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Questions and Answers
What is the definition of infertility?
Which hormone is primarily responsible for stimulating the maturation of ova and sperm?
What percentage of women aged 15-44 are reported to have impaired fecundity?
During which phase of the menstrual cycle does ovum maturation primarily occur?
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What condition describes a reduced level of fertility characterized by unusually long time for conception?
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What is the main role of progesterone during the menstrual cycle?
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How many ova do females have at birth approximately?
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What is NOT a cause of damaged chromosomes in ova?
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What percentage of conceptions is typically lost through resorption within the first 6 weeks?
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Which component is involved in the formation and maturation of sperm?
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What is the relationship between male caffeine intake and assisted reproductive technologies outcomes?
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How does alcohol intake influence conception chances?
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Which level of male alcohol intake is associated with the greatest decrease in chance of conception?
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What adverse effect is caffeine exposure linked to during pregnancy?
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Which of the following hormonal changes is NOT associated with alcohol consumption?
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What is a significant effect of under nutrition on fertility?
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Which hormone is NOT produced by fat cells?
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What critical body fat level supports normal hormone production?
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How can acute under nutrition impact male fertility?
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Which of the following factors can negatively influence fertility?
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What is one consequence of low body fat on female reproductive health?
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Which of the following is a consequence of obesity observed in studies?
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What impact does high exercise levels have on fertility?
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What is a major benefit of weight reduction for overweight and obese individuals seeking fertility?
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How does exercise influence fertility according to the provided content?
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What role do antioxidants play in relation to fertility?
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What has preliminary research indicated about zinc supplementation?
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Which of the following dietary factors is linked to reduced fertility outcomes?
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What phenomenon can occur from free radical damage as mentioned in the content?
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Which of the following vitamin supplements is linked to improved sperm health?
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What was the fecundability odds ratio (FR) for nonsmoking women consuming 300-700 mg/day of caffeine?
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What is the effect of adipose tissue on androgen levels?
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Which of the following is a consequence of increased fat mass in women?
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What is a reported benefit of weight loss in overweight/obese individuals?
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Which dietary approach has been shown to improve fertility outcomes in women according to the findings by Best et al. 2017?
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What impact does obesity have on testosterone levels in men?
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Which factor is not influenced by obesity according to the content?
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What is a common outcome of weight-loss interventions in men?
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Which statement correctly describes catechol estrogens?
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Study Notes
Definitions
- Fertility is the actual production of children.
- Fecundity is the biological capacity to bear children.
- Infertility is the lack of conception after 1 year of unprotected intercourse.
Statistics
- 12.1% of women aged 15-44 have impaired fecundity.
- 6.7% of married women aged 15-44 are infertile.
- 12% of women aged 15-44 have used infertility services.
- 9-15% of couples in developed countries are involuntarily childless.
- Healthy couples have a 20-25% chance of becoming pregnant within a given menstrual cycle.
- 30-50% of conceptions are lost by resorption into the uterine wall within the first 6 weeks of conception.
- 9% of conceptions are lost to miscarriage in the first 20 weeks of pregnancy.
Subfertility
- Subfertility is a reduced level of fertility characterized by unusually long time to conception.
- Subfertility can involve multiple miscarriages, sperm abnormalities, and infrequent ovulation.
- ~18% of couples experience subfertility due to delayed time to conception (at least 12 months) or repeated, early pregnancy losses.
Reproductive Physiology
- Puberty is when humans become biologically capable of reproduction.
- Ova are eggs that females produce and store within the ovaries.
- The menstrual cycle is a ~4 week interval in which hormones direct the buildup of blood and nutrient stores within the uterus. This is also when the ovum matures and is released.
Reproductive Hormones
- GnRH stimulates the pituitary to release FSH and LH.
- FSH stimulates the maturation of ova and sperm.
- LH stimulates the secretion of estrogen, progesterone, and testosterone.
- Estrogen stimulates the release of GnRH during the follicular phase, follicle growth, and maturation of the follicle. It also stimulates vascularity and storage of glycogen and other nutrients within the uterus.
- Progesterone prepares the uterus for a fertilized ovum, increases vascularity of the endometrium, and stimulates cell division of fertilized ova.
Male Reproductive System
- Male reproductive capacity results from the interaction between the hypothalamus, pituitary glands, and testes.
- The process is ongoing, not cyclic.
- The process involves GnRH, FSH, LH, and testosterone (androgens).
- Testosterone and androgens stimulate the maturation and release of sperm from the testes.
- Spermatogenesis is the formation and maturation of sperm mediated by testosterone.
Physiological Factors Contributing to Normal Fertility
- Normal menstrual cycle.
- Production of ova.
- Sperm maturation, production and storage.
- Endocrine alterations.
- Sperm motility.
Causes of Infertility
- Hormonal imbalances.
- Uterine anatomical abnormalities.
- Ovarian dysfunction.
- Tubal blockage.
- Endometriosis.
- Polycystic ovary syndrome (PCOS).
- Male factors (e.g., low sperm count, poor sperm motility).
- Infection.
Nutrition-Related Disruptions in Fertility
- Under nutrition.
- Weight loss.
- Obesity.
- High exercise levels.
- Intake of specific foods and food components, including alcohol, caffeine, nutrients, and high fat diets.
Under Nutrition and Fertility
- Chronic under nutrition has a small impact on fertility and fecundity.
- Chronic under nutrition is more likely to result in small, frail infants, and infant death during the first year of life.
- Acute under nutrition results in a dramatic decline in fertility.
- The effects of acute under nutrition are reversed when food intake is recovered.
- Under nutrition reduces reproductive capacity by modifying hormonal signals that regulate ovulation and menstrual cycles in females.
- Under nutrition also impairs sperm maturation in males.
Body Fat and Fertility
- Fat cells produce hormones, including estrogen, androgens, and leptin.
- Excessive and inadequate levels of body fat alter hormone balance and affect the reproductive cycle.
- A BMI greater than 20 kg/m2 is the critical level of body fat that triggers and sustains normal hormone production.
- Low body fat can lead to delayed onset of menstruation, amenorrhea, lowered libido, and reduced sperm production.
Adiposity and Fertility
- Obesity between the ages of 9 and 12 is more likely to be associated with fertility difficulties.
- Higher overall adiposity, but not central adiposity, is associated with longer time to pregnancy in Asian women.
- Men with a BMI greater than 25 kg/m2 have fewer chromatin-intact normal-motile sperm cells per ejaculate.
- Both morbid obesity and being underweight have a negative effect on sperm quality, particularly epididymal maturation.
Adiposity and Fertility - Mechanisms
- Adipose tissue converts androgens to estrogen by aromatization. Obese men have lower circulating levels of testosterone.
- Adiposity influences the direction of estrogen metabolism to more potent or less potent forms.
- Obese women and girls have a diminished capacity for estrogen to bind sex-hormone-binding-globulin.
Excess Fat Mass and Infertility
- Increased numbers of fat cells result in a cascade of changes, including:
- Increased leptin and insulin levels.
- A preferential increase in LH, but not FSH, levels. High insulin levels increase ovarian testosterone production/action.
- These changes stimulate the partial development of follicles that secrete supranormal levels of testosterone, but which rarely ovulate.
Weight Loss and Fertility
- Weight loss in overweight/obese individuals improves ovulation, menstrual irregularities, live birth, natural conception, reduced miscarriages, and energy restriction alone leads to improvements in reproductive parameters.
- Weight loss in men improves DNA Fragmentation Index, morphology, and motility.
Exercise and Fertility
- Physical fitness and exercise are associated with improved fertility outcomes.
- Each hour of vigorous exercise per week is associated with a 7% lower risk of ovulatory infertility.
- Exercise increases insulin sensitivity, which is related to ovarian function.
Oxidative Stress, Antioxidants, and Fertility
- Antioxidants, such as vitamins E, C, and beta-carotene protect reproductive cells from oxidative stress.
- Free radicals can harm polyunsaturated fatty acids in sperm membranes (decreasing motility and the ability to fuse with the egg), DNA within the sperm cell, egg and follicular development, and the implantation of the egg in the uterine wall.
Supplementation Clinical Trials and Fertility
- Supplemental intakes of vitamin E and selenium improve sperm quality in infertile men.
- Regular intake of vitamin C, E, and beta-carotene supplements increases sperm number and motility.
- Zinc supplements improve sperm quality.
- Recent meta-analysis shows promise for the use of selenium, zinc, CoQ10, and/or w-3 FA for sperm health.
Caffeine and Fertility
- Epidemiological studies show that high intakes of caffeine are linked to reduced fertility.
- Compared with nonsmoking women with a caffeine intake less than 300 mg/day, nonsmoking women who consumed 300-700 mg/day of caffeine had a fecundability odds ratio (FR) of 0.88 (95% confidence interval (CI), 0.60-1.31), while those with a higher consumption had an FR of 0.63 (95% CI, 0.25-1.60).
- Caffeine is an adenosine receptor antagonist that may influence fertility by affecting ovulation, menstrual characteristics, sperm quality, and sperm DNA damage.
Alcohol and Fertility
- Alcohol intake alters the hormonal milieu.
- Alcohol decreases estrogen and testosterone levels, disrupts the menstrual cycle, and disrupts testicular function.
- 1-5 drinks/week is associated with a ~40% decreased chance of conception.
- Over 10 drinks/week is associated with a ~66% decreased chance of conception.
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Description
Test your knowledge on the concepts of fertility, fecundity, and infertility. This quiz covers important definitions, statistics, and the intricacies of subfertility. Enhance your understanding of reproductive health and the challenges many face in conceiving.
