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
• Healthy couples have a 23% to 30%
chance of conception within a given
menstrual cycle
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
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
2010 Nutrition Objectives for the
Nation Related to Preconception
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
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
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
Reproductive Physiology:
Sperm and Men
• Sperm production
begins during
puberty, decreases
somewhat after age
35 with production
continuing to old age
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
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
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
Changes in
the Ovary
and
Uterus
Male Reproductive System
• Interactions among hypothalamus, pituitary
gland, and testes
• Androgens — Testosterone
• Sperm are stored in the epididymis & released
in semen
Sources of Disruptions in Fertility
•
•
•
•
•
•
Adverse nutritional exposure
Contraceptive use
Severe stress
Infection
Tubal damage or other structural damage
Chromosomal damage
Factors Related to Altered Fertility
Nutrition-Related Disruptions in
Fertility
•
•
•
•
•
Undernutrition
Weight loss
Obesity
High exercise levels
Intake of specific foods & food components
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
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
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
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
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
Diet and Fertility
• Diet may impact hormones
• Main dietary practices are vegetarian diets,
low fat intake, high intakes of dietary fiber,
soy, caffeine, & alcohol
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.
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.
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
Plant Foods and Fertility
• Low-fat, high fiber linked to reduced estrogen
& irregular periods
• Isoflavones (from soy) decrease levels of
gonadotropins, estrogen, & progesterone
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
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% 
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
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
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
Nutrition-Related Side Effects of
Contraceptives
Other Preconceptual Nutrition
Concerns
• Very-early-pregnancy nutrition exposures
• Folate status prior to conception
– Neural tube defects
• Recommended dietary intakes for
preconceptional women
Nutritional
Disruptions
MyPyramid Recommendations for
Preconceptional Women
Model Preconceptional Nutrition
Programs
• Preconceptional benefits of WIC
• Decreasing iron deficiency in preconceptional
women in Indonesia
• Preconception care: Preparing for pregnancy
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
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
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
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
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