nutrition and micronutrients in pregnancy advances in maternal and neonatal health

Nutrition and Micronutrients in Pregnancy

Advances in Maternal and Neonatal Health

2Nutrition and Micronutrients in Pregnancy

Evidence of Nutritional Intervention Effectiveness

Maternal malnutrition

Folate

Iron

Iodine

Vitamin A

Zinc

Calcium


Maternal Malnutrition and Pregnancy Outcome

Severe nutritional deprivation (Netherlands 1944–45)

Birth weight significantly influenced by starvation Perinatal mortality rate not affected No increase incidence of malformation In healthy women, state of near starvation is needed to

affect pregnancy outcome Severe nutritional deprivation (Netherlands 1944–46)

Periconception: Decreased fertility, increased neural tube defect

1st trimester: Increased stillbirths, preterm births, early newborn deaths

3rd trimester: Low birth weight, small for gestational age, preterm birth

Cunningham et al 1997; Susser and Stein 1994.


Maternal Malnutrition and Pregnancy Outcome (continued)

Dietary restriction trials in pregnant women

High weight for height or high weight gain Inconclusive results to demonstrate or exclude effect on

fetal growth or any significant effect on other outcomes Mixed result with nutritional supplementation trials

High protein: No evidence of benefit on fetal growth Balanced protein and energy: minimal increase in average

birth weight (~30 g) and small decrease in incidence of small for gestational age newborns

Women manifesting nutritional deficits can benefit from a balanced energy/protein supplementation

Enkin et al 2000; de Onis, Villar and Gülmezoglu 1998.


Folic Acid

Strong evidence that folic acid prevents preconceptionally recurrent and first occurent neural tube defects

Increasing evidence that folic acid reduces risk of some other birth defects

Improves the hematologic indices in women receiving routine iron and folic acid

USPHS/CDC recommends for US women

400 g/day: All women in childbearing age 1 mg/day: Pregnant women 4 mg/day: Women with history of neural tube defect

deliveries take folic acid 1 month prior to conception and during first trimester

Czeizel 1993; Czeizel and Dudas 1992; Mahomed et al 1998; MRC Vitamin Study Research Group 1991.


Nutritional Supplementation and Anemia

WHO definition of severe anemia: Hemoglobin < 7 g/dL

Level of risk

Moderate anemia (Hgb 7–11 g/dL): Not increased Severe anemia: Significant risk

Severe anemia associated with:

Low birth weight newborns Premature newborns Perinatal mortality Increased maternal mortality and morbidity


Anemia and Obstetrical Hemorrhage

Anemia does not cause obstetrical hemorrhage (even severe anemia)

Etiology of obstetric hemorrhage

Early pregnancy: Abortion complications Mid/late pregnancy to delivery: Previa, abruption, atony,

retained placenta, birth canal laceration Primary factors affecting outcome:

Rapid intervention to prevent exsanguination Availability of skilled provider, drugs, blood and fluids

There is no evidence that high levels of hemoglobin are beneficial in withstanding a hemorrhagic event.

Enkin et al 2000; Mahomed 2000a.


Iron Supplementation

Iron requirements:

Average non-pregnant adult:

– 800 g iron lost/day– + 500 g iron lost/day during menses

Pregnant woman: Increased need

– Expanded blood volume– Fetal and placental requirements– Blood loss during delivery

Routine vs. selective iron supplementation:

Prevalence of nutritional anemia Routine iron and folate supplementation where nutritional

anemia is prevalent Recommended dose: 60 mg elemental iron + 5 g folic acid

Mahomed 2000b; WHO 1994.


Iodine Supplementation

Iodine deficiency is a preventable cause of mental impairment

Iodine supplementation and fortification programs have been largely successful in decreasing iodine deficiency conditions

Population with high levels of mental retardation (e.g., some parts of China):

Supplementation may be effective at preconception up to mid-pregnancy period

Form of iodine supplementation (iodinating food or oral/injectable iodine) depend on:

– Severity of iodine deficiency– Cost– Availability of different preparation

Enkin et al 2000; Mahomed and Gülmezoglu 2000.


Vitamin A Indications for vitamin A supplementation:

Vertical transmission of HIV (ongoing) Infant survival Maternal anemia: Positive interaction with iron in reducing

anemia Infection Maternal mortality:

– Vitamin A vs. placebo RR 0.60 (0.37–0.97)– Beta-carotene vs. placebo RR 0.51 (0.30–0.86)

Potential adverse effects of Vitamin A and related substances:

Total daily dose > 10,000 IU before 7th week of gestation associated with birth defects: craniofacial, central nervous system, thymic cardiac

Overall effectiveness and safety of vitamin A supplementation needs to be evaluated

Rothman et al 1995; Suharno et al 1993;

West et al 1999.


Other Micronutrients: Calcium

Association between reduction in pregnancy induced hypertension (PIH) and calcium supplementation

Reduction of incidence of PIH Routine supplementation likely beneficial in women at high

risk of developing PIH or have low dietary calcium intake High calcium doses (2 g/day) not associated with adverse

events Need adequately sized and designed trials in different

settings to confirm beneficial effects Recommend increase in calcium intake through diet in women

at risk of hypertension or low calcium areas

Bucher et al 1996; Kulier et al 1998; Lopez-Jaramillo et al 1997.


Calcium Supplementation: Objective and Design

Objective: To assess effects of calcium in prevention of hypertensive disorders of pregnancy

Methods: Meta analysis of randomized controlled trial

Outcomes:

Mothers: Hypertension +/- proteinuria, maternal death or serious morbidity, abruption, cesarean section, length of stay

Newborns: Preterm delivery, low birth weight/small for gestational age, neonatal intensive care unit admission, length of stay, still birth/death, disability, hypertension

Atallah, Hofmeyr and Duley 2000.


Calcium Supplementation: Results

Mothers:

Hypertension+/-proteinuria:

– Less hypertension: RR 0.81 (0.74–0.89)– Less pre-eclampsia: RR 0.70 (0.58–0.83)– Better if low calcium intake, high risk

Newborns:

Low birth weight: RR 0.83 (0.71–0.98), best for women at highest risk

Chronic hypertension: RR 0.59 (0.39–0.91) No difference in preterm delivery, neonatal intensive care

unit admission, stillbirth, death



Calcium Supplementation: Conclusions

Calcium decreases risk of hypertension, pre-eclampsia, low birth weight, and chronic hypertension in children

Recommend for high risk women with low calcium intake, if pre-eclampsia is important in the population

Calcium has other health benefits not related to pregnancy:

Maintaining bone strength Proper muscle contraction Blood clotting Cell membrane function Healthy teeth



Summary of Nutritional Review Findings

Evidence of nutritional intervention effectiveness

Iron supplementation Periconceptional folic acid intake Iodine use Balanced energy/protein supplementation Calcium

Confirmatory studies to examine effectiveness

Vitamin A Zinc


References

Atallah AN, GJ Hofmeyr and L Duley. 2000. Calcium supplements during pregnancy for prevention of hypertensive disorders and related problems (Cochrane Review), in The Cochrane Library, Issue 3.

Bucher HC et al. 1996. Effect of calcium supplementation on pregnancy-induced hypertension and preeclampsia: a meta-analysis of randomized controlled trials. JAMA 275(4): 1113–1117.

Cunningham FG et al. 1997. Williams Obstetrics, 20th ed. Appleton & Lange: Stamford, Connecticut.

Czeizel AE. 1993. Controlled studies of multivitamin supplementation on pregnancy outcomes. Ann N Y Acad Sci 678: 266–275.

Czeizel AE and I Dudas. 1992. Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation. N Engl J Med 327 (26): 1832–35.

de Onis M, J Villar and M Gülmezoglu. 1998. Nutritional intervention to prevent intrauterine growth retardation: Evidence from randomized controlled trials. Eur J Clin Nutr 52(Suppl 1): S83–S93.


References (continued)

Enkin M et al. 2000. A Guide to Effective Care in Pregnancy and Childbirth, 3rd ed. Oxford University Press: Oxford.

Kulier R et al. 1998. Nutritional interventions for the prevention of maternal morbidity. Int J Gyn Obstet 63: 231–246.

Lopez-Jaramillo P et al. 1997. Calcium supplementation and the risk of preeclampsia in Ecuadorian pregnant teenagers. Obstet Gynecol 90(2):162–167.

Mahomed K. 2000a. Iron supplementation in pregnancy (Cochrane Review), in The Cochrane Library. Issue 4. Update Software: Oxford.

Mahomed K. 2000b. Iron and folate supplementation in pregnancy (Cochrane Review), in The Cochrane Library.Issue 4. Update Software: Oxford.

Mahomed K and A Gülmezoglu. 2000. Maternal iodine supplements in areas of deficiency (Cochrane Review), in The Cochrane Library. Issue 4. Update Software: Oxford.


References (continued)

Mahomed K et al. 1998. Risk factors for pre-eclampsia among Zimbabwean women: maternal arm circumference and other anthropometric measures of obesity. Paediatr Perinat Epidemiol 12: 253–262.

Medical Research Council Vitamin Study Research Group. 1991. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. Lancet 338 (8760):131–137.

Rothman KJ et al. 1995. Teratogenicity of high vitamin A intake. N Engl J Med 333 (21): 1369–1373.

Suharno D et al. 1993. Supplementation with vitamin A and iron for nutritional anaemia in pregnant women in West Java, Indonesia. Lancet 342: 1325–1328.

Susser M and Z Stein. 1994. Timing in prenatal nutrition: A reprise of the Dutch famine study. Nutrition Reviews 52 (3): 84–94.

West Jr. KP et al. 1999. Double blind, cluster randomised trial of low dose supplementation with vitamin A or beta carotene on mortality related to pregnancy in Nepal. Br Med J 318: 570–575.

nutrition and micronutrients in pregnancy advances in maternal and neonatal health

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