Macro and Trace Minerals Pregnancy vs. Lactation Requirements

Question 1

Zinc Requirements

Answer 1

Pregnancy: Zn requirements in last part of pregnancy + EAR non-pregnant
- ↑ requirements to meet accumulation in maternal and fetal/embryonic tissues
- 27% fractional absorbance of zinc

Lactation: ↑ dietary requirement to meet the needs to producing breast milk
- Fractional absorption of 27% + ↑ 11% absorption = 38%
- reutilized Zn from involution of uterus and ↓ maternal blood volume

Question 2

Iodine Requirements

Answer 2

Pregnancy: ↑ recommendation to prevent miscarriage, stillbirth, birth defects and congenital hypothyroidism (severe deficiency → cretinism)
- infant deficiency caused by maternal deficiency
- leading cause of cognitive disability

Lactation: ↑ requirement to supply breast milk contents based on daily loss into milk

Question 3

Selenium Requirements

Answer 3

Pregnancy: Small ↑ requirement to saturate fetal selenoproteins
- highly bioavailable, no adjustment for absorption

Lactation: ↑ requirement to supply breast milk contents based on daily loss into milk
- Most Se in milk as selenomethionine with > 90% bioavailability → no adjustment for absorption

Question 4

Copper Requirements:

Answer 4

Pregnancy: ↑ requirement to meet accumulation in fetal tissues and pregnancy products
- based on 65-70% bioavailability

Lactation: ↑ requirement to supply breast milk contents based on daily loss into milk
65-70% bioavailability

Question 5

Manganese Requirements:

Answer 5

Pregnancy: AI ↑ extrapolated requirement based on ↑ mass gain during pregnancy
- based on 16kg weight gain added to non-pregnant AI

Lactation: ↑ AI based on median intake without deficiency
- AI No change in requirement but median intake ↑ in lactating women, and AI is influenced by this ↑

Question 6

Chromium Requirements:

Answer 6

Pregnancy: ↑ extrapolated requirement based on ↑ mass gain during pregnancy
- based on 16kg weight gain added to non-pregnant AI

Lactation: ↑ requirement to replace losses into breast milk
- 1% absorption rate

Question 7

Molybdenum Requirements:

Answer 7

Pregnancy: ↑ extrapolated requirement based on ↑ mass gain during pregnancy
- based on 16kg weight gain added to non-pregnant AI

Lactation: ↑ requirement to replace losses into breast milk

Question 8

Fluoride Requirements:

Answer 8

Pregnancy: AI no change in recommendation for pregnancy
- based on carries vs water fluoride concentrations and fluoride intake for anyone > 6 months old

Lactation: No change in AI
- [F] very low in breast milk and infant/mother levels insensitive to changes in intake

Question 9

Calcium Requirements:

Answer 9

Pregnancy: No ↑ in requirement
- 25-30g transferred to fetus (3rd trimester mostly) + ↑ intestinal absorption efficiency
- balances transfer without depleting maternal stores: no changes in maternal bone mass

Lactation: No change in RDA from adult RDA
- Ca from bone resorption - no change in absorption (intake does not minimize bone loss)
- ↓ renal Ca excretion
- bone loss regained upon ovarian function

Question 10

Phosphorus Requirements:

Answer 10

Pregnancy: No ↑ requirement during pregnancy
- 10% ↑ intestinal absorption to meet any additional needs

Lactation: ↑ requirement for P content of breast milk
- requirement decreases as lactation progresses
- ↑ bone resorption and ↓ PTH → ↑ serum [Pi] independent of intake

Question 11

Magnesium Requirements

Answer 11

Pregnancy: ↑ requirement during pregnancy to balance ↓ serum [Mg] from hemodilution/↓ serum protein
- No shown ↑ in absorption or conservation of Mg

Lactation: RDA = Adult RDA
- Magnesium transfer into breastmilk but no ↑ in requirement
- ↑ bone resorption and ↓ urinary excretion to provide Mg for milk
- Milk [Mg] stable through lactation

Question 12

Iron Requirements

Answer 12

Pregnancy: ↑ requirement during pregnancy due to expansion of blood volume and fetal development
- absorption ↑ from 18 to 25% 2nd/3rd trimester
- Iron absorbed = basal losses + Fe deposited in fetus/related tissues + expansion of Hb mass
- Supplement recommended assumption of inadequacy (low intake + absorption)

Lactation: ↓ requirement because no menstruation
- Fe requirement to supply breast milk + replace basal losses (Assume 18% absorption rate)
- adolescent RDA is higher for growth

Question 13

Anemia grades blood levels and risks associated

Answer 13

Moderate anemia = < 80 g/L
- perinatal maternal mortality
- most women are deficiency

Severe anemia = < 40 g/L
- 2x risk of maternal death
- premature delivery and perinatal infant mortality → workload ↑ to deliver O2
- LBW → limited expansion of maternal RBC

Hyperferritinemia = > 130 g/L
- associated with adverse pregnancy outcomes too like preeclampsia and HTN associated with ↓ plasma volume (causes low nutrient delivery)