Nutrition During Pregnancy

Nutrition During Pregnancy

• General Outcome: Become familiar with physiological changes in pregnancy and how these changes influence nutritional needs.
• Specific Outcomes:
  • Describe physiological changes during pregnancy.
  • Identify recommended weight gain ranges for various pre-pregnancy weight categories (underweight, normal, overweight, obese).
  • Identify relationships between nutritional status during pregnancy and long-term health outcomes in offspring.

Time-Related Terms

• Periconceptional: Period before conception, approximately 14 days before the next menstrual period.
• Trimester 1: Weeks 0-12.
• Trimester 2: Weeks 13-28.
• Trimester 3: Weeks 29-40.
• Preterm: Babies born before 37 weeks.
• Term: Babies born between 38 and 42 weeks.
• Postterm: Pregnancy lasting more than 42 weeks.
• Infancy: Period after birth.
• LMP: Last menstrual period (used to estimate gestational age).
• Perinatal: Definition varies from 20 to 24 weeks gestation to 7 to 28 days after birth.
• Fetal death/Stillbirth: Fetus dies after week 20 of pregnancy.
• Perinatal mortality: Fetus dies between 20 weeks of gestation or death of an infant who is less than a month old.
• Neonatal mortality: Death from delivery to 28 days.
• Post-neonatal mortality: Death from 28 days after birth to 1 year.
• Infant mortality: Death from birth to age 1 year.

Infant Mortality

• Indicator of a country's health level.
• Number of deaths of infants under one year per 1,000 live births.
• Decrease in mortality suggests improvements in social circumstances, safe nutrition, and infectious disease control.

Child Mortality in Malaysia

• Infant mortality rate declined from 41 to 6.9 deaths per 1,000 live births in Malaysia between 1970 and 2017.
• Malaysia has experienced significant improvements in health.

Causes of Infant Mortality

• Conditions originating in the perinatal period.
• Meningitis.
• Pneumonia.
• Chronic lower respiratory disease.
• Congenital malformations, deformations, and chromosomal abnormalities.

Maternal Mortality

• Deaths due to pregnancy and childbirth complications.
• Global maternal mortality ratio declined from 2000 to 2020 by 34%.
• 95% of maternal deaths occur in low and lower middle income countries.
• More than 80% of pregnancy related deaths are preventable.

Causes of Maternal Mortality

• Severe bleeding (mostly after childbirth).
• Infections (usually after childbirth).
• High blood pressure (pre-eclampsia).
• Complications from delivery.
• Unsafe abortion.

Maternal Mortality Ratio in Malaysia

• 1970: 141 deaths per 100,000 live births.
• 2019: 21 deaths per 100,000 live births.

Physiology of Pregnancy

• Pregnancy starts at conception approximately 14 days before the next menstrual period.
• Pregnancy averages 38 weeks (266 days), but 40 weeks (280 days) is common to relate to LMP.
• Gestational age: Duration from conception.
• Menstrual age: Estimated from the LMP.

Normal Physiology Changes During Pregnancy

• Anabolic phase (first half): Increased food intake, lipid absorption, and accumulation; increased estrogen and progesterone levels.
• Catabolic phase (second half): Increased lipolytic activity, decreased lipoprotein lipase activity, decreased insulin sensitivity, increased maternal lipid levels.

Maternal Anabolic Phase

• Blood volume & cardiac output increases.
• Fat, nutrients, and liver glycogen stores are built up.
• Maternal organs grow.
• Appetite & food intake increases.
• Exercise tolerance decreases.

Maternal Catabolic Phase

• Mobilization of fat & nutrient stores.
• Blood glucose, triglycerides, and fatty acids increase.
• Fasting metabolism accelerates.
• Catabolic hormones increase.

Fetal Growth

• Approximately 10% of fetal growth occurs in the first half of pregnancy, with the remaining 90% in the second half.

Body Water Changes

• Increased blood volume, extracellular fluid, and amniotic fluid are associated with pregnancy.
• High fluid gains are associated with edema and weight gain.

Hormonal Changes

• Placenta produces hormones (hCG, hCS, Estrogen, Leptin, Progesterone).

Hormones in more detail

• hCG: Stimulates estrogen and progesterone production, and endometrial growth.
• hCS: Increases insulin resistance, promotes maternal protein synthesis, and mobilizes fat.
• Estrogen: Increases lipid formation and storage, promotes uterine and breast development, improves ligament flexibility.
• Leptin: Regulates appetite, lipid metabolism, and weight gain.
• Progesterone: Maintains the implantation, relaxes uterine muscles, and stimulates breast development.

Carbohydrate Metabolism

• Glucose is the fetus' preferred fuel.
• Early pregnancy: Increased insulin production, conversion of glucose to glycogen and fat.
• Late pregnancy: Increased hCS and prolactin inhibit the conversion of glucose to glycogen, and insulin resistance increases in the mother, relying more on fats for energy.

Accelerated Fasting Metabolism

• Increased utilization of glucogenic amino acids for fat oxidation.
• Increased production of ketones to support fetal use in the absence of glucose.
• Prolonged use of ketones may lead to impaired fetal development.

Protein Metabolism

• Protein is needed for maternal and fetal tissue synthesis.
• About 925 grams of protein are accumulated during pregnancy.
• Maternal protein intake supports fetal and maternal needs.
• Protein needs are met through reduced nitrogen excretion and amino acid conservation.

Fat Metabolism

• Maternal fat accumulation in the first half of pregnancy.
• Increased fat mobilization in the second half of pregnancy for fetal needs.
• Blood lipid levels rise dramatically during pregnancy.

Placenta

• Derived from the Latin word for "cake".
• Round and disk-like shape.

Placenta Functions

• Hormone and enzyme production.
• Nutrient and gas exchange between mother and fetus.
• Waste product removal from the fetus.
• Acts as a barrier to harmful compounds.

Nutrient Transfer in Placenta

• The placenta uses 30-40% of the glucose from maternal circulation.
• Fetus also receives small amounts of water and other nutrients from amniotic fluid.
• Factors influencing nutrient transfer include molecule size, solubility, and concentration gradients. Smaller, more lipid-soluble molecules transfer more easily than larger ones.

Mechanisms of Nutrient Transport

• Passive diffusion: Nutrients move from high to low concentration.
• Facilitated diffusion: Receptors on cell membranes speed up nutrient transfer.
• Active transport: Energy (ATP) is used to move nutrients against a concentration gradient.
• Endocytosis: Large molecules are engulfed and transported into cells.

Fetus Not a Parasite

• The fetus depends on the mother for nutrients.
• Maternal nutrient intake affects fetal growth and development more than maternal health.
• Nutrients first support maternal needs then placental development.

Mineral Metabolism

• Maternal calcium absorption and mobilization from bones increase.
• Increased needs for sodium and other minerals.
• Restricted sodium intake can impact growth.