The type of nutrition that a mother gets during pregnancy, both qualitatively and quantitatively, can be the deciding factor in a child’s well-being. A study1 showed that there was a small (70 g) but significant increase in birthweight among infants of mothers receiving multiple micronutrients as compared with infants of mothers receiving iron-folic acid supplements – hence signifying the importance of giving not just the traditional supplements. It is essential that the mother intake a very healthy diet: according to American College of Obstetricians and Gynecologists (ACOG), pregnant women should increase their usual servings of a variety of foods from five basic food groups to include the following:
Three to four servings of fruits and vegetables
Nine servings of whole-grain or enriched bread, cereal, rice, or pasta for energy
Three servings of milk, yogurt, and cheese for calcium
Three servings of meat, poultry, fish, eggs, nuts, dried beans, and peas for protein
Separate and specific supplements for the nutrients found in the above foods should only be taken to make sure all the requirements are being met, not as a replacement for a healthy diet.
The specific nutrients required by women in the pre-pregnancy and pregnancy state have already been discussed. This section talks more about the effects that malnutrition (lack of specific essential nutrients) during pregnancy state will have on the health of a child.
The effects being studied in this report focus more on cognition, language, social and emotional behavior.
In order to properly identify the specific effects of malnutrition, it would be beneficial to first allocate a time-period during which development is most sensitive. This period is termed the ‘critical period’ and extends from gestation to first 2 years of life. However this may vary study to study and also with reference to different aspects of development being studied.
A Broad Perspective
Maternal malnutrition, which amounts to a BMI of <18.5 kg/m2, is almost 40% prevalent in regions like India and Bangladesh – which can be considered a critical level.2
Decreased BMI has been linked to various adverse effects on pregnancy.
Cephalopelvic disproportion is one of the major factors that may cause complications during vaginal birth. These include increased chances of hypoxic injury and consequential effects on the brain. Hence decreased BMI is an indicator for assisted birth or Cesarian procedures.
Malnourished pregnant women are more prone to infections like Gardnerella Vaginosis and Candidiasis. Gardnerella may lead to pre-term delivery of a premature baby that has decreased mental functioning.
Undernutrition involves decreased levels of Calcium which leads to abnormalities picked up on Cardiotocography, representing issues in the contractile function of the heart. This may lead to hypoxia.
IUGR has been known to result in placental insufficiency which leads to developmental delays of the fetus.
Malnutrition in the mother initiates a vicious cycle, resulting in an unhealthy baby. In case the baby is a girl, she grows up to be an unhealthy mother and this starts a cycle.
Effects Of Macronutrients
As stated before, what a mother eats during pregnancy can have a profound effect on the development of her baby. In 1986, Barker hypothesized that nourishment in utero can stress the fetus in ways that permanently affected development, creating a ”reprogramming” of the fetus’s developing phenotype-for example, by creating a different insulin response to the nourishment available in utero, which expressed itself in later life as chronic disease. The
”Barker hypothesis” has become widely accepted and grown into the field of developmental origins of health and disease, which seeks to delineate the mechanisms by which unbalanced nutrition in utero and during infancy can permanently affect health.
A pregnant female needs to be given diet counseling and a 24-hour diet-diary helps to serve the purpose of monitoring her eating habits. It should be screened for:
At least five fruits and vegetables
Adequate protein and desirable fats
Intake of appropriate amounts of calories and nutrient-rich foods
Effects of Micronutrients on Cognitive and Behavioral Function
A study in 19953 revealed that there is now evidence that clearly shows that micronutrients may have independent as well as cumulative or interactive effects on behavior.
While not a lot of studies report the specific mechanism in which micronutrient deficiencies cause underdevelopment of the above3. The afore-mentioned study gives a general model of how these may be effected: nutrition ƒ brain development ƒ behavior, suggests that malnutrition affects brain growth and development and hence future behavioral outcomes.
It has also been documented that food supplementation for pregnant women in Taiwan benefited child motor development at 8 months4
The early effects of iodine deficiency in the foetus are probably due to reduced maternal T4 transfer before the onset of foetal thyroidal function. During the first trimester of pregnancy, the foetus is fully dependent on maternal T4. This maternal T4 is converted by type II deiodinase, thereby providing the developing foetal brain with T3, which is the active hormone that binds to specific nuclear receptors. Foetal thyroid function becomes active only in the second trimester. At birth, 20-40% of the T4 measured in cord blood is still originating from the mother, indicating that iodine deficiency of the mother will affect the thyroid status of her newborn
Iodine is a clear example of a nutrient that, if deficient during the critical period, has long-term adverse effects on brain development. It has in fact been described as the world’s greatest single cause of preventable brain damage and mental retardation5
Speaking with reference to our own setting, The Southeast Asia region accounts for 26% of the global population with insufficient iodine intake6
The deficiency has been classified as mild (50-99 mg/day); moderate (20-49 mg/day); severe (o20 mg/day) and its damaging influence lies in the fact that it plays a role in thyroid hormone synthesis. Thyroid hormone is essential for metabolism of various cells and has been reported to play a role in various neurobiologic processes, such as neurogenesis, neuronal migration, axon and dendrite formation, myelination, synaptogenesis and neurotransmission.
Severe iodine deficiency during pregnancy has been shown to increase the risk of stillbirths, spontaneous abortions and congenital abnormalities. Of these, the most severe is
cretinism, which is a state of mental retardation mostly in combination with dwarfism, deaf-mutism and spasticity.6
Also, it has been shown that the intellectual functioning and motor skills of the offspring of mothers with iodine deficiency were impaired7
Differences in psychomotor development of iodine-deficient children becomes apparent after the age of about 2.5 years6
According to a World Health Organization (WHO) review of nationally representative surveys from 1993 to 2005, 42% of pregnant women have anemia worldwide. Amongst this massive number, almost 90% of anemic women reside in Africa or Asia.8
This number is so high because the women of childbearing age are at risk for iron-deficiency a) because of blood loss during menstruation and then b) increased iron demands during pregnancy.
An analysis done to evaluate maternal mortality in anemic pregnancy also estimated the effect of anemia on child cognition2
The combined analysis of the five available trials found 1·73 (95% CI 1·04-2·41) lower IQ points per 10 g/L decrease in haemoglobin. A separate meta-analysis of iron supplementation trials showed an overall benefit of 1-2 IQ points, in children receiving iron, but there was no effect in children younger than 27 months9
The fact that the annual incidence of spina bifida fell sharply from a range of 2.34 – 4.03/1000 to 2.11/1000 between ’91 to ’96 after flour supplementation with iron and folate, shows that iron deficiency plays a major role in causing neurological defects in children.10
Other micronutrient deficiencies of concern in maternal and child health include calcium, iodine, the B vitamins (especially folic acid and vitamin B12), and vitamin D.
Vitamin D deficiency in utero can cause poor fetal growth and skeletal mineralisation and is followed by lower concentrations of the vitamin in breast milk. Rickets and poor bone mineralisation subsequently appear during the first years of life.
Vitamin D has also been known to play a role in glucose regulation, immune function, and good uterine contractility in labor11
A study investigating Vitamin A12,showed that supplementation does not affect the risk of maternal mortality, perinatal mortality, neonatal mortality, stillbirth, neonatal anaemia, preterm birth or the risk of having a low birthweight baby. It has, however shown to reduce risk of maternal clinical infections, which may be considered to consequently be of help to neonatal health.
It also plays a critical role in visual perception and a deficiency is the leading cause of childhood blindness13
Vitamin A also has a role in cell differentiation, the immune system and reproduction. Vitamin A is particularly important during periods of rapid growth, both during pregnancy and in early childhood.
The fetus is relatively protected from calcium deficiency in utero but a deficiency may cause CTG abnormalities as mentioned previously.
Vitamin B12 plays a pivotal role in forming RBCs and synthesis of DNA. A deficiency results in pernicious anemia which leads to constant fatigue and breathlessness. It also helps in formation of myelin sheath and a deficiency would lead to neuropathy and nerve degeneration.
Hence an adequate supply of vitamin B is required during pregnancy.
Folate levels need to be substantial atleast 3 months before conception, and need to be supplemented before and during pregnancy for a healthy pregnancy. Poor folate levels at the time of conception are known to cause neural tube and other birth defects, preterm delivery and possible pre-eclampsia. Additionally, folate-related anemia may continue into later stages of growth and lead to increased predisposition to infections.