Stress and Fertility Flashcards
What is Fertility and Infertility?
-Fertility: capacity to reproduce (entails both getting pregnant and carrying to term)
-Infertility: 12 months trying with no pregnancy; or inability to carry to term
What are Gonads?
-a sex gland in which gametes are produced;
-in women, the ovary produces egg
-in men, the testis produces sperm
Which hormones regulate the production of gametes?
-the hypothalamus releases a releasing hormone which travels to the anterior pituitary
-in the anterior pituitary, Luteinizing hormone
(LH) and Follicle-stimulating hormone (FSH) are released
-gonads are released
What is the HPG Axis?
GRH –> anterior pituitary [releasing LH & FSH] –> gonads
What are the effects of LH levels being too high or too low?
-when LH is too high: reduces the production of gametes (eggs/sperm); premature menopause; testicular failure
-when LH is too low: it reduces/fails gonad function
How does LH function in males and females?
-females get a monthly surge of LH which triggers ovulation
-males production of sperm [spermatogenesis] and testosterone [sexual desire] are influenced by this hormone
What are the effects of FSH levels being too high or too low?
-FSH stimulates production of germ cells [become gametes]
-when FSH is too high: premature menopause / testicular failure
-when FSH is too low: failure of gonadal function
How does FSH function in males and females?
-females: growth and recruitment of ovum; promotes pregnancy continuation
-males: stimulated maturation of seminiferous tubules and spermatogenesis
How does stress affect the reproductive system?
-affecting GnRH neurons in the hypothalamus, altering GnRH release.
-influencing gonadotroph cells in the anterior pituitary, affecting LH and FSH secretion.
-modifying the feedback of sex steroids on the hypothalamus and pituitary.
How does acute and chronic immobilization stress suppress reproductive function in male rats?
-stress increases glucocorticoids, leading to higher RFRP expression in the dorsomedial hypothalamus (DMH).
-RFRP inhibits the HPG axis, reducing reproductive function.
-stress activates the HPA axis, which suppresses the HPG axis.
-immobilization stress 3hrs/day for 14 days also significantly reduced LH production
How does stress suppress reproduction function in female rats?
stress –> increased HPA axis activity –> decreased release of GnRH –> decreased production of LH –> decreased activation of HPD axis –> decreased implantation sites and viable fetuses in female mates
What was the procedure of the forced swimming stress study on Wistar rats?
-rats forced to swim for 3mins at 32°C daily for 15 days.
-measured testicular, seminal vesicle, and ventral prostate weight.
-stressed and control males were mated with sexually mature females
What are the findings of the study on the effects of forced swimming stress on male adult rats?
-fertility was not impaired; females still became pregnant
-significant decrease in spermatid production was observed
-prolonged stress affected spermatogenesis, but this was only evident after a full cycle of sperm production
What was the procedure for studying the effects of pre-pubertal immobilization stress on male rats?
-40-day-old rats were immobilized for 6 hrs/day for either 15 or 60 days.
-at 55 days old, their sexual behavior was tested with receptive adult females.
-at 100 days old, their fertility was assessed by mating with sexually mature females.
What were the findings of pre-pubertal immobilization stress on male rats in adulthood?
-increased sexual performance at the onset of puberty.
-significantly decreased fertility rates in adulthood.
What are the effects of prenatal stress on reproductive outcomes in rats?
-fewer conceptions, more spontaneous abortions, and fewer viable young [Offspring have low birth weight and lower neonatal survival rates]
-alters adrenal and gonadal hormone balance during fetal hypothalamic differentiation. [leads to reproductive dysfunctions in adulthood, especially in females]
-Prenatal stress reduces fertility and fecundity
What are some stress related disorders in women that are affected by environmental aspects?
-chronic anovulation
-hypothalamic amenorrhea
-pseudocyesis
-stress-related eating disorders
-exercise and menstrual dysfunction
-hyperprolactinemia
-early pregnancy failure
What are some stress related disorders in men that are affected by environmental aspects?
-decreased sperm count
-decreased sperm motility [swimmability]
-altered sperm morphology [shape of sperm head]
-impotence
-ejaculatory disorders
-decreased serum luteinizing hormone and testosterone
What did the study looking at fertility and workplace hazards find?
(infertile men: no underlying organic medical cause, no female reproduction problem; fertile men: pregnancy in < 12 months)
-solvents & paintings materials, stress, VDTs, shift work
-stress effect in dose-response manner
-sperm motility and morphological index
[these were significant predictors of infertility and/or affecting the ability of carrying the baby to term]
What did the study looking at conception and stress find?
-hypothesis: less stress = months with conception; more = months without
-results: self-reports [questionnaires] revealed that women were less likely to get pregnant on the months they were the most stressed; no effect was seen in the hormonal assays collected [urinary cortisol, adrenaline and epinephrine] potentially due to collections at night (when cortisol drops)
What did the study looking at age and social position in women with fertility problems [but medically reproductively able] find?
-age up = less effect of stress on fertility [no difference w/ age]
-lower social position = more effect of stress on fertility
-higher social position = less effect of stress on fertility
What did research examining if sperm quality is affected by major stressful events find?
The experience of two or more life events was associated with:
-decreased sperm concentration, TC, and percent motile sperm
-increased likelihood of classification below WHO thresholds for “normal” for concentration, motility, and morphology
What are the effects of stress on sperm quality?
-emotion stress effects fertility
-a study of 20 men showed stress reduced healthy sperm
-participants were split into two groups, one receiving CRM therapy
-CRM therapy increased healthy sperm count.
Explain the cycle of infertility and stress.
-infertility causes stress which leads to more infertility [which leads to stress…]
-stress causes infertility, and infertility causes stress
-couples struggling with infertility are under a lot of pressure [particularly women]; when stress reduces [after adoption] they can get pregnant
