Nutrition During Pregnancy GTN218/3 PDF

GTN218/3 – Nutrition in Life Cycle Topic 3: Nutrition During Pregnancy Dr Nur Nadia Mohamed [email protected]...

GTN218/3 – Nutrition in Life Cycle Topic 3: Nutrition During Pregnancy Dr Nur Nadia Mohamed [email protected] 09 767 7550  General outcome Become familiar with physiological changes during pregnancy and demonstrate how those changes influence their nutritional needs Specific outcome 1. Describe the physiological changes that normally occur during pregnancy. 2. Identify recommended weight gain ranges for women who enter pregnancy underweight, normal weight, overweight and obese. 3. Identify relationships between nutritional status and nutrition-related concerns during pregnancy and long-term health outcomes in offspring Time-related terms before, during & after pregnancy  Time-related terms before, during & after pregnancy Very preterm Preterm Term Postterm Babies born before Babies born before Babies born between Pregnancy that lasts 32 weeks 37 weeks 38 to 42 weeks of more than 42 weeks gestation  Important Terms & Definitions Fetal death/Stillbirth The fetus dies after week 20 of pregnancy Fetus dies between 20 weeks of gestation or death of an Perinatal mortality infant who is less than a month old Neonatal mortality Deaths from delivery to 28 days Post-neonatal Deaths from 28 days after birth to 1 year mortality Infant mortality Deaths from birth to age 1 year  Infant Mortality Used as an indicator for level of health in a country – The number of deaths of infants under one year old per 1,000 live births Decrease in mortality = Improvements in social circumstances, safe & nutrition food availability & infectious disease control Child Mortality Rates, 1970 – 2019 In Malaysia, infant mortality rate declined from 41 deaths per 1,000 live births in 1970 to 6.9 in 2017 Malaysia has experienced dramatic improvements in health  Meningitis Conditions originating in the perinatal period Pneumonia Causes of Infant Mortality Congenital malformations, deformations Chronic lower respiratory & chromosomal abnormalities disease  Maternal Mortality Refers to deaths due to complications from pregnancy or childbirth From 2000 to 2020, the global maternal mortality ratio declined by 34% Almost 95% of all maternal deaths occurred in low & lower middle-income countries More than 80% of pregnancy-related deaths are preventable Causes of Maternal Mortality Severe bleeding (mostly bleeding after childbirth) Infections (usually after childbirth) High blood pressure during pregnancy (pre-eclampsia) Complications from delivery Unsafe abortion Maternal Mortality Ratio, 1970 – 2019 In Malaysia, maternal mortality ratio fell from 141 deaths per 100,000 live births in 1970 to 21 in 2019  Physiology of Pregnancy Pregnancy begins at conception – Approximately 14 days before the next menstrual period Pregnancy averages 38 weeks (266 days) However, the duration is given as 40 weeks (280 days) – because it is measured from the date of the first day of the last menstrual period (LMP) Gestational age = Duration of pregnancy as week from conception Menstrual age = Time in pregnancy estimated from (LMP) Normal Physiology Changes During Pregnancy Anabolic Phase Catabolic Phase (Occur in the first half of pregnancy) (Occur in the second half of pregnancy) Marked by increased food intake & Enhanced lipolysis & elevated lipid accumulation maternal lipid level in bloodstream  Maternal Anabolic Phase (0 – 20 weeks) Blood volume ↑ 20% Blood volume expansion, increased cardiac output Plasma volume ↑ 50% Edema ↑ estrogen, progesterone Buildup of fat, nutrient & liver glycogen stores & insulin to promote lipid deposition Heart, thyroid, liver, Growth of some maternal organs kidneys, uterus, breasts, adipose tissue Progesterone is Increased appetite, food intake (positive energy balance) responsible for increased appetite during pregnancy Less oxygen available Decreased exercise tolerance because body works harder to give nutrients & oxygen  Maternal Catabolic Phase (20+ weeks) Stored fats are broken Mobilization of fat and nutrient stores down from adipose tissue to provide energy Cholesterol & triglycerides Increase blood glucose, triglycerides & fatty acids are needed for growth & development of baby Lipids as a maternal Accelerated fasting metabolism energy source; glucose & amino acids for fetus Increased catabolic hormones  Approximately 10% of fetal growth is accomplished in the first half of pregnancy & the remaining 90% occurs in the second half  Body Water Changes During pregnancy: purpose To expand blood flow & Increased volumes of plasma, nutrient transfer to the extracellular fluid & amniotic fluid placenta and fetus ⅔ intracellular (blood & body tissues) Total body High gains are associated with water ↑ increasing degrees of edema 7 to 10 liters and weight gain ⅓ extracellular (fluid in spaces between cells) Edema: Swelling (usually legs & feet) due to an accumulation of extracellular fluid  Hormonal Changes Many of the normal physiological changes that occur during pregnancy are modulated by hormones produced by the placenta hCG Estrogen Leptin Progesterone hCS  Carbohydrate Metabolism Glucose is preferred fuel for fetus Carbohydrate – Increases in insulin production metabolism in – Conversion of glucose to glycogen & fat early pregnancy – Increase of hCS & prolactin inhibit Carbohydrate conversion of glucose to glycogen and fat metabolism in – Insulin resistance builds in the mother, late pregnancy increasing her reliance on fats for energy to ensure a constant supply of glucose for fetal growth and development  Accelerated Fasting Metabolism Utilization of glucogenic amino acid Fasting > 12 hours Fat oxidation Increased production of ketones Accelerated fasting metabolism allows pregnant women to use stored fat for energy while sparing glucose & amino acids for fetal use However, fasting can increase the dependence of the fetus on ketone bodies for energy Prolonged fetal utilization of ketones → abnormal growth & impaired intellectual development of the offspring Glucogenic amino acid: An amino acid that can be converted into glucose through gluconeogenesis  Protein Metabolism for synthesis of new maternal & fetal tissues About 925 gram of protein are accumulated during pregnancy needed in high amounts during pregnancy Maternal & fetal needs for protein are primarily fulfilled by mother’s intake of protein during pregnancy Increased need for protein is met through reduced levels of nitrogen excretion & conservation of amino acids for protein tissue synthesis.  Fat Metabolism Accumulation of maternal fat Increased fat mobilization in the in the first half of pregnancy second half of pregnancy Blood lipid levels increase dramatically Plasma triglyceride Cholesterol-containing lipoproteins Phospholipids Fatty acids  Fat Metabolism Increased cholesterol supply is used by placenta for steroid hormone synthesis Fetus use cholesterol for nerve & cell membrane formation High concentrations of cholesterol & triglycerides observed during pregnancy have not been found to promote the development of atherosclerosis It does not appear to alter Cholesterol-lowering diet during pregnancy has cord and neo-natal been found to lower maternal cholesterol levels cholesterol levels  Mineral Metabolism Maternal absorption of calcium To provide the fetus with & rate of calcium mobilization calcium needed for bone from bones increase formation Increased requirements for sodium & other minerals Low-salt or low-sodium diets Sodium restriction can are not recommended during lead to functional & pregnancy growth impairments Placenta Derived from Latin word for “cake” – Round & disk-like shape  Function of Placenta 1 Hormone and enzyme production 2 Nutrient & gas exchange between mother & fetus 3 Removal of waste products from the fetus 4 Acts as a barrier to many harmful compounds Many harmful substances (alcohol, excessive vitamins, drugs & certain bacteria e.g. listeria) can pass through the placenta to the fetus Placenta prevents the mixing of fetal & maternal blood until delivery  Nutrient Transfer in Placenta The placenta uses 30–40% of glucose delivered by maternal circulation The fetus receives small amounts of water and other nutrients from ingestion of amniotic fluid  Nutrient Transfer in Placenta Factors influencing nutrient transfer across placenta – The size & charge of molecules for transport – Lipid solubility of the particles being transported – Concentration of nutrients in maternal & fetal blood Small molecules (water) & can easily pass through the placenta lipids (cholesterol & ketones) Large molecules aren’t transferred at all (insulin & enzymes) Mechanisms of Nutrient Transport Across Placenta PASSIVE FACILITATED ACTIVE ENDOCYTOSIS DIFFUSION DIFFUSION TRANSPORT Nutrients are Nutrients & other Receptors (carriers) transferred from blood molecules are engulfed by on cell membranes with higher Energy (from ATP) & placenta membrane and increase the rate of concentration to blood cell membrane released into fetal blood with low concentration nutrient transfer receptors supply Fetus Is Not a Parasite Fetus cannot take whatever nutrients it needs from the mother’s body When maternal nutrient intakes fall below optimum levels, fetal growth & development are compromised more than maternal health Nutrients will first be used to support maternal needs, then for placental development Fetus is harmed more than the mother by poor maternal nutritional status