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Lecture 2 - 2004

Lecture 2 - 2004

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Lecture 2 - 2004

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  1. Lecture 2 - 2004 • Physiological adaptations to pregnancy • Psychology • Energy • Weight Gain

  2. Physiology of Pregnancy

  3. Systematic Adjustments to Pregnancy • Cardiovascular • Respiratory • Urinary

  4. Cardiac output during three stages of gestation, labor, and immediately postpartum compared with values of nonpregnant women. All values were determined with women in the lateral recumbent position.

  5. Change in cardiac outline that occurs in pregnancy. The light lines represent the relations between the heart and thorax in the nonpregnant woman, and the heavy lines represent the conditions existing in pregnancy. These findings are based on x-ray findings in 33 women.

  6. Mean glomerular filtration rate in healthy women over a short period with infused inulin (solid line), simultaneously as creatinine clearance during the inulin infusion (broken line), and over 24 hours as endogenous creatinine clearance (dotted line).

  7. King J. Physiology of pregnancy and nutrient metabolism. Am J Clin Nutr 2000;71 (suppl):1218S-25S

  8. Adjustments in Nutrient Metabolism • Goals • support changes in anatomy and physiology of mother • support fetal growth and development • maintain maternal homeostasis • prepare for lactation • Adjustments are complex and evolve throughout pregnancy

  9. General Concepts 1. Alterations include: • increased intestinal absorption • reduced excretion by kidney or GI tract 2. Alterations are driven by: • hormonal changes • fetal demands • maternal nutrient supply

  10. 3. There may be more than one adjustment for each nutrient. 4. Maternal behavioral changes augment physiologic adjustments 5. When adjustment limits are exceeded, fetal growth and development are impaired.

  11. Birth weight of 11 children born to a poor woman in Montreal; 8 children were born before receiving nutritional counseling and food supplements from the Montreal Diet Dispensary and 3 children were born afterward.

  12. 6. The first half of pregnancy is a time of preparation for the demands of rapid fetal growth in the second half

  13. Hormonal Adjustments • Estrogens: increase significantly in pregnancy, influence carbohydrate, lipid, and bone metabolism • Progesterone: relaxes smooth muscle and causes atony of GI and urinary tract • Human Placental Lactogen (hPL): stimulates maternal metabolism, increases insulin resistance, aids glucose transport across placenta, stimulates breast development

  14. Late gestation is characterized by: • Anti-insulinogenic and lipolytic effects of Human chorionic somatomammotropin, prolactin, cortisol, glucagon) Which Results in: • Glucose intolerance, insulin resistance, decreased hepatic glycogen, mobilization of adipose tissue

  15. Mean (±SEM) plasma lipid concentrations (mg/dL) throughout gestation (n = 42) and during the luteal (I) and follicular (II) phases postpartum (p.p.; n = 23). The dashed lines represent the mean values of the control group (n = 24). (FC = free cholesterol; PL = phospholipids; TC = total cholesterol; TG = triglycerides.)(

  16. Maternal Nutrient Levels • Increased triglycerides • Increased cholesterol • Decreased plasma amino acids & albumin • Plasma volume increases 40% (range 30-50%) • nutrient concentration declines due to increased volume, but total amount of vitamins and minerals in circulation actually increases.

  17. Mean hemoglobin concentrations (  —  ) and 5th and 95th (  —  ) percentiles for healthy pregnant women taking iron supplements

  18. Maternal Nutrient Levels

  19. Nitrogen Balance (g/day)

  20. Alterations in maternal physiology facilitate transfer of nutrients to the fetus.

  21. Nutrient Transportation Across The Placenta

  22. Factors Affecting Placental Transfer • Diffusion distance - diabetes and infection cause edema of the villi • Maternal-placental blood flow • Blood saturation with gases and nutrients • Maternal-placental metabolism of the substance

  23. Psychology of Pregnancy • Psychosocial tasks • Rubin • Leaderman’s tasks • Fathers • Cultural awareness

  24. Developmental Tasks of Pregnancy (Rubin, 1984) • Seeking safe passage for herself and her child through pregnancy, labor, and delivery. • Ensuring the acceptance by significant persons in her family of the child she bears. • Binding-in to her unknown baby. • Learning to give of herself.

  25. Lederman, RP. Psychosocial Adaptation in Pregnancy, 2nd Ed. 1996 • Developmental Tasks of Pregnancy • acceptance of pregnancy • identification with motherhood role • relationship to the mother • relationship to the husband/partner • preparation for labor • processing fear of loss of control & loss of self esteem in labor

  26. Psychosocial adjustment during pregnancy: the experience of mature gravidas(Stark, JOGNN, 1997) • N=64 older gravidas (> 35), 46 younger gravidas (< 32) in third trimester • Lederman prenatal self evaluation questionnaire - examines conflicts for 7 steps • In general conflicts about maternal role were similar in both groups • Older gravidas had less concern about fear of helplessness and loss of control in labor - regardless of parity

  27. Developmental Tasks of Fatherhood • Accepting the pregnancy • Identifying the role of father • Reordering relationships • Establishing relationship with his child • Preparing for the birth experience

  28. Laboring for Relevance: Expectant and New Fatherhood(Jordan, Nursing Research, 1990) • N=56 expectant fathers followed prospectively • “Tasks” • grappling with the reality of the pregnancy and child • struggling for recognition as a parent from mother, coworkers, friends, family baby and society • plugging away at the role-making of involved fatherhood

  29. Jordan, cont. • Identified concerns: • Men not recognized as parents but as helpmates and breadwinners • Men felt excluded from childbearing experience by mates, health care providers, and society • Fathers felt that they had no role models for active and involved parenthood

  30. Energy Requirements in Pregnancy • Energy costs of pregnancy: • increased maternal metabolic rate • fetal tissues • increase in maternal tissues

  31. RDA for Energy in Pregnancy - Old • Energy cost of pregnancy = 80,000 kcal (Hytten and Leitch, 1971) • maternal gain of 12.5 kg • infant weight of 3.3 kg • 80,000/250 days (days after the first month) • Additional 300 kcal per day recommended in second and third trimester • total of 2,500 for reference woman

  32. DRI for Energy - New

  33. Estimated Energy Requirement • Average dietary energy intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, height, level of physical activity consistent with good health. • In children, pregnant and lactating women the EER is taken to include the needs associated with deposition of tissues or secretion of milk

  34. DRI for Energy in Pregnancy - 2002

  35. BEE: Basal Energy Expenditure • Increases due to metabolic contribution of uterus and fetus and increased work of heart and lungs. • Variable for individuals

  36. Growth of Maternal and Fetal Tissues • Still based on work of Hytten • Based on IOM weight gain recommendations