|Nutrition and Population Links - Breastfeeding, Family Planning and Child Health - Nutrition Policy Discussion Paper No. 11 (ACC/SCN, 1992, 68 p.)|
Prema Ramachandran, Indian Council of Medical Research, New Delhi, India.
Ancient folklore and medical knowledge emphasize that the mother-child dyad is a vulnerable group from a health and nutritional point of view. Nutritionists have shown that these segments not only require more dietary intake but are also more susceptible to adverse health consequences following nutritional deprivation. Global studies have unequivocally demonstrated the association between undernutrition and increased risk of maternal, perinatal and infant mortality and morbidity. Results of small scale clinical trials of food supplementation to undernourished groups suggest that reduction in morbidity and mortality rates and improvement in birth weight and growth in infancy could be achieved by food supplementation.
Based on these findings massive food supplementation programmes aimed at improvement of maternal and child nutritional status among poorer segments of the population were initiated by many developing countries. Very few of these programmes have been formally evaluated. Critics argue that by and large these programmes have not produced any significant improvement in maternal and child health or nutritional status. This, they claim is partly due to administrative bottle necks and logistic problems in getting the food to the target women. Even if this was achieved, food sharing and food substitution were so common that the net increase in dietary intake was no more than 100-150 kcal/day. There is also a growing awareness that unless coupled with health care, increasing food intake alone might not result in improved nutritional and health status of the individual. Because of the increasing awareness of these problems, the newer programmes, like the integrated child development scheme in India, try to achieve an integration of food supplementation, health care and health education.
Recent studies have highlighted some more issues. In undernourished communities any reduction in dietary intake below habitual level is associated with adverse effects on nutritional status of the mother child dyad and reproductive and lactational performance. In many developing countries about a third of all pregnancies occur in lactating women. Many of these women continue to breastfeed their infants. The dual stress of pregnancy and lactation has been shown to have an adverse effect on maternal and infant nutritional status and health.
With mounting social and economic pressures the number of women taking up nontraditional work outside home is rapidly increasing. The stress of work at and outside from home might under some circumstances result in deterioration of nutritional status of the mother-child dyad. However given minimal extra inputs, the increased purchasing power due to gainful employment of women outside home might contribute towards improvement in health and nutritional status of mother child dyad. Data from some of the recent studies on nutritional status and its influence on the mother-child dyad will be briefly reviewed in the following pages.
Effect of Pregnancy on Maternal Nutritional Status
Nutritionists believe that pregnant women need more food to meet the nutrient demands of the growing foetus in utero. Some of the earlier studies and computations suggest that an extra intake of about 300 kcal/day at least in the later half of pregnancy is needed.1,2 However, diet surveys indicate that even in developed countries among women who do not have any economic constraints dietary intake during pregnancy is essentially similar to the intake in the pre-pregnant period; often well below the recommended dietary allowances without any apparent adverse effect either on maternal nutritional status or outcomes of pregnancy. 3,4 Recent studies using currently available sophisticated precision instruments suggest that in pregnancy there is a dip in basal metabolic rate and work activity from mid trimester.5 It is now believed that the nutrient saving from this reduction, might be of sufficient magnitude as to meet the needs of foetal growth, and that well nourished women may not need extra dietary intake during pregnancy.
In women from developed countries the average weight gain during pregnancy is about 12 Kg of which 4 Kg. is due to deposition of body fat.1,3,4,6 It was believed that this fat deposition was essential to meet the rapidly increasing nutrient needs in late pregnancy and lactation. However recent studies suggest that these women seldom lose the extra fat deposition in pregnancies or lactation unless they take deliberate steps to reduce weight by reducing dietary intake. The weight (fat) gained remains and forms the beginning of problem of obesity in later life.1
Women from developing countries especially those from poorer segments of the population subsist on diets which contain only 1200 - 1800 kcal/day and are inadequate with respect to all nutrients. There is no increase in dietary intake during pregnancy either. In spite of the continued low dietary intake, they go through pregnancy without any marked deterioration in nutritional status. The weight gain in pregnancy is about 6 kg and the fat loss ranges from 0-2 kg at the end of pregnancy. There is no deterioration in maternal nutritional status with increasing parity provided the inter-pregnancy interval is about 3 years.7 These data suggest that among women habitually subsisting on a low dietary intake, there is no deterioration in maternal nutritional status even if dietary intake, does not improve during pregnancy. However data from Gambia demonstrate that a further reduction in dietary intake especially when combined with increased physical work, would result in deterioration in maternal nutritional status.8 Studies from India have shown that continued lactation during pregnancy has a similar detrimental effect on maternal nutritional status.7 Steps to reduce physical activity and promote birth spacing might form effective non-nutritional interventions to prevent deterioration in maternal nutrition. Supplementary feeding during the pre-harvest season might help in preventing deterioration in maternal nutrition associated with decreased dietary intake, and heavy manual labour.8
Effect of Maternal Nutrition on Pregnancy
Computations based on studies undertaken in the early fifties had shown that the maternal and perinatal mortality rates were higher and birth weight of infants was lower in countries and communities where maternal dietary intake was low during pregnancy.9,10,11,12 Based on the data from these studies and theoretical computations of dietary requirements during pregnancy it was suggested that unless extra nutrient needs during pregnancy were met, the course and outcome of pregnancy might be compromised.
However studies undertaken by the Medical Research Council at Aberdeen (UK)3 and by Vanderbilt University in U.S.A.4 showed that in well nourished women dietary intake varied considerably without any adverse impact on either on maternal nutritional status during pregnancy or outcome of pregnancy. Studies conducted in New Guinea indicated that a similar situation existed in some developing countries.13 These studies also indicated that the majority of pregnant women, if allowed to eat according to their appetite did not consume more food during pregnancy.3,4,13
Dietary intake of the majority of women from poorer segments of the population in developing countries is very low and undernutrition is common. Anaemia and undernutrition antedate pregnancy. Dietary intake continues to remain quite low throughout pregnancy. Undernutrition and anaemia often get aggregated during pregnancy and consequently maternal morbidity, mortality and perinatal mortality rates are high among women belonging to this segment of population.7,10,11,12 Available data suggest that there is a close association between maternal undernutrition (as indicated by maternal body weight and haemoglobin status) and low birth weight. However in depth analysis of data suggest that the association is, at least in part attributable to coexistent adverse environmental factors and poor health care.7,10,11,12
Several investigators have attempted to improve the existent low dietary intake by food supplementation programmes, with the hypothesis that increased dietary intake and consequent improvement in maternal nutritional status should result in improvement in outcome of pregnancy and birth weight. Results from some of the closely supervised small scale studies undertaken in the early sixties did in fact suggest that food supplements might improve the birth weight of the offspring by about 200g.14,15 However, in these studies women were under close medical supervision throughout the latter half of pregnancy; it is possible that some of the observed benefits might be attributable to early detection and prompt treatment of obstetric and other health problems in these women.
Data from large scale community based studies on the effects of food supplementation on pregnant women have not been encouraging.11,15,16,17 One of the major problems in such studies is to ensure that the woman in fact took the food supplements. Many supplements were no more than substitutes for a home meal; in others, foods sharing reduced the quantity of food supplement consumed by the pregnant women. In either case the net increment in the dietary intake of pregnant woman was quite low.
Studies from Guatemala15 and Gambia18 have shown that even among those women whose net calorie intake was improved by 500 - 700 kcal daily, the improvement in maternal body weight and birth weight was observed only among the women whose body weight was very low.11 Thus, a review of the available data suggests that food supplementation, unless given to those whose food consumption has been reduced below habitual level and combined with adequate antenatal care, might not be a very effective, feasible and economical method of combating maternal undernutrition and adverse pregnancy outcome. However, if food supplementation is used as a tool to ensure enrolment of pregnant women and delivery of appropriate antenatal care services among poorer segments of the population in developing countries, it might result in a considerable improvement of the health and nutrition status of the mother-child dyad.
It has long been recognized that anaemia is a major nutritional problem in pregnant women. The association between anaemia on the one hand and lower birth weight, higher perinatal mortality and increased maternal morbidity and mortality has been well documented.19 More recent investigations have shown that anaemic women form a high risk group and at least part of the adverse outcome seen in association with anaemia is attributable to the obstetric and other health problems in anaemic women. Studies undertaken in the National Institute of Nutrition, India and elsewhere have shown that effective treatment of anaemia, preferably in the second trimester of pregnancy, and provision of adequate antenatal care to anaemic pregnant women resulted in a significant reduction in the adverse obstetric outcome seen in association with anaemia.7,21
Ample data exist to show that administration of oral iron to women would prevent any fall in maternal haemoglobin levels during pregnancy. Based on this the National Prophylaxis Programme of Iron and Folate distribution to pregnant women was initiated. The preliminary data from evaluation of this National programme suggest that there are several bottlenecks which come in the way of the tablets reaching all pregnant women in the country including problems in identification of pregnant women and ensuring that they get the tablets. Even when this is ensured many women do not take the tablets regularly. In India anaemia antedates pregnancy and gets aggravated during pregnancy; the dosage of the tablet administered in the prophylaxis programme is not sufficient for treatment of anaemia. Screening of all pregnant women for anaemia as a part of antenatal care, treating those who are anaemic appropriately and administering prophylactic iron folate tablets to non-anaemic women might be essential to eradicate anaemia and its adverse impact during pregnancy.7 As a long term programme, ensuring consumption of salt fortified with iron would improve iron and haemoglobin status of the whole population including women prior to the occurrence of pregnancy.
Effect of Lactation on Maternal Nutrition
Lactating women secrete about 500-800 ml milk a day and lactation involves energy loss of about 500-600 kcal a day. Nutritionists recommend an additional dietary intake of up to 500 kcal/daily to meet the extra nutrient needs of lactating women.2 However, studies undertaken in developing countries indicate that among poorer segments of the population, dietary intake does not increase during lactation. In spite of continued low dietary intake, lactating women lose only about 1-2 kg of weight during the first year of lactation. With waning lactation, these women tend to regain their body weight over the next year or two, provided they do not become pregnant during this period.21 Obviously adaptive changes have been evolved over millennia to ensure that lactation does not result in deterioration of maternal nutritional status. However, there are limits beyond which these adaptive processes also fail. The added stress of manual work and reduction in dietary intake was shown to be associated with weight loss in lactating women in Gambia.8 Studies from India had shown that the added stress of pregnancy and continued lactation resulted in a reduction in maternal weight.7
Studies in Gambia have demonstrated that the food supplements to lactating women do not result in improvement in body weight.22 These data suggest that with the availability of food, reversal of adaptive processes is given precedence over body weight gain. Weight gain is one of the parameters widely used for evaluation of the food supplementation programmes. Data from Gambia22 and elsewhere22 suggest that at least in pregnant and lactating women, weight gain may not follow improvement in dietary intakes and so should not be used as a parameter to evaluate the success of food supplementation.
Effect of Maternal Nutrition on Lactation
Ample data exist to suggest that maternal undernutrition does not have any adverse effect on duration of lactation. The mean duration of lactation in undernourished women from poorer segments of the population in developing countries ranges from 18-26 months. Obviously this is a protective adaptation evolved over time to ensure that maternal undernutrition does not have any adverse effect on the breastfed infant.23
During the last few years, information regarding volume of milk ingested by solely breastfed infants in developed and developing countries has become available. These data suggest that undernourished mothers do secrete an adequate quantity of milk especially considering the fact that their infants are lighter.8,23 However, if over and above the existing moderate maternal under-nutrition, there are additional stress factors like reduction in dietary intake, increase in work8 or advent of next pregnancy23, then the volume of milk secreted tends to fall.
Studies from developed and developing countries have indicated that they are no significant differences in the calorie content or proximate principle composition between milk secreted by well nourished and undernourished women.24 However, there are some variations in the fat content of the milk; vitamin and mineral concentrations are lower in the breast milk of undernourished women.
Obviously nature has evolved adaptive processes to ensure that infants get an adequate quantity of milk containing appropriate nutrients for a sufficiently long time to ensure their normal growth and survival in spite of chronic moderate maternal undernutrition.
Nutritional Consequences of Conception During Lactation
It is well documented that lactation prolongs postpartum amenorrhea and provides protection against pregnancy in the first few months of lactation. However, with increasing duration of lactation, the contraceptive effect wanes off. Among traditional low income groups of women, prolonged lactation for 20-30 months is common; contraceptive use is not widespread in these women. Under these circumstances about 1/3rd of all pregnancies occur in lactating women. Studies conducted in the National Institute of Nutrition, India, showed that conception during the first year of lactation is not common (15.8%) and tends to occur in working women and those who introduce supplements to breastfed infants early in the third or fourth month of lactation. The majority of conceptions occur during the second (33.6%) and third year of lactation (51.6%). A substantial number of women continue to breastfeed their infants during pregnancy and face the concurrent dual stress of pregnancy and lactation.
Diet surveys undertaken among women who had conceived during lactation have shown that their food intake is essentially similar to the non-pregnant women. It is possible that the dual stress of pregnancy and lactation would widen the already yawning gap between actual intake and nutrient requirements in this group of women.
Irrespective of the duration of lactation and period of gestation, women who continued lactating during pregnancy (Study group) had lower body weights than their non-lactating pregnant counterparts (control group). The differences in body weight were more marked in the small group of women who had conceived during the first six months of lactation.23
A comparison of the reproductive performance between the study and control group indicated that there were no significant differences in the course and outcome of pregnancy. However, birth weights were significantly lower both in the study and control group women in whom the interpregnancy interval was less than one year. Infants born to mothers who conceived within 6 months of lactation had lower birth weight and higher infant mortality rate.23
These studies have demonstrated that a short interpregnancy interval and conception during lactation have an adverse effect on maternal and infant nutrition, birth weight and infant survival. Ensuring adequate contraceptive care at an appropriate time to lactating women might therefore constitute an important non-nutritional intervention in reducing the magnitude of maternal and infant undernutrition among poorer segments of the population in developing countries.
Nutritional Consequences of Gainful Employment of Women
Womens participation in economically productive activity outside the home is not a new phenomenon. Mankind evolved in circumstances where families worked together in traditional, agricultural and other activities both in and outside home, and so, have evolved adaptive processes to ensure that these activities do not have a lasting adverse effect. Over the last few decades, due to socio-economic pressures, increasing urbanization and mechanization of agricultural activities have resulted in urban and rural women seeking employment outside home in nontraditional activities. It is estimated that in India working women constitute about 12% of the total population and the number is increasing every year.
Some of the recent studies have shown that the dual stress of work in and outside home has had an adverse effect on maternal nutritional status, reproductive performance, lactation and infant health. It is, however, possible that employment outside home might benefit working women and her family by increasing their purchasing power.
Results of studies undertaken in the National Institute of Nutrition, India, had shown that irrespective of socio-economic class all working women perceived that child care, especially during the first 6 years, is a major problem. In the urban upper and middle income group, work outside home was not associated with any alteration in health, nutritional status or reproductive performance of women. The extra income was useful in improving the standard of living for the family, providing better education for the children and planning for financial security after retirement.
In the low middle income group among women employed in jobs involving moderate physical activity because of the increased purchasing power there was some improvement in maternal nutritional status, as assessed by body weight.
In rural areas the women from families of landless labourers and marginal farmers perform heavy manual work and subsist on very low wages. Because of poor dietary intake and dual stress of work at home and manual labour outside home, the majority of these women are undernourished and weigh less than housewives from the same community.23
Studies from Gambia have also shown that heavy manual labour and low dietary intake have an adverse effect on maternal body weight both during pregnancy and lactation8. Rural women have to continue to work outside home in order to ensure that there is no further deterioration in purchasing power of the family. However, imaginative intervention programmes if effectively implemented might go a long way in reducing the physical work done-at home and at work and help in improvement of maternal nutritional status.
Infant Feeding Practices and Infant Nutrition
It is now well accepted that breast feeding is the best form of infant feeding for all segments of the population in all countries. Breast milk provides appropriate nutrients in adequate quantities to ensure optimal growth in early infancy. Presence of anti-infective factors in breast milk and the fact that breast milk reaches the infant without any contamination ensures minimal mortality due to infection in breast fed infants. Available global data from all segments of the population suggest that up to 6 months of age solely breastfed infants grow as well as those who receive supplements. It would therefore appear that, contrary to theoretical predictions based on recommended dietary allowances during infancy, breast milk alone might be sufficient to support the growth of infants up to 6 months of age. Wherever possible, growth of infants should be monitored by monthly weighing. If the infant is growing normally and appears to be satisfied by breast feeding alone, it is not necessary to introduce supplements before 6 months of age.23,25 In communities where weighing is not possible, if the child is not thriving, or crying (due to hunger) soon after breast feeds, supplements may be introduced before 6 months. In the absence of these problems it might be advisable not to introduce supplements prior to 6 months of age because under the existing conditions of poor environmental sanitation such a practice is associated with increased risk of morbidity due to infection and consequent under nutrition.25
A wide variety of processed cereal-pulse based supplements are available on the market. They are widely used by the urban mothers belonging to middle and high income groups. Recipes for a large variety of low cost home made infant food supplements prepared from locally available foodstuff like cereal, pulse sugar and jaggery have been published by several institutions in India. However, community based studies have shown that very few women are able to prepare these special foods daily. Even when prepared these weaning foods become heavily contaminated with bacteria and if fed a few hours after preparation can cause diarrhoea. It would therefore appear that giving freshly cooked unseasoned rice or wheat and pulse twice a day might be the most feasible method of introducing supplements to breastfed infants under the existing condition in India. It is important that over the next 6 months the infant gets used to eating almost the whole range of adult food when it is freshly cooked. Studies from the National
Institute of Nutrition, India have shown that this practice was associated with a tripling of birth weight by the first year, relatively low morbidity due to infection and a reasonably long interpregnancy interval even in the absence of contraceptive care. Delay in introduction of supplements beyond 6 months of age is associated with growth faltering and increased susceptibility to infection due to undernutrition.23 It is essential to ensure that health education messages advocating introduction of freshly cooked cereal pulse based semi solid supplements to infants by 6 months of age, reach and are followed by urban rural women from low income groups in developing countries.
Mild and moderate degrees of maternal undernutrition continue to be widely prevalent among poorer segments of the population in developing countries. The majority of these women consume only 1200 - 1800 kcal/day throughout their reproductive years. Due to ill understood but effective adaptive processes, the continued low dietary intake during pregnancy and lactation does not result in further deterioration of maternal nutritional status provided a) the inter pregnancy interval is over 3 years; b) there is no further reduction in dietary intake and/or increase in physical activity. Chronic mild and moderate maternal undernutrition does not have any adverse effect on duration of lactation, quantity or quality of milk secreted. Solely breastfed infants double their birth weight by 6 months, and if supplements are begun by 6 months triple their birth weight by the first year. Ideally, food for adequate nutrition and health care should be available to all those who need it. Since this could not be achieved easily. An attempt was made during the 1970s to provide food supplements to identified vulnerable segments of the population: pregnant women, lactating women and preschool children. Because of the bottlenecks in reaching the most needy, difficulty in ensuring that supplements result in the expected increase in net dietary intake and problems in providing appropriate health care, these food supplementation programmes did not have the expected beneficial impact on maternal and child health.
It is however possible that if efforts are concentrated on reaching women belonging to the three readily recognizable high risk groups (those whose dietary intakes are falling below habitual level, those who are performing heavy manual labour and those who face the dual stress of pregnancy and lactation) and providing them with food supplements and health care as a package, the beneficial impact might be substantial.
Chronic moderate maternal undernutrition and anaemia have been shown to be associated with adverse outcomes of pregnancy. Food supplementation coupled with effective treatment of anaemia and adequate antenatal care to detect and promptly treat obstetric problems in the high risk groups would ward off these adverse effects.
The dual stress of lactation during pregnancy results in deterioration in maternal nutritional status especially when the interpregnancy interval is less than 1 year. Contraceptive care initiated at the appropriate time during lactation would go a long way in preventing the adverse effect of the advent of the next pregnancy during lactation.
Among rural low income groups, womens heavy manual work in agricultural operations coupled with low dietary intake does have an adverse effect on maternal nutritional status especially during pregnancy and lactation. Innovative, inexpensive labour saving devices might reduce hard physical labour in these women and might prevent deterioration in nutritional status especially when coupled with a food supplementation programme to ensure that further reduction in dietary intake does not occur in the pre-harvest season.
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Kathleen Merchant, Stanford Center for Research in Disease Prevention, Palo Alto, USA.
It is obvious that the phenomena of lactation concurrent with pregnancy is occurring commonly. Dr Ramachandran reports that one third of all pregnancies occur in lactating women in a sample from India and we have found that one half of all pregnancies occur in lactating women in our sample from Guatemala. Therefore, clearly it is worthy of further attention from researchers and those in health service delivery.
There are two aspects of Dr Ramachandrans message that concern me. In particular, I am concerned with the repeated reference to adaptive processes, a vague notion that is commonly invoked to explain discrepancies in our quantification of energy balance of human female reproductive processes of pregnancy and lactation. Rather than evidence of adaptive processes, these apparent energetic discrepancies are likely to be evidence of our inadequacies in measurement of two difficult components of energy balance, dietary intake and physical work expenditure. As was acknowledged, biological mechanisms for these adaptive processes have not been identified as yet. I have not seen thorough, reliable quantification of dietary intake in free-living populations that provides enough accuracy to warrant the conclusions that adaptive processes with no apparent negative consequence to mother or child are operating.
The investigators studying the Gambian population have recently reported the discovery of large inaccuracies in previously reported dietary data that call into question their conclusions regarding these purported adaptive processes. Unless we are cautious with respect to use of this explanation, a number of inconsistencies arise in our interpretation of available data. The generalization that women from developing countries ... in spite of continued low dietary intake ... go through pregnancy without any marked deterioration in nutritional status obscures two of your later crucial observations that there is no deterioration in maternal nutritional status with increasing parity provided that interpregnancy interval is about 3 years and that data from Gambia demonstrate that a further reduction in dietary intake especially when combined with increased physical work, would result in deterioration in maternal nutritional status. The importance of these later two statements should not be underestimated.
This brings me to my second concern. What percentage of marginally nourished or undernourished women in India have interpregnancy intervals of about 3 years? I would venture to guess that this percentage is relatively low, particularly since Dr Ramachandran reports that one third of women become pregnant during lactation and one hundred percent of these occur within the first three years of lactation, with about 50% in the first two yours of lactation. This causes me to question whether a conclusion that Due to ill-understood but effective adaptive processes the continued low dietary intake during pregnancy and lactation does not result in further deterioration of maternal nutritional status is appropriate given that one of the conditions on this statement may be met in relatively few cases.
Finally, I would like to add that in our research in Guatemala, we found that a non-pregnant/non-lactating interval was important for the adequate recuperation and repletion of maternal fat stores. Therefore emphasis on the solely non-pregnant interval may result in the inadvertent oversight of the importance of a potentially recuperative non-lactating interval.