Nutrition and Health in Pregnancy

Nutrition During Pregnancy (Part 2)

• General Outcome: Become familiar with physiological changes during pregnancy and demonstrate how these changes influence nutritional needs.

• Specific Outcomes:

  • Describe physiological changes during pregnancy.
  • Identify recommended weight gain ranges for underweight, normal weight, overweight, and obese women.
  • Identify relationships between nutritional status and nutrition-related concerns during pregnancy and long-term health outcomes in offspring.

Pregnancy Weight Gain

• Indicator of: Plasma volume expansion, positive calorie balance, and dietary adequacy.
• Adequate weight gain: Improves newborn weight and health status.
• Diet Restrictions: Avoid dieting during pregnancy; the fetus may not receive critical nutrients.
• Premature birth: Mothers who gain too little weight during pregnancy risk premature birth and low birth weight infants. Infants born with low birth weight may develop serious health issues later in life, such as heart disease, diabetes, hypertension, and other chronic diseases.

Pregnancy Weight Gain Recommendations

• Pre-pregnancy weight status: Influences the relationship between weight gain and birth weight. Higher pre-pregnancy weight correlates to lower recommended weight gain for healthy-sized infants.
• Underweight women: Need to gain more weight during pregnancy.
• Overweight/obese women: Need to gain less weight during pregnancy. They can use their energy stores to support fetal growth.

Recommended Weight Gains

• Table: Weight gain recommendations based on pre-pregnancy BMI. Underweight, Normal Weight, Overweight and Obese categories are included. Specific weight gain ranges for full-term pregnancies and twin pregnancies (11.4-24.5kg) are provided.

Pregnancy Weight Gain Recommendations

• Exceeding recommendation (overweight/obese women): Can lead to large for gestational age newborns, caesarean deliveries, and higher postpartum weight retention.
• Restriction below recommended ranges: Is not recommended and does not decrease the risk of pregnancy-related hypertension. It can be associated with increased infant death and low birth weight.

Rate of Pregnancy Weight Gain

• First half of pregnancy: Low rate of weight gain is normal.
• Third trimester: More significant weight gain is expected (>0.7 kg/week).
• Mid-pregnancy: Rate of weight gain is generally highest, as the fetus gains most of its weight. Lower birth weights and thinness, as well as increased postpartum weight retention, can occur if weight gain is not consistent with the recommended rates throughout the pregnancy.

Composition of Weight Gain in Pregnancy

• Fetal contribution: Only about half of the total weight gain is attributed to the fetus.
• Maternal contribution: Most weight gain is from increased maternal tissues(uterus, placenta, amniotic fluid, breasts, etc). Specific weight gain components at 10, 20, 30, and 40 weeks are shown.

Body Fat Changes

• Purpose of storing body fat: Pregnant women store body fat to meet their own and the fetus's energy needs, as well as to prepare for the energy demands of lactation.
• Peak fat storage: The most significant increase in body fat storage occurs during weeks 10-20 of pregnancy.
• Body fat after pregnancy: Fat levels generally decrease towards the end of pregnancy.

Postpartum Weight Retention

• Recent changes: The average weight retained by women one year after delivery is higher now than 30 years ago.
• Current typical weight loss profile: Women typically lose about 6.4 kg during the first 6 weeks after delivery.
• Post-6 week weight loss: The rate of weight loss beyond 6 weeks after delivery decreases, and the majority of weight loss will occur in the first 6 weeks postpartum.
• Difficult weight loss: Weight loss is more difficult in women who gained over 20kg. Overweight/obese women are most likely to gain weight between pregnancies.

Prevention of Excessive Body Weight After Delivery

• Appropriate weight loss rates: Daily weight losses of 0.5–1 kg are appropriate for maintaining a healthy rate of weight loss after delivery. A combination of diet and exercise is needed.
• Breastfeeding: Exclusive breastfeeding may support healthy postpartum weight loss.

Energy & Nutrient Needs During Pregnancy

• Nutrient increase: The requirement for all nutrients increases during pregnancy.
• Macronutrients, micronutrients & fluids: Pregnant mothers should pay close attention to these.

Energy Requirements During Pregnancy

• Fetal contribution: The fetus accounts for about half the increased energy needs during pregnancy.
• Timing of maternal/fetal growth: The change in pregnancy energy requirements can vary based on the timing of maternal and fetal tissue formation during the pregnancy.
• Assessment: Assessment of calorie intake adequacy is facilitated by pregnancy weight gain measurement.

Recommendations of Additional Energy Needs

• Table: Table of additional energy needs (kcal/day) for pregnant women in Malaysia, categorized by age, pregnancy trimester (1st, 2nd, 3rd), and expected added daily caloric requirements given for each trimester by age range. Values reflect estimations given from the NCCFN (2017) survey.

Carbohydrate Metabolism

• Early Pregnancy: Glucose is the preferred fuel. Carbohydrate metabolism increases insulin production and converts glucose to glycogen and fat.
• Late Pregnancy: Increase in hCS & prolactin inhibit conversion of glucose to glycogen and fat; Insulin resistance increases, increasing reliance on fats for energy to ensure a consistent supply of glucose for fetal growth and development.
• Daily Intake Minimum: Women need at least 175 grams of carbohydrates (CHO) during pregnancy to meet the needs for fetal brain glucose requirements.

Carbohydrate Requirements During Pregnancy

• Proportion of daily calories: Carbohydrates should contribute 45–65% of total energy intake.
• Nutrient sources: Sources of carbohydrates (vegetables, fruits, and whole grains) that do not contain added sugars and fat may help to manage pregnancy weight gain. These sources also provide fiber and antioxidants.

Carbohydrate Requirements During Pregnancy

• Artificial sweeteners: May modify the gut microbiome and influence metabolism of glucose and insulin, also important for satiety.
• Alcohol impact: Alcohol acts as a toxin that passes through the placenta to the fetus and can interrupt normal growth and development. This may also increase the risk of abnormal mental development of the offspring.

Protein Requirements During Pregnancy

• Increase in requirements: Protein requirements increase during pregnancy primarily due to protein tissue accretion.
• Reduced energy use: Less protein is used for energy, so additional protein is needed.
• Protein supplements: Protein supplements do not benefit the outcome of pregnancy in well-nourished women.

Fat Requirements During Pregnancy

• Energy and development: Used as an energy source for fetal growth and development. A source of fat-soluble vitamins and fatty acids is crucial for fetal development.
• Component of cells: Linoleic (omega 6) & alpha-linolenic (omega-3) fatty acids are structural components of cell membranes, high in fetal brain, retina and relevant neural tissues.
• DHA: DHA is a major structural component of phospholipid membranes in the central nervous system of the fetus, accumulating most rapidly during the third trimester and the first year of life.

Micronutrients that are most critical during pregnancy

• Increased requirements: The requirements for vitamins and minerals increase during pregnancy due to placental and fetal growth, expansion of maternal tissues and plasma volume, and increased nutrient needs for tissue maintenance.
• Necessary vitamins and minerals: The highlighted micronutrients (Folate, Iron, Choline, Sodium, Water, Iodine, Calcium, Vitamin A, Vitamin D) are crucial for maintaining a healthy pregnancy.

Folate

• Neural tube development: Critical for neural tube development in the first 28 days of pregnancy, and a low availability of folate during 21-27 days after conception may result in abnormalities in neural tube development.
• Fetal growth: Linked to reduced fetal growth and pregnancy-related anemia.
• Dietary sources: Good dietary sources include banana, avocado, orange juice, and leafy greens. Dietary supplements (folic acid) can duplicate the effect of dietary folate sources in certain cases.

Choline

• Essential nutrient: A water-soluble compound that is neither a vitamin nor a mineral, and is important for fetal development.
• Precursor molecule: A precursor of intracellular messengers and component of phospholipids in cell membranes.
• Liver production: Synthesized by the liver.
• Food sources: Dietary sources include eggs and meat.

Vitamin A

• Cell differentiation: Involved in cell differentiation.
• Fetal development/malformations: High intake (over 10,000 IU/day) & medications (e.g., Accutane, Retin-A) can cause fetal malformations, including heart defects, and those of lungs, urinary tract, and heart.
• Supplement considerations: Most supplements contain beta-carotene, not retinol, and high beta-carotene intake has not been linked to birth defects.

Vitamin D

• Skin synthesis: Produced by the body when exposed to UV rays.
• Fetal growth/bone development: Supports fetal growth, calcium deposition in fetal bones, and tooth/enamel formation.
• Deficiencies: Deficiency compromises fetal and childhood development and can affect blood calcium levels at birth, skeletal formation, tooth and enamel development.
• Health concerns: Increased risk of deficiency in obese and vegan women.

Calcium

• Fetal mineralization: Important for fetal skeletal mineralization and maintenance of maternal bone health.
• Transfer from mother to fetus: About 30 grams of calcium are transferred from the mother to the fetus during pregnancy.
• Third trimester demand: Fetal demand for calcium is highest in the third trimester when fetal bones are mineralizing rapidly.
• Dietary needs: Adequate daily intake needs can be met by 2–3 cups of milk, calcium-fortified soymilk, and calcium-fortified orange juice.

Iron

• Fetal development: Needed to supply the growing fetus and increase maternal red blood cell mass.
• Dietary sources: Sources include meat, poultry, fish, and iron-fortified foods.
• Deficiencies: Iron deficiency shows as depleted iron stores, affecting overall health and general function, and increasing susceptibility to infection and poor attention span.
• Severe iron deficiency: Can lead to iron deficiency anemia, characterized by low hemoglobin, paleness, exhaustion, and rapid heart rate.

Iodine

• Thyroid function: Crucial for thyroid function and energy production, as well as fetal brain development.
• Deficiency: Deficiency during pregnancy can cause hypothyroidism in offspring.
• Dietary sources: Iodine is found in fish, shellfish, seaweed, and some types of tea.
• Supplements: Supplements should be used by women diagnosed with iodine deficiency, or who are at risk of deficiency.

Sodium

• Fluid balance: Essential for maintaining the body's water balance.
• Increased needs: Sodium requirements increase during pregnancy due to plasma volume expansion.
• Restriction: Sodium restriction during pregnancy is not usually recommended, but should be considered if there is a medical condition that warrants such restriction. Women are generally advised to consume salt according to individual taste preferences.

Water

• Increased needs: The need for fluids increases to 3 liters/day during pregnancy due to the increase in maternal bloodstream volume to regulate temperature and create amniotic fluid as well as to combat fluid retention.
• Recommendations: Recommendations for daily water intake are 8–12 glasses per day. More intake may be needed based on physical activity levels and the ambient temperature and humidity. Light-colored urine is a strong indicator of adequate fluid intake.

Nutrition-Related Concerns During Pregnancy

• Common issues: Nausea and vomiting, heartburn, constipation, craving and aversion, edema and leg cramps, gestational diabetes, and pregnancy-induced hypertension.

Nausea and Vomiting

• Timing: Occurs throughout pregnancy, not just morning.
• Causes: Possibly related to increased levels of hCG, estrogen, and progesterone in early pregnancy
• Protective hypothesis: Proposed to protect the fetus from toxins and diseases
• Rarity of complications: Nausea/vomiting during pregnancy associated with lower risk of miscarriage

Heartburn

• Mechanism: Stomach acid relaxes the sphincter above the stomach, allowing stomach acid to enter the esophagus.
• Hormonal causation: Pregnancy hormones and enlarged uterus can contribute to heartburn.

Constipation

• Mechanism: Pregnancy hormones can relax the gastrointestinal muscles which can impact digestive function
• Dietary management: Increasing dietary fiber intake, alongside adequate fluid intake, can often support regular bowel function and address constipation within pregnancy.
• Lifestyle strategies Exercise can also improve bowel function.

Craving and Aversion

• Sensory changes: Changes in taste and smell perception.
• PICA: Associated with craving non-food items (ice, dirt, clay, etc.). May be related to essential nutrient deficiencies.
• Unrelated to preterm delivery or abnormal newborn weight: These cravings, and the disorder PICA, are not associated with preterm delivery or abnormal newborn weight.

Edema and Leg Cramps

• Physiological edema: Mild physiological edema develops during the third trimester.
• Uterine pressure: The enlarging uterus puts pressure on the vena cava, reducing blood flow back to the heart.
• Magnesium deficiency: Leg cramps may result from a possible magnesium deficiency during pregnancy and lactation.

Gestational Diabetes

• Cause: Insulin production issues or insulin resistance lead to elevated blood glucose levels.
• Resolution: Condition usually resolves after delivery.
• Maternal consequences: Increased risk of preeclampsia, hypertension, and obesity in the mother.
• Offspring consequences: Increased risk of birth defects and related neonatal complications.

Pregnancy-Induced Hypertension

• Gestational hypertension: Develops after 20 weeks. High maternal blood pressure (≥ 140/90 mmHg) with no proteinuria. May progress to preeclampsia.
• Preeclampsia: High maternal blood pressure (≥ 140/90 mmHg) alongside proteinuria (>300 mg in 24 hours). May progress to eclampsia.
• Eclampsia: Severe preeclampsia with seizures.

Effects of Nutritional Status & Lifestyle on Pregnancy Outcome

This section discusses the numerous effects of various lifestyle factors on pregnancy outcomes. It covers a wide range of factors (Obesity, Multifetal, Adolescence, HIV/AIDS, Alcohol Vegetarianism, Dieting, Caffeine, Exercise, Smoking, Illegal drugs, and Food safety). The details regarding these various factors are provided in the following descriptions below.

• Specific factors and their outcomes or effects are presented in different sections of the detailed notes.