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Chapter 2 Preconception Nutrition

Chapter 2 Preconception Nutrition. Nutrition Through the Life Cycle Judith E. Brown. Preconception Overview: Infertility. ~15% of couples are infertile 40% of couples diagnosed as “infertile” will conceive within 3 years without use of technology

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Chapter 2 Preconception Nutrition

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  1. Chapter 2Preconception Nutrition Nutrition Through the Life Cycle Judith E. Brown

  2. Preconception Overview:Infertility • ~15% of couples are infertile • 40% of couples diagnosed as “infertile” will conceive within 3 years without use of technology • Healthy couples have a 23% to 30% chance of conception within a given menstrual cycle

  3. Preconception Overview:Miscarriage • Miscarriage: Loss of conceptus in 1st 20 weeks of pregnancy • Causes of miscarriages: • Defect in fetus • Maternal infection • Structural abnormalities of uterus • Endocrine or immunological disturbances

  4. Preconception Overview:Subfertility • Subfertility: Reduced level of fertility characterized by unusually long time for conception • ~18% of couples are subfertile • Examples: • Having multiple miscarriages • Sperm abnormalities • Infrequent ovulation

  5. 2010 Nutrition Objectives for the Nation Related to Preconception

  6. Reproductive Physiology • Development of female & male reproductive systems • Begins during first months after conception & • Continue to grow & develop through puberty • Capacity for reproduction • Establishes during puberty when hormonal changes stimulate maturation of reproductive system

  7. Reproductive Physiology:Ova and Women • Women born with life-time supply of ~7 million immature ova • ~400-500 ova will mature & be released during fertile years

  8. Reproductive Physiology:Ova and Women • Chromosomes in ova • May be damaged by • Oxidation • Radioactive particle exposure • Aging • Women >35 years more likely to have disorders related to chromosomal defects than younger women

  9. Reproductive Physiology:Sperm and Men • Sperm production begins during puberty, decreases somewhat after age 35 with production continuing to old age

  10. Hormonal Effects During the Menstrual Cycle • Gonadotropin-releasing hormone (GnRH) • Stimulates pituitary to release FSH and LH • Follicle-stimulating hormone (FSH) • Stimulates maturation of ovum & sperm • Luteinizing hormone (LH) • Stimulates secretion of estrogen, progesterone, & testosterone

  11. Hormonal Effects During the Menstrual Cycle • Estrogen • Stimulates release of GnRH in follicular phase & follicle growth & maturation of follicle • Stimulates vascularity & storage of glycogen & other nutrients within uterus • Progesterone • Prepares uterus for fertilized ovum, increases vascularity of endometrium, & stimulates cell division of fertilized ova

  12. Two Phases of Menstrual Cycle • Follicular Phase—(first half of menstrual cycle) • Follicle growth & maturation • Main hormones: GnRH, FSH, estrogen, & progesterone • Luteal Phase—(last half of menstrual cycle) • After ovulation • Formation of corpus luteum •  in estrogen & progesterone stimulate menstrual flow • Postaglandins & cramps

  13. Changes in the Ovary and Uterus

  14. Male Reproductive System • Interactions among hypothalamus, pituitary gland, and testes • Androgens — Testosterone • Sperm are stored in the epididymis & released in semen

  15. Sources of Disruptions in Fertility • Adverse nutritional exposure • Contraceptive use • Severe stress • Infection • Tubal damage or other structural damage • Chromosomal damage

  16. Factors Related to Altered Fertility

  17. Nutrition-Related Disruptions in Fertility • Undernutrition • Weight loss • Obesity • High exercise levels • Intake of specific foods & food components

  18. Undernutrition and Fertility • Chronic undernutrition • Primary effect: birth of small & frail infants with high likelihood of death in the first year of life • Acute undernutrition • Associated with a dramatic decline in fertility that recovers when food intake does

  19. Body Fat and Fertility • Decreased fertility seen with low or high body fat due to alterations in hormones • Estrogen & leptin • Levels increased with high body fat & reduced with low body fat • Both extremes lower fertility • Infertility lower with BMI <20 or >30

  20. Weight Loss and Fertility in Females • Weight loss >10-15% of usual weight decreases estrogen • Results in amenorrhea, anovulatory cycles, & short or absent luteal phases • Treatment with fertility drug Clomid not effective in underweight women

  21. Weight Loss and Fertility in Males • Studies from World War II showed 50% decrease in male fertility during starvation • Sperm viability & motility decrease with wt. 10 to 15% <normal & cease at wt >25% < normal

  22. Exercise and Infertility • Adverse effects of intense physical activity • Delayed age at puberty • Lack menstrual cycles • Appear to be related to hormonal and metabolic changes • Related to caloric deficits • Reduced levels of estrogen • Low levels of body fat • Decreased bone density

  23. Diet and Fertility • Diet may impact hormones • Main dietary practices are vegetarian diets, low fat intake, high intakes of dietary fiber, soy, caffeine, & alcohol

  24. Oxidative Stress, Antioxidant Status, and Fertility • Oxidative stress in men • Decreases sperm motility • Reduces ability of sperm to fuse with an egg • Oxidative stress in women • Harm egg and follicular development • Interfere with corpus luteum function • Interfere with implantation of the egg.

  25. Oxidative Stress, Antioxidant Status, and Fertility • Antioxidants. • Vitamin E • Vitamin C • Beta-carotene • Selenium • Found in vegetables and fruits. • Protect cells of the reproductive system, including eggs and sperm.

  26. Oxidative Stress, Antioxidant Status, and Fertility • Zinc status and Fertility in Men. • Plays important roles • In the reduction of oxidative stress • In sperm maturation • In testosterone synthesis • Has been investigated for potential role in infertility

  27. Plant Foods and Fertility • Low-fat, high fiber linked to reduced estrogen & irregular periods • Isoflavones (from soy) decrease levels of gonadotropins, estrogen, & progesterone

  28. Preconception Iron Status, Fertility, & Pregnancy Outcome • Rate of infertility lower in women who use iron supplements or iron from plant foods • Pre-pregnancy iron deficiency linked to preterm delivery & low iron status of infant • ~1/2 of U.S. women enter pregnancy with inadequate iron stores

  29. Caffeine and Fertility • Caffeine appears to prolong time to conception • Daily caffeine intake & reduction in conception is: • 300 mg results in ~27%  • 500 mg results in ~50% 

  30. Alcohol and Fertility • Alcohol may decrease estrogen & testosterone levels or disrupt menstrual cycles • Studies on weekly drinks consumed show: • 1-5 drinks  39%  in conception • >10 drinks  66%  in conception

  31. Other Factors Contributing to Infertility in Males • Antioxidant nutrients • Protect sperm from oxidative damage • Vitamin D—Low status related to infertility • Alcohol intake—toxic effect on testes • Heavy metal exposure • Lead—impacts testes & sperm • Mercury—decreases sperm & semen • Halogens

  32. Other Factors Contributing to Infertility in Males • Glycols—from antifreeze • Hormones • synthetic estrogens, DDT, PEs, PCBs • Heat • sperm count can be reduced by elevating the temperature of the scrotum and testes • Steroid abuse • side effects include atrophy of testicles, absence of sperm, and decreased libido

  33. Nutrition-Related Side Effects of Contraceptives

  34. Other Preconceptual Nutrition Concerns • Very-early-pregnancy nutrition exposures • Folate status prior to conception • Neural tube defects • Recommended dietary intakes for preconceptional women

  35. Nutritional Disruptions

  36. MyPyramid Recommendations for Preconceptional Women

  37. Model Preconceptional Nutrition Programs • Preconceptional benefits of WIC • Decreasing iron deficiency in preconceptional women in Indonesia • Preconception care: Preparing for pregnancy

  38. CDC’s Preconceptional Health Initiative • Recommends that primary health care visits include: • Preconception health & pregnancy outcome education • Screening for vaccination, weight, iron & folate status • Assessment of alcohol use • Management of diabetes & celiac disease

  39. Another CDC Recommendation “Each woman, man, & couple should make a reproductive life plan that includes whether & when they want to have children & how they will maintain their reproductive health.” Centers for Disease Control & Prevention, 2006

  40. Nutrition Programs and Services Delivery Before Pregnancy • Recently developed nutrition care standards • By the American Dietetic Association • Called “Nutrition Care Process” • Part of new technology-based systems • To facilitate health-services delivery • Cost evaluation • Electronic charting • Coding and outcome measurement

  41. Nutrition Programs and Services Delivery Before Pregnancy • The Nutrition Care Process Step 1: Nutrition assessment Step 2: Nutrition diagnosis Step 3: Nutrition intervention Step 4: Nutrition monitoring and evaluation See Table 2.10 for summary

  42. Suggested Readings • Before Your Pregnancy – A 90-Day Guide for Couples on How to Prepare for a Healthy Conception. By Amy Ogle, MS,RD and Lisa Mazzullo, MD • Integrated Perinatal Health Framework A Multiple Determinants Model with a Life Span Approach by Dawn P. Misra, PhD, Bernard Guyer, MD, Adam Allston, MPH Am J Prev Med 2003;25(1) Posted on Blackboard

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