Life Cycle Nutrition: Pregnancy, Lactation, & Infancy Chapter 14

Pregnancy Nutrition may affect fertility Preparation before pregnancy Achieve and maintain healthy body weight Choose an adequate and balanced diet Be physically active Receive regular medical care Manage chronic conditions Avoid harmful influences

Stages of Embryonic and Fetal Development

The Placenta and Associated Structures

Growth and Development During Pregnancy Critical periods Times of intense development Many happen in the first several weeks! Mother’s nutritional status crucial beginning at moment of conception About 1/2 of pregnancies are unplanned Adverse influences on organ and tissue development Alcohol, tobacco, and other substance use Imbalances of key nutrients

Critical Periods of Development

Folate Status Low: neural tube defects Anacephaly Brain either missing or fails to develop Spina bifida Incomplete closure of spinal cord & its bony encasement 400 micrograms/day of folic acid recommended, plus food sources Neural tube develops in first 6 weeks

Neural Tube Development

Spina Bifida

Other Key Nutrients Pre-formed vitamin A Iron Too much is teratogenic UL: 3,000 mcg (10,000 IU)/day Accutane and Retin-A: potent teratogens Beta-carotene is safe! Iron Good status is important prior to conception If low, mother can experience anemia during pregnancy Omega-3 fatty acids: DHA/EPA Crucial for neurological development Sources: seafood, grass-fed beef, omega-3 eggs Watch out for mercury Limit: albacore tuna Avoid: tilefish, shark, swordfish, king mackerel

Maternal Weight Underweight Overweight & obesity Weight and health prior to conception Influences fetal growth and pregnancy outcomes Underweight Increased rates of preterm births (before 37 weeks), low birth weight, and infant deaths Increases child’s risk for heart disease or diabetes Overweight & obesity Medical complications: HTN, gestational diabetes, preeclampsia, prolonged labor, difficulty breastfeeding Risks for infant

Recommended Weight Gains

Components of Weight Gain

Maternal Weight Weight loss after pregnancy: takes time! Some lost in childbirth (~10 pounds) Weeks after delivery: fluid volume returns to normal (about another 5 pounds) Return to pre-pregnancy weight not typical during this time Many retain a couple of pounds with each pregnancy (as body fat) Retention of seven or more pounds Diabetes and hypertension Chronic diseases later in life Breastfeeding helps significantly

Exercise During Pregnancy Can continue exercise throughout pregnancy Adjust duration and intensity Benefits: Prevention/management of gestational DM Easier labor Fewer discomforts during pregnancy Reduced stress Maintaining fitness can help with post-pregnancy weight loss “Low-impact” activities Avoid excessively high internal body temperature

Energy & Nutrient Needs: Pregnancy and Lactation Needs tend to be higher than any other time in life Increased BMR Depositing and maintenance of new fetal and maternal tissues Energy: 15 to 20% more energy than before pregnancy Even greater increase in micronutrient needs Choose nutrient-dense foods Differences between pregnancy and lactation requirements Many needs even greater in lactation

Macronutrients Carbohydrate Protein Essential fatty acids Ample carbohydrate is necessary; fuels fetal brain during pregnancy 175 g or more/day (no less than 135 g/d) Protein RDA – additional 25 grams per day (or adjust to 1.1 g/kg) Supplements are discouraged Essential fatty acids Omega-3 and omega-6 fatty acids for brain material

Micronutrients Blood production, cell and tissue growth in mother and fetus Needs for synthesis of DNA and new cells Folate Vitamin B12 Vitamin B6 Iron Zinc Bone and connective tissue Calcium Vitamin D Vitamin C Increased energy utilization B vitamins Some recommendations remain the same; others increase Prenatal vitamin usually recommended Does not take the place of a nutrient-rich diet! Does not meet all needs

Water Water needs increase Blood volume Production of other fluids Fluids for fetus 6-9 liters of water accumulated during pregnancy! Increase intake from 2.7 liters to 3 liters/day

Needs During Lactation Energy needs and exercise Uses almost 500 extra kcalories per day Need 330-400 from food, the rest from fat stores Minimum: 1800 kcal/day to meet all needs Exercise is compatible with breastfeeding Energy nutrients Recommendations increase above pregnancy recommendations for carbohydrates and fibers Micronutrients: relative to pregnancy, several increased recommendations for vitamins and minerals, some decreased Water 1 additional liter of water per day to prevent dehydration

Bottle Feeding & Formula Weak/small infants may have difficulty suckling Bottles provide more forceful flow Drugs and communicable diseases Avoiding risk to infant health outweighs benefits of breast milk Infant formula Not milk or milk substitutes!!! Most based on cow’s milk, some soy or elemental Most fortified with iron Some fortified with EFA--more expensive Baby bottle tooth decay Usually due to allowing baby to take bottle to bed

Nutritional Needs of Infancy Growth more rapid than any other time of life Kcal needs per kg of body weight are high ~100 kcal/kg/day vs. 30 in adults Macronutrient proportions differ from adult needs Small stomach More fat needed to increase energy density Type of fat also important to support nervous system development DHA (n-3) and AA (n-6) Both contained in breast milk Addition of these is not required in formula in US

Macronutrient Distribution: Infant vs. Adult

Assessing Infant Growth