Nutritional interventions for the prevention of maternal morbidity

Objective: To review the effectiveness of nutritional interventions to prev ent maternal morbidity. Methods: This is an overview of systematic reviews and individual randomized controlled trials (if no systematic review availa ble) of nutritional interventions during pregnancy. For each nutrient inter vention the main maternal morbidity data reported were extracted. These wer e pre-eclampsia/eclampsia, pregnancy-induced hypertension, hemorrhage, anem ia, infection and obstructed labor. In addition, the trial settings, the nu mber of trials and participants' characteristics were systematically extrac ted. Results: The systematic reviews considered in this paper had only few trials that reported the selected maternal outcomes. Outcome measures are b ased sometimes on one trial only. Most of the interventions compared single micronutrient supplementation with placebo/no treatment and did not show s ignificant benefits for the supplementation groups. Calcium supplementation in women at high risk of pregnancy hypertension reduced the incidence of h igh blood pressure (RR, 0.35; 95% CI, 0.21-0.57) and pre-eclampsia (RR, 0.2 2; 95% CI, 0.11-0.43). Similarly, in women with low dietary calcium intake, calcium supplementation resulted in a significant reduction in the inciden ce of high blood pressure (RR, 0.49; 95% CI, 0.38-0.62) and pre-eclampsia ( RR, 0.32; CI, 0.21-0.49). In women at low risk of pregnancy hypertension or with adequate baseline calcium intake, the beneficial effects of calcium s upplementation are small and unlikely to be of clinical significance. Both, iron and folate supplementation reduced the number of women with low pre-d elivery hemoglobin. Conclusions: Routine calcium supplementation seems to b e a promising intervention for pregnant women at risk of developing preecla mpsia or have low calcium intake, but these findings need to be confirmed w ith a trial with adequate power in different settings. In populations with high incidence of nutritional anemia routine iron and folate supplementatio n should be recommended during ante-natal care. It is unclear at this stage if adding vitamin A to iron and folate supplementation in anemia prevalent areas provides further benefits. There is inadequate data on the benefits or harms of routine iron or folate supplementation in adequately nourished populations. With regard to other micronutrient supplementation, such as zi nc, magnesium and fish oil, randomized controlled trials with sufficient po wer to detect clinically important differences in maternal and infant outco mes are needed. (C) 1998 International Federation of Gynecology and Obstetr ics.