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close this book04. Micronutrients and Pregnancy Outcome
View the document(introduction...)
View the documentSummary
View the documentIntroduction
Open this folder and view contentsIron
View the documentVitamin A
View the documentFolic Acid
View the documentZinc
View the documentIodine
View the documentMagnesium
View the documentCalcium
View the documentVitamin C
View the documentVitamin B1 (Thiamine), Vitamin B6, (Pyridoxine), Vitamin B12 (Cobalamin)
View the documentDiscussion
View the documentReferences

Discussion

As can be seen from table one, there is a large body of evidence supporting the concept that deficiencies in micronutrients adversely affect maternal health and pregnancy outcome. It is important to underline here that not one micronutrient alone is responsible for this adverse effect. It is therefore very unlikely that the supplementation or correction of one deficiency will yield high effects, as long as other deficiencies remain. There is no magic bullet to improve maternal and child health through a single nutrition supplement. What the possible effect would be of a multivitamin-mineral supplement, which would cover all needs of pregnant women, is at present impossible to tell. So far no controlled supplementation studies have published their results, and few are under way (Scholl & Reilly 2000).

A second consideration is that most of the described effects and results of supplementation relate to overt deficient subjects. It is therefore difficult to translate the effect of a supplementation to the general population or to make generalisations for all populations. Most of the controlled supplementation studies have also been performed in populations of industrialised countries where deficiency states are less frequent. The observed effects might thus be an underestimation of what one could expect in a developing country. So far very few studies are available in these population groups.

Table 1. Overview of the effects of micronutrients on pregnancy outcome

Micronutrient

Maternal mortality

Birth weight

Preterm delivery

Delivery complications

Pre-eclampsia

Remarks

Iron

Possible

Yes, U shaped relation

Yes, U shaped relation

Probable

No info

Lack of controlled supplementation studies

Vitamin A

One study only Not clear

Possible

Possible

Hiv transmission risk decreased

B carotene


Iodine

Not documented

Yes

Yes

Not documented

Not documented

Important congenital malformations

Zinc

Not documented

Yes

Yes


Yes

Effect is clear in deficiency states

Folate

Not documented

Not documented

Not documented

Abortions Congenital malformations

Not documented

The need for a minimal dietary intake to protect congenital malformations is clearly established

Magnesium

Not documented

Possible

Possible

Decrease documented

Not clear

No evidence enough to support a general supplementation

Calcium

Not documented

Possible

Possible

Possible

yes

Effects found in risk groups or groups with low calcium intake

Vitamin C

Not documented

Not documented

Possible

Abruptio?

Possible

Very few studies

Thiamine B1

Not documented

IUGR?

Not clear

Not clear

Not clear

Very few studies

Pyridoxine B6

Not documented

possible

Possible

Better Apgar scores

Possible

Very few studies

Cobalamin B12

Not documented

Not documented

Not documented

Not documented

Possible

Very few studies

For some deficiencies the maximum effect of a correction is found when this happens in early pregnancy. For folic acid the supplement should ideally be given before conception and the highest effects of an iron supplement can be expected when taken in the first trimester. This, however, has major repercussions on the implementation strategies. In developing countries, women usually don’t consult for a pregnancy until well in the second half of pregnancy. This is often too late to correct a deficit and find a consequent improvement in maternal and child health. Providing supplements also means that the health system must be able to provide the supplements on a regular basis and with certain continuity. The experience with iron supplements has demonstrated that this is usually where the strategy is flawed. Drug availability is often erratic and health services are not always accessible throughout the year.

The cost of a supplement is also not negligible and varies from 1 to 8 US dollars for iron supplementation programs, according to the study and the way the costs are calculated.

The effect of a supplement of iron is also mitigated by the confusion between iron deficiency and anaemia itself, which has a much wider causality. Often the underlying causes of anaemia, other than iron, are poorly addressed and many of the studies suggest that the confounding might be more important than iron deficiency. Low haemoglobin values during pregnancy should be first addressed with a strategy to correct anaemia in a broad sense in which iron deficiency is only one of the many possible factors. It is highly likely that effects on maternal health will be much more important than with provision of iron alone.

It seems thus that apart from an iodine fortification program, there is little scope for improving the micronutrient status of pregnant women with supplementation programs alone. Hope of achieving an improvement must lie in upgrading the nutritional status of women of childbearing age in general and providing nutritional advice during pregnancy. A nutrition approach should be integrated in ante natal care programs. The challenge will be how to define the role of the health services in both specific activities during the ante natal care program, as in a more development directed approach. Judging from the experiences so far, the results will be slow in coming, and they will need an intersectoral approach given the multicausal nature of the problem. It would be good if an intermediate solution could be found. This will need to be found in a supplementation of all micronutrients needed in pregnancy. Since no results of such studies are available, there is an urgent need to do a large scale controlled supplementation intervention study.