NTRN 328 Exam 1: Preconception

Why do we care abt preconception nutrition?

• Why preconception nutrition?

  • Before you get pregnant

  • Nutrition matters because you need a specific body composition, enough nutrients to even conceive 

  • During Critical periods most women don't even know they are pregnant → need to maintain good nutrition in order to help the fetus during those critical first weeks where neural development is occurring

  • 50% of pregnancies in the US are unplanned

What is fertility?

Fertility: the natural capability to produce offspring

When are women most fertile?

• Most fertile years for women are late teens and late 20s 

  • Still able to conceive after but this is when women are most fertile and the eggs are most viable 

  • Past this time the potential to conceive begins to decline → stops 4-10 years prior to menopause 

  • There is a 20-25% chance of conception each menstrual cycle 

    • In the US it averagely takes 6 months to conceive 

• By age 40, <5% change of conceiving per cycle 

Fertility in men

• Men: sperm production begins during puberty and declines somewhat after age 35

What is infertility?

• Infertility: inability to conceive after having regular, unprotected sex for >1 year 

  • ~15% of couples are infertile in the US 

  • ~44% of couples diagnosed as infertile will eventually conceive without use of technology

What is the chance of conception during a menstrual cycle?

Healthy couples have a 20-25% chance of conception within a menstrual cycle

what is sub-fertility?

• Subfertility: reduced level of fertility characterized by unusually long time for conception

  • Often defined as taking >6 months

What are sources of disruption in fertility?

• Adverse nutritional exposure 

  • Weight status (of both parents)

  • Smoking (interferes with absorption of lots of nutrients) or drinking (alterations in sperm when males consume lots of alcohol → change in viability and motility) 

• Contraceptive use 

• Serve stress

  • One of the main reasons for rising infertility in the US right now 

• Infection 

• Tubal damage or other structural damage 

  • PCOS, endometriosis

• Chromosomal damage 

What is a miscarriage?

Miscarriage: loss of conceptus in the first 20 weeks of pregnancy → after considered a stillbirth

What are some causes of a miscarriage?

• Causes of miscarriage: 

  • Defect in fetus 

  • Maternal infection 

  • Structural abnormalities of uterus 

  • Endocrine of immunological disturbances 

• Most common cause is a chromosomal and structural abnormality 

  • Protects baby and mom → baby would not be able to survive so the fetus miscarriage 

• Most often occurs within the first 6 weeks of pregnancy but most vulnerable weeks are the first trimester

What are ova?

• Ova: eggs females produce and store within the ovaries 

  • Women born with lifetime supply of ~7 million immature ova 

  • ~400-500 ova will mature and be released during fertility yeats 

  • Quality of eggs decrease with age

What is puberty?

• Puberty: time at which humans become biologically capable of reproduction 

  • Males: testicular enlargement → sperm production 

  • Females: menstrual cycle

What are the hormonal effects during the menstrual cycle?

• Hormonal effects during the menstrual cycle

  • Hypothalamus secretes gonadotropin-releasing hormone 

    • Regulates body temp, emotions, mood, regulates reproductive physiology 

  • GnRH → stimulates pituitary to release FSH and LH

    • When women have disordered eating hypothalamus does not secrete GnRH 

      • Sometimes it never comes back leading to infertility

  • Follicle stimulating hormone 

    • Stimulates maturation of ovum 

    • Production of estrogen 

      • Thickens the uterine lining → filled with blood so it becomes vascularized → filled with a lot of nutrients 

  • Luteinizing hormone 

    • Triggers ovulation → release of egg from a woman's ovaries 

Discuss estrogen and ovulation

• Estrogen 

  • Increases before ovulation

  • Stimulates vascularity and store of glycogen (glucose) and other nutrients within uterus → lots of energy stored in the uterine cavity 

    • We want this because so an egg can implant

what forms after ovulation?

• After ovulation a corpus luteum forms in the ovary 

  • Temporary structure that secretes progesterone and estrogen 

  • Degenerates after a few days unless pregnancy has begun 

what does progesterone do?

– Secreted by corpus luteum after ovulation
– Prepares uterus for fertilized ovum
• Thickening of uterine lining

What is the first half of the menstrual cycle?

• 1st half of menstrual cycle is follicular phase 

• Follicular phases: follicle/ovum growth and maturation 

• Main hormonesL GnRH, FSH, LH, and Estrogen 

What is the second phase of menstruation?

• 2nd half is luteal phase 

• Luteal Phase

  • After ovulation 

  • Formation of corpus luteum → increases estrogen and progesterone → thickening of uterine lining 

  • If ovum is not fertilized, corpus luteum will degenerate 

    • Decreases in estrogen and progesterone stimulate menstrual flow 

    • Shedding of the lining bc luteum has dissolved 

  • If ovum is fertilized, the luteum will stay intact bc we need it to continue producing estrogen and progesterone to maintain uterine lining 

    • Eventually it will dissolve but will stay intact for a while 

Discuss the male reproductive system

• Male reproductive system 

  • Reproductive capacity established by interactions among hypothalamus, pituitary gland and testes 

    • Process is ongoing rather than a cycle 

  • GnRH signals release of FSH and LH 

    • Triggers testosterone production by the testes 

  • Testosterone stimulates the development and maturation of sperm 

    • Takes 70-80 days for sperm to mature 

  • Mature Sperm 

    • Stored in epididymis 

    • Released in semen

Discuss body fat and fertility

• Body fat and fertility

  • Excessive or/and inadequate levels of body fat are related t declines in fertility in women and men (estrogen and leptin)

  • Excessive body fat and fertility 

    • More likely to be subfertile

  • Inadequate body fat and fertility 

    • Critical level of body fat needed for reproduction functions 

    • Infertility common 

    • Leads to amenorrhea → loss of period

How does undernutrition in previously well nourished women effect fertility?

• Undernutrition among previously well nourished women 

  • Associated with dramatic decline in fertility 

    • Recovers when food intake improves 

    • Rebound can take several or many years 

  • Food shortages have been accompanied by dramatic in birth rates 

    • Ireland and holland

How does weight loss among women with a healthy weight effect fertility?

• Weight loss and fertility among women with a healthy weight 

  • Weight loss >10-15% of weight decreases estrogen, LH and FSH 

    • Results in amenorrhea, anovulatory cycles, and short or absent luteal cycle 

    • 18.5-24.9 BMI is healthy 

    • To conceive, though, a BMI of 20 is optimal 

  • Treatment with fertility drug clomid does not improve fertility until weight is gained 

    • Clomid increases the secretion of FSH and LH in attempt to jumpstart that menstrual cycle → but women who are under 20 BMI clomid is not effective 

Discuss weight loss and fertility in males

• Weight Loss and fertility in males 

  • Studies from WWII: 50% decrease in male fertility during starvation 

    • Decrease in sperm viability and motility when weight reached 10-15% below normal healthy and are able to fertilize that egg

  • Ceased when loss excessed 25% of normal weight

How does oxidative stress affect fertility?

• Oxidative stress: high presence of unwanted free radicals

  • Men: decrease sperm motility and decrease ability to fuse with an egg 

  • Women: harm follicular development

What role does zinc play in fertility?

• Zinc

  • Men: plays important role in sperm maturation 

    • Deficiency → impair normal reproductive function 

      • Decline in production, motility, viability 

    • Food Sources of Zinc: nuts, dairy, whole grains 

What role does folate play in fertility?

• Folate

  • Intake of multivitamin with folate associated with: 

    • Men: increase sperm count/motility; decrease abnormal sperm 

    • Women: decrease in ovulatory infertility

what role do soy isoflavones play in fertility?

• Soy isoflavones

  • Soy based compounds that mimic the action of the hormone estrogen 

  • If soy is consumed in moderate quantities typically we do not see any changes BUT when consumed too much it can decrease sperm count and decrease fertility in females

what role does caffeine play in fertility?

• Caffeine 

  • Conflicting research 

    • Slight negative or no effect

what role does iron play in fertility?

• Iron 

  • Women: 9-16% of women of child bearing age are deficient in iron

    • Deficiency may be associated with infertility

What role does alcohol play in fertility?

• Men: decrease sperm concentration, total count and percent with normal shape 

• Alcohol may increase testosterone levels 

  • 5-10 drinks/wk: 39% decrease in conception 

  • >10 drinks/wk: 66% decrease in conception 

• We don't want females to consume any alcohol when trying to conceive in order to prevent FAS

How does heavy metal exposure effect fertility?

• Heavy Metal Exposure 

  • Men: decreased sperm production; abnormal sperm motility and shape 

Discuss physical activity and fertility

• Physical activity and fertility 

  • Women: intense levels may delay menarche and result in amenorrhea 

    • Physical activity is encouraged when trying to conceive because it helps with blood flow and can help with stress → stress is bad when trying to conceive 

    • BUT when a women is engaging in too much physical activity and is not eating enough calories to replace that ones she is burning → not enough calories to compensate for the ones lost during physical activity → can caused delayed menarche and amenorrhea

what is periconception?

• Periconception: one month before conception through three months after conception 

  • Critical period when nutritional and other exposures can impact: 

    • Conception

    • Pregnancy maintenance 

    • The growth, developing and health of the offspring 

What are the recommended dietary intakes for women during the periconceptual period? Folic Acid, Iron, Alcohol

• Women during the periconceptual period 

  • Recommended dietary intake 

    • Folic Acid: 600mcg/day

      • Not enough → NTD like spina bifida → brain stem and spinal cord are not forming properly 

    • Iron: 27mg/day

      • A woman's blood volume doubles during pregnancy → we need iron bc of its role in red blood cell development

    • Alcohol 

      • Limit to no alcohol consumption → prevent FAS 

Discuss why periconceptial folate status is important

• Periconceptual Folate Status 

  • Folate: essential nutrient required for: 

    • DNA replication 

    • Amino acid synthesis 

    • Vitamin metabolism 

  • Inadequate folate status prior to conception 

    • ~50% neural tube defects 

• Efforts to encourage folic acid consumption among women 

  • RDA for women 20-39 years old: 600mcg/day 

  • 1998 FDA mandate → enrich all grain with folic acid (bread, pasta, etc)

  • Difference between folate and folic acid 

    • Folate is the natural form of the vitamin 

    • Folic acid is the synthetic form that we add to our enriched grains and supplements 

What are the functions of iron?

• 
  

  • Functions of Iron 

    • Hemoglobin 

      • Protein in blood that is helping carry oxygen

    • Myoglobin

      • Protein in muscle that is helping carry oxygen 

    • Part of many enzymes (collagen synthesis, DNA synthesis)

    • Required for new cell, amino acid, and hormone synthesis 

    • Iron helps carry oxygen throughout the body

  
  

What is iron deficiency anemia? What can this result from?

• Iron deficiency is very common in the US 

• Iron deficiency anemia is when we have tapped out and don't have enough stored iron and not enough iron circulating as well

• Deficiency can result from:

  • Inadequate intake 

  • Poor absorption of iron

  • Blood loss (menstrual cycles)

What % of women enter pregnancy with an iron deficiency?

14%

Deficiency prior to pregnancy increases risk of?

• Deficiency prior to pregnancy increases risk of 

  • Infertility 

  • Iron-deficient anemia during pregnancy 

  • Infant will be born with low iron stores 

  • Preterm delivery 

How can we achieve adequate iron intake?

• Achieving adequate intake 

  • Animal sources (heme iron) 

  • Vitamin C 

    • Can help to increase our bodies ability to absorb iron 

  • Sources: red meat, poultry, dried beans, dark green leafy vegetables, tofu, beans, lentils, fortified breakfast cereals

What is premenstrual syndrome (PMS)?

• Premenstrual syndrome (PMS)

  • Syndrome characterized by by like disrupting physiological and psychological changes that begin in the luteal (second half) phase and end with menses 

  • Symptoms occur in 15-25% of menstruating women 

What is premenstrual dysphoric disorder (PMDD)?

• Premenstrual dysphoric disorder (PMDD): a severe form of PMS 

  • Characterized by marked mood swings, depressed mood, irritability, and anxiety

What are possible causes of PMS and PMDD?

• Possible causes: thought to be related to abnormal serotonin activity following ovulation 

  • Serotonin: neurotransmitter (chemical in the brain that helps relay signals from one area of the brian to another)

  • Imbalance → alterations in mood and depression 

• Antidepressants that contain selective serotonin reuptake inhibitors (SSRIs) reduce PMS symptoms 

What can we do treat PMS/PMDD?

• PMS, PMDD treatment/management 

  • Cannot cure PMS → disease management approach 

  • Decreasing caffeine intake may help reduce the severity of symptoms 

    • PMS symptoms increase in severity with increase coffee intake 

    • Risk of severe symptoms 8x higher with 9-10 cups of coffee/day compared to non coffee drinkers 

  • Calcium 

    • May help alleviate and reduce severity of PMS symptoms

    • 1200 mg/day from foods and/or supplements 

  • Physical activity and stress reduction 

  • Magnesium, calcium, vitamin D, vitamin B6

How does weight status affect fertility?

Obesity and being underweight increase likelihood of reproductive health problems

How does obesity affect fertility? How does this effect men and women respectively?

• Obesity 

  • Central (intra-abdominal, visceral) body fat interferes with reproduction in women and men 

  • Having a higher body fat results in an increase of insulin 

    • Insulin is a hormone in the body produced by the pancreas

      • Enables energy/glucose to be absorbed into cells from the blood 

  • High levels of circulating insulin decreases sex hormone binding globulin 

  • SHBG stands for sex hormone binding globulin. It's a protein made mostly in your liver. It binds (attaches) to sex hormones in your blood. SHBG helps control the amount of sex hormones that are actively working in your body.

    
    

  WOMEN

  • High levels of testosterone disrupts egg development → leads to anovulatory cycles as a result of this

    
    

    MEN

  • In males, we see males with obesity tend to have higher levels of aromatase production → this is the enzyme that creates estrogen → converts high levels of testosterone to estradiol → we need testosterone to produce sperm → lower level of testosterone are going to impair sperm production in men 

What are interventions for obesity in pregnancy?

• Interventions 

  • Weight Loss

    • Should be 1st treatment choice for individuals with obesity 

    • Fertility problems can be reduced or eliminated with weight loss 

  • Weight reduction methods 

    • Focus on lifestyle changes 

      • Decrease caloric intake 

      • Increase physical activity levels 

    • Weight loss surgery only if other interventions fail 

How can a bariatric surgery affect fertility?

• Pregnancy after bariatric surgery 

  • Fertility may return after surgery 

  • Bariatric surgery increases risk for nutrient deficiencies 

    • Calcium, iron, copper, zinc, thiamin, vitamins, B6, B12, and D

    • Intrinsic factor is cut off → is what allows for absorption → not enough absorption

  • Pregnancy not recommended during first year post surgery

How does being underweight affect fertility? What is the treatment for this?

• Underweight 

  • Hypothalamic amenorrhea: cessation of menstruation related to changes in hypothalamic signals that maintain ovulation 

  • Reduced levels of GnRH →low/no release of FSH and LH from pituitary (needed for egg maturation and release) 

  • Caused by deficits in energy nutrients 

  • Related to eating disorders and female athlete triad 

  • First treatment is weight gain by eating healthful diet 

    • Gains of 6-11 lbs typically restores fertility

What is the female athlete triad?

• Female athlete triad 

  • Disordered eating, irregular menstrual cycles, and bone loss 

  • Most common outcomes or side effects is amenorrhea and the inability to conceive 

How can too much physical activity affect fertility?

• Physical Activity 

  • Intense physical activity can affect the menstrual cycle due to insufficient caloric intake

What is diabetes mellitus?

Condition in which the body’s ability to produce or respond
to insulin is impaired, resulting in abnormal metabolism of
carbohydrate and elevated levels of glucose in the blood

What are the three types of diabetes?

• Type I Diabetes: Autoimmune disease resulting from
  destruction of insulin-producing cells (10% of cases)

• Type II Diabetes: Body unable to use insulin normally,
  produce enough insulin, or both due to excess body fat (90%
  of cases)

• Gestational Diabetes:Temporary condition; onset during
  pregnancy

How can diabetes affect a pregnancy?

• Elevated blood glucose levels during first 2 months of
pregnancy are teratogenic
– Exposure that produces malformations in an embryo or
fetus

• Uncontrolled diabetes associated with a 2-3 fold
increase in congenital abnormalities in newborn
– Malformations of pelvis, CNS & heart in newborns
– Higher rates of miscarriage
– Macrosomia (>8 pounds, 13 ounces; 4,000 grams)
• C-sections

What should women with diabetes do prior to pregnancy?

Women with diabetes prior to pregnancy
• Nutritional management of the disease
– Blood glucose control (<100 mg/dL)
– Resolution of coexisting health problems
– Health maintenance

What should women without diabetes do prior to pregnancy?

Women without diabetes prior to pregnancy
• Prevention of gestational & type II diabetes
– Pre-pregnancy weight loss
– Balanced diet rich in fruit, vegetables, lean protein & fiber
– Physical activity

What is Polycystic Ovarian Syndrome?

Hormonal disorder resulting in enlarged ovaries with
small cysts on the outer edges

How can PCOS affect fertility?

• increases Risk of: obesity, insulin resistance, increases blood insulin levels
• Symptoms: irregular cycles, infertility, hirsutism, acne
• 5-10% of women of childbearing age
• Leading cause of female infertility
• Cause is uncertain
– Insulin resistance is a possible factor
– Appears to have strong genetic component

What can women with PCOS do to manage their condition and improve fertility?

Primary goal: Increase insulin sensitivity
– Insulin-sensitizing drugs
• Dietary Recommendations
– Lean proteins, non-starchy vegetables, whole grains/high
fiber, regular meals
• Limit intake of refined grains; consume with protein or fat
• Weight loss & physical activity  improve prognosis
– Symptoms can substantially improve with weight loss of
5-10% of initial body weight

What is Phenylketonuria (PKU)?

Inborn error of metabolism resulting in elevated blood
phenylalanine due to lack of phenylalanine hydroxylase

What does phenylalanine hydroxylase do? What would high levels in the blood during pregnancy do?

• Phenylalanine hydroxylase: converts the essential amino
acid phenylalanine to tyrosine
• High levels of phenylalanine in the blood during
pregnancy
– Accumulates in the embryo and fetus
– Impairs normal central nervous system development
• Preventable cause of intellectual disability

What is the management for a woman with PKU?

• Low-phenylalanine diet for life
– Limit or omit: beef, poultry, pork, fish, milk, yogurt,
eggs, cheese, soy products, certain nuts and seeds,
wheat, aspartame (artificial sweetener)

What is celiac disease?

Autoimmune disease that causes the body to produce an
immune response in the small intestine to the
protein gluten

Prevalence in U.S. is ~1 in 133
• Often heritable
• Related to somewhat higher rates of infertility and
substantially higher rates of subfertility

What are the two types of celiac disease?

• Classical: Malabsorption, diarrhea, weight loss, growth failure

• Non-Classical: milk GI complications, abdominal pain, dermatitis herpetiformis

What is the management for someone with celiac disease?

• Eliminate gluten from the diet
– Wheat, rye, barley
• Gluten found in many non-grain foods, too (hot dogs, deli
meats, supplements, chips, bouillon, salad dressings,
etc.)
• Correction of vitamin & mineral deficiencies

Explain conception time frames

• Conception can only occur when a woman is in the fertile window of her menstrual cycle 

  • Directly related to timing of ovulation 

  • Ovulation occurs halfway through cycle 

    • Example: 28 days cycle → ovulation occurs day 14

  • Ovulation → egg released from an ovary and travels down the fallopian tube by contractions 

  • Fertile windows often vary between women and cycles 

    • Usually 6 days

    • 5 days preceding ovulation plus the day of ovulation

    • This is because perm is capable of living up to 5 days in the female reproductive tract 

    • If sperm fertilizes the egg/ovum → zygote 

      • Fertilized egg cell resulting from union of a female gamete with male gamete 

      • Travels down fallopian tube and begins dividing rapidly 

        • Forming cluster of cells 

      • Zygote reaches the uterus