subgroup with previous severe pre-eclampsia, the mean diastolic BP change in the calcium group (-2.6mmHg) was statistically larger than in the placebo group (+0.8mmHg), (mean difference -3.4, 95% CI -0.4 to -6.4; p=0.025). The effect of calcium on diastolic BP at 12weeks was greater than in those with non-severe pre-eclampsia (p=0.020, ANOVA analysis).

CONCLUSIONS

There is an overall trend to reduced BP but only statistically significant in the diastolic BP of women with previous severe pre-eclampsia. This is consistent with our hypothesis that this group is more sensitive to calcium supplementation, however results need to be interpreted with caution.

Kangaroo mother care to reduce morbidity and mortality in low birthweight infants

BACKGROUND

Kangaroo mother care (KMC), defined as skin-to-skin contact between a mother and her newborn, frequent and exclusive or nearly exclusive breastfeeding, and early discharge from hospital, has been proposed as an alternative to conventional neonatal care for low birthweight (LBW) infants.

OBJECTIVES

To determine whether there is evidence to support the use of KMC in LBW infants as an alternative to conventional care after the initial period of stabilization with conventional care.

SEARCH STRATEGY

We used the standard search strategy of the Neonatal Review Group of the Cochrane Collaboration. MEDLINE, EMBASE, LILACS, POPLINE and CINAHL databases (to December 2002), and the Cochrane Controlled Trials Register (The Cochrane Library), were searched using the key words terms "kangaroo mother care" or "kangaroo care" or "kangaroo mother method" or "skin-to-skin contact" and "infants" or "low birthweight infants".

SELECTION CRITERIA

Randomized trials comparing KMC and conventional neonatal care in LBW infants.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data were extracted independently by two reviewers. Statistical analysis was conducted using the standard Cochrane Collaboration methods.

MAIN RESULTS

Three studies, involving 1362 infants, were included. All the trials were conducted in developing countries. The studies were of moderate to poor methodological quality. The most common shortcomings were in the areas of blinding procedures for those who collected the outcomes measures, handling of drop outs, and completeness of follow-up. The great majority of results consist of results of a single trial. KMC was associated with the following reduced risks: nosocomial infection at 41 weeks' corrected gestational age (relative risk 0.49, 95% confidence interval 0.25 to 0.93), severe illness (relative risk 0.30, 95% confidence interval 0.14 to 0.67), lower respiratory tract disease at 6 months follow-up (relative risk 0.37, 95% confidence interval 0.15 to 0.89), not exclusively breastfeeding at discharge (relative risk 0.41, 95% confidence interval 0.25 to 0.68), and maternal dissatisfaction with method of care (relative risk 0.41, 95% confidence interval 0.22 to 0.75). KMC infants had gained more weight per day by discharge (weighted mean difference 3.6 g/day, 95% confidence interval 0.8 to 6.4). Scores on mother's sense of competence according to infant stay in hospital and admission to NICU were better in KMC than in control group (weighted mean differences 0.31 [95% confidence interval 0.13 to 0.50] and 0.28 [95% confidence interval 0.11 to 0.46], respectively). Scores on mother's perception of social support according to infant stay in NICU were worse in KMC group than in control group (weighted mean difference -0.18 (95% confidence interval -0.35 to -0.01). Psychomotor development at 12 months' corrected age was similar in the two groups. There was no evidence of a difference in infant mortality. However, serious concerns about the methodological quality of the included trials weaken credibility in these findings.

REVIEWER'S CONCLUSIONS

Although KMC appears to reduce severe infant morbidity without any serious deleterious effect reported, there is still insufficient evidence to recommend its routine use in LBW infants. Well designed randomized controlled trials of this intervention are needed.

Intra-umbilical vein injection and retained placenta: evidence from a collaborative large randomised controlled trial. Grupo Argentino de Estudio de Placenta Retenida

OBJECTIVE

To determine whether intra-umbilical vein injection with saline solution, with or without oxytocin, reduces the need for manual removal of placenta compared with expectant management.

DESIGN

Multicenter, randomised controlled trial.

SETTING

Eleven hospitals in four cities of Argentina: Buenos Aires, Corrientes, Rosario, and Salta.

PARTICIPANTS

Two hundred and ninety-one women showing no evidence of placental separation thirty minutes after vaginal delivery.

INTERVENTIONS

Three different management strategies: 1. intra-umbilical vein injection of saline solution plus oxytocin; 2. intra-umbilical vein injection of saline solution alone; and 3. expectant management.

MAIN OUTCOME MEASURES

Primary: manual removal of the placenta. Secondary: blood loss after trial entry, haemoglobin level at 24 to 48 hours and at 40 to 45 days after delivery, blood transfusion, curettage, infection, and days of hospital stay.

RESULTS

Rates of subsequent manual removal were similar: intra-umbilical vein injection of saline solution plus oxytocin (58%; RR 0.92; 95% CI 0.73-1.15), or saline alone (63%; RR 1.00; 95% CI 0.80-1.24), compared with expectant management (63%). There were also no detectable effects of the active managements on any of the secondary measures of outcome.

CONCLUSIONS

Based on evidence available from randomised controlled trials, including this trial, it is unlikely that intra-umbilical injection with or without oxytocin, is clinically useful. We recommend that this intervention should not be used in third stage management of labour.

The Latin American trial of psychosocial support during pregnancy: effects on mother's wellbeing and satisfaction. Latin American Network For Perinatal and Reproductive Research (LANPER)

A randomized controlled trial including 2235 women at high risk of low birthweight was conducted in four Latin American institutions. The objective of this trial was to evaluate a psychosocial support intervention during pregnancy aimed at improving perinatal health and mothers' psychosocial conditions. The core of the intervention was four to six home visits where emotional support, counseling and strengthening of the woman's social network was provided. Outcomes were measured at 36 weeks of pregnancy, post-partum and 40 days after delivery. The intervention was not successful in either altering women's perception of social support and satisfaction with the reproductive experience, as well as maternal and newborn's health care. It is concluded that although high levels of psychosocial distress during pregnancy may play an independent role in determining adverse pregnancy outcomes, this adverse effect does not appear to be ameliorated by psychosocial interventions conducted only during pregnancy, particularly those of a magnitude that can be realistically implemented (in content and frequency) at public care services in most developing countries.

A randomized trial of psychosocial support during high-risk pregnancies. The Latin American Network for Perinatal and Reproductive Research

BACKGROUND

It is often suggested that psychological and social support and health education for women at high risk for delivering a low-birth-weight infant can improve the outcomes of pregnancy, but the evidence is inconclusive. We undertook this prospective trial to evaluate a program of home visits designed to provide psychosocial support during pregnancy.

METHODS

At four centers in Latin America, 2235 women at higher-than-average risk for delivering a low-birth-weight infant were recruited before the 20th week of pregnancy. The women were randomly assigned either to an intervention group (n = 1115) that received four to six home visits from a nurse or social worker in addition to routine prenatal care or to a control group (n = 1120) that received only routine prenatal care (with a mean of eight prenatal visits). The principal measures of outcome were low birth weight (< 2500 g), preterm delivery (< 37 weeks of gestation), and specified categories of maternal and neonatal morbidity.

RESULTS

The women who received the home visits as well as routine prenatal care had outcomes that differed little from those of the women who received only routine care. The risks of low birth weight (odds ratio for the intervention group as compared with the control group, 0.93; 95 percent confidence interval, 0.68 to 1.28), preterm delivery (odds ratio, 0.88; 95 percent confidence interval, 0.67 to 1.16), and intrauterine growth retardation (odds ratio, 1.08; 95 percent confidence interval, 0.83 to 1.40) were similar in the two groups. There was no evidence that the intervention had any significant effect on the type of delivery, the length of hospital stay, perinatal mortality, or neonatal morbidity in the first 40 days. There was no protective effect of the psychosocial-support program even among the mothers at highest risk.

CONCLUSIONS

Interventions designed to provide psychosocial support and health education during high-risk pregnancies are unlikely to improve maternal health or to reduce the incidence of low birth weight among infants.

Biochemical changes associated with blood pressure reduction induced by calcium supplementation during pregnancy

In a study population that comprised 34 normal black pregnant women, biochemical changes are compared between a group of women who received 1.5 gm of calcium supplementation a day and a group of women who received placebos. The blood pressure-lowering effect of calcium supplementation appears to involve a mechanism that relates parathyroid hormone and plasma renin activity. Other alterations in calcium and magnesium metabolism, as reflected by increased urinary calcium excretion and serum magnesium levels, may also contribute to this effect. Subgroups of study participants with initial (less than 26 weeks' gestation) low levels of serum calcium and plasma renin activity are the ones with the largest reductions in blood pressure. Whether these alterations can produce a reduction in the incidence of pregnancy-induced hypertension is the next question to be answered in this area.

Calcium supplementation reduces blood pressure during pregnancy: results of a randomized controlled clinical trial

Fifty-two healthy pregnant women were enrolled in a double-blind, randomized, controlled clinical trial. After the 26th week of gestation, the women were given either 1.5 g of elemental calcium per day or a placebo. Subjects in the calcium group, after adjustment for race and initial blood pressure (BP), had a term mean systolic and diastolic BP value of 4-5 mmHg lower than those in the placebo group (P less than .05). The incidence of pregnancy-induced hypertension was 11.1% in the placebo group and 4.0% in the calcium group, a nonsignificant difference. Combining these values with previous data, we found a dose-effect relationship between calcium intake and BP reduction during the third trimester of pregnancy. Further research should be directed at understanding the mechanism of this effect and trying to demonstrate a reduction in pregnancy-induced hypertension with calcium supplementation in a larger population.

The evaluation of the methods used in the diagnosis of intrauterine growth retardation

Several methods used in the diagnosis of intrauterine growth retardation (IUGR) were evaluated with epidemiologic techniques. The strong effect of IUGR prevalence on the positive predictive and false-positive values of these methods is discussed. If correctly used, the combination of clinical measurements and perinatal risk factors can have a predictive power as high as any of the other more sophisticated techniques. The data reviewed show that at present biparietal diameter measurements, nonstress test/oxytocin challenge test or hormone values do not contribute to a better IUGR prediction than when the above mentioned methods are applied. For IUGR detection, ultrasound evaluation should include ratios of anthropometric measurements and may be complemented with amniotic fluid volume assessment. It is suggested that these procedures be reserved to a selected high risk population. Efforts should be made to evaluate new technologies through randomized controlled trials before they are introduced to the general population, particularly in developing countries.

Epidemiologic observations on the relationship between calcium intake and eclampsia

In Guatemala, the obstetric population has a very low incidence of eclampsia despite the presence of factors that would be expected to favor appearance of the disease. In this study, the eclampsia incidence and calcium intake for three countries, Guatemala (low eclampsia incidence, high calcium intake); Cali, Colombia (high eclampsia incidence, low calcium intake); and the USA (low eclampsia incidence, high calcium intake) have been compared. Crude rates for eclampsia incidence were adjusted to control the effects of well-documented predisposing factors: age, parity, and prenatal care. Results of the study support an association between calcium intake and development of eclampsia.

Reduction of blood pressure with calcium supplementation in young adults

Epidemiologic and animal studies have suggested an inverse relationship between calcium intake and BP. Furthermore, calcium intake seems to be inversely correlated with the incidence of eclampsia in pregnancy. In a randomized clinical trial, young adults were allocated to a calcium-supplemented group receiving 1 g/day of elemental calcium (15 men and 15 women) or a placebo group (14 women and 13 men) for a period of 22 weeks. The calcium-supplemented group showed a significant decrease in diastolic BP; this effect was stabilized after nine weeks in women and six weeks in men. The reduction in diastolic BP was 5.6% and 9% from the initial values for women and men, respectively. This study supports epidemiologic and animal evidence of the effect of calcium intake on BP and suggests the need for more research exploring the mechanisms involved in the observed effect.

The timing factor in the pathophysiology of the intrauterine growth retardation syndrome

Three different types of intrauterine growth retardation can be identified depending on the moment at which supplies to the fetus are diminished. When a reduction in sustenance occurs early in the first trimester of pregnancy, a well-proportioned but growth-retarded baby may be expected. When the negative factors develop around the 30th week of pregnancy, the result is a disproportionately growth-retarded infant. Both types of retardation can be illustrated using longitudinal uterine height and biparietal diameter values and by neonatal anthropometry. Epidemiological examples exist defining factors which produce these two kinds of retardation. The third type occurs when a reduction in food supplies takes place in the last month of pregnancy and causes a depletion of the fetal fat stored. Weight retardation is observed with little or no height impairment. In planning public health activities such as nutrition interventions for developing countries, the type of intrauterine growth retardation present in the target population should be considered in order to determine which type of intervention would be most appropriate, and establish its correct timing.

Breastfeeding in developing countries

The calculated protein and calorie requirements and nutritional status of intrauterine-growth-retarded infants of poor mothers in underdeveloped countries were compared with the estimated amounts of protein and calories supplied in the mother's milk and their nutritional status both before and during lactation. These mothers were only able to provide 69% of the infants' protein requirements at birth, falling to 51% at three months of age 123% of calorie requirements were supplied at birth, falling to 55% at three months. Conversely, in terms of g protein per 100 kcal, 56% of requirements were met at birth, rising to 95% at three months-figures which reflect the decreasing protein requirement with age. Socioeconomic factors determine nutritional status in developing countries and it is the responsibility of governments to ensure the health and adequate nutrition of mothers and infants.

Effects of orciprenaline on uterine contractility and maternal heart rate. A quantitative study

Amniotic pressure and maternal heart rate were recorded continuously and simultaneously in 15 women in labor or prelabor. Orciprenaline (Alupent) was administered through an intravenous infusion pump at the rate of 10 and 20 mug/min. Uterine contractility and maternal and fetal heart rate were measured before its onset and during the infusion. The development and stabilization of the effects were studied. Continuous intravenous infusions of orciprenaline at rates of 10 and 20 mug/min are recommended. They proved to be very useful in obtaining uterine inhibition with a minimum of undesirable side effects.