Effects of calcium supplementation during pregnancy on maternal, fetal and birth outcomes

Meeting the challenges of micronutrient malnutrition in the developing world

BACKGROUND

Malnutrition still remains one of the major public health challenges, particularly in developing countries. Major risk factors for undernutrition such as suboptimal breastfeeding and micronutrient deficiencies (vitamin A and zinc) are responsible for more than one-third of all under five child deaths and 11% of the global total disease burden.

SOURCES OF DATA

Several strategies have been employed to supplement micronutrients. These include education, dietary modification, food provision, supplementation and fortification either alone or in combination.

AREAS OF AGREEMENT

Supplementation is the most widely practiced intervention while fortification can also be a potentially cost-effective public health intervention and target a larger population through a single strategy. Universal coverage with the full bundle of interventions including micronutrient provision, complementary foods, treatments for worms and diarrheal diseases and behavior change programs package could be the way forward in achieving the Millennium Development Goals (MDGs).

AREAS OF CONTROVERSY

Bio-fortification and agricultural interventions including home and school gardening are relatively newer strategies and require further research as they have the potential to impact nutritional status of populations at large.

GROWING POINTS

Effectiveness of the various interventions is well recognized; however, consensus needs to be built around approaches to scale up coverage and delivery strategies to reduce disparities and provide equitable access.

AREAS TIMELY FOR DEVELOPING RESEARCH

Future studies should focus on evaluating various approaches to address malnutrition with a standard methodology and defined outcomes. This will help gauge the actual morbidity and mortality impacts of these specific interventions and the long-term viability of these programs. On a broader scale, strategies to address food insecurity and poverty alleviation are the key as these are complex sustainable development issues, linked to health through malnutrition, but also to sustainable economic development, environment and trade.

Biological mechanisms for nutritional regulation of maternal health and fetal development

This review paper highlights mechanisms for nutritional regulation of maternal health and fetal development. Malnutrition (nutrient deficiencies or obesity) in pregnant women adversely affects their health by causing or exacerbating a plethora of problems, such as anaemia, maternal haemorrhage, insulin resistance, and hypertensive disorders (e.g. pre-eclampsia/eclampsia). Maternal malnutrition during gestation also impairs embryonic and fetal growth and development, resulting in deleterious outcomes, including intrauterine growth restriction (IUGR), low birthweight, preterm birth, and birth defects (e.g. neural tube defects and iodine deficiency disorders). IUGR and preterm birth contribute to high rates of neonatal morbidity and mortality. Major common mechanisms responsible for malnutrition-induced IUGR and preterm birth include: (i) abnormal growth and development of the placenta; (ii) impaired placental transfer of nutrients from mother to fetus; (iii) endocrine disorders; and (iv) disturbances in normal metabolic processes. Activation of a series of physiological responses leading to premature and sustained contraction of the uterine myometrium also results in preterm birth. Recent epidemiologic studies have suggested a link between IUGR and chronic metabolic disease in children and adults, and the effects of IUGR may be carried forward to subsequent generations through epigenetics. While advanced medical therapies, which are generally unavailable in low-income countries, are required to support preterm and IUGR infants, optimal nutrition during pregnancy may help ameliorate many of these problems. Future studies are necessary to develop effective nutritional interventions to enhance fetal growth and development and alleviate the burden of maternal morbidity and mortality in low- and middle-income countries.